THE ECOLOGICAL IMPACT
       OF LAND CLEANUP
       AND RESTORATION
       REPRINTED - JULY 1993
 OFFICE OF RADIATION AND INDOOR AIR
US ENVIRONMENTAL PROTECTION AGENCY
       WASHINGTON, DC 20460

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                            PREFACE
     This document was  first published in 1978 as  EPA  Technical
Report 520/3-78-006.   It presents the results of work carried out
by the  General  Electric Company, Tempo Division, under contract
with the Environmental Protection Agency.

     The material was developed in support of proposed guidance on
Dose Limits  for Persons Exposed to Transuranium Elements  in the
General Environment and is intended to provide information useful
for planning of localized remedial actions and for preparation of
Environmental Impact Statements where required.  Although written
primarily from the viewpoint of radiation protection, the scope of
the document is  sufficiently broad to have widespread applicability
to many other situation where  cleanup  of  residual  environmental
contamination may be required.

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                                     ABSTRACT
      The basic types of cleanup procedures  for removing  or deactivating
 spilled contamination involve moving people and animals  from the  affected  area
 scraping or grading the contaminated soil into windrows, plowing  the  contamina-
 tion under, or digging up the contamination and hauling  it away.  This report
 describes and evaluates these various land-type cleanup  effects in  terms of
 impact of the technique on the environment. The cleanup procedures are listed
 in the following table with brief definitions  of proposed  cleanup actions
 Conclusions about the effects of cleanup on the soil, vegetation, and animals
 in an area are summarized in the composite  effects shown in the following
 table as a composite ranking for all the areas studied.  The rankings are
 numbered from 0 through 5 for each cleanup  treatment.  Interpretations of
 these rankings are as follows:

           0 - No measurable change is produced in the ecosystem.

           1 - The preferred cleanup because adverse environmental
               effects upon recovery and side effects of  treatment
               are minimal,

           2 - A conditionally acceptable treatment because  of sig-
               nificant impact by the treatment and/or the equipment
               upon the area.

           3 -  Acceptable  as a "last  resort" cleanup to remove
               exceptionally hazardous material while incurring
               maximum acceptable impact.

           4 -  Causes  unacceptable damage but can be used as  an
               interim cleanup  if the  injury is erased during the
               final  treatment.

           5  -  Not  applicable  to  the  land type  for which it is proposed.

     The rankings  considered  the  environmental insult generated during the
cleanup, the physical possibility of restoring the area to its original  pro-
ductive state, side effects  caused by the equipment needed to perform the
cleanup, the  impact upon  the environment adjacent to the cleaned up area,  and
the social  acceptance of  the cleanup work.   Not all treatments were expected
to be evaluated with  all  land types; these exceptions are indicated in the
table as being outside the  scope of this effort.

     The primary criterion  for the evaluation of cleanup effects was the suit-
ability of the denuded surface as a medium for plant growth.  Establishment of
a vegetative  cover before serious wind and water erosion despoiled the site was
considered first and, if revegetation was probable,  the time to recover  the
initial pre-cleanup productivity was considered next.   This is the context in
which the rankings were defined.

-------
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                                  CONTENTS
Abstract
Figures
Tables
Acknowledgments "
INTRODUCTION
   Statement of the Problem
   Purpose of the Report
   Scope of the Report
   Literature Base
   Study Approach
   Impact Evaluation
   Use of the Report
   Conclusions
                        PART  I - NATURAL ECOSYSTEMS
CHAPTER 1-DESERT
   1.1  Overview
        1.1.1   Desert Climate
        1.1.2
        1.1.3
        1.1.4
   1.2
  1.3
  1.4
Soils
Topographic Factors
Vegetation
1.1.4.1  Great Basin Desert
         Mojave Desert
         Sonoran Desert
         Chihuahuan Desert
         Desert Grassland
       1.1.4.2
       1.1.4.3
       1.1.4.4
       1.1.4,5
1.1.5  Desert Succession
Natural Perturbations
1.2.1  Natural Processes
1.2.2  Fire
1.2.3  Climate
Man-Made Perturbations
1.3.1  Fencing
       Overgrazing
       Mechanical Disturbance
       Atomic Test Target Areas
       Restoration
Effects of Cleanup Procedures on Deserts
       (Treatment 1-1)  Chemical Stabilizers
       (Treatment 1-2)  Clear Cutting Vegetation
       (Treatment 1-3)  Stumping and Grubbing
       (Treatment 1-4)  Scraping and Grading
       1.3.2
       1.3.3
       1.3.4
       1.3.5
                                                            111
                                                          xviii
                                                            xxi
                                                           xxiv
                                                              1
                                                              1
                                                              1
                                                              2
                                                              5
                                                              5
                                                              6
                                                              7
                                                              9
 1-1
 1-1
 1-2
 1-4
 1-7
 1-8
 1-8
 1-10
 1-10
 1-11
 1-11
 1-12
 1-13
 1-13
 1-14
 1-17
 1-18
 1-18
 1-19
1-20
1-23
1-26
1-26
1-27
1-30
1-32
1-33

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                           CONTENTS (continued)
              (Treatment 1-5)
              (Treatment 1-6)
              (Treatment 1-7)
              (Treatment 1-8)
              (Treatment 2-1)
              (Treatment 2-2)
              (Treatment 2-3)

              (Treatment 2-4)

              (Treatment 2-5)

              (Treatment 2-6)

              (Treatment 2-7)

              (Treatment 2-8)
   1.5
   1.6
   1.7
   1.8
       (Treatment 3-1)
      ' (Treatment 3-2)
       (Treatment 3-3)
       (Treatment 4-1)
      '(Treatment 4-2)
       (Treatment 5-0)
       (Treatment 6-1)
       (Treatment 6-2)
       (Treatment 7-0)
Recovery Following Cleanup
1.5.1  Unassisted Succession
1.5.2  Cleanup Recovery Categories
Quantitative Assessment of Cleanup
1.6.1  Impact Assessment
1.6.2  Recovery Assessment
Conclusions
Desert References
Shallow Plowing
Deep Plowing
Soil Cover Less than 25 cm
Soil Cover 25 to 100 cm
Remove Plow Layer
Remove Shallow Root Zone
Scrape and Grade, Mechanically
Stabilize
Remove Plow Layer, Mechanically
Stabilize
Remove Shallow Root Zone, Mechanically
Stabilize
Scrape and Grade,,Chemically
Stabilize
Remove Plow Layer, Chemically
Stabilize
Remove Shallow Root Zone, Chemically
Stabilize
Barriers to Exclude People
Exclude Large Animals
Exclude Large and Small Animals
Asphalt Hard Surface Stabilization
Concrete Hard Surface Stabilization
Application of Sewage Sludge
High  Pressure Washing
Flooding
Soil  Amendments Added
            Impacts
CHAPTER 2-PRAIRIE
   2.1  Overview
        2.1.1  Tall grass Prairie
        2.1.2  Mixedgrass Prairie
        2.1.3  Shortgrass Prairie
        2.1.4  Other Grasslands
   2.2  Natural Perturbations
        2.2.1  Drought
        2.2.2  Flooding
        2.2.3  Fossorial Animals
   2.3  Man-Made Perturbations
        2.3.1  Close Cropping and Grazing
        2.3.2  Compaction
        2.3.3  Plowing
1-37
1-37
1-37
1-39
1-39
1-39

1-39

1-40

1-40

1-40

1-41

1-41
1-41
1-41
1-42
1-43
1-44
1-44
1-44
1-44
1-44
1-46
1-46
1-52
1-52
1-53
1-55
1-58
1-60
2-1
2-1
2-1
2-2
2-3
2-3
2-4
2-4
 2-5
 2-5
 2-6
 2-6
 2-7
 2-7
                                      vi

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                          CONTENTS (continued)
 2.4
2.3.4  Natural Succession
2.3.5  Range Improvement
       2.3.5.1  Mulches
       2.3.5.2  Seeding
       2.3.5.3  Shrub Removal
       2.3.5.4  Moisture Trapping
Effects of Cleanup Procedures on Prairie
       (Treatment 0-1)  Natural  Rehabilitation
       (Treatment 1-1)
       (Treatment 1-2)
       (Treatment 1-3)
                              Chemical  Stabilization
                              Clear Cutting Vegetation
                              Stumping  and Grubbing
               	 _  .,   Scraping  and Grading
             (Treatment 1-5)   Shallow Plowing
             (Treatment 1-6)   Deep Plowing
       (Treatment 1-4)
             (Treatment 1-7)
             (Treatment 1-8)
             (Treatment 2-1)
             (Treatment 2-2)
             (Treatment 2-3)

             (Treatment 2-4)

             (Treatment 2-5)

             (Treatment 2-6)

             (Treatment 2-7)

             (Treatment 2-8)
                        Soil  Cover  Less  than  25  cm
                        Soil  Cover  25  to 100  cm
                        Remove  Plow Layer
                        Remove  Shallow Root Zone
                        Remove  Scraping  and Grading,
                        Mechanically Stabilize
                        Remove  Plow Layer, Mechanically
                        Stabilize
                        Remove  Shallow Root Zone, Mechanically
                        Stabilize
                        Remove  Scraping  and Grading,
                        Chemically  Stabilize
                        Remove  Plow  Layer, Chemically
                        Stabilize
                        Remove  Shallow Root Zone, Chemically
                        Stabilize
                        Barriers to  Exclude People
                        Exclude Large Animals
                        Exclude Large and Small Animals
                        Asphalt Hard Surface Stabilization
                        Concrete Hard Surface Stabilization,
            (Treatment 3-1)
            (Treatment 3-2)
            (Treatment 3-3)
            (Treatment 4-1)
            (Treatment 4-2)
2.5  Recovery After Cleanup
     2.5.1  Irreversible Changes
     2.5.2  Rates of Recovery Following Cleanup
            2.5.2.1  First Year Following Cleanup
            2.5.2.2  Fifth Year Following Cleanup
            2.5.2.3  Tenth Year Following Cleanup
            2.5.2.4  Climax
2.6  Quantitative Assessment of Cleanup Impacts
     2.6.1  Impact Assessment
     2.6.2  Recovery Assessment
2.7  Conclusions
2.8  Prairie References
 2-7
 2-9
 2-9
 2-9
 2-10
 2-10
 2-10
 2-11
 2-11
 2-12
 2-12
 2-13
 2-13
 2-14
 2-14
 2-14
 2-14
 2-15

 2-15

 2-17

 2-17

 2-17

 2-18

 2-18
 2-18
 2-18
 2-19
 2-19
 2-20
 2-21
 2-21
 2-21
 2-22
 2-26
 2-27
 2-28
2-30
2-30
2-31
2-34
2-35
                                  vn

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                            CONTENTS (continued)
CHAPTER 3-DECIDUOUS FOREST
   3.1  Overview
        3.1.1  Mixed Mesophytic Forest
        3.1.2  Oak-Hickory Forests
        3.1.3  Appalachian Oak-Chestnut Forest
        3.1.4  Oak-Hickory-Pine Forest
        3.1.5  Southern Mixed Forest
        3.1.6  Beech-Maple Forest
        3.1.7  Maple-Basswood Forest
        3.1.8  Hemlock-Hardwood Forest
        3.1.9  Theoretical Considerations
   3.2  Natural Perturbations
        3.2.1  Fire
        3.2.2  Primary Successions
   3.3  Man-Made Perturbations
        3.3.1  Surface Mining
        3.3.2  Post-Agricultural Successions
               3.3.2.1  Southeastern States
               3.3.2.2  Northeastern States
               3.3.2.3  Central States
   3.4  Cleanup Procedures, Effects on Ecosystems
               (Treatment  0-1)  Natural Rehabilitation
               (Treatment  1-1)
               (Treatment  1-2)
               (Treatment  1-3)
               (Treatment  1-4)
               (Treatment  1-5)
               (Treatment  1-6)
                (Treatment  1-7)
                (Treatment  1-8)
                (Treatment 2-1)
                (Treatment 2-2)
                (Treatment 2-3)

                (Treatment 2-4)

                (Treatment 2-5)

                (Treatment 2-6)

                (Treatment 2-7)

                (Treatment 2-8)

                (Treatment 3-1)
                (Treatment 3-2)
                (Treatment 3-3)
                (Treatment 4-1)
                (Treatment 4-2)
Chemical Stabilization
Clear Cutting Vegetation
Stumping and Grubbing
Scraping and Grading
Shallow Plowing
Deep Plowing
Soil Cover Less than 25 cm
Soil Cover 25 to 100 cm
Remove  Plow Layer
Remove  Shallow Root Zone
Remove  Scraping and Grading,
Mechanically Stabilize
Remove  Plow Layer, Mechanically
Stabilize
Remove  Shallow Root Zone, Mechanically
Stabilize
Remove  Scraping and Grading,
Chemically Stabilize
Remove  Plow Layer, Chemically
Stabilize
Remove  Shallow Root Zone, Chemically
Stabilize
Barriers to Exclude  People
Exclude Large Animals
Exclude Large and  Small  Aninals
Asphalt Hard Surface  Stabilization
Concrete Hard Surface Stabilization
3-1
3-2
3-2
3-2
3-2
3-3
3-3
3-3
3-4
3-4
3-7
3-7
3-9
3-9
3-9
3-12
3-12
3-14
3-15
3-17
3-17
3-17
3-17
3-18
3-19
3-19
3-19
3-20
3-20
3-21
 3-22

 3-22

 3-23

 3-23

 3-24

 3-24

 3-24
 3-25
 3-25
 3-25
 3-26
 3-26
                                     viii

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                            CONTENTS (continued)
               (Treatment 5-0)  Application of Sewage Sludge
               (Treatment 6-1)  High Pressure Washing (<3 mm)
               (Treatment 6-2)  Flooding to 30 cm"
               (Treatment 7-0)  Soil Amendments Added
   3,5  Recovery Following Cleanup
        3.5.1  Irreversible Changes
        3.5.2  Rates of Recovery
        3.5.3  Succession Stages Following Cleanup
               3.5.3.1  First Year
               3.5.3.2  Fifth Year
               3.5.3.3  Tenth Year
               3.5.3.4  Fiftieth Year
               3.5.3.5  100 Years After Cleanup
               3.5.3.6  Climax
   3.6  Quantitative Assessment of Cleanup Impacts
        3.6.1  Impact Assessment
        3.6.2  Recovery Assessment
   3.7  Conclusions
   3.8  Deciduous Forest References
CHAPTER 4-CONIFEROUS FORESTS
   4.1  Overview
        4.1.1  Boreal Formation
        4.1.2  Rocky Mountain Forest Complex
               4.1.2.1  Subalpine Spruce-Fir Climax
               4.1.2.2  Douglas Fir Climax
               4.1.2.3  Ponderosa Pine  Climax
               4.1.2.4  Pi fion-Juniper Climax
        4.1.3  Sierra Nevada Forest Complex
               4.1.3.1  Western Slope
               4.1.3,2  Eastern Slope
        4.1.4  Pacific Conifer Forest
        4.1.5  Coniferous  Forests Occurring as Sub and Postclimaxes
        Natural  Perturbations
        4.2.1  Fire
               4.2.1.1  Unassisted Recovery Sequence
               4.2.1.2  Assisted Recovery Sequence
        4.2.2  Other Natural  Perturbations
        Man-Made  Perturbations
        4.3.1  Clearcutting
        4.3.2  Strip Mining
        4.3.3  Controlled  Burning
        Effects  of Cleanup  Procedures on  Coniferous Forests
               (Treatment  0-1)  Natural  Rehabilitation
                                Chemical  Stabilization
                                Clearcutting Vegetation
                                Stumping  and Grubbing
                                Scraping  and Grading
                                Shallow  Plowing
                                Deep Plowing
4.2
4.3
4.4
            (Treatment 1-1)
            (Treatment 1-2)
            (Treatment 1-3)
            (Treatment 1-4)
            (Treatment 1-5)
            (Treatment 1-6)
3-26
3-27
3-27
3-27
3-27
3-27
3-27
3-30
3-30
3-31
3-31
3-34
3-34
3-35
3-35
3-36
3-38
3-39
3-41

4-1
4-1
4-4
4-5
4-8
4-8
4-9
4-10
4-11
4-11
4-12
4-13
4-14
4-16
4-16
4-16
4-17
4-19
4-19
4-20
4-20
4-21
4-22
4-22
4-23
4-23
4-28
4-29
4-29
4-30
                                     ix

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                            CONTENTS  (continued)
               (Treatment 1-7)
               (Treatment 1-8)
               (Treatment 2-1)
               (Treatment 2-2)
               (Treatment 2-3)

               (Treatment 2-4)

               (Treatment 2-5)

               (Treatment 2-6)

               (Treatment 2-7)

               (Treatment 2-8)
                             Soil  Cover Less  than  25  cm
                             Soil  Cover 25 to 100  cm
                             Remove Plow Layer
                             Remove Shallow Root Zone
                             Remove Scraping  and Grading,
                             Mechanically Stabilize
                             Remove Plow Layer,  Mechanically
                             Stabilize
                             Remove Shallow Root Zone,  Mechanically
                             Stabilize
                             Remove Scraping  and Grading,
                             Chemically Stabilize
                             Remove Plow Layer,  Chemically
                             Stabilize
                             Remove Shallow Root Zone,  Chemically
                             Stabilize
                             Barriers to Exclude People
                             Exclude Large Animals
                             Exclude Large and Small  Animals
                             Asphalt Hard Surface  Stabilization
                             Concrete Hard Surface Stabilization
                             Application of Sewage Sludge
               (Treatment 3-1)
               (Treatment 3-2)
               (Treatment 3-3)
               (Treatment 4-1)
               (Treatment 4-2)
               (Treatment 5-0)
   4.5  Recovery After Cleanup
        4.5.1  Irreversible Changes
        4.5.2  Rates of Recovery
               4.5.2.1  First Year
               4.5.2.2  Fifth Year
               4.5.2.3  Fiftieth Year
               4.5.2.4  100 Years After Treatment
   4.6  Quantitative Assessment of Cleanup Impacts
   4.7  Conclusions
   4.8  Coniferous Forest References
CHAPTER 5-AEOLIAN MOUNTAIN PEAKS
   5.1  Overview
        5.1.1  The High Mountain Peak Environment
        5.1.2  The Aeolian Life Zone
               5.1.2.1  The Nival Phase of the Aeolian Zone
               5.1.2.2  The Aquatic Phase of the Aeolian Zone
               5.1.2.3  The Terrestrial Phase of the Aeolian Zone
        Natural Perturbations
        5.2.1  Erosion and Mudflow Phenomena
        5.2.2  Avalanches
        5.2.3  Landslides
        5.2.4  Overgrazing
        5.2.5  Recovery
5.2
   5.3
   5.4
     Man-Made Perturbations
     5.3.1  Regrading and Replanting
     5.3.2  Alternative Techniques
     Effects of Cleanup Procedures on Aeolian Mountain Peaks
4-30
4-31
4-32
4-32

4-32

4-34

4-34

4-34

4-34

4-34
4-34
4-34
4-36
4-36
4-36
4-37
4-38
4-38
4-39
4-45
4-48
4-49
4-50
4-52
4-55
4-58

5-1
5-1
5-1
5-5
5-6
5-7
5-7
5-13
5-14
5-15
5-17
5-17
5-17
5-18
5-18
5-19
5-20

-------
                         CONTENTS (continued)
5.5
     5.4.1  Proposed Treatment Techniques
            (Treatment 0-1)  Natural Rehabilitation
                             Chemical Stabilization
                             Clear Cutting Vegetation ("Removal")
                             Stumping and Grubbing
                             Scraping and Grading
                             Shallow Plowing
                             Deep Plowing
                             Soil Cover Less than 25 cm
                             Soil Cover 25 to 100 cm
                             Remove Plow Layer
                             Remove Shallow Root Zone
                             Remove by Scraping and Grading,
                             Mechanically Stabilize
                             Remove Plow Layer, Mechanically
                             Stabilize
                             Remove Shallow Root Zone, Mechanically
                             Stabilize
                             Remove by Scraping and Grading,
                             Chemically Stabilize
                             Remove Plow Layer, Chemically
                             Stabilize
                             Remove Shallow Root Zone, Chemically
                             Stabilize
                             Barriers to Exclude People
                             Exclude Large Animals
                             Exclude Large and Small Animals
                             Asphalt Hard Surface Stabilization
                             Concrete Hard Surface Stabilization
                             Application of Sewage Sludge
                             High Pressure Washing (<3 mm)
                             Flooding to 30 cm
                             Soil Amendments Added
     5.4.2  Alternative Treatment Techniques
            (Treatment 8-1)  Snowfences and Wind Barriers
                             Watershed Control Devices Constructed
                             Snow and Ice Additives
                             Removal of Contaminated Snow and Ice
       ^	 — - — -  — /
       (Treatment 1-1)
       (Treatment 1-2)
       (Treatment 1-3)
       (Treatment 1-4)
       (Treatment 1-5)
       (Treatment 1-6)
       (Treatment 1-7)
       (Treatment 1-8)
       (Treatment 2-1)
       (Treatment 2-2)
       (Treatment 2-3)

       (Treatment 2-4)

       (Treatment 2-5)

       (Treatment 2-6)

       (Treatment 2-7)

       (Treatment 2-8)
          i
       (Treatment 3-1)
       (Treatment 3-2)
       (Treatment 3-3)
       (Treatment 4-1)
       (Treatment 4-2)
       (Treatment 5-0)
       (Treatment 6-1)
       (Treatment 6-2)
       (Treatment 7-0)
       (Treatment 8-2)
       (Treatment 8-3)
       (Treatment 8-4)
Recovery After Cleanup
      ,5.1  Irreversible Changes
     5.5.2  Rates of Recovery
     5.5.3  Successional Stages
            5.5.3.1  First Year
            5.5.3.2  Fifth Year
            5.5.3.3  Tenth Year
5.6  Quantitative Assessment of Cleanup Impacts
5.7  Conclusions
5.8  Aeolian Mountain Peak References
5-20
5-22
5-22
5-22
5-22
5-22
5-23
5-23
5-23
5-24
5-24
5-24

5-24

5-24

5-25

5-25

5-25

5-25
5-25
5-26
5-26
5-26
5-26
5-26
5-26
5-27
5-27
5-27
5-27
5-27
5-28
5-28
5-29
5-29
5-29
5-30
5-30
5-30
5-30
5-31
5-34
5-36
                                  XI

-------
                            CONTENTS (continued)
CHAPTER
   6.1
6-TUNDRA
Overview
   6.2
   6.3
   6.4
        6.1.4
        6.1.5
       Geographical Distribution
       Environment
       Vegetation
       6.1.3.1  Arctic Tundra
       6.1.3.2  Alpine Tundra
       Animal Life
       Soils
Natural Perturbations
6.2.1  Fire
6.2.2  Drought
6.2.3  Grazing
Man-Made Perturbations
Effects of Cleanup Procedures on Tundra
       (Treatment 0-1)  Natural Rehabilitation
               (Treatment 1-1)
               (Treatment 1-2)
               (Treatment 1-3)
               (Treatment 1-4)
               (Treatment 1-5)
               (Treatment 1-6)
               (Treatment 1-7)
               (Treatment 1-8)
               (Treatment 2-1)
               (Treatment 2-2)
               (Treatment 2-3)

               (Treatment 2-4)

               (Treatment 2-5)

               (Treatment 2-6)

               (Treatment 2-7)

               (Treatment 2-8)
   6.5
       (Treatment 3-1)
       (Treatment 3-2)
       (Treatment 3-3)
       (Treatment 4-1)
       (Treatment 4-2)
       (Treatment 5-0)
       (Treatment 6-1)
       (Treatment 6-2)
       (Treatment 7-0)
Recovery After Cleanup
6.5.1  Irreversible Changes
Chemical Stabilization
Clearcutting Vegetation
Stumping and Grubbing
Scraping and Grading
Shallow Plowing
Deep Plowing
Soil Cover Less than 25 cm
Soil Cover to 25 to 100
Remove Plow Layer
Remove Shallow Root Zone
Remove Scraping and Grading,
Mechanically Stabilize
Remove Plow Layer, Mechanically
Stabilize
Remove Shallow Root Zone, Mechanically
Stabilize
Remove Scraping and Grading,
Chemically Stabilize
Remove Plow Layer, Chemically
Stabilize
Remove Shallow Root Zone, Chemically
Stabilize
Barriers to Exclude People
Exclude Large Animals
Exclude Large and Small Animals
Asphalt Hard Surface Stabilization
Concrete Hard Surface Stabilization
Application of Sewage Sludge
High Pressure Washing
Flooding to 30 cm
Soil Amendments Added
6-1
6-1
6-2
6-2
6-3
6-4
6-10
6-11
6-11
6-16
6-16
6-17
6-17
6-17
6-19
6-20
6-20
6-21
6-21
6-22
6-23
6-23
6-23
6-23
6-23
6-23

6-24

.6-2*

6-24

6-24

6-24

6-24
6-24
6-24
6-25
6-25
6-25
6-25
6-25
6-26
6-26
6-26
6-26
                                     xii

-------
                            CONTENTS (continued)
   6.6
   6.7
   6.8

CHAPTER
   7.1
   7.2
   7.3
   7.4
6.5.2  Rates of Recovery
6.5.3  Succession Stages Following Cleanup
       6.5.3.1  First Year
       6.5.3.2  Fifth Year
       6.5.3.3  Tenth Year
       6.5.3.4  Climax
Quantitative Assessment of Cleanup Impacts
Conclusions
Tundra References

7-COASTAL INTER-TIDAL MARSHES
Overview
7.1.1  Occurrence of Coastal Marshes
7.1.2  Related Land Types
Natural Perturbations
Man-Made Perturbations
7.3.1  Impact on Baseline Ecosystem Components
7.3.2  Unassisted Recovery Sequence
Effects of Cleanup Procedures on Coastal Marshes
       (Treatment 1-1)  Chemical Stabilization
       (Treatment 1-2)  Clear Cutting Vegetation
       (Treatment 1-3)  Stumping and Grubbing
       (Treatment 1-4)  "
       (Treatment 1-5)
       (Treatment 1-6)
       (Treatment 1-7)
       (Treatment 1-8)
       (Treatment 2-1)
               (Treatment 2-2)
               (Treatment 2-3)

               (Treatment 2-4)

               (Treatment 2-5)

               (Treatment 2-6)

               (Treatment 2-7)

               (Treatment 2-8)

               (Treatment 3-1)
               (Treatment 3-2)
               (Treatment 3-3)

               (Treatment 4-1)
               (Treatment 4-2)
               (Treatment 5-0)
               (Treatment 6-1)
Scraping and Grading
Shallow Plowing
Deep Plowing
Soil Cover Less than 25 cm
Soil Cover 25 to 100 cm
Remove Plow Layer
Remove Shallow Root Zone
Remove by Scraping and Grading,
Mechanically Stabilize
Remove Plow Layer, Mechanically
Stabilize
Remove Shallow Root Zone, Mechanically
Stabilize
Remove by Scraping and Grading,
Chemically Stabilize
Remove Plow Layer, Chemically
Stabilize
Remove Shallow Root Zone, Chemically
Stabilize
Barriers to Eixclude People
Barriers to Exclude Large Animals
Barriers to Exclude Large and
Small  Animals
Asphalt .Hard Surface Stabilization
Concrete Hard Surface Stabilization
Application of Sewage Sludge
High Pressure Washing (<3 mm)
 6-26
 6-28
 6-28
 6-28
 6-28
 6-29
 6-29
 6-29
 6-31

 7-1
 7-1
 7-5
 7-5
 7-6
 7-7
 7-7
 7-8
 7-15
 7-16
 7-16
 7-16
 7-19
 7-19
 7-20
 7-20
 7-20
 7-21
 7-21

 7-21

 7-22

 7-22

 7-22

 7-22

 7-22
 7-22
7-23

7-23
 7-25
7-25
7-25
7r26
                                   xiii

-------
                            CONTENTS  (continued)
               (Treatment 6-2)   Flooding to 30 cm
               (Treatment 7-0)   Soil  Amendments Added
   7.5  Recovery After Cleanup
   7.6  Quantitative Assessment of Cleanup Impacts
   7.7  Conclusions
   7.8  Coastal  Inter-Tidal  Marsh References

                        PART II - MANAGED ECOSYSTEMS

CHAPTER 8-AGRICULTURE
   8.1  Overview
   8.2  Natural  Perturbations
   8.3  Man-Made Perturbations
        8.3.1  Runoff and Fertilization
        8.3.2  Soil Compaction
        8.3.3  Compaction and Runoff
        8.3.4  Infiltration and Crops
   8.4  Effects  of Cleanup Procedures on Agriculture
               (Treatment 0-1)
               (Treatment 1-1)
               (Treatment 1-2)
               (Treatment 1-3)
               (Treatment 1-4)
               (Treatment 1-5)
               (Treatment 1-6)
               (Treatment 1-7)
               (Treatment 1-8)
               (Treatment 2-1)
               (Treatment 2-2)
               (Treatment 2-3)

               (Treatment 2-4)

               (Treatment 2-5)

               (Treatment 2-6)

               (Treatment 2-7)

               (Treatment 2-8)

               (Treatment 3-1)
               (Treatment 3-2)
               (Treatment 3-3)

               (Treatment 4-1)
               (Treatment 4-2)
               (Treatment 5-0)
               (Treatment 6-1)
Natural Rehabilitation
Chemical Stabilization
Clearcutting Vegetation
Stumping and Grubbing
Scraping and Grading
Shallow Plowing
Deep Plowing
Soil Cover Less than 25 cm
Soil Cover 25 to 100 cm
Remove Plow Layer
Remove Shallow Root Zone
Remove Scraping and Grading,
Mechanically Stabilize
Remove Plow Layer, Mechanically
Stabi1i ze
Remove Shallow Root Zone, Mechanically
Stabilize
Remove Scraping and Grading,
Chemically Stabilize
Remove Plow Layer, Chemically
Stabilize
Remove Shallow Root Zone, Chemically
Stabilize
Barriers to Exclude People
Barriers to Exclude Large Animals
Barriers to Exclude Large and
Small Animals
Asphalt Hard Surface Stabilization
Concrete Hard Surface  Stabilization
Application of Sewage  Sludge
High  Pressure Washing  (<3 mm)
                                          7-26
                                          7-26
                                          7-26
                                          7-26
                                          7-33
                                          7-34
8-1
8-1
8-5
8-8
8-10
8-11
8-13
8-14
8-14
8-15
8-16
8-17
8-18
8-18
8-19
8-20
8-20
8-20
8-21
8-21

8-22

8-24

8-24

8-2*

8-25

8-25
8-25
8-25

8-26
8-26
8-27
8-27
8-28
                                      xiv

-------
                            CONTENTS (continued)
   8.5
   8.6
   8.7
   8.8
       (Treatment 6-2)  Flooding to 30 cm
       (Treatment 7-0)  Soil Amendments Added
Recovery Following Cleanup
8.5.1  Irreversible Changes
8.5.2  Rates of Recovery
Quantitative Assessment of Cleanup Impacts
Conclusions
Agriculture References
CHAPTER 9-URBAN/SUBURBAN AREAS
   9.1  Overview
   9.2  Natura.l  Perturbations
   9.3  Man-Made Perturbations
   9.4  Effects  of Cleanup Procedures
               Lawn,  Plant and
               (Treatment 0-1)
               (Treatment 1-1)
               (Treatment 1-2)
               (Treatment 1-3)
               (Treatment 1-4)
               (Treatment 1-5)
               (Treatment 1-6)
               (Treatment 1-7)
               (Treatment 1-8)
               (Treatment 2-1)
               (Treatment 2-2)
               (Treatment 2-3)

               (Treatment 2-4)

               (Treatment 2-5)

               (Treatment 2-6)

               (Treatment 2-7)

               (Treatment 2-8)

               (Treatment 3-1)
               (Treatment 3-2)
               (Treatment 3-3)
               (Treatment 4-1)
               (Treatment  4-2)
               (Treatment*5-0)
               (Treatment  6-1)
               (Treatment  6-2)
               (Treatment  7-0)
                              on
                                                cm
                                                cm
                      	__  _..  Urban/Suburban Areas
 9.4.1   Lawn,  Plant and Soil Area  Treatments
                         Natural Rehabilitation
                         Chemical  Stabilization
                         Clear  Cutting Vegetation
                         Stumping  and Grubbing
                         Scraping  and Grading
                         Shallow Plowing
                         Deep Plowing
                         Soil Cover Less than 25
                         Soil Cover 25 cm to 100
                         Remove Plow Layer
                         Remove Shallow Root Zone
                         Remove Scraping and Grading,
                         Mechanically Stabilize
                         Remove Plow Layer, Mechanically
                         Stabilize
                         Remove Shallow Root Zone, Mechanically
                        Stabilize
                         Remove Scraping and Grading,
                         Chemically Stabilize
                         Remove Plow Layer, Chemically
                        Stabilize
                         Remove Shallow Root Zone, Chemically
                        Stabilize
                        Barriers to Exclude People
                        Exclude Large Animals
                        Exclude Large and Small  Animals
                        Asphalt Hard Surface Stabilization
                        Concrete Hard Surface Stabilization
                        Application of Sewage Sludge
                        High Pressure Washing
                        Flooding to 30 cm
                        Soil Amendments  Added
9.4.2  Impervious, Artificial  Surface Treatments
       (Treatment 8-1)  Washing with  High Pressure Water (>3 mm)
       (Treatment 8-2)  Vacuuming
 8-28
 8-28
 8-29
 8-29
 8-29
 8-30
 8-37
 8-38
 9-1
 9-1
 9-4
 9-4
 9-5
 9-8
 9-8
 9-8
 9-8
 9-8
 9-9
 9-9
 9-9
 9-9
 9-9
 9-11
 9-11

 9-11

 9-11

 9-12

 9-12

 9-12

 9-12
 9-12
 9-12
 9-12
 9-12
9-13
9-13
 9-13
9-13
9-13
9-13
9-14
9-15
                                    xv

-------
                            CONTENTS (continued)
               (Treatment 8-3)   Sweeping
               (Treatment 8-4)   Mechanized Street Flushing
               (Treatment 8-5)   Surface Removal  Techniques
               (Treatment 8-6)   Other Removal  Methods
               (Treatment 8-7)   Containment
   9.5  Recovery After Cleanup
   9.6  Quantitative Assessment of Cleanup Impacts
   9.7  Conclusions
   9.8  Urban/Suburban Land Areas References

                             PART III - WILDLIFE
CHAPTER 10 -WILDLIFE
   10.1 Overview
   10.2 Effects on Birds
        10.2.1 Short-Term Effects
        10.2.2 Long-Term Effects
               10.2.2.1 Deserts
               10.2.2.2 Prairies
               10
               10
        10.
   2.2.3 Deciduous Forests
   2.2.4 Coniferous Forests
10.2.2.5 Aeolian Mountain Peaks
10.2.2.6 Tundra Areas
10.2.2.7 Coastal Inter-Tidal  Marshlands
              .2.2.7
       .2.3 Land Uses
            10.2.3.1 Agricultural Areas
            10.2.3.2 Suburban Areas
10.3 Effects on Mammals
     10.3.1 Short-Term Effects
            10.3.1.1 Large Carnivores
            10.3.1.2 Medium-Sized Carnivores
              ,3.1.3 Small Carnivores
               10.
               10.
               10,
               10,
   3.1.4 Large Herbivores
   3.1.5 Small Herbivores
   3.1.6 Large Omnivores
               10.3.1.7 Small Omnivores
               10.3.1.8 Insectivores
               10.3.1.9 Flying Mammals
        10.3.2 Long-Term Effects
               10.3.2.1 Large Carnivores
               10.3.2.2 Medium-Sized Carnivores
               10.3.2.3 Small Carnivores
               10.3.2.4 Large Herbivores
               10.3.2.5 Small Herbivores
               10.3.2.6 Large Omnivores
               10.3.2.7 Small Omnivores
               10.3.2.8 Insectivores
               10.3.2.9 Flying Mammals
        10.3.3 Land Types
               10.3.3.1 Deserts
                                                           9-16
                                                           9-16
                                                           9-17
                                                           9-17
                                                           9-17
                                                           9-18
                                                           9-18
                                                           9-21
                                                           9-21
10-1
10-1
10-8
10-8
10-10
10-12
10-14
10-15
10-15
10-16
10-16
10-17
10-18
10-18
10-19
10-20
10-20
10-21
10-21
10-22
10-22
10-22
10-23
10-25
10-25
10-25
10-26
10-26
10-26
10-27
10-27
10-27
10-28
10-28
10-29
10-29
10-29
10-31
                                     xvi

-------
CONTENTS (continued)
               10.3.3.2 Prairies
               10.3.3.3 Deciduous Forests
               10.3.3.4 Coniferous Forests
               10.3.3.5 Tundra Areas
               10.3.3.6 Coastal Inter-Tidal Marshlands
        10,3.4 Land Uses
               10.3.4.1 Agricultural Areas
               10.3.4.2 Suburban Areas
   10.4 Conclusions
   10.5 Wildlife References

                            PART IV - APPENDICES
APPENDIX A-STABILIZERS
   A.I  Introduction
   A.2  Types of Stabilizers
        A.2.1  Chemical
        A.2.2  Mechanical
        A.2.3  Physical
        A.2.4  Chemical with Mechanical Characteristics
   A.3  Stabilizer Groupings
   A.4  Ratings of Stabilizer Groupings
        A.4.1  Application
        A.4.2  Durability
        A.4.3  Vegetation Recovery
   A.5  Land Types and Land Use Classes
   A.6  Appendix A References
APPENDIX B-IMPACT ASSESSMENT
   B.I  Introduction
   B.2  Derivation of Recovery Index from Successional Sere
   B.3  Ranking of Disturbance from Cleanup Treatments
   B.4  Recovery Index Number Assignment
   B.5  Appendix B References
APPENDIX C-LAND TYPES
APPENDIX D-CLEANUP TREATMENTS
APPENDIX E-GLOSSARY
                                             10-31
                                             10-32
                                             10-32
                                             10-32
                                             10-33

                                             10-33
                                             10-34
                                             10-35
                                             10-39
                                              A-l
                                              A-l
                                              A-l
                                              A-l
                                              A-l
                                              A-3
                                              A-3
                                              A-4
                                              A-5
                                              A-5
                                              A-6
                                              A-6
                                              A-7
                                              A-7

                                              B-l
                                              B-l
                                              B-l
                                              B-4
                                              B-5
                                              B-ll
                                              C-l
                                              D-l
                                              E-l
        xvi i

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                                  FIGURES
Number                                                                   Page
 1-1    The North American Desert and its  subdivisions.                   1-9
 1-2    Great Basin Desert roadway unused  for 15 years.                   1-22
 1-3    Mojave Desert roadway unused for 17 years.                        1-22
 1-4    Great Basin Desert 11 years after  blading and  forming windrows.   1-24
 1-5    Mojave Desert.  An unintended water catchment  basin  in  a
        disturbed area.                                                  1-24
 1-6    Mojave Desert.  Larrea growing in  compacted area  alongside
        asphalt roadway.                                                 1-25
 1-7    Mojave Desert.  The effect of increased moisture  from roadside
        cut on Larrea growth.                                            1-28
 1-8    Great Basin Desert.  A 2 ha rectangular plot 11 years after
        blading.                                                          1-34
 1-9    Great Basin Desert 11 years after  blading.                        1-34
 1-10   Great Basin Desert.  Demarcation line between  land bladed
        11 years  ago (right) and non-bladed land  (left).                  1-35
 1-11   Great Basin Desert.  Area in foreground and right was bladed
        11 years  prior to the photograph.                                 1-35
 1-12   Great Basin Desert 17 years after  application  of  water  to
        reduce dust followed by blading.                                 1-36
 1-13   Great Basin Desert recovery 17 years after  blading.               1-36
 1-14   Great Basin Desert 17 years after  plowing.                        1-38
 1-15   Great Basin Desert.  Foreground first treated  with hot,
        rapid-cure road oil stabilizer, then scraped.                     1-45
 1-16   Soil 17 years after application of a hot  rapid-cure  road oil
        stabilizer.                                                      1-45
 1-17   Sequence of ecologic recovery following cleanup.                  1-47
 1-18   Recovery sequence following shallow plowing and  clearcutting
        vegetation.                                                      1-48
 1-19   Sequence of ecologic recovery following cleanup.                  1-49
 1-20   Sequence of ecologic recovery following cleanup.                  1-50
 2-1    Natural recovery and recovery with reseeding of  prairie.          2-23
                                    xviii

-------
                             FIGURES  (continued)
Number^
 2-2

 2-3

 3-1

 3-2

 3-3

 4-1
 4-2

 4-3
 4-4
 4-5
 4-6
 4-7

 5-1
 5-2
 5-3

 6-1

 7-1

 7-2

 7-3

 7-4

 7-5
 Time course of change after mowing (1-2)  and  stumping  and
 grubbing (1-3) of woody component of prairie.
 Recovery of prairie following mechanical  soil  stabilization
 and response to the erection of fencing.
 Natural  recovery (0-1)  and  generalized  typical  reclamation
 of deciduous forest following cleanup.
 Recovery of deciduous forest following  clear  cutting (1-2)
 and stumping and grubbing (1-3).
 Recovery of deciduous forest following  hard surface
 stabilization.
 Natural  forest  vegetation of the  United States.
 Vegetation  chart for  the Santa  Catalina Mountains, southeastern
 Arizona.
 Sequence  of ecological  recovery following cleanup.
 Sequence  of ecological  recovery following cleanup.
 Sequence  of ecological  recovery following cleanup.
 Decrease  in  runoff  following  clearcutting coniferous forests.
 Clearcutting  the whole  stand, with reproduction secured by
 seed disseminated from  seed trees located outside the cut
 stand.
 Alpine and aeolian  regions of the world.
 Alpine-aeolian zonation in the eastern Himalaya
 Diurnal sun/shade temperature ranges in air and subsurface
 soil at 15,500 feet.
 A word model illustrating the sequence of events in the
 recovery of damaged arctic tundra vegetation.
 Diagram of the wetland classification hierarchy for the
 estuarine ecological system  to the order level.
A typical effects linkage shows the disturbance web and
environmental impacts of soil removal.
 Recovery of coastal  inter-tidal  marsh following chemical
soil stabilization and application of shallow  soil  cover
Recovery of coastal  inter-tidal  marsh following vegetation
removal and shallow layer soil removal.
Response of coastal  inter-tidal  marsh to the erection of
fencing.
 Page

 2-24

 2-25

 3-28

 3-32

 3-33
 4-3

 4-7
 4-42
 4-43
 4-44
 4-46

 4-48
 5-3
 5-4

 5-9

 6-27

 7-4

 7-11

 7-27

7-28

7-29
                                    xix

-------
Number
 8-1
 8-2
 8-3
 8-4
 B-l
                             FIGURES  (continued)
Indigenous vegetation zones of the conterminous  United States.
Surface soil moisture-wind velocity soil  loss factor as a
percent of soil loss at Garden City, Kansas.
Rainfall erosivity index, based on maximum 30-minute intensity,
from an average of annual maximums.
Idealized effective precipitation, vegetation, and sediment
yield on west to east transect.
Example of times for recovery from cleanup in coniferous
forest by natural and managed rehabilitation.
Page
8-3

8-6

8-7

8-8

B-3
                                       xx

-------
                                   TABLES
Number
 1-1

 2-1
 3-1
 3-2
 4-1
 4-2
 4-3
 4-4

 4-5

 4-6

 4-7

 5-1

 5-2

 6-1
 6-2
 6-3
 6-4

 7-1

 7-2

 7-3
 Estimates  of the  years  to  recover  productivity after application
 of the 'various  cleanup  procedures.
 Predicted  recovery  index in  prairie  for cleanup treatments.
 Parameter  trends  during deciduous  forest succession.
 Predicted  recovery  index in  deciduous forest for cleanup
 treatments.
 Measurements  on forest  clearings.
 Average possible  depth  of  compaction to 10 percent soil voids.
 Major forest  types  of the  United States.
 Approximate age of  representative coniferous forests where
 number of  trees per acre is  reduced by suppression.
 Height of dominants in  a fully stocked stand at 100 years--
 good to medium site fully  stocked.
 Approximate basal area  (m2/ha) of representative conifer
 species—good to medium site, fully stocked.
 Recovery index in coniferous forest for various cleanup
 treatments.
 Movement of mountain detritus within measured mudflows as
 examples of erosion.
 Estimates of the years  to reach recovery after various cleanup
 treatments.
 Comparison of arctic and alpine environments and vegetation.
 Representative poorly drained tundra soil.
 Representative well  drained tundra soil.
 Change in conditions caused by seismic lines and winter roads
with paired control  plots  in 1970.
Net primary production and plant biomass  for major ecosystems
and for the earth's  surface.
 Effects of ditching a Delaware tidewater marsh  on  the  aquatic
 invertebrate populations.
Effects of denuding and/or soil  removal  on  physical  and
chemical characteristics of marshlands.
                                                                  Page
 1-54
 2-32
 3-5

 3-37
 4-25
 4-33
 4-40

 4-49

 4-51

 4-51

 4-54

 5-16

 5-33
6-12
6-14
6-15

6-18

7-2

7-9

7-13
                                    xx i

-------
                              TABLES  (continued)
Number
 7-4    Effects of soil  removal  and placement  of dredge spoil in
        marshlands-
 7-5    Predicted years  to reestablish  precleanup marshes.
 8-1    Relationship between annual precipitation, species  composition,
        and moisture consumption,  Rocky Mountains to  Missouri transect
        of prairie.
 8-2    Effectiveness of ground cover in soil  erosion loss  at construc-
        tion sites in deciduous forest  zones.
 8-3    Control systems  and relative effectiveness.
 8-4    Commercial crop  species in managed ecosystems.
 8-5    Rooting depths of agricultural  crops in fertile,  deep, well
        drained soils.
 8-6    Predicted recovery index of irrigated desert  agriculture  for
        cleanup treatments.
 8-7    Predicted recovery index of agricultural lands in grasslands
        for cleanup treatments.
 8-8    Predicted recovery index of agricultural lands in forests
        for cleanup treatments.
 9-1    Relative rating of environmental impact of treatments on  a
        scale of 0 (no impact) to 100 (greatest impact).
10-1    Examples of bird species impacted by maximum  disturbance  to
        specified types  and sizes of land areas.
10-2    Examples of small herbivorous mammals impacted by maximum
        disturbance to specified types and sizes of land  areas.
10-3    Examples of mammals other than small herbivores impacted  by
        maximum disturbances to specified types and sizes of land
        areas.
10-4    Relative impacts of land cleanup treatments on wildlife
        following maximum possible land disturbance.
10-5    Relative time for recovery of wildlife  following  maximum
        disturbance to land and cleanup treatment.
 A-l    Ratings of individual stabilizers for use  in different land
        types.
 A-2    Manufacturer  and application information  for soil stabilizers.
 B-l    Hypothetical  forest sere.
 B-2    Hypothetical  grassland  sere.
 B-3    Evaluation of the effects  of cleanup  procedures.
Page

7-15
7-31


8-4

8-9
8-10
8-12

8-12

8-34

8-35

8-36

9-19

10-13

10-24


10-30

10-36

10-38

 A-2
 A-8
 B-2
 B-2
 B-6
                                     xxi i

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                             TABLES (continued)
Number

 B-4
 B-5
 B-6
Years estimated for hypothetical ecosystem to reach climax
after the indicated cleanup.

Hypothetical coniferous sere as represented by the development
of a Spruce-hemlock forest on mineral soil exposed by glacial
retreat.

Recovery indexes for cleanup of hypothetical  coniferous
forest.
Page


B-7



B-9


B-10
                                   xxi i i

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                              ACKNOWLEDGMENTS
     This report was written as a collaborative effort among the Chapter authors
and project participants.  The principal authors are listed alphabetically,  in
reverse order.  They are:

          Dr. John F. Thames — University of Arizona, Tucson, Arizona
          Richard H. Rowland - GE-TEMPO, Santa Barbara, California
          Dr. James C. McBrayer - University of Michigan (now at Oak Ridge,
                                  Tenn.)
          Dr. Howard A. Hawthorne — GE—TEMPO, Santa Barbara, California
          James C. Johnson —Moss § Johnson Associates, Springfield, Mo.
          Kenneth E. Gould - GE -TEMPO,  Santa Barbara, California
          Dr. Lome G. Everett - GE-TEMPO, Santa Barbara, California
          F. Stephen Dobson — GE—TEMPO, Santa Barbara, California (now
                              at University of Michigan)

     Project participants provided the support essential for acquiring reference
materials, supporting documents and ran down those elusive half-documented
citations so well remembered — almost.  These supporters included Dr. Tika Verma,
Gerald Harwood, Dr. Guenton Slawson, Rosalie Oren, Gregory Mohr, Susan Neighbors,
and Evelyn McDonald.
                                     xxiv

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                                   INTRODUCTION
 STATEMENT OF THE PROBLEM
      In the  industrialized  development  and commerce of  today's technological
 society a variety of goods  are  transported by  land, sea, and air.  Among
 these goods  in transit  at any particular instant are some which are toxic or
 injurious to man coining into direct or  indirect contact with them.  Indirect
 contact includes drinking contaminated  groundwater, consumption of plants
 that  absorbed contamination from soil,  and using dairy products or meat from
 contaminated animals.

      Contaminating accidents may also originate when industrial processes
 malfunction.   These  include explosions  at chemical process plants, inadvertent
 releases  by  plant operators, and a variety of other dumps or leaks.

      The  frequency of contaminating accidents has increased yearly until they
 have  become  an almost daily event.  In most cases, the contaminant is spread
 by natural forces and human traffic during evacuation of the residents.  By
 the time  the  contaminant is identified and the zone of contamination delineated,
 the contaminant may have penetrated environmental materials and decontamina-
 tion may be  required.  The methods of decontamination are numerous and varied.

 PURPOSE OF THE REPORT
     This report is concerned with the ecological impacts of specific cleanup
 treatments on the land where they are carried out.   The report provides
guidance to rational selection among the cleanup procedures likely to be sug-
gested by State, Federal or local government officials,  industrial representa-
tives of the entity responsible for the contaminating accident,  concerned
citizens' groups, or local environmental managers called in for their expertise.
The priorities of these groups are most likely to be divergent and emotionally
intense under the stress of immediate,  local, present danger.

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     This report is intended to present the best unbiased,  neutral  estimate
of how local environments will be changed by specific common cleanup  treat-
ments, the relative magnitude of the changes they may cause, and their dura-
tion.
     Local conditions have the greatest force in determining how interrelated
environmental actions occur.  Therefore, the cleanup treatment to be  used at  a
given site must be decided upon with input from local geologists, foresters,
soil scientists, agronomists, botanists, dairymen, animal husbandmen, zoologists:
or other professionals intimately acquainted with the contaminated area.

SCOPE OF THE REPORT
     This report provides two classes of generic data that may be helpful in
deciding what steps should be taken when contamination occurs.

     A chapter is devoted to each of seven land types and two managed eco-
systems in  the United States.  Generic descriptions  are given in Part I for
the  seven land types and in Part II for the managed  ecosystems of agricultural
lands and urban/suburban areas.  The vegetation of the seven  land types is
described in detail with brief descriptions of  their climate  and upper soil
profile.    The history of ecosystem recovery from natural  and man-made
catastrophes is reviewed as a guide to predicting how specific  cleanup treat-
ments will  affect  vegetative recovery.

     The  second class of information is  the generic  data arising from descrip-
tions of the effects each of  24  specified  cleanup treatments  has upon the
soils and vegetation in  the affected ecosystems.  This information includes
a recovery  scenario, quantitative  assessment of cleanup  impacts, and citing
the best and worst treatments  for  each land type.

      The purpose  of the  descriptions  is to provide  a general  framework  for
 coordinating  information from which to predict both the  short-term effects of
 cleanup and resultant  long-term changes.   Different plants succeed in different
 land types  but all the plants lack a means of avoiding  cleanup  trauma.   What-
 ever cleanup treatment is used will rearrange some  of the  soils and  damage
 most of the plants in a heavily contaminated area.   Land types  and cleanup

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 treatments were  indicated by  the  EPA tp be  the  items of major  interest, and
 specific  biota of  lower  level  interest.  Thus,.defining the ways in which the
 soil-plant web subsequently develops over time  after injury is  the main thrust
 in  the  quantitative  assessments.

     After several attempts to describe fauna.],  displacement and recoloniza-
 tion after cleanup in  separate ecosystems it became obvious that excessive
 redundancy lay along that approach,  in that animal families are adaptable to
 several ecosystems.  To  escape such  redundancy, the major faunal groups are
 described and predictions made of their response in each disturbed ecosystem,
 and each  managed land  type, where they occur naturally.  Part III presents
 material  on two  divisions of animal  wildlife, the birds and the mammals.
 Animal  families  cross  land types  in  the same context that cleanup treatments
 cross land types in Parts I and II of the report.  Evaluation of the ecologi-
 cal impact of cleanup  treatments  was  confined to mammals and birds.  Ecological
 impact is defined as the reaction of a population to disturbance of their
 habitat by cleanup.  The reactions considered were those large  enough to be
 measured  quantitatively under  field  conditions.  The population attributes
 considered suitable for monitoring to define changes in the population were
 size (in  numbers of individuals)  and/or alterations in the numbers of species
present in the area of concern.   These attributes of populations were taken
 as representative of habitat stability for evaluating cleanup effects.

     The  critical component in population recovery of wildlife  is the restora-
 tion of vegetative species suitable for the wildlife.  The impact assessment
 tables presented in the chapters  are based upon best estimates  for vegetative
recovery  times, or productivity changes.

     Almost any spot in the United States could be involved in a contaminant
spill from some source.  The seven natural land types chosen represent most
of the United States.  The land area of the United States, including Alaska
and Hawaii, totals approximately  10,900,000 km2 of which approximately 240,000
km2 are measured as inland waters.  The area not covered by water (approximately
 10,660 km2) can be measured as approximately 1,068,770,000 hectares, excluding
public lands,  and can be subdivided into the land types shown below.  The

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percentage breakdown of the seven natural ecosystems and the two managed eco-
systems follows (note that the land-use class of ecosystems overlaps the
natural ecosystems):
Chapter

1
2
3
4
5
6
7

8
9
Land Type
NATURAL ECOSYSTEMS
Desert
Prairie
Deciduous Forest
Coniferous forest
Mountain
Tundra
Coastal Inter- tidal
LAND-USE CLASSES
Agriculture
Urban/ suburban
Total land
surface
(percent)

0.4
49.8
28.9
7.4
8.7
4.4
0.3

45.4
7.7
hectares

4,168,000
532,567,000
309,302,000
78,875,000
93,090,000
47,133,000
3,634,000

485,328,000
82,509,000
      The  areas  examined for cleanup range from a hectare (the size  of a
 country home) to approximately 4 sections of land,  which is  not large for a
 typical dryland grain farm but is approximately the mean area of a  county.
                                         2          2
 In metric terms, these areas are 0.01 km  and 10 km ,  respectively.  Inter-
                      2           2
 mediate areas 0.10 km  and 1.0 km  are also addressed.

      The  time scales for which cleanup impacts are defined range froa short
 term (a few years) to those times when the cleanup is  no longer visible
 (hundreds of years).  An arbitrary cutoff point at 100 years was imposed in
 determining whether a treatment was acceptable.  If more than a century is
 required  for recovery, the treatment is considered unacceptable.

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 LITERATURE BASE             ,               .
      More than 400 publications  are  cited in  the  report  and  approximately
 3,500 others  were  retained for inspection and discarded.  Personal contacts
 with other professionals  in the  areas  addressed were made freely.  The pre-
 ferred data base is included in  this report.

 STUDY APPROACH
      The  assembled study  team was  comprised of professional  ecologists actively
 engaged in field work in  the land  areas  to which  they were assigned for this
 project.   All were familiar with environmental impact assessment methodology
 and  the professional literature  in their fields.

      The  ecologist constructs  a  mental model  of the ecosystem climate, geology,
 soils,  vegetation,  and animal  forms  and  predicts  the ecological impact of
 cleanup operations.  Published observations are reviewed to  develop an outline
 of the  ecological  boundaries of  the  ecosystem developed on the land type being
 studied.   When published  literature  was  inadequate or absent, personal
 experience was used to predict the impact  of  cleanup treatments on the eco-
 system  being described.  The impact  predictions; in Sections  4 and 5 of each
 chapter represent  a blend of the published data and personal experience.  The
predicted  onset of recovery appears  in Section 6 of each chapter and presents
 the quantitative assessment for  the  impact forecasts in Section 4.

      Contamination cleanup has been postulated in this report to occur only
in land type tracts that support recognized and. developed ecosystems where
recovery following cleanup progresses along secondary succession,  rather than
ecosystem development by primary succession (new substrate occupied,  such as
earthquake uplift scarps).

      In considering the sequence in which cleanup treatments should be addressed,
it became obvious that the intensity of environmental impact of a  specified
cleanup treatment varied from land type.to land type;  e.g.,  surface grading a
shallow soil layer on grassland was less disruptive than putting the  same
depth and width through*a forest.  Arbitrarily, a uniform sequence and presenta-
tion of cleanup treatments was maintained throughout the report for the sake

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of continuity.  Those persons interested in following a specific treatment
through all land types are advantaged by this methodology,  hopefully with
little disadvantage to those persons intent on examining ecologic impacts'
within particular land types.

     Cleanup treatment impacts were ranked across all land types according  to
the gross environmental disturbance they would generate.  The disturbance was
translated into "median years-to-recover," presented in relative times to
recovery (recovery indexes), and tabulated in Section 6 of each chapter.
Details of these derivations are given in Appendix B.          ^

     The endpoint of recovery from cleanup for the prairie, deciduous forest,
and coniferous forest is ecological:  the reestablishment (succession) of the
original species of plants and animals at the pre-contamination productivity
(biomass).  Six of the chapters deal with ecosystems which do not have identi-
fiable succession and a different concept of endpoint is used in those chapters.
The four chapters of desert, mountain, tundra, and marshes use "years-to-recovery"
of their pre-contamination productivity (biomass) as the terminal point of
rehabilitation.  In the managed ecosystems of Chapters 8 and 9, the recovery
endpoints are determined by economic productivity and public acceptance, since
physical recovery can be expedited via use of machinery.  The concept of
ecological rehabilitation is inappropriate in these managed ecosystems because
they lack the attributes of succession.

IMPACT EVALUATION
     The equipment projected to be used for cleanup was limited to that operated
by small .-contractors or to farm machinery.  The technical evaluation steps, are
shown in Appendix B as a sequence of steps.  Where data were sparse for an eco-
system, the author integrated his field experience with published data to
construct the tables prepared for individual chapters.

     Idealized trend  curves were developed for Section 5 in many ecosystem
chapters to illustrate the time course of recovery to  full productivity  for
some of  the descriptive ecosystem parameters.  The ordinates are without units
either because they have no dimensions  (e.g., homeostasis) or  they are broad
generalizations'  over  an array of heterogeneous sites.   Representative types

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 of cleanup treatments were selected for the illustrations  to  indicate  the
 variety of parameters common to particular ecosystems.

 USE OF THE REPORT
      The report is  subdivided into 3 Parts and 5  Appendices.   In  Part  I  seven
 natural ecosystems  and some of their natural derivations are  defined.  Part  II
 presents managed ecosystems which  are imposed on  natural ecosystems and  are  no
 longer bound by the initial native ecosystem balances.  Part  III  deals with
 avian and mammalian wildlife displaced by  cleanup.   Appendix  A summarizes
 judgments of stabilizer chemicals  and their application to various .land  types.
 The methodology used to derive recovery indices for  those  ecosystems having
 easily recognizable successions is  presented in Appendix B.   Appendices  C,
 D,  and E,  respectively,  give definitions of the land types studied, cleanup
 treatments  considered,  and a glossary of terms.

      Each chapter in Parts I  and II  is  divided into  seven  sections.  The first
 three sections  give ecologic data  sources  used in evaluating  the  cleanup impacts,
 In  Sections  2 and 3 the  ecological  basis is  given for the  judgments utilized
 in  Sections  4,  5, 6,  and 7.

      Each cleanup treatment  is  defined  in  Appendix D and the  impact of each is
 defined  in Section  4.  Section  5 gives  a brief scenario of how the ecosystem
 is  envisioned to change  between cleanup and  the time at which no  further
 changes  are measurable within present detection instrument capabilities.
Quantitative assessments of the magnitude of cleanup impact are made, recovery
time predicted, and  the  effects of using the cleanup treatment on larger areas
evaluated.  In Section 7,  the cleanup treatments that are best suited to the
ecosystem are named, as are those which are inappropriate.

     Agricultural uses of ecosystems modify the basic characteristics beyond
the capabilities of native forces to change them on a short-term basis.  The
modified ecosystems are evaluated in Chapter 8 separately from their parent
ecosystems.  Urban/suburban landscapes also bear few recognizable imprints of
their ecosystem origins and are described in Chapter 9 as a unit of managed
ecosystems.

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     For nonecologists who desire an accurate but direct presentation of the
essence of ecology, the paperback book, "Communities and Ecosystems," by R. H.
Whittaker, is recommended.  In general, the ecosystem is viewed as following
a definite sequence of recovery with time that is predictable,  called succes-
sion.  As the cleaned up ecosystem enters into natural recovery, the initial
small, short-lived invader species is gradually replaced by long-lived and
larger species which tend to exert more and more control over their surround-
ings.  An example is the high-himidity understory of park-like dimensions
which has developed under beech-sugar maple in the deciduous forest zones.
The collective steps in recovery which follow one another are called the sere
and its use in this report is illustrated in Appendix B.  Formal classical
ecologists will doubtless object to this abbreviated presentation on the grounds
that  it is "applied ecology."

     This report was written to summarize what is known and published in tech-
nical journals, books, and reports about how cleanup affects the environment.
Unfortunately, the published data fall far, far short of being continuous in
both time and in the consecutive details of recovery.  References are cited
where information is derived from the  literature; if no reference is cited,
the information is the author's own projection of the recovery after cleanup
is completed.

     The ecosystems in Part I are described in terms of recovery from cleanup
without additional interference or assistance by man.  The kinds of assistance
that are appropriate to perform on three of the ecosystems are collected into
the Agriculture chapter in Part II because these are the land types that produce
the commercial foods and  fiber at the  greatest rates.*  The reclamation pro-
cesses that are appropriate after plowing—irrigation, reseeding, transplant-
ing, fertilizing,  contour tilling, and harvesting—are widespread management
practices of agriculture.  These are presented in Chapter 8 only to a limited
degree since this  report  deals with cleanup impacts—not with impact erasure.
Discussion of  these management practices within ecosystem chapters has been
restricted to  special  cases that are unique to natural  systems.
 *These three land types  are  desert  (Chapter  1), prairie  (Chapter  2), and
  deciduous  forest (Chapter 3).

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 CONCLUSIONS
      Cursory inspection of the conclusions  sections  of the  chapters  shows
 that generalization and condensation  to produce  a  single  conclusion  for the
 report is  not effective.   The most  disruptive  technique was concluded to be
 paving over a compacted subgrade.   However, estimates  of  the time for this to
 be  weathered and  assimilated  differ among ecosystems.   The  general conclusion
 about ecosystems  was that  succession  was relatively  unchanged by a variety of
 techniques that assisted in early and rapid revegetation.   Mulches,  stabilizers,
 plowing, and fertilizers were  very  effective in  reintroducing new growth but
 the particular ecosystem controlled which species would succeed into climax.
 Plantings  of hardwoods  in  grasslands  or coniferous ecosystems would have no
 effect on  the time  to climax or eventual climax:  species, although grasses are
 most  likely  to provide  early cover  in any of the widespread ecosystems.

     This  report has addressed the  impacts of particular cleanup techniques on
 specified  ecosystems but other areas of study remain.  The effectiveness of
 cleanup techniques in removing or stabilizing contamination needs to be  addressed.
The greatest need is the Development of a methodology to quantify (into  monetary
terms) the information collected on environmental impact.

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              PART I
        NATURAL ECOSYSTEMS
CHAPTER 1,  DESERTS
CHAPTER 2,  PRAIRIES
CHAPTER 3,  DECIDUOUS FORESTS
CHAPTER 4,  CONIFEROUS FORESTS
CHAPTER 5,  AEOLIAN MOUNTAIN PEAKS
CHAPTERS,  TUNDRAS
CHAPTER 7,  COASTAL INTER-TIDAL MARSHES

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                                  CHAPTER 1
                                    DESERT


 1.1  OVERVIEW

      There is little accord among scientists as to what constitutes a desert.
 It is generally agreed that sparse to absent vegetation due to little rainfall
 is the distinguishing feature,  but where some scientists limit the definition
 of desert to areas receiving less than 50 mm of rainfall annually, others
 include regions with 360 nun of  annual rain,  or even more.   In addition,  it  is
 recognized that the rainfall amount alone is riot the primary determinant of des-
 ert type,  but that seasonal moisture fluctuation,  temperature, and edaphic  fac-
 tors are also important.   For example,  the polar regions are true  deserts because
 they lack vegetation and exhibit  low levels  of atmospheric  water vapor.   There
 are also regions of the  world which receive  in excess of 300 mm of annual
 precipitation but are dry,  barren and relatively devoid  of  vegetation.   Such
 regions  are  termed edaphic  deserts because the physical  cause of aridity is
 in  the nature of the porous surface soil which allows moisture penetration
 at  a rate  too rapid to permit plant  sustenance regardless of the amount  of
 rain that  may fall.

      The focus  in this discussion is  on the  desert  of North America,  specifi-
 cally the  desert of the United States.  This desert  is a large irregular  belt
 on  the western  side of the  continent  covering  about  940,000 square kilometers
 from mid-Idaho  to Northern Mexico  and roughly  corresponding  to the rain
 shadowed intermontane region between the coast ranges and the  Rocky Mountains.
 It  includes major  parts of the states of Arizona, Nevada, Utah, and lesser
parts of California, Colorado, Idaho, New Mexico, Oregon, Texas, and Wyoming.
     The physical  geography and human utilization of the region exhibit great
 internal variety,  but its overall aridity associated with an excess of evapora-
tion over precipitation, high percentage of sunshine, great temperature extremes,
high diurnal air temperature, low atmospheric humidity,  frequent winds and a
predominance of eroded landscapes give it an unquestioned unity.  In general,

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the region is characterized by rainfalls less than 250 mm per year.   In  these
areas the environmental gradients are altitudinal gradients,  where temperature
decreases and precipitation-increases with elevation.   Desert communities occupy
the lowest, driest areas and juniper and pinon-juniper woodlands are on  the
higher more mesic regions.  The eastern and northern boundaries merge into
grassland prairie.  An intermediate land type, the desert grassland, will also
be briefly discussed.
     In this report, areas receiving 250 mm or less of rain per year will be
classed as desert.  The peripheral desert grasslands receiving somewhat  greater
annual moisture will be called arid areas.  This is not an arbitrary classifica-
tion but rather one based on the requirement for unassisted revegetation.
Moisture is the dominant factor in vegetation growth and it is generally con-
ceded that once relatively large areas of vegetation have been destroyed, about
250 mm of rainfall per year is the minimum needed for revegetation without
           ,  .   .    .   39,51,60
supplemental  irrigation.
     In the discussion below are considered  the  climatic, edaphic and topographic
features which explain a desert, and the vegetative factors which characterize
it.  The goal of  this summary  is to  form a basis for understanding the  effects
produced by natural and anthropogenic  fman-made)  environmental perturbations.

1.1.1  Desert Climate
     Geographers  have attempted  to  classify  desert  types by  climates, usually
in terms of precipitation  and  temperature  and their seasonal  variation.   The
basis  for  the most  widely  used classification scheme  is  the  Koppen  system which
is based on distribution  of vegetation.    Vegetation is sensitive  to tempera-
ture and precipitation  and tends to reflect  these variables  in a general way.
Because  aridity,  the distinguishing feature  of desert areas,  is a measure of
dryness, an  index based on water balance  of  an area would be superior to the
Koppen system for a climatic  analysis.  Meigs?9 building on  the indices developed
by Thornthwate    which were  closely reflective of water  balance considerations,
 formulated a classification scheme which includes a more explicit, appreciation
 of the role of evaporation,  storage of moisture in the soil and the seasonal
 variability of precipitation.  The Meigs classification uses season of rain-
 fall,  maximum temperature of the hottest month and minimum temperature of the
 coldest month to differentiate arid areas.
                                     1-2

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      Based on Meigs1  considerations of climate,  the American Desert can be
 divided into four regional districts.*  The northernmost of these,  the Great
 Basin,  has cool or cold winters,  frequent snowfall and annual precipitation
 ranging from 100 to 220 mm of which only about 40 percent falls in  the summer
 months.  In the southern part are the hot deserts:  the Mojave, with winter
 rains;  Sonoran, with summer and winter rains;;  and Chihuahuan, with  summer rains.
 The Chichuahuan is somewhat isolated but the other three lie in a continuous
 series.
      In general,...the  temperature  of the North  American desert increases toward
 the south while total precipitation decreases.   In any given latitude,  precipi-
 tation  increases both east and west of about the 115°  meridian.  The frequency
 and amount of precipitation vary  directly as a function,of elevation with ele-
 vation  accounting for about 80 percent of the  variance in rainfall  statistics.
 The southwest corner  is the hottest,  driest desert area.
      A  curve  of precipitation amount  plotted against time of year for desert
 areas is  characteristically bimodal,  with peaks  in the winter and summer.   The
 relative  dominance  of one  peak or the other has  profound  influence  on the  ecol-
 ogy of  the areas.   Orographic barriers are largely responsible for  affecting
 the seasonal  distribution  of rainfall in  the cool  Great Basin desert.   This area
 lies in the zone  of westerly cyclonic storms but much  of  the  moisture in these
 storms  is  extracted by the western boundary mountains.  These storms  bring much
 of  the  annual precipitation during the winter and  early spring months.  In  the
 hot deserts to  the  south,  two major climatic influences cause different sea-
 sonal patterns  of rainfall.   In the eastern part,  the  Chihuahuan  and  to a  lesser
 extent  the  eastern  Sonoran,  the major rain is during the  summer.  This  summer
 rain results from a seasonal  shift in global weather patterns  which cause moist
 air from the Gulf of Mexico  to be  drawn over the area.  Convective precipitation
 originates in this moist air mass.  The western  extent of this  effect is about
 the Arizona-California border.  To the west  of this line, the Mojave receives
winter rain from frontal systems of the cyclonic storms from  the west or north.
Only rarely does summer rain, usually from moist air from the Gulf of California,
fall in this area.  ThevMojave ^is  the driest of  the areas, with some locations
reporting only 50 mm of rain a year.  As a rule, the lower annual average rain-
falls are associated with higher variance from, the average.          , .„••
*The nomenclature for the desert areas is based on work by Shreve.
                                     1-3

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     It is important to recognize that the frequency and intensity of rain  are
                               37
important ecological variables.    A summer rain totaling 150 mm in a given
locality might be the result of one or two rains during the season, perhaps with
a duration of two to three hours for each rain.   Beatley  has shown that in
Mojave desert ecosystems, heavy (>25 mm) rainfall triggers phenological events.
There is a predictable relationship between early winter heavy rain and successful
vegetative and reproductive growth of shrubs the next spring.  Productivity of
desert plants is directly related to the distribution and numbers of desert
animals.7  However, in deserts, where small differences in the amount of moisture
are of great significance, the numerical relations among species are not con-
                                                                     89
sistent from year to year or necessarily correlated with seed supply.
     The climatic division of the American deserts into hot and cool temperature
regimes and into summer, winter and intermediate precipitation patterns is
reflected in the classification and existing distribution of desert vegetation,
but the recovery potential of an area will be an interaction between available
moisture and local soil conditions.

1.1.2  Soils
     An ecosystem typically consists of a complex mosaic of overlapping patterns
that reflect, within the limitation of time and local materials, not only
present but past patterns of distribution of biota.  A  soil profile adjacent
to a Mesquite (Prosopis juliflora) or to a creosote bush  (Larrea tridentata)
may differ markedly from a profile 2 meters away on barren ground.  However,
the major soil type of almost  all desert areas  is similar.  The basic charac-
teristics are coarse texture;  an accumulation of carbonates within a few feet
of the surface contributing to the formation of a hardpan or a caliche  layer;
and low organic matter content.
                                                               83  84 85
     The United States Comprehensive  Soil Classification System   '   '   classi-
fies the soil order underlying almost all of the American deserts  as Aridisols.
Soils of other orders, especially the Entisols, are also present but less
extensive in deserts.  The Aridisols  at  the northern edge of the Great  Basin
Desert are replaced by Mollisols.
     Shantz70 has  noted  that  regions  defined  as arid by geographers cover  an
estimated 43 percent  of  the world's  land area;  however if defined on the basis
of climate,  arid regions occupy only 36 percent of the earth's surface,
                                     1-4

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 35 percent if defined'on the basis of vegetation, but Aridisols cover only
 about 25 percent of the surface.  Thus, worldwide regions of soils classified
 in the Aridisol order do not conform to all the parameters of either climatic
 or vegetation zones.
      The Aridisols,  formed under low rainfall,  are leached little and are  there-
 fore high in calcium,  magnesium, and other soluble elements.   Desert soils
 seem particularly subject to the formation of impervious  surface layers—either
 by physical  processes  or through the surface development  of algae and lichens—
 so that the  effective  drought is accentuated by excessive runoff.   The Aridisols
 are usually  dry and  are never moist  as long as  90 consecutive days during  a
 period when  temperature is suitable  for plant growth.   The low rainfall also
 limits plant growth  so  that  the  soils  are  low in organic  matter and have low
 carbon/nitrogen ratios.   The soils are young in profile development and show
 little evidence of leached upper horizons.   The combined  A and B horizons
 are frequently  less  than 30  cm thick.   As  a rule the A  horizons are light
 colored whereas B  horizons are similar or  slightly darker in  color.   The C
 horizons are light-colored and usually calcareous.  All horizons are  neutral
 or  mildly alkaline.
     Entisols are  of such  recent  development  that  no horizons  have  formed.  They
 are most  extensive on steep  actively eroding;  slopes or  alluvial  fans  where the
 rate of sedimentation is high.
     Mollisols  contain a thick A  horizon high in humus and a base of  calcium or
 magnesium.   In  the northern  Great  Basin Desert  they are formed under  vegetation
 consisting chiefly of grasses.  The climatic regime is moist in  winter and dry
more than 60 consecutive days  in  summer.
     Much of the diversity in  soil profiles reflects their origin.  Coarser
 fragments are found  in soils developed nearer the base of mountains and hills,
and finer textures are found toward the middle valleys.  Clay, if present,  is
usually found in the B horizons in more level areas.  Carbonate content of
 soils  is usually closely correlated with the origin of parent material, and is
highest in areas immediately adjacent to limestone mountain ranges.  High
carbonate concentrations are almost always correlated with the presence of a
restrictive hardpan.   Low carbonate soils are most often developed on alluvium
of mixed igneous and,sedimentary rocks.
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     The particle size distribution of the soils also reflects formation of
alluvial deposits.  Variation in texture is largely due to differences in
distributions of sand and silt particle size fractions.  At low elevations
there is characteristically a low clay content, but increased clay concentra-
tions are found on alluvial sediments in closed drainage basins.
     The climatic regime in which Aridisols form is characterized as one in
which precipitation is less than evapotranspiration during most of the year and
no water percolates through the soils.  This has two important consequences.
First, horizons of soluble salts underlying calcium carbonate and gypsum are
normally found at the average depth of water penetration.  This depth will be
important in relation to the consequences of a given depth of soil removal.
Second, since rainfall is seasonal, there will be periods when precipitation
is in excess of evapotranspiration and water will be stored in the soil to be
used in the spring or fall growing season.  Thus, the time of year in which a
postulated cleanup takes place relative to the seasonal characteristics of
rain in that area is important for predicting ecosystem response.
     There is ample evidence of accelerated soil-forming processes under desert
                                                                 .      52    .
shrubs.  The highest concentrations of organic carbon, organic nitrogen   and
available phosphorus   occur in the upper horizon under shrubs.  Salts also
accumulate under  shrubs, probably through litter decomposition from leaf fall,
                                                                           54
although Odum noted that microbial decomposers would be limited  by dryness.
(Odum speculated  that rodent herbivores were important in this aspect of nutrient
cycling.)  In the transition zone between the Mojave and Great Basin deserts,
the average carbon/nitrogen ratios have been determined to be about 10 while
in the A horizon  under shrubs, values between  12 and 15 are common  (the range
was 5-30).  Only  in the A horizon did organic  carbon content exceed 1 percent.
These low C/N ratios could be due to  low organic matter of desert soils, an
increase in nitrogen fixation, or a combination.    Nitrogen fixing Azotobacters
are usually few or  lacking on desert  soils.4   Other differences in soils under
shrubs are noted:   soil pH tends to be  lower,  conductivity of  saturation extracts
higher, nitrates  and chlorides accumulate more and  exchangeable  cations are
        66
greater.
      Algae and fungi  grow  in  and on the soils  contributing to  fixation  of
atmospheric nitrogen  and to  soil stabilization by  forming  crusts.     These
                                       1-6

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crusts attain a thickness of 2 to 3 millimeters and are sufficiently tough to
permit their removal from the soil surface, as a film.  They may result in
considerable water runoff by sealing soil  surfaces or they may result in
improved water-holding capacity.  In addition to stabilizing the surface of
cohesionless soil, algae can add considerable quantities of nitrogen to the
soil through their nitrogen-fixing ability.    Soil fungi may be necessary in
nutrient cycling.  Symbiotic mycorrhizae,  root fungi, associated with the white
bursage Ambrosia and the grass Hilaria rigidu are necessary for phosphorus
       .            •                              07
absorption in soils with low available phosphorus.

1.1.3  Topographic Factors
     The effects of altitude on temperature and precipitation have been de-
termined in many desert localities.   There is an average decrease of 1°F for
each 100 m rise in elevation but the rate varies with the season of year and
                      88
with local conditions.     South slopes at a 90° angle to the sun receive 1.5
                                          80
times as much heat as level areas.   Shreve   listed the principal features of
altitudinal climatic change as:
          1.   shortening the frostless season
          2.   lowering  the daily curve of temperature throughout
              the frostless season
          3.   increasing the intensity and duration of all  critical
              phases of low temperature during the frost season
          4.
          5.
          6.
              shortening the arid fore-summer, a critical period
              increasing rainfall and thus soil moisture
              decreasing evaporation.
           4
     Beatly  showed the importance of local topography on vegetation distribu-
tion.  Low temperatures resulting from downslope drainage of cold air into
closed basins coupled with differences in seasonal precipitation resulted in
anomalous vegetation mosaics at the transition between the Great Basin and
Mojave deserts.
     A second effect of local topography is its relationship to rainfall.  On
flat or gently sloping surfaces, rainfall leads to unconcentrated flow over
large areas, with thin and ^extensive sheets of moving water, known as sheetflow,
This results in the removal of a thin layer of soil from the entire surface.
Generally only the smaller soil particles are removed, to be deposited in low
                                    .,1-7

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lying areas.   Naturally rill and gully erosion occur also,  and  a  distinctive
feature of desert areas is the erosional pattern.

1.1.4  Vegetation
     The climatic divisions of the American desert of Meigs correspond very
                                                       78
well with the four regional deserts described by Shreve   and shown in Figure 1-1.
In each of these regions further subdivisions into mosaics of vegetation types
are made by plant association communities which are distinguished by distinctive
combinations of dominant species.  Desert perennial plants grow both singly
and more often in clumps, separated by bare areas of desert soil.  Often a
clump of vegetation contains more than one species of plant; as many as 10
                                                         81
different species have been recorded from a single clump.    The size and
spacing of the clumps are irregular.  Some plants, such as creosote bush (Larrea
tridentata) thrive in several desert areas but other plants are restricted almost
exclusively to a particular desert region.  These indicator plants are:
          Great Basin   —   Sagebrush  (Artemisia tridentata)
          Mojave        —   Joshua Tree  (Yucca brevifolia)
          Sonoran       —   Saguaro  (Cereus giganteus)
          Chihuahuan    —   Agave  (Agave lechuguilla)

     1.1.4.1  Great Basin Desert-
     Numerous mountain ranges are  scattered over  the Great  Basin resulting in a
sharp vertical zonation of  the  plant  life culminating  in either a xeric or a
mesic forest cover on the range tops.   The actual desert occupies the  floors of
the detrital valleys.
     The vegetation is a monotonous open  shrubland  with almost no cacti or large
plants.  A distinctive feature  of  the vegetation  is  the predominance of com^
munities which are very  simple  in  composition  or  have  as much  as 95 percent  of
                                        82
their  stand made  up of a  single species.    The commonest  dominants are shad-
scale  CAtriplex  confertifolia), sagebrush (Artemisia tridentata), rabbitbrush
 (Chrysothamnus  spp.),  blackbush (Coleogyne ramosissima),  and winter  fat
 (Eurotia  lanata).  Open  stands  of  greasewood  (Sarcobatus  vermiculatus)  are
found  on  the  saline  flats.   Indian rice grass [Oryzopsis  hymenoides),  indigo
bush (Dalea  spp.), fourwing saltbush  (Atriplex canescens)  and  a  number of
                                       1-8

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                    «

  GREAT BASIN DESERT
(I    1 MOJAVE DESERT
                                       SONORAN DESERT
                                       CHIHUAHUAN DESERT
Figure 1-1.  The North American Desert and Its subdivisions
             (after Shreve/b).
                             1-9

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herbaceous plants and perennials are also found.  Shrub coverage averages 24   -i
                                                                      4
percent in the various associations, with a range of 15 to 37 percent.
     The precipitation in several localities is higher than in any other part
of the American desert.  It ranges from 100 to 270 nun.  The winter temperatures
are low, and frequent snowfalls occur.

     1.1.4.2  Mojave Desert—
     This is the smallest unit of the American desert and lies almost wholly in
California, with a small wedge extending into both southern Nevada and north-
western Arizona.  Its elevated margins are delineated by the range of the Joshua
Tree (Yucca brevifolia).  The bajadas are mostly dominated by creosote bush
(Larrea tridentata), but communities of four-wing saltbrush  (Atriplex canescens)
and complexes of Grayia-Lycium, Lycium shockleyii and Ambrosia dumosa are
extensive.  On the northern edge Coleogyne ramosissima and Grayia spinosa are
dominant.  Shrub coverage averages about 16 percent ranging from 7 to 23 per-
cent.   More spring ephemerals are found because of the mild, moist winters.
     Annual precipitation decreases from 125 mm on the west to less than 50 mm
on the east, and occurs during the late winter.

     1.1.4.3  Sonoran Desert—
     The subtropical Sonoran is the most varied of the American deserts and
exceeds the other three deserts in the number and variety of its life forms.
The desert lies between sea level and about 1,000 m.  Above this upper limit
are isolated mountain masses that, due to orographic  factors, can receive as
much as 700 mm of precipitation per year yet be located within a short distance
of Larrea plains.
     More than half of the Sonoran Desert is dominated by plants with a stature
of less than 1.5m.  Almost pure stands of Larrea, Ambrosia, Lyeium and Atriplex
are found.  Larrea and Ambrosia dominate the lower portion of the desert but
they are joined by many shrub, tree, and succulent subdominants which become
more and more prominent toward higher elevations and  greater rainfall.  Often
two species, or sometimes three form the entire vegetation of an area.  On
plains and bajadas below 300 m elevation the total perennial flora rarely
                   Q 9
exceeds  10 species.    The most prominent cactus is the saguaro (Cereus giganteus)
Barrel cac'ti  (Echihocactus spp.), hedgehog cacti  (Echinocerrus  spp.), and prickly
                                    1-10,

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 pears  (Opuntia  spp.) are common.  Small  legume trees such as palo verde  (Cercidium
 floridum) and C. microphyllum) and  ironwood  (Olneya tesota) are prominent.
 Ephemerals are  of two kinds,  spring and  summer flowering because of the bimodal
 rainfall pattern characteristic of  the Sonoran.
              82
     As Shreve   notes,                       ;
          "With the prevailing simplicity of composition, it follows that
          the entrance or exit of a single species, or a great change in
          the relative abundance of two  or more species, may make a profound
          change in the physiognomy of the vegetation."
                   •t
     Precipitation ranges from almost nothing to 300 mm on the eastern edge.

     1.1.4.4  Chihuahuan Desert—
     The easternmost of the American Deserts is the Chihuanhuan Desert in the
 United States covering part of New  Mexico and Western Texas adjacent to the
 Rio Grande.  A  large island of Chihuahuan Desert flora occurs along the San
 Pedro Valley of Arizona, well away  from the main body of the parent desert.78
     The Chihuahuan is separated from the main part of the American desert and
makes no contact with other desert  regions.  To the north and east it grades
 into semiarid prairiej while to the west the Continental Divide separates it
 from the Sonoran Desert.  Larrea, common to the Mojave, Sonoran and Chihuahuan,
 is not continuous across the grassland that lies along the Continental Divide.
     The prevailing plants are low  shrubs, Larrea, Acacia, Prosopis or long leaf
 succulents, Agave lechuguilla, and Hechtia.  Several species of Yucca and in-
frequent cacti Opuntia are also found.  Dominance is shared by shrubs, succulents
and semisucculents.   The vegetation is most lush in the warm season,  and there
are no winter and early spring ephemerals as in the other deserts.
     Precipitation ranges from 70 to 500 mm,  and about 80 percent falls between
the middle of June and the middle of September.   Winter temperatures  are low,
with occasional periods of 30 to 72 hours of freezing.

     1.1.4.5  Desert Grassland—
     This arid biome is considered  in this chapter because the southern section
forms a division between^the Sonoran and Chihuahuan deserts and because some
                                                                   i
areas now classified as desert were once this grassland.   (The northern and
                                                                       98
western edges of the Great Basin Desert merges into the Palouse prairie   of
                                     1-11

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western Oregon and Washington.  Recovery in this area is similar to that of the
                                                           72
short-grass prairie detailed in Chapter 2.)  Shantz and Zon   believed that
precipitation greater than 300 nun per year was required to establish and maintain
the Aristida-Bouteloua grassland.
     The desert grassland has undergone significant changes in recent years.
In some locations grasses have been supplanted by shrubby vegetation, mesquite,
acacias and burroweed.  Clements19 believed that much of what is now desert was
once grassland before overgrazing destroyed the grass, but more recent studies
emphasize the interaction of overgrazing with climatic change.
     In the remaining Desert Grassland, annual precipitation ranges from 300 to
400 mm, with summer moisture slightly exceeding that of winter.

1.1.5  Desert Succession
     A desert ecosystem is obviously not a static system, but usually tends to
approximate a dynamic equilibrium or to fluctuate around a stationary state.
An ecological climax is an example of that dynamic equilibrium and the process
by which the equilibrium is reached is termed succession.  In order to understand
the effects of some environmental disruption, it is clearly important to distin-
guish equilibrium systems from those that have not yet even approximated steady
state.  Equally important is to  identify differences that may exist between
exceedingly slow changes, which  are hardly distinguishable from the equilibrium
state, and changes that are more or less rapid.  The rate of change is as  funda-
mental for the concept of ecological succession and development as is the  question
of whether the climax equilibrium actually exists.
     The concepts of Climax and  succession in desert areas will be reviewed in
the next sections of this chapter by identifying the empirical observations of
changes that have resulted from  natural and man-caused environmental perturbations.
     A caveat is required first  however.   It  is not universally agreed  that suc-
cession occurs in desert environments;  if  by  succession  it is meant that each  of
a sequence of communities alters or modifies  the physical  environment to be
favorable  for the next member in the sequence.  Shantz    considered  succession
to be  important as a  basis for recognizing and  understanding  plant communities.
                                                19  20                            1
Other  arid  land investigators, notably Clements  '    and Allred and  E.  Clements
stressed plant succession.  However, the  primary  interest of  these writers was
                                      1-12

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-in arid  lands, not deserts.   Shreve   cautioned  about  applying  the  succession
concept  to deserts:                                 ,-     •      ..-.
          In a consideration  of  the dynamic  aspects of the vegetation  of
          the region  in which the  initial, sequential  and final  stages of
          a succession are characterized by  the  same species, and often by
          the same individuals,  it is doubtful' whether'these conceptions,
          formed  in regions with a .very dissimilar vegetation,  are  of  much
          real utility.                      ,,'              '  '  '        "
     Muller   was in  general  agreement and found no serai succession in recovery
of disturbed Chihuahuan Desert.  Muller also noted that  often the definition of
climax and the serai  stages leading to it are made to  narrow that very little
of the earth's surface may be said to be in  climax condition.
     Some features of recovery and succession after the  proposed cleanup pro-
cedures  are qualitatively similar  to ecosystem recovery  after natural,  or man-
induced  vegetation changes which have been documented  for desert areas.  These
features are presented in the next sections.

1.2  NATURAL PERTURBATIONS

1.2.1  Natural  Processes
     Succession on naturally  disturbed desert habitats such as washes  which
are periodically  scoured by floods, actively eroded bedrock areas,  or  flood
                             ;       *. •   '             -  gg        •     :;._,...,
deposition on bajadas, has been  studied little.  Wells  .noted that the charac-
teristic shrubs of these natural disturbed areas, Thamnosma, Hymenoclea, and
Salazaria, can be established in man-made disturbed areas and play  a role ,
similar  to that of pioneer successional plants of more humid areas.
     Campbell has described natural vegetation succession in wind-formed hollows
(blowouts) between mesquite dunes  as following five sequential  stages.    The
sequence only operates during a  succession of favorable, i.e., wet, years.  (The
major mesquite growth is in the  spring when  other perennials are practically
dormant.)  The first  stage is the  Mat Stage.  If moisture has accumulated in
the blowout, species with a prostrate habit  such as Tribulus become established.
If moisture continues, either in the same or the following growing  season a
Weed Stage begins, Ambrosia for  example.  This stage results in a gradual
decline  in sand movement as the  root systems develop.  The third stage is the
                                    lv-1'31

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Gutierrezia Stage,  usually in the following growing season.   At this point  all
of the plants of preceding stages are found.  Together they have a. generalized
drought-resistant root system.  Wind and sand erosion is reduced and leveling
of the dunes along with sand deposition in the blowout area begins.  If two
or three years of above-average moisture have occurred the Sporobolus Stage
of grasses begins.  This is followed by a Bouteloua climax.  Succession to the
fourth stage requires three to four years of ample rainfall.  No estimate was
given of the time to climax.
     Muller studied succession, or rather a cyclic phenomenon, in a Larrea-
Ambrosia association in the Chihuahuan Desert.    In this area erosion removed
the climax association and all existing soil down to a clay hardpan.  Muller
noted that succession, indeed plant growth, could not occur until the clay
weathered and until a few inches of sand and gravel were washed from adjoining
plains.  The general sequence of recovery noted was shallow rooted grasses,
sparse shrubs tolerant of a slight soil covering over the clay, dense shrubs
as the soil deepened, sparse  representations of Larrea, the climax association.
No time for this process was  given.  At the time of climax all the  species of all
of the stages were present  leading Muller  to reject the idea  of succession in
desert scrub.

1.2.2  Fire
     Fire  is known to influence  desert plant distribution.  Controversy  exists
regarding  the role of fire  in maintaining  desert grasslands,  that is,  the  des-
ert grassland may be  an  artificial biome  (a disclimax)  initiated  and maintained
by man.   If  this  is true,  artificial manipulation  of  deserts  might result  in
grassland.   Numerous  writers68'87 have  hypothesized that  grasslands are  a  product
of repeated  fire set  by  primitive man.  Humphrey40 among  others9 has applied
this  hypothesis to desert grasslands,  largely on the  historical evidence that
areas  now desert were formerly grasslands, which through a combination of over-
grazing  and  fire suppression continued to desert climax.   The theory says  grass-
 lands were maintained by frequent fires which prevented establishment of seeding
 shrubs.   Once the sequence of fire  was broken, by overgrazing and fire suppres-
 sion,  seed bearing shrubs became established and a self-perpetuating, irreversible
vegetation change began.
                                     1-14

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     The incidence of fire in the past compared to the present is a critical
point.  The controversy has been reviewed by Hastings and Turner35 who conclude
after examining travel journals of 22 early explorers that fires did not occur
frequently in the desert grassland in the past—although it is noted that fires
may have been locally important.  They cite other factors which will be dis-
cussed later as cause of the decrease in size of desert grasslands.
     There is an extensive literature of the effects of burning on desert vege-
tation.  Although .these studies report intentional man-caused fire rather than
natural perturbations, they will be discussed here.  The major thrust of these
studies was range improvement by using fire to remove undesirable brush and allow
grass and palatable forage species to grow.  (This work shows implicit belief
in the fire theory of desert grasslands.)
     The results appear to be contradictory.  Humphrey41 found that burning prior
to the spring rains killed burroweed (Haplopappus spp.), partially controlled
mesquite and favored perennial grasses.  Pickford57 in the Great Basin desert
found that burning destroyed sagebrush and allowed grasses to increase and a
more recent work   indicates that forage species and grasses are increased
about 70 percent three years after burning.  Reynolds   obtained conflicting
results for a June burning of Great Basin vegetation.  The density and produc-
tivity of the area were reduced and remained below control areas for three
growing seasons.  The first year productivity was down 50 percent and the next
two years down 10 percent.  The treatment did kill 90 percent of the burroweed,
half the cholla, and one-quarter of the prickly pear.
                          46
     Longstreth and Patten   have developed a model which postulates a number
of interacting factors that result in increased water and nitrate loss as
brush is converted into grassland.  The loss of soil nitrate would result in
decreased productivity which agrees with Reynolds observations.   It has been
noted that on heavily grazed ranges fire had little effect on the proportion
of grasses to forbs, but on lightly grazed ranges fire significantly reduced
grasses and increased forbs.     This also might explain some of the conflicting
results noted of the effectiveness of brush burning on range improvements.
     The effects of fire>are not permanent.  The perennial vegetation of many
desert plants resprouts from the root crown of a pre-fire plant, then grows at
                                     1-15

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the rate normal for the plant species.  The time for complete recovery is
unknown; however 40 to 50 years, about 1/2 of the life span of desert plants,  may
be a good estimate.  '    Range reclamation experts recommend three to five-
year intervals between burnings to minimize undesirable species, but no indica-
tion is given of the amount of recovery to the pre-burn condition during this
time.  Beatley  measured vegetation parameters on adjacent burned and unburnsd
plots in Grayia-Coleogyne and Coleogyne associations in the Mojave-Great Basin
transition.  The plots had been burned 13 and about 22 years prior to her study.
The burned areas were quite distinctive and easily seen in the vegetation mosaic.
The cover of herbaceous perennials in the burned area was only 20 percent that
of unburned plots; however, winter annuals increased by a factor of 2.5 and
grass (Bromus) was increased by a factor of 3 in the burned plots.
     Pechanec recommended burning of sagebrush range in the late summer or early
fall after the seeds of perennial grasses had matured.    The spring was recom-
mended by Semple as the best time to burn, for then the soil is damp and losses
of organic matter were not likely to be great.    The principle appears to be
avoidance of detrimental effects on the perennial seed.
              58 59
     Piemeisel  '   made detailed studies of the early stages of secondary
plant succession after fire in the Great Basin desert.  He notes that the original
sagebrush dominated cover was exceedingly complex.  The community was composed
of perennials with bulbs, tuberous roots, and rhizomes and perennials forming
mats, rosettes and tussocks.  Most growth is made between October and July; the
time of autumn rains and the beginning of the next hot summer.  Growth is inter-
rupted by winter cold and terminated by summer heat.  The annuals grow in spring
and summer.  The successional order is first Russian Thistle (Salsola spp.), then
mustards (Sophia parviflora or Norta altissima), then downy chess (Bromus
tectorum).  These successional changes usually take place within five or six
years.  Grazing by livestock or rodents may result in holding the vegetation
at one of these lower stages and retarding or preventing the reestablishment of
perennials.
                                     1-16

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 1.2.3  Climate
      Long term climatic fluctuations  which influence vegetation are well  docu-
 mented.   For example,  a synchronous change from  juniper  and  pine woodland to
 desert grassland occurred about 8000  years ago in the Mojave,  Sonoran  and
 Chihuahuan deserts,  probably associated  with changes in  global atmospheric circula-
 tion patterns influenced by the melting  of continental glaciers.92   Shorter term
 and more recent fluctuations are more pertinent  to predicting  desert ecosystem
 response to cleanup  operations  since  rainfall, the major variable in climatic
 change,  is also the  critical determinant  of both desert  vegetation  community
 type and speed of recovery.
      Studies of tree rings  have documented 25- to 60-year periods of moist  cool
 climates interspersed  with  dry  warm climates  in  the southwestern deserts  since
                  J f.  O S3
 the 15th century.  '     These studies  show climatic anomalies  to be  of non-
 uniform  geographic extent.   For example,  in the  early to  mid 1600's  the Mojave
 and large  portions of the Great,Basin  deserts  experienced a climate  warmer
 and drier  than  usual while most  of  the Sonoran and  eastern Great  Basin were
 normal,  and  the Chihuahuan was  cooler  and  moister  than usual.27
     Recognition of the  existence of these  climatic  fluctuations  helps to  inter-
 pret apparent historical vegetation changes and  their causes.  A  number of
 authors  have noted that the change  from desert grassland  to desert in the  late
 1800's coincided with a marked  increase in man's use  of grassland as cattle range,
 and have speculated a cause and  effect relationship between overgrazing and the
decrease in grass cover and increase in desert shrub vegetation.14'32  Hastings
and Turner   documented the influence of climatic change on this massive shift
 in regional vegetation and concluded that the new ecosystem was a response to
the unique combination of climatic and cultural stress.  Climatic change reduced
soil moisture to a level below that required to establish new grass.  Over-
grazing contributed to the imbalance between infiltration and runoff through
compaction of the soil  and removal of existing grass.
                                       1-17

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1.3  MAN-MADE PERTURBATIONS

1.3.1  Fencing
     Studies of evidence of vegetation change resulting from the exclusion of
livestock from formerly heavily grazed land are abundant.  Shreve recorded
                                                      77                       81
changes in Sonoran vegetation 22 years after exclusion   and again at 30 years.
He noted a general increase in plant population, that is, the number of species
remained rather constant over the years but the total number of plants increased.
The increase in the first 22 years was greatly exceeded in the next 8 years.  No
                                              Q
evidence of succession was found.  Blydenstein  followed Shreve's work at 50
years.  He compared the original enclosures with nearby control sites.  In both
the protected and unprotected sites the same species grew and in the same order
of abundance.  The most notable change was an overall increase in density of
vegetation in the enclosed areas.  Grasses and shrubs were beginning to replace
Larrea.
     Gardner,30 reporting after 30 years of protection, found grass density about
twice as great in the enclosed area.  A more recent study of only 10 years'
duration   noted no vegetation change.  The authors speculated that soil compac-
tion by grazing animals and/or erosion might account for the absence of effect.
                  Q *zr\
     Other authors     believe that it is soil erosion more than any other
feature that is responsible for the many instances of slow recovery following
livestock exclusion.  When there has been little or no erosion and the original
plant species have not been entirely removed, protection from grazing may lead
to a rapid change in species composition and an increase in palatable (to cattle)
        34
species.
     To test the effect of rodents on range quality Brown   established plots
that were grazed by cattle and rodents, by rodents only, and ungraded by both
cattle and rodents.  He found that mesquite and Opuntia  increased for all treat-
ments but the poisonous shrub burroweed (Haplopappus) decreased under total
exclusion.  Morris53 found that excluding rodents increased the density of
native perennial grasses.  A more recent study on 0.3 ha plots  indicates that
seed-eating rodents and ants are  in direct competition  for the  available food
supply.  The exclusion of either .taxon results  in an  increase  in numbers and
                                     1-18 •

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 bioraass of the other than results in a compensatory impact on plant population.
 When both fauna populations are excluded a 2- to 5-fold increase in plant density
 is noted.^
      It has been speculated that the existence of a fence leads to increased
 animal utilization along the fence line, resulting in soil compaction and vege-
 tation removal,  Hansen33 showed that cattle do not graze more closely and tram-
 ple the vegetation near a fence than they did a hundred feet  or more away.
      Fences can act as  protective as well as excluding landscape features.  Elk
 in Washington have been restricted to the Cascade Mountains in historic times.
 However,  they recently  moved onto the ERDA Hanford research site which is fenced
 and not subjected to livestock  grazing.64

 1.3.2  Overgrazing
      The  effects  of cattle  grazing on desert grasslands have  been extensively
 studied,  but  it is not  always clear whether  the  observed effect,  characteristically
 an increase  in  density  in unpalatable shrubs and  a decrease in perennial  grass,
 were  due  directly to  grazing or  to associated factors,  e.g.,  soil  compaction by
 the grazing animal.   Most of the  literature  deals  with  the  role of livestock in
 promoting shrub invasion of grassland.   Hastings and Turner35  have summarized
 these  studies and  classified them to  emphasize four ways  in which  domestic
 grazing animals have  been thought  to  contribute to  the  spread  of woody  plants.
 The animals may act as  disseminators  of  seeds, may reduce  competition by
 selectively removing  one species  which inhibits growth  of  another, might  serve
 as a  fire suppression by removing  the grass  fuel from an area,  or  might reduce
 the moisture  content  of the upper  layer  of the soil by  compaction.
                          18
     Christian  and  Slatyer   have  suggested  a sequence of events which  follows
overgrazing and leads to irreversible (within human memory) change in vegeta-
tion.  First, a depletion of perennial grass occurs, followed by wind erosion
and a reduction of  surface litter.  The result is  increased rainwater runoff,
decreased water penetration, and higher soil temperatures.  All of these factors
create a more arid microclimate which inhibits re-establishment of the original
vegetation.
     The effect of grazing on lands that are now desert is  less well studied
than the effect on desert grasslands.  Total primary productivity  is low^in
                                      1-19

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                                                                         Over-
desert areas and the grazing pressure on the most palatable species is high.*
However, a characteristic of shrubs that persist in arid lands is adaptation ;to
stress.48  Rapid regrowth is a characteristic that enables shrubs to dominate
desert areas.  A number of shrubs are known to increase primary productivity
and produce more new shoot growth when defoliated or closely cropped.
grazing can also lead to a change in species composition and introduction of
non-native species.  Pechanec56 reported overgrazing of sagebrush  (Artemisia
tridentata) in the Great Basin desert has led to the introduction of cheat-
grass  (Bromus tectorum) at the expense of native perennial grasses.  If more
species are removed than introduced, ecosystem stability will be lessened.
     McKell48 has noted that the worth of any shrub species can only be deter-
mined  by assessing its relation to  the major ecosystem and the extent  to  which
user groups depend on  it.  Thus changes  in  species composition are not necessarily
detrimental but must be evaluated  in relation to  land use.  For example,  the salt
desert shrub community in the Great Basin desert  moves toward dominance by  black-
sage  (Artemisia nova)  when protected from grazing, while  intense winter grazing
promotes an  increase in shadscale  (Atriplex confertifolia).    This  is not  an
                                 48
undesirable  change for a rancher.
1.3.3  Mechanical Disturbance
     The effects on vegetation of compaction of non-agricultural desert soils by
vehicles or animals, and by land alteration through blading or plowing, are
generally specified by empirical observation rather than experimental measure-
ment.
     Almost any mechanical disturbance of the soil results in compaction since
no soil is free from susceptibility to compaction.  The magnitude of the compac-
tion affects the rate of vegetation recovery.  Compaction invariably results
in long lasting visible effects.  Jeep and tank tracks from desert training
early  in World War  II are prominent in the Mojave, and Indian trails and wagon
 *The definition of  "most  palatable"  is  obscure  since  relative  shrub  abundance
  and local  environment  may  modify  animal  preferences.   The  phenomenon  of  "scarcity
  improves palatability" is  well  documented  in range management.48
                                     1-20

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45
                                             or.
tracks of the last century can still be seen.    Although compaction slows
recovery, natural processes eventually mitigate the effect.  For example,
although the streets of 19th century mining towns are still clearly visible,
vegetation succession is occurring.            '
     The primary effects of compaction are a greatly reduced soil pore space and
increased bulk density which alter the relative amount of soil components present
in a given volume of soil.  These processes lead to a decrease in water infiltra-
tion, a decrease in water storage capacity and restricted air movement.  This
damage to soil structure severely impairs plant growth through decreased soil
moisture and by limiting root penetration.  A reduction in pore space from 55
                                                           29
to 34 percent has been shown to eliminate all plant growth.
     The secondary effects of compaction are changes in microclimate, since soil
bulk density and thermal capacity are increased while diffusivity is almost
unaffected.  Soil temperature changes of -7°C have been recorded in compacted
vehicle tracks (vegetation removal increased temperature by almost the same
amount indicating a dynamic interaction between the effects of these processes)
Changes in microclimate can affect the germination of seeds.
                                                                         99
     Few data are available on recovery of compacted desert areas.  Wells
showed possible succession in compacted areas.  Gardner   and Buffington
speculated that compaction, and subsequent erosion were major factors in inhibit-
ing regrowth in disturbed areas.  Figures 1-2 and 1-3 show the persistence of
compacted areas in the Great Basin and Mojave deserts.
     Recovery of plowed and furrowed desert land is somewhat better documented,
however.  Rickard and Shields  ' measured the early stages of recovery on 2.5 ha
plots denuded of vegetation by removing the surface 7-30 cm of soil with a bull-
dozer.  After two years no shrubs had reappeared.  Annuals were less abundant
than on adjacent undisturbed areas.  This was probably related to the removal
of seeds with the surface dirt.  Since annual growth is highly correlated with
rainfall and seeds can lay dormant until climatic conditions are optimum for
growth, the surface might contain the seeds from the previous three or four years'
production.  Bunchgrass (Oryzopsis) was present only when the roots of the pre-
disturbance plant had not been completely removed.  The authors concluded that
mechanical soil and plant removal were more deleterious than plant destruction
by atomic tests.

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Figure 1-2.  Great Basin Desert roadway unused for
             of compaction are evident.  (Photo courtesy of UCLA.)
                                                 years.  The effects
Figure 1-3.
                  Mojave Desert roadway unused for 17 years.   (Photo
                  courtesy of UCLA. )
                                  1-22

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      Abandoned farm land in desert areas generally follows the pattern of
 invasion by Russian Thistle (Salsola)  during the first growing season, then
 the replacement of Salsola by grass,  beginning in the second growing season,
 and.finally the gradual .reestablishmerit of the original brush vegetation.59
 Gardner   shows that thirty-years of  protection were not.enough to. erase
 the visible effects of plowing.   Since soil is'known to be" compacted by improper
 tillage,    compactionris probably the'effect, noted.   A disc harrow will compact
 soil  at shallow depths (7-10 mm)  while heavy machinery and trucks will drastically
 compact the upper  12-15 mm.   Plowing  often compacts  soil at the plow depth.
      Mechanical land alteration  can also be beneficial to  desert vegetation
                   '.  -  •     11 "; -     '       ''           '     '  •         •' '
 recovery.   Brown and Everson;   found that primary productivity on a ten year
 old furrow  in  the  Sonoran desert  was two and one half times greater .than on the
 intra-furrow areas.   The furrow  impedes runoff, increases  infiltration and
 reduces evaporation.   Figure  1-4  shows  this effect.   These factors combine  to
 increase available  soil  moisture  and increase localized plant growth.   This
 technique of land  surface manipulation  is used  to assist the  recovery of mine
 spoil banks  where different  surface topographies—deep chiseling,  offset
 listering,  gouging  and  basin  construction—are  routinely used.90  It is also
 employed to  contour  water catchment basins to assist  agricultural  production
 in  desert areas.     Occasionally  a  catchment  basin is inadvertently created.95
 Figure 1-5  shows an  unplanned catchment .basin and Andicates how-plant  growth
 is  enhanced^by  the  slight  extra water.   Figure  1-6. indicates  that  the  increased
 water from roadway runoff can c'punt.eraet  the  effects  of'compaction in  desert
 soils.  '     •''•..    ' '     .      '.'•.:          '•-'•'   "   • .'    •••'••.;
1.3.4  Atomic Test Target Areas
     Atomic test and associated construction activities at the Nevada Test Site
have produced massive, and often-repeated, environmental perturbations,  A
typical surface or low altitude atmospheric detonation would destroy, by blast
and thermal radiation, the vegetation in a circular area of 2-3 km2.  An under-
                                    2                     ''-'.-'
ground detonation could cover ;3-4 km  of desert with dirt ejected from the crater.
In addition, large areas would be cleared of vegetation or leveled to accommodate
diagnostic test equipment.

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Figure 1-4.
                  11 years .after blading and forming windrows.
   fence at right encloses an area which has excluded grazing
     s for 11 years.  (Photo courtesy of UCLA.)
Great Basin Desert
The fe
animal

 Figure 1-5.
Mojave Desert.  An unintended water catchment basin in a dis-
turbed area.  This basin concentrated the sparse moisture to
allow plants growing within it to become better established
than in the surrounding area.  (Photo courtesy;of UCLA.)
                                    1-24

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      Figure 1-6.   Mojave Desert.   Larrea growing in compacted area alongside
                   asphalt roadway.   Mojave species can reestablish themselves
                   on disturbed areas if sufficient moisture,  such as runoff
                   from highway, is  present.   (Photo courtesy  of UCLA.)

     Three  circular  zones of damage  have been  identified around  an  atmospheric
test burst  point.    The first  is an area  about  1  km  in diameter where all
surface vegetation has been eliminated by  blast  or fire.  The  inner 0.2 to  0.5
km portion  has had the seed containing layer of  soil  removed by  blast winds.
The second  is an area extending about 1 km beyond  the  first zone where the
perennial brush is broken but grass  survives relatively unharmed.   Finally,
there is an area of  shrub survival.  This  last area may respond  to  ionizing
radiation effects in the following growing season.62'63
     The immediate injury is attributable to mechanical and thermal effects;74
however, recovery may be influenced by ionizing radiation.   Radiation has, been
suggested as "stimulating" the growth of annuals,3 or conversely as causing
no observable effect.
     The pattern of revegetation is well documented3'67'74'75'76 and the early
stages proceed faster than recovery on bladed areas.76  During the first year
the inner portion of the barren zone is sparsely populated  by  annuals, evidently
from seeds introduced naturally.  In the outer portion of this'zone the ground
cover by annuals exceeds the total coyer ,of nearby undisturbed areas, possibly
                                     1-25

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because of the lack of competition with perennials for the available moisture.
As the spring annuals die, the summer maturing Salsola dominates.   Beyond the
perimeter of denudation recovery occurs through the crown sprouting of the
shrub species.  In the second to fourth year the species composition of
annuals changes.  Grasses begin to dominate and the area resembles the grass-
land scars of natural burn areas.  Sal.tbrush (Atriplex canescens), a characteris-
tic species of roadsides, sandy washes and other disturbed areas,  becomes
abundant.  The short term changes in vegetation are analogous to the succession
                 qq                        74                               j
observed by Wells   in a deserted townsite.    After twenty years, summer and
winter annuals were found to be abundant, but there was virtually no recovery
of the original perennial shrubs.  The few shrubs which persisted were
                         67
apparently crown sprouts.
     Little work has been done to document the vegetation recovery on crater
ejecta.  After nine years, Romney   reported that Salsola and summer and winter
annuals were abundant except where the ejecta was "too thick," and speculated
that the soil moisture infiltration rate on the loose dirt was too great to
support vegetation.

1.3.5  Restoration
     Attempts have been made to  transplant  seedlings  and  rooted cuttings of
shrubs to  speed the process of revegetation.   '     It was concluded  that without
supplemental  irrigation transplanting  perennial vegetation was a  futile effort.
Plant response  and climatological behavior  indicate that  at  least  two  and perhaps
three consecutive years of favorable  soil  moisture  are necessary  for sage
 (Artemisia tridentata) seedling  survival.     In one experiment where additional
moisture was  supplied  to  each transplanted  plant,  small animals destroyed all
unprotected plants within a  few  weeks.     Construction of topographic  features
which concentrate available  natural moisture  appears  to be the most  practical
method of  speeding recovery.

 1.4  EFFECTS  OF CLEANUP  PROCEDURES  ON DESERTS
     A number of cleanup  techniques  are available which vary in cost and  efficiency.
 This  section  will  list some  of  these  techniques  in the  order specified by the  EPA
 and will:   (1)  explain the  technique;  (2)  discuss its effect on the local ecology;
 (3) indicate  the closest  analogy to  vegetation succession and recovery from some
 natural  or man-induced environmental  perturbation;  and  (4)  discuss the effect  of
 increasing treatment area.
                                      1-26

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       It  is assumed that the methods used  in  construction  industry and  in  farming
 to protect the  surrounding areas  from  harm,  especially  from  erosion or the de-
 position of eroded material, will be used.   This will generally require the
 construction of silt dams and diversions.

       (1-1)  Chemioal Stabilizers
       The general purpose of chemical stabilizers is to  bond  the surface soil
 particles together to form a protective layer and isolate the subsoil from erosion
 due to wind or ,rain.  The procedure often accompanies construction or road build-
 ing activities'.  Chemical stabilizers could be used to  immobilize a contaminant
 for a short (one to two years)  period with a single application,  for longer time
 periods with periodic application, or they could be used in conjunction with
 other cleanup techniques (e.g.,  scraping)  to increase the effectiveness of the
 technique by bonding the contaminant to easily removed clumps,  or to'ameliorate
 the erosion effects after the  cleanup,  especially on steeply sloping areas.
 Vegetation is  normally removed prior to treatment in construction  activities;
 however,  most  of the  chemicals,  especially the polymer emulsions  or  resins,  could
 be  applied  over vegetation  if  it was necessary to quickly immobilize the  contamina-
 tion.

      Appendix A lists  the chemical stabilizers preferred for  desert  areas.  They
 include oil and  latex  polymers,  polyacylamides (PPA),  polyvinyl alcohol resin
 adhesives and other resins and polymers.   These preferred  treatments generally
 have  an effective life of less than  one  year.  Other chemical agents such  as salt,
 sodium hydroxide, sodium carbonate,  or  iron chloride,  also cause aggregation of
 soil  particles.  The ecological  effect  of  these deflocculants is dependent on  the
 soil  ion exchange capacity and is highly area  specific,  thus  will not be dis-
 cussed here.  Attempts to stabilize Pu contaminated soils at  the Nevada Test Site
 with deflocculants have been reported.95
     The soil bonding produced by the chemical stabilizers will reduce moi-sture
 infiltration and increase rain runoff.  The chemical surface  will also form a
mechanical barrier to seed germination.  Some types of treatment will result in
absorption of solar energy and an increase in soil temperature.   The increase may
be great enough  to inhibit seed germination as the chemical surface begins to
degrade;  however, this is unlikely since desert plants are tolerant to high surface
temperatures.
                                    1-27

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     The ecological effects result  from changes in available  soil  moisture.  Water
runoff from the impervious surface  will increase vegetation growth on areas
immediately surrounding the treated area,  much like vegetation growth is enhanced
next to desert roads (Figure 1-7).   Care must be taken that this runoff does not
erode the soil from adjoining areas.
     If vegetation is not removed prior to treatment, bunchgrass and perennial
growth will continue during the next growing season, either by normal branch
sprouting or,  if the treatment kills the above-ground portion of the plant,  by
root crown sprouting.  Since moisture will be able to enter the soil at the
junction of the plant trunk and the earth, increased growth should occur since
much of the available moisture will be channeled  to the shrub, and the treat-
ment will eliminate competition from nearby  ephemerals while reducing soil
moisture evaporation.  Ephemeral vegetation  and annual grasses will not appear
until the surface  begins  to degrade.  This might  be the next growing season or
the year following, depending on the time of year of treatment application.   In
    .
     Fiqure 1-7.  Mojave Desert.   The effect of increased moisture
                  roadside cut on Larrea growth.  (Photo courtesy of UCLA.)
                                      1-28

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 time, about a year depending on the chemical selected,  cracks will develop in
 the surface.  Moisture will concentrate in these cracks and allow .germination of
 seeds resulting in localized vigorous growth which will accelerate the breakdown
 of the surface.  Moisture concentration at the cracks may have a deleterious effect,
 If heavy rain occurs prior to the breakup of the crust  and the establishment of
 annuals, erosion can begin under the crack area.  The probable results would
 include faster breakup of the crust, gully erosion in the treatment area possibly
 exposing hardpan and a change in the drainage pattern.
      Although the effective duration of most chemical treatments is about a year,
 clumps of stabilized soil,  5-20 cm in diameter will  persist for longer periods
 of time.  Recovery of the area, compared to surrounding areas,  depends on re-
 covery of the ephemerals and grasses,  which in turn  is  related to the  breakdown
 of the clumps of stabilized material.   This should occur within three  to five
 years after treatment.
      If the vegetation  is removed  prior to treatment, recovery of bunchgrass and
 perennial  shrubs will proceed from the underground portion  of the perennial
 vegetation as the surface degrades.  The area  will recover  full  biological
 productivity within three to five  years except  where  the  soil  has been  compacted
 by the brush removal or chemical application equipment.   The  treatment  area  will
 be visible until  the perennial  vegetation  achieves full  stature—about  twenty
 to thirty  years.   The compaction effects of the  heavy equipment  will be  visible
 for a  longer time.                                              .
      If the  chemical layer  is not  toxic  to  animals it will not  inhibit  the
 burrowing  activities of rodents; moreover,  the burrowing might bring to  the
 surface  the  material the  chemicals were  intended to bind.   If the area  is
 relatively small,  i.e.,  1 ha, the rodents will probably not be displaced but
 will forage  for food outside the treatment  zone.   If the treated  area is larger
 than the animals' normal  forage range, about 50 m for pocket mice to 100 m for
              2 25
 Kangaroo Rats,  '   a migration  to other  areas can be expected.  The effect
 of  this migration on the  surrounding area would be difficult, if not impossible,
 to measure.   It is generally hypothesized that: desert rodent species diversity
 is directly related to precipitation, through the relationship between precipita-
 tion and primary production.    It is doubtful whether the surrounding habitat
 could support the additional population.  The weaker members would die off.
As vegetation reappears in the treated areas, animals will return.  Desert rodents
                                    1-29

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 of different  species  harvest  different  sizes  of  seeds  and  forage  in different
 microhabitats.12   Since there is little evidence of sequential desert vegeta-
 tion succession,  there should be no change in animal species  diversity  as  the
 treated area  is recolonized.   If vegetation is removed however, changes in rodent
 diversity might be expected until the area is well along toward full  recovery.
 This point is discussed later,
      Progressively greater care must be exercised for the larger  treatment areas
 to handle rain runoff.  If the largest areas are treated on a routine basis over
 a number of years, ground water recharge will be inhibited.  The  effects must
 be estimated for each individual case.

      (1-2)  Clear Cutting Vegetation
      Vegetative cover can intercept part of the deposit of an airborne contaminant,
 and removing vegetation might remove a considerable portion of the contaminating
 material while also inhibiting transfer and possible concentrations through food
, chains.
      A number of methods are available for vegetation removal.  Hand hoeing and
 shovel cutting would be applicable for the smallest area, or for steep hillsides;
 however, mechanical techniques would be required for  larger areas.  These mechanical
 techniques include cabling and anchor chaining  and  are common in range improve-
               31
 ment programs.
      In cabling,  a 45  to 60  m long 3.75 cable is dragged  between two tractors
 traveling on parallel  courses.   The  cable  breaks off  or uproots brush.  Cabling
 can be used where the  brush  breaks easily  and is not  willowy.  The technique
 results  in little effect on  perennial  bunchgrass  and  usually  leaves the
 A soil horizon and humus at  the  base of the  brush  intact,  an important considera-
 tion for  revegetation.
      Anchor  chaining  consists of dragging  a  heavy (up to  50  kg per link)  chain
 through  the  vegetation to  break or uproot  plants.   The general procedure  is much
  like cabling  but the  ground  is more disturbed,  the underbush humus is  usually
  scattered, and soil  stabilizing algae clumps are broken.   Chaining will  clear
  brush  up to  the  size  of small trees.  The spacing of the parallel  tractors,
  and thus the spacing of the  compacted areas, is dependent upon density of
                                      1-30

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 vegetation, weight and length of chain, size of tractor, bite of tractor tread,
 and ground slope.

      The effects of hand removal would be relatively benign.  Most perennial
 vegetation would resprout in the following growing season.  The seeds of annual
 vegetation would not be disturbed.
      Soil compaction by the mechanical equipment would be the major deleterious
 effect of mechanical removal.   Broken perennials would resprout from underground
 plant parts.   The summer annual forb Russian Thistle (Salsola)  would invade the
 area, especially the chained area,  the following summer since Salsola only
 germinates where the soil surface has been scarified.94  Salsola roots cannot
 penetrate compacted soil  and would  thus be restricted to areas  between the
 tractor paths.   Winter annual  grasses (Bromus)  and the Salsola  might delay re-
 vegetation of the areas by native species  by their effective use of available
 soil  moisture.   Salsola can thrive  at below normal desert rainfall  levels;93
 with  normal rain annual grasses,  followed  by native ephemerals,  would become
 established.   Recovery would be more  rapid than if the seed  containing layer of
 soil  were removed.
      Erosion  by  wind would  be  a major problem until the annual  vegetation  or
 algal mat  was reestablished, .or until  natural soil compaction by rainfall  occurred
 This problem  is  largely non-ecological  however,  since  the main  effect  of eolian
 erosion  is .the removal  of the A horizon of soil, which  virtually does  not  exist
 in desert  soils.  The major  danger would be  due. to winds  spreading  the  con-
 taminant beyond  the treatment area.   Dust  from  the  area  should produce  no  lasting
 effects on the surrounding vegetation;  however,  10  km2  denuded of vegetation
 could produce a  highly visible and undesirable  dust cloud.
     Vegetation removal is likely to affect microclimate.  The low-level wind
 speed profile will be changed due to changes in aerodynamic roughness.44  This
change will lead to increased evaporation,  increased soil temperature and de-
creased humidity.  These will affect both the revegetation of the treatment area
and the plant growth outside the area.23
     Temporary food reduction would be the  major effect on animals.   This effect,
like chemical  stabilization, will increase  with increasing treatment area.
                                    1-31

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     (1-3)   Stumping and Grubbing
     This procedure would produce a drastic perturbation on the desert  area,
and would probably only be used in conjunction with another cleanup technique if
it were desired to restrict the regrowth of perennial vegetation.
     Desert plants have extensive root systems.  The ratio of root to top of
plant varies from 0.5 to more than 4, and the majority of plants have a greater
biomass below ground than above.    The structural roots systems range from
massive tap roots and secondary root systems to filamentous systems.  The depth
of roots somewhat depends on the depth of hardpan or caliche deposits,  but unless
these deposits are shallow most roots will extend to a depth of 1 m.  Creosote
bush roots are known to extend 2m.
     Roots can be removed by hand.  However, mechanical methods would probably
be employed.  A backhoe or crawler type tractor with a "hula dozer" blade can be
used to remove root systems.
     The major ecological problems are again associated with soil compaction by
the equipment.  However, the earth disturbed while removing the roots could
cover the annual-seed containing layer of soil and slow the initial stages of
natural recovery to two or five years.  If caliche were brought to the surface,
it could form a pavement-like crust that might further restrict plant growth.
     The treatment will destroy rodent burrows and probably result in immediate
death to a great portion of the  local rodent population.  Long term effects
will be related to the destruction of the food supply.  Beatly  has shown that
in Southern Nevada the dominance order of some heteromyids changes following
brush removal or ground clearing,  i.e., replacement  of Dipodomys microps by the
smaller D. merriami.  She  suggested an animal vulnerability to elimination by
predators of the larger  species  where there  are  few  shrubs in  the  environment.
     The environmental  effects  will  scale with the  size of the area:  the greater
area disturbed, the  greater the effect.
     Areas  of the  Great  Basin and  Chihuahuan deserts which receive more  than 250
mm of annual precipitation could be  reseeded with grass to result  in desert  grass-
land;   however, the  prognosis  for recovery  within a human generation in  other
desert  areas  is poor.
                                      1-32

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      (1-4)  Sapopinff and Grading
      The upper layer of soil to about 5 cm depth along with the contaminant would
 be removed by road grader, land scraper, bulldozer or vacuum cleaner.   This is a
 drastic perturbation on the desert environment since it removes the small amount
 of A horizon soil that exists under brush and also removes the seed containing
 layer of soil.  Wind and water erosion potential would be maximized and a further
 deleterious effect would be soil compaction by the earthmoving equipment.
      Under most circumstances the above ground portions of perennial vegetation
 would be removed with the soil layer.   However,  it has been suggested  that leaving
 200-800 shrubs per ha would speed recovery by providing seed for natural  re-seed-
 ing.     Desert perennial plant density normally ranges from 400 to  3000 plants
 per ha.     Thus,  between one half and  one quarter of the perennial  shrubs would
 remain  if this suggestion is followed.
      If both soil  and plants are removed,  some resprouting of shrubs could be
 expected;  however,  the treatment would  remove all  traces of bunch grass.   The
 revegetation sequence of Salsola,  annual  grasses,  native annuals, and  the
 gradual  ^introduction of perennial  species as outlined  in Section  III  would
 occur.   Recovery would be  slow.  Animal  recovery would  be  expected  to  follow
 plant recovery.

      If  some  shrubs are  allowed  to remain, the effect on the  animals would not
 be  as drastic,  since  the  brush would supply animal cover and  food and provide
 seed  for continued revegetation.  The humus under  the plant could contain  seeds
 of  ephemerals and would partially preserve the fertile  shrub  site in which
 seedlings can become  established.
      In addition to the potential off-site problems that are associated with
 erosion, some provision must be made either to remove or to store the contaminated
 soil.  This normally will require a tract of  land  in addition to the treatment
area.
     Figures 1-8 through 1-13 show the recovery that might be expected  eleven
and seventeen years after scraping a desert area.
                                     1-33

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Figure 1-8.
Great Basin Desert.  A 2 ha rectangular plot 11 years after
blading.  Many grasses are present.  The poisonous shrub
Halogeton can be seen in the lower part of the photograph.
(Photo courtesy of UCLA.)
 Figure  1-9.  Great  Basin  Desert  11 years  after  blading.   (Photo courtesy
             of  UCLA.)
                                   1-34

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Figure 1-10.   Great Basin Desert.   Demarcation line between land bladed
              11 years ago (right)  and non-bladed land (left).   The bare
              areas may relate to  depth of blading.  (Photo courtesy
              of UCLA.)
  Figure 1-11.  Great Basin Desert.  Area in foreground and right was
                bladed 11 years prior to the photograph.  (Photo
                courtesy of UCLA.)
                                 1-35

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 Figure 1-12.   Great Basin
                  reduce
            Desert
to
of UCLA.)
            years after application  of water
dust followed by blading.   (Photo courtesy
Figure 1-13.  Great Basin Desert recovery 17  years  after  blading.  The
              cover in the foreground bladed  area is  about  25% of  the
              undisturbed area.   It is unknown  if the plant grew from
              seeds or crown shoots.   (Photo  courtesy of  UCLA.)
                                1-36

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      (1-5)  Sliallow Plowing
      It is assumed this technique plows -the soil to a maximum depth of 10 cm
between the perennial shrubs.  It disturbs both annuals and bunch grasses but
not most of the shrubs.
      The ecological impact would be less than for surface scraping.  The shrubs
would provide food and cover for animals and a seed reservoir for new growth.
Little humus would be lost and the seed-containing layers of soil would not be
removed.  Scarification of the soil would enhance Sal sola growth for the first
two or three years.  This growth would have little effect on germination of
annuals since Salsola is a summer germinating plant while other annual forbs
and grasses are spring and fall germinating.  The potential for wind erosion
      •                                                                  • >
would be increased until ground cover by annuals is established.  The potential
for water erosion could either be increased or decreased depending on the plowing
technique.
      The visual effect, e.g., low furrows, would be visible for many years.  There
would be little effect on animal food supply or population density.

      (1-6)  Deep Plowing
      Plows capable of plowing as deep as 100 cm are available.   This technique
would result in a complete destruction of the local ecosystem.   Succession would
start from bare ground.  The relatively thin soil under perennial, plant clumps
would be destroyed and most of the seed-containing soil would be turned under.
Animal life would be displaced or destroyed.
      Larger areas would undergo initial stages of recovery more slowly than
smaller areas unless some form of revegetation were attempted.
     Figure 1-14 shows the recovery to be expected from deep plowing.

      (1-7)   Soil Cover Less than 25 em
     The purpose of this technique would be to bury and immobilize the contaminant.
It is a relatively drastic treatment.   It would be difficult, if not impossible,
to accomplish without affecting the hydrological drainage system outside the
treatment area.   As new drainage patterns are established and old ones abandoned,
the vegetation of individual areas would change, although the overall  effect on
the region might remain unchanged.
                                    1-37

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Figure 1-14.
                 Great Basin Desert 17 years after plowing.   The area in the
                 foreground was plowed to a depth of about 30 cm.   Cover on
                 plowed area is about 25% of that of the undisturbed area.
                 (Photo courtesy of UCLA.)
     If the soil were placed without extensive compaction,  some shrubs would
survive since a. few desert shrubs are evidently adapted to  periodic silting by
erosional processes.  Few data are available on the plants  that could survive;
it is assumed those found in washes or arroyos such as Hymenoclea or Thamnosma
could withstand limited soil cover and grow.  However, it is epxected that most
shrubs and all bunch grasses and annuals would be incapable of growth or germina-
tion.
     Recovery would be essentially the same as starting from bare ground.  Un-
less some type of seeding program were instituted, the growth of annuals on the
larger-sized treatment areas would not occur until winds deposited seed.
     Compaction density of the fill will be an important variable for regulating
the time of the initial stages of recovery.  If no compaction occurs the situa-
tion could approximate that around nuclear craters where the water infiltration
rate is so great that germination cannot occur.  Alternatively, compacting to
a density greater than the original soil would also inhibit plant growth.
                                     1-38

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      (1-8)  Soil Cover 25 to 100 cm           :
      This technique would result in the complete loss of the treatment area
ecosystem as well as off-site changes induced by changing surface drainage
patterns.  Recovery of the treatment area would be from bare ground.

      (2-1)  Remove Plow Layer                 \
      This cleanup procedure increases the severity of method 1-4, Surface Scrap-
ing and Grading, by removing slightly more soil.  When the top 10 cm of soil are
removed all annual seed, humus, bunch grass and the meristematic tissue of
most  shrubs would also be removed.  A few shrubs would resprout from the roots,
but most would not.  Recovery would essentially start with bare earth.  In some
desert locations extensive deposits of caliche are found at plow depth.  If
these are exposed the existing slow rate of recovery would be retarded.

      (2-2  Remove Shallow Root Zone
          This method would remove the top 40 cm of soil from the contaminated
area.  This technique would remove both the A and B soil horizons and expose
the calcarous C horizon.  The result would be complete destruction of the local
ecosystem.  Recovery would begin from bare ground.
     In any of the surface alteration procedures, i.e., scraping, grubbing,
plowing, or soil removal, loss of vegetation and the exposure of the soil to
winds and rain will lead to erosion problems.  The magnitude of these problems
is discussed in Chapter 2, Prairies, and Chapter 8, Agriculture.

     (2-3)  Scrape and Grade* Mechanically Stabilize
     This technique would use mechanical methods to provide stability to the
freshly scraped soil to retard or prevent soil erosion.  The method would be
expected to lessen the impact due to erosional deposition on surrounding areas.
However, none of the possible mechanical stabilization processes would
appreciably speed natural^recovery, and some of the possible processes would
slow it.
     Two categories of mechanical stabilization are considered here:  compac-
tion and manufactured materials such as nettings, meshes, or plastic films.
                                     1-39

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     Soil can be mechanically compacted by bulldozer, rollers,  or vibratory
processes to a density that rejects water.  The degree of compaction is largely
a function of the amount of clay in the soil.  The compacted soil can resist
wind and water erosion for decades.  Eventually natural processes allow ephemerals
and grasses to become established.  This vegetation helps loosen the soil so that
natural revegetation processes can occur.  If the soil has a very high clay content,
as is the case for dry lake playas, revegetation might require centuries.
     Although the surrounding area is protected from material eroded from the
treatment area, the increased water runoff during a rain, unless controlled,
would cause severe erosion problems on the adjacent land.
     Manufactured material, like netting, placed over the scraped area would
provide protection against water erosion, and limited protection to winds.
The ecological effect would be substantially the same  as if the mechanical
stabilization were not done.
     Plastic film could also provide a protective layer.  If exposed to air the
film would last 3 months to 2 years, depending on the composition of the film.
Films covered by earth could last much longer; however, winds could quickly
remove the cover.  As the film degraded, normal restoration would occur.

     (2-4)  Remove Plow Layer, Mechanically Stabilize
     A severe environmental disruption.  The effect would be substantially the
same as described above, expect the compaction of the clay C horizon found in
many desert areas would form a long lasting barrier to recovery.

     (2-5)  Remove Shallow Root Zone,  Mechanically Stabilize
     A severe environmental disruption.  The effect would be substantially the
same as described above.

     (2-6)  Scrape and Grade* Chemioally Stabilize
     This composite method,  like the mechanically stabilized methods described
above, would depend ,on  soil removal to reduce contamination and  a stabilizer  to
both fix  any remaining  contaminant  in place  and to retard soil erosion.  Any
cleanup procedure that  removes soil results  in  loss  of the  local desert  eco-
system.   The chemical  (and mechanical) stabilizers protect  the surrounding
 *Appendix A  lists  the  stabilizers.   It  is assumed here that one of the preferred
  stabilizers of Appendix A,  as  listed in Treatment  1-1 above, would be used.

                                      1-40

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 areas from losses due to erosion,  but at the cost of slower recovery at the
 treatment area.
      The effects of scraping and grading were described in treatment 1-4 above.
 The addition of  a chemical  stabilizer would retard the in-itial  stages of re-
•covery until the stabilized crust  was degraded.   Shallow scraping  will leave  some
 perennial brush  roots capable of resprouting,  but forbs and grasses  cannot
 germinate until  the surface develops  cracks which allow wind borne seeds to be
 deposited.
      Since the stabilizer will  prohibit  water infiltration,  provision must  be
 made for mitigating the  effects of runoff on the  surrounding areas.

      (2-7)   Remove  Plow Layer,  Chemically  Stabilize
      Soil  removal  is  a drastic  environmental  perturbation,.  The  chemical
 stabilizer  would retard the initial stages of recovery one to two  years.

      (2-8)  Remove Shallow Root Zone,  Chemically Stabilize  •••.--.
      The ecological effects are substantially  the  same  as  described  above.

      (3-1)  Barriers to Exclude People
      This treatment would depend on isolating  the  contaminated area  from human
contact.  This will only be  effective if the contaminant cannot  enter  the food
web  leading  to man.  The most probable barrier would be chain link fencing  six
to ten feet  high.  Such fencing can be expected to be useful  for 25"to 30
years.
     As  long as provision is made  for animal passage the barrier would have no
effect on local  ecology.  Some cultural, e.g., archaelogical, features would
also be protected by the barrier.

     (3-2)  Exclude Large Animals
     Fences can be designed to inhibit animal movement.  If cattle and large
game animals are excluded from the contaminated area, one direct link  in man's
food web will be blocked.
     Studies, described in preceding sections, have shown that cattle  exclusion
does not result in changes  in vegetation species composition  (at least over the
                                     1-41

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50-year measurement period), but that the number of individual plants,  and thus
the total productivity of the fenced area, increases markedly.  An increase in
primary productivity should lead to an increase in the number of small  herbi-
vores .
     A fence might produce deleterious effects on large animals in two  ways.
First, it might exclude animals from natural water places.  Second, it  could
impede a natural migration path.  Lack of a secondary watering place would prove
fatal.  If other migration .routes were available they would probably be used.

     (3-3)  Exclude Lco^ge and Small Animals
     This procedure would inhibit the transfer of the contaminant through the
food web.  Barriers can be made to stop both the immigration and emigration of
animals.  It is assumed that large grazing animals, e.g., cattle, burros,
antelope, deer, would be removed from the contaminated area.  It would be possible
                                                          2
to exclude birds from the smallest treatment zone  (0.01 km ) and it might be
worth the effort if a particular microenvironment,  e.g., one containing an
endangered plant species, were to be preserved, but it would be impractical  to
exclude birds  from larger areas.  The actual isolation of the food web leading
to man would require analysis of the local conditions and extent of man's use of
local birds.
      It might  also be possible to remove  small  animals from  areas  smaller  than
about 1 km", but it  is doubtful  if attempts at  either direct  physical  removal
or removal by  poisoning  from larger  areas would be  effective.
      If  small  seed-eating animals are removed  it  is postulated  that a  compensa-
tory increase  in seed eating insect  populations will  result  in  about the  same
utilization of the  local plant  resource.  J
      The  effect of inhibiting  small  animal  movement,  rather  than  removal,  is
 less clear  and is  undoubtedly  related to the  size of  the  area fenced.  The inter-
 action  between plants,  herbivores,  and  carnivores plays  an  important role in
 the  local ecology.   Plants  could exist  in very small  enclosed spaces.  Herbi-
 vores and carnivores require areas at  least as large  as  their foraging range.
 Only the largest  area,  10 km ,  may be  large enough to support a population of
 carnivores in a closed  system,  based on ecologies existing  on small isolated
                                      1-42

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desert areas such as islands.  It is not clear what the effect of smaller
fenced areas would be.  One study, using the vole Microtus, found that 0.8 ha
fenced plots evidently destroyed the species' natural population control and
regulatory mechanism.  The fenced population expanded until it was about three
times as large as control populations on adjacent sites.  The result was
overgrazing and destruction of the habitat, followed by starvation induced
                   43
population decline.    No evidence of this phenomenon was observed on 8 ha
plots in the Mojave desert  '   although herbivore population densities within
the fenced ardas differed from adjacent control densities in non-uniform ways.
     As long as the vegetation is not degraded or destroyed, recolonization of
the areas after removal of the fence would be relatively rapid.  The abundance
of small mammals respond quickly to periods of good vegetation growth.  They
have been reported to increase their densities at least five-fold within one
                24        25
breeding season.    French   has shown that desert rodents in the Mojave Desert
disperse to great distances both as young animals and as adults during the non-
breeding season.
     Continued maintenance of isolated animal populations could affect the gene
composition of the group.  The smallest groups would be affected the most.

     (4-1)  Asphalt Hard Surface Stabilization
     In this procedure asphalt or hot rapid cure road oil would be applied over
the contamination to immobilize it.   The vegetation would be removed prior to
the asphalt treatment, but might remain for the road oil application.
     The technique limits wind erosion; however, drainage and runoff of rain-
water to adjoining areas would be a problem.
     In the asphalt treatment the ecology of the treatment area would be de-
stroyed.  Some perennial plants would surviv;e the road oil, but the area would be
virtually useless to support annual  vegetation or animals.  It is expected that
vegetation at the edge of the area would exhibit enhanced growth due to addi-
tional available moisture.
     The asphalt and. road oil treatments will affect local microclimate.  De-
creased surface roughness will result in changes in the wind profile and will
decrease humidity.  The local heat balance will be changed since an essentially
spongy surface of low heat conductivity will be turned into an impermeable
                                    1-43

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layer with high capacity for absorbing and conducting heat.  This will raise local
air temperatures.  In calm weather conditions an inversion in the nocturnal
atmosphere can be created that will affect surface wind flow and temperatures
over a relatively large area.  This "heat island" effect has been noted in
                        2 44
areas as small as 0.1 km .    The lowered humidity and increased temperature
will deleteriously affect the small annuals and ephemerals more than the
perennials.
     No recovery can begin until the surface begins to degrade.  This should occur
in about three to five years for the road oil and five to ten years for asphalt.
(However, asphalt can be placed over a compacted base at a thickness which will
survive fifty years or more.)
     As cracks develop in the surface both moisture and wind borne seeds will be
concentrated.  The resulting growth will help break up the surface.  As more
of the surface degrades, annuals, then perennial plants, will become established.
                                                      2
The largest area considered for this treatment, 0.1 km  should not reduce infiltra-
tion and recharge to the extent that ground, water would be affected.  However,
the water table under large paved desert areas, such as airports, has been shown
to move closer to the surface in response to reduced surface evaporation.
Figures 1-15 and 1-16 show recovery from road oil stabilization.

     (4-2)   Concrete  Hard Surface Stabilization
     This treatment is outside the scope of work.

     (5-0)   Application of Sewage Sludge
     This treatment is outside the scope of work.

     (6-1)   High Pressure Washing
     This treatment is outside the scope of work,

     (6-2)   Flooding
     This treatment is outside the scope of work.

     (7-0)   Soil Amendments Added
     This treatment is outside the scope of work.
                                    1-44

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                                                .'  •*• -
                                               I,-'5*-' i* '•.
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  Figure 1-15.  Great Basin Desert.  Foreground first treated with hot,
             rapid-cure road oil s-tabili;:er, then scraped.  Photo 17
             years after disturbance.  (Photo courtesy of UCLA.)
Figure 1-16. Soil 17 years after application of a hot rapid-cure road oil
          stabilizer.  The soil pieces vary from 1 to 5 cm thick.
          Vegetation is growing in the area. (Photo courtesy of UCLA.)
                          1-45

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1.5  RECOVERY FOLLOWING CLEANUP
     Earlier in this chapter it was noted that the concept of a single stable
climax vegetation in each desert type was not valid.  A number of different
stable ecosystems may be possible depending largely on long term climatic
factors.35  Further, existing ecosystems are dynamic and changing with time*
Thus, recovery is best defined in terms relative to surrounding areas rather than
to some standard climax ecosystem, or to some measured pre-treatment condition.
It has also been shown that there are no irreversible changes; given enough
time the desert will adjust to any insult.  Treatments which lead to massive
erosion and land form change will be permanently altered visibly although the
change will not affect the equilibrium ecosystem.
     The endpoint for natural secondary succession and unassisted recovery follow-
ing application of one of the cleanup techniques can be specified in a number of
ways depending largely on the effort undertaken to measure the completeness of
recovery.
     These endpoints include:
     (1)  No measured difference, other than normal variance based on measure-
          ment technique and ecological variability, in selected ecosystem com-
          ponents between the treatment area and adjoining undisturbed areas.
     (2)  No visible difference between treated and untreated areas apparent
          to a desert ecologist,  without benefit of field measurements.
     (3)  No visible difference to the layman.
In this chapter endpoint 3 is specified as defining recovery to climax condition.
Figures 1-17 through 1-20 give the recovery  sequence for  several of the  cleanup
techniques between  the  end of cleanup  and  climax  as defined  by  endpoint  3.   See
Appendix  B for applications.

1.5.1   Unassisted Succession
     The  vegetation stages  leading to  the  defined recovery,  based  on  information
presented in Sections  1.2  and  1.3 of this  chapter are  summarised below.*
 *These stages may not be serai in that the vegetation which forms the pioneer
  community is present at climax—indeed,  the same plants may be present.
                                     1-46

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                                                      1 1 CHEMICAt STABILIZATION
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         °Also Scraping and Grading. Remove plow layer. Soil cover <25 cm
                     10
                               100200
    Figure  1-17.   Sequence of  ecologic  recovery  following  cleanup.
                                       1-47

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          1-5 SHALLOW PLOWING
                                                1-2 CLEAR CUT VEGETATION
                                          >£
                                          °



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       Figure 1-18.   Recovery  sequence following shallow plowing
                      and clearcutting vegetation.
                                    1-48

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          1-3  STUMPING AND GRUBBING8
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                                               2-6 to 2-8 SOIL REMOVAL. CHEMICAL STABILIZATION*1
                                                    tl

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           Includes. Scraping *nd Grading-Chemically stabilize. Remove Plow layer-Chemically stabilize.
           Remove shallow root zone-Chemically stabilize                       '



    Figure  1-19.   Sequence  of  ecologic  recovery  following cleanup.
                                           1-49

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2-3 to 2-5  SOIL REMOVAL. MECHANICAL STABILIZATION3     4-1.4-2 HARD SURFACE STABILIZATION
                                                      UJ
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            ^Includes Scraping and Grading-Mechanically stabilize. Remove plow layer-Mechanically stabilize.

             Remove shallow root zone-Mechanically stabilize



      Figure  1-20.   Sequence  of  ecologic  recovery following cleanup.
                                            1-50

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It is assumed that secondary succession begins with bare ground, which contains
no particular deleterious edaphic features such as surface clay hardpan or
caliche.
     Bare ground, if scarified, is invaded by Russian Thistle (Salsola) the
first summer following cleanup.  '  '  '    During the first year pioneer annuals
and grasses appear if adequate moisture is available, otherwise an additional year
or two may elapse.  The timing of this initial annual colonization is'also de-
pendent on the size of the affected area.  Areas larger than about 3 km  will
require an additional year.    The introduction of non-native annual grasses is
at the expense of native perennial grass.    The result of this initial stage
in secondary succession is an annual grassland which can persist for decades,
or possibly hold at grassland stage by grazing and range management techniques.56
During this stage the density of grass and epheraerals on the treated area is two
to three times that on adjacent areas  although the total productivity of the
area is lowered   largely because older perennial shrubs produce the greatest
biomass.    There may be a shift in the relative species composition of rodents,
which is restored as perennial shrubs reappear.
     Starting in the second year—again, assuming adequate moisture—pioneer ,
shrubs characteristic, of disturbed sites, e.g., Atriplex, Thamnosma, Salazaria,
and Hymenoclea appear.
                      59,99
     In the third year perennial shrubs which will make up the climax community
begin to sprout.  Perennial vegetation requires a number of consecutive years
of above normal soil moisture and some relief from small animal grazing to become
established.    Individual plants reach maturity in about 30 to 40 years.  '
The area can be expected to have a perennial shrub density of about 20 percent
that of surrounding areas in 13 years  and about 25 percent in 17 or 20 years.  '
Complete recovery of the area should occur in about 80 years.  '
     Manipulation of the landscape to create pockets which trap moisture may be
used to speed the intermediate stages of succession, i.e., the early perennial
shrub stage.    Enhancements of shrub density by factors of 2 within these
features have been noted   but there is a corresponding lessening of density on
nearby plots due to restricted soil moisture so the net density for the area is
about the same.  The landscape manipulation would speed the restoration of the
                                      1-51

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original rodent species composition by providing earlier food and cover  for  the
displaced species.

1.5.2  Cleanup Recovery Categories
     From the preceding summary of a hypothetical desert secondary succession
and the description of the cleanup techniques presented in Section 1.4,  it is
clear that there are major divisions in impact among those cleanup techniques
that delay recovery, those that result in bare ground with no vestige of or-
ganic matter, and those where factors which relate to bare ground recovery are
ameliorated.  In the first category it is important to note that eventually
the bare ground condition is approximated; therefore the time difference in
recovery amo.ng all the procedures that remove and stabilize the soil is  actually
the time from the application of the treatment until the bare ground approxi-
mation is achieved.  The consequences of this outlook are significant, for it
implies that once the seed containing layer of soil and the roots of perennial
plants are removed, the time to recovery is relatively independent of treatment
type.  In the last category, recovery from a given cleanup procedure is  di-
rectly related to the difference between the disruption produced by the cleanup
procedure and the bare ground state.

1.6  QUANTITATIVE ASSESSMENT OF CLEANUP IMPACTS
     The rationale underlying assessment of the ecological impact of various
cleanup techniques is to be able to relate the cleanup procedure to the potential
hazard of a contaminant so that the environmental costs associated with the
cleanup can be weighed against the benefits of hazard reduction.  Since these
cleanup techniques will have different levels of efficiency  for different types
of contaminants,  some measure of the impact of each procedure is necessary for
this evaluation to be made.
     A number of  measures are  available  to estimate the rate of ecological
 recovery.   They are usually in terms of  changes in energy cycles,  nutrient
 cycles,  food chains, density patterns in time and space,  and various control
 mechanisms.   Unfortunately, the interrelationships among most of these  in
 desert ecosystems are Largely unknown.
                                      1-52

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      In this section,  time of recovery to the climax desert  community is  taken
 as a surrogate for ecological impact quantification.  Implicit  in  this measure
 is the assumption that recovery time integrates  the effects  of  changing primary
 productivity,  species  composition of both plants and animals and chemical and
 energy cycling in the  environment.   Any other measure of the differential impacts
 among the treatment types would scale about  the  same as  time to recovery  and
 would produce  the same ordering of impacts.
      Unfortunately, the measure selected cannot  be  precise.   First,  deserts are
 not homogeneous areas.  Local eadphic and climatic  factors interact  with  local
 variations  in  plant and animal  species to influence recovery rates.   Second,
 recovery is very sensitive to moisture,  especially  in the early stages of
 pioneer vegetation growth.  This  means that  the  temporal distribution of  rainfall,
 as well as  its magnitude,  is  an important variable.   These climatic  factors tend
 to have a greater variance from the  mean as  the  mean decreases.  Third, the
 magnitude of impact depends on  the severity  of the  cleanup in any  given situa-
 tion,  for example,  shallow plowing was shown  in  Section  1.5  to  be  relatively benign.
 If,  however, the  perennial vegetation  is  plowed  (a  circumstance which might be
 dictated  by local  conditions) and  if  the  plowing occurred at  such  a  time  that
 the  loosened seed  containing  surface  soil  were blown away by winds,  recovery
 would  require  40  to 80  years  rather  than  the  12  years  estimated.
     Table  1-1  lists the median time  to  complete recovery for each cleanup
 procedure for  various  sized areas.  There  is no  clear  relationship between size
 of area and  impact  listed  in  the literature; however,  the impact is  expected to
 increase  as  the area increases.                ;

 1.6.1   Impact  Assessment
     For all size areas there is a relationship  between severity of  impact and
magnitude of surface disruption.  Soil removal, no matter how slight, constitutes
a major perturbation to the ecosystem.  Unfortunately, most procedures require
 soil removal.
     The real choices are:  first, do nothing other than erect a barrier;
second, stabilize or turn under part of the contaminant;  third,  remove con-
taminated vegetation; fourth,  remove contaminated soil.  Choice  1,2, or 3
would allow time to evaluate expected effects in detail for a particular loca-
tion, but would be of limited  usefulness against a hazardous  contaminant that
                                      1-53

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                                                                          1-54

-------
 could enter man's food chain.  The real decision may be between erecting, main-
 taining, and monitoring a barrier until the contaminant is no longer hazardous,
 or performing a cleanup procedure whose effects cannot be eradicated naturally
 for 80 to 100 years and where ameliorative reclamation may be impossible.  In
 one respect this simplifies the cleanup decision since it implies that the only
 variable which needs to be considered in desert environments is the efficiency
 of the cleanup procedure.
      In summary, cleanup techniques can be grouped into two major categories
 of severity of/impact, each category being further subdivided into groups of
 slightly differing degrees of impact.  In the first category, that of less-
 severe impact, the group of treatments having the least impact is the erec-
 tion of barriers (3-1  through 3-3).   The next lowest impact group includes
 those procedures which are less extreme in the degree of bare ground state
 produced.   In this group are chemical stabilization (1-1),  shallow plowing
 (1-5),  and  clear cutting (1-2).   In  each of these treatments, the seed-con-
 taining layer of soil  is not removed, and perennial plants  achieve relatively
 rapid  recovery.   Ephemeral  and  annual grass growth is either enhanced or  un-
 affected.

      In  the  second  category,  that of  much greater impact, the first  group
 includes scraping  and  grading  (1-4),  soil  cover  less  than 25 cm  (1-7),  and
 plow  layer removal  (2-1), as  these procedures  result  in  a bare ground state.
 Of very  similar  impact,  though  slightly  greater,  are  stumping and  grubbing (1-3),
 shallow root  zone removal  (2-2), deep plowing  (1-6),  soil cover  greater than  25
 cm (1-8), and  soil removal  in combination  with chemical  stabilization (2-6
 through 2-8).  The  last group, that with  the most  severe impact, includes  the
 treatments that  combine soil removal  with  mechanical  stabilization  (2-3 through
 2-5), and hard-surface stabilization  (4-1  and 4-2), as the resulting  soil  compac-
 tion would further delay forbs and grasses establishment and  perennial vegeta-
 tion germination.

 1.6.2  Recovery Assessment
     As discussed in Section 1.5, there are major divisions  among cleanup  tech-
niques with regard to time to recovery.   In general, those treatments involving
 less perturbation to the seed-containing layer of soil will result in shorter
recovery times than the treatments which effect the bare ground condition.
                                       1-55

-------
     Areas with barriers (3-1 to 3-3) will not experience succession in the   .;
sense of the other cleanup technologies.  The effects of barriers on vegetation
are somewhat dependent on the extent of pre-treatment overgrazing but are gen-
                                                                     8 77 81
erally considered to be favorable by increasing the density of plants »  '
and reducing animal-caused compaction.14'30  The longer an area is protected
                                                                          77 81
from grazing pressure, the greater the total number of plants and biomass,  »
However, exclusion of large animals might result in changed plant species compo-
sition leading to an'increase in poisonous species,10 and containment of rodent
populations might lead to massive density fluctuations and a reduction of vege-
tation biomass.43  For these treatments, the size of area would have little
effect; however rodent population fluctuation would not be expected for the
largest area.
     Chemical stabilization (1-1), shallow plowing (1-5), and clear cutting
vegetation (1-2) can be considered a family of treatments with sequentially
increasing recovery time related to the amount of initial environmental disrup-
tion.  In each treatment the seed-containing layer of soil is not removed, and
perennial plants (or their roots) remain to form the basis for relatively rapid
recovery.  Chemical stabilization affects annual production for one or two grow-
ing seasons but should not otherwise alter recovery.  Shallow plowing allows
most of the perennial shrubs to remain.  Scarification of the surface will allow
Salsola to become established and reduce erosion, but once the soil is naturally
compacted to pre-treatment density and local erosion removes the plow furrows,
recovery will be complete.  The slightly greater soil moisture found in the
plow furrows should enhance ephemeral and annual grass growth; however, even
this impact will be unmeasurable within 10 to 12 years.  With both chemical
stabilization and shallow plowing, it is expected that the recovery time would
                                                 2
increase slightly as the area increases over 1 km  .
     Clear cutting vegetation allows perennial plants to resprout from existing
roots, thus time to total recovery is shortened and  is equal to  the time required
for a perennial shrub to reach mature stature — about 40 years.  The ephemerals
and grasses should not be affected by this procedure.  Shrubs have been  shown-.
to increase productivity when closely cropped.     Hand  cutting  would not  result
in the surface  scarification necessary  for Salsola germination.  Chaining  would
disturb  some of the seed-containing  soil  layer and slow  the  early phases  of
                                       •1-56

-------
 recovery, but the slowest portion of recovery, regrowth of the perennial vege-
 tation would not be affected and recovery within 40 years can be expected.   The
 size of area would have no effect on recovery time with this treatment.
      The procedures of scraping and grading (1-4), removal of plow layer (2-1),
 and soil cover less than 25 cm (1-7) result in an initial bare ground state and
 exhibit the same successional pattern and timing as natural revegetation.   Full
 recovery is expected in about 80 years.   The size of area is expected to have
 a slight effect on recovery time as the  area size increases beyond 1  km2.
      Four of the techniques,  stumping and grubbing (1-3), remove shallow root
 zone (202), .deep plowing (1-6),  and soil cover greater than 25 cm (1-8)
 result  in similar recovery patterns.  Each treatment is capable of removing
 or destroying all vegetation  and both the A and B soil horizons, therefore  total
 recovery is  retarded somewhat by the presumed  existence of hardpan on the sur-
 face.   The hypothetical  succession  stages and  their initiation are about the
 same as for natural  revegetation; however,  at  any given equal  time plant density
 would be slightly less  for these  treatments than  for natural  succession.  It is
 estimated  that  recovery  would occur in approximately 85 years.   The size of area
 is  expected to  have  a slight  effect on recovery time as the area size increases
 beyond  1  km  .
      Procedures  which use  stabilization  in  conjunction with soil  removal (2-3
 through 2-8)  result  in slightly  longer recovery times  than the  preceding group,
 but  the recovery is  not  qualitatively different.  The  chemically-stabilized  com-
 bination treatments  (2-6 through 2-8) result in a delay of the  initial invasion
 phase for  a year or  two, and  climax should  be  achieved in 80 to  85  years.  The
 siz.e of area  is  expected to have a  slight effect on  recovery time  as  the area
 size increases beyond 1 km  .  The mechanically-stabilized combination treat-
ments (2-3 through 2-5), exemplified by compaction,  would delay the establish-
ment of the pioneer  forbs and grasses for 2 to  10 years  and would  lengthen the
time until perennial vegetation germinated  to  about  15  years.  About 90 to 95
years would be required for full recovery.  It  is expected that increasing area
 size would increase the time of recovery.   Hard-surface stabilization is an
extension of mechanical compaction;  here, however, no pioneer species can becpme
established until the hard surface  begins to degrade.   From that point however,
recovery will occur  in about 80 years.
                                       1-57

-------
     In summary, to a large extent, recovery time is relatively independent of
cleanup technique when the seed-containing soil layer and vegetation roots are
removed.  The most drastic treatment adds only about 15 percent to the overall
time of recovery, compared to natural revegetation.

1.7  CONCLUSIONS
     One important topic has not been explicitly addressed.  That is, what is
the goal of restoration?  The goal might be to restore the area to the pre-
disturbance ecological community.  It might be to establish a similar, though
not exact, community, for example, a pure stand of creosote bush in place of
mixed perennial species.  It might be to change the land use from desert to
desert grassland for grazing or even to agricultural land.
     Two important factors dominate desert revegetation and ecological recovery
of disturbed areas.  First, moisture is the critical determinant both of the
speed of recovery and the relative dominance of perennial shrubs or perennial
grasses.  Recovery is usually impeded by the generally low infiltration rate
of desert soils so that much of the precipitation is lost as runoff.  Second,
there is no serai succession; the perennial plants first established form
the stable climax community.  A mature stable community is normally achieved in
about 80 years after a disturbance.  Superimposed on these factors is evidence
that natural vegetation changes occur in response to long term climatic change,
and there is historic evidence that vegetation changes occurred at a time scale
that is comparable to that of unassisted revegetation.  Successive dry years
reduce perennial grass cover, while a series of wet years has the opposite ef-
fect.  A goal of returning a desert to a pre-cleanup condition may be impossible
if, during the restoration period, climatic conditions which existed prior to
the cleanup change.  A new stable communuty may exist, but it might be different
from surrounding communities.
     Of the treatments evaluated, several would require thoughtful considera-
tion prior to their use based on their deleterious effect on recovery of the
ecosystem.  These are:  hard-surface stabilization  (4-1, 4-2), soil removal
followed by chemical stabilization (2-6 through 2-8), removal of the shallow
root zone (2-2), soil cover greater than 25 cm (1-8), deep plowing  (1-6),
stumping and grubbing (1-3), removal of the plow layer (2-1), soil cover less
than 25 cm (1-7), and scraping and grading  (1-4).  As discussed in Section 1.6,
                                       1-58

-------
the common factor in all of these treatments is the effecting of a bare ground
condition; once this happens, recovery time is greatly increased over the time
involved for treatments that do not create this condition.
     Preferred treatments, therefore, in terms of ecosystem recovery, would be:
erection of barriers (3-1 through 3-3), chemical stabilization (1-1), shallow
plowing (1-5), and clear cutting vegetation (1-2).  Unfortunately, for many
postulated materials requiring cleanup, the ecologically preferred treatment
may not be the most effective for hazard reduction.
                                       1-59

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     Environments, U.S. Energy Research and Development Administration, NVO-153,
     1975.
                                      1-65

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96.
97.
          , and
_, Radioecology and Ecophysiology of Desert Plants
at the Nevada Test Site.  USAEC Publication TID-25954, 1972.

          , E. F. Frolich, and G. V. Alexander, Effect of Steam Sterilization
     of Soil on Two Desert Plant Species.  Plant and Soil 39: 453-456, 1973.
98.  Weaver, J. E. and F. E. Clements, Plant Ecology.  New York, McGraw-Hill,
     2nd Ed., 1938.

99.  Wells, P. V., Succession in Desert Vegetation on Streets of a Nevada Ghost
     Town.  Science 134:670-671, 1961.

100. Willard, E.E. and C.M. McKell, Simulated Grazing Management Systems in
     Relation to Short Growth Responses.  J. Range Management 26:171-174, 1973.
                                      1-66

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                                   CHAPTER 2
                                    PRAIRIE
2.1  OVERVIEW
     Before overgrazing and cultivation of the 1870's broke the cover, the
native grasslands covered between 2.6 and 2.9 million square kilometers.of the
                         40
contiguous United States,   or nearly one-third of the land surface.  As a
general rule, grasslands occurred in areas having between 25 and 75 cm annual
          .22
precipitation.    Less precipitation usually resulted in desert and more
resulted in forest; exceptions occurred, however.  Tallgrass prairie extended
as far east as Ohio (up to 100 cm mean annual precipitation), at least partially
the result of recurring fires, and grasses formed the understory of desert shrub
communities having as little as 18 cm precipitation per year.

     Grassland communities, as the name implies, are dominated by grasses and
typically contain little woody vegetation.  The grassland growth form is a
single, uniform layer of vegetation which does not provide for the variety of
                                                         48
niches found in more diverse communities, such as forests.     Consequently,
the diversity of birds and insects, which can take advantage of vertical  strati-
fication, is reduced.   Grazing mammals predominate and range from large,  running
herbivores,  such as bison, to a considerable diversity of herbivorous and
granivorous rodents.

     The term prairie is used in this report to mean midcontinent, perennial
grassland.   Kiichler   has identified approximately 15 grassland vegetation types
within this region.  There is a general increase in cover from west to east
which roughly corresponds to rainfall distribution.

2.1.1  Tall grass Prairie
     Tallgrass prairie consists of grasses 150 to 250 cm in height with roots
extending to depths of 180 cm or more.    The dominant Andropogon-Panicum-
Sorghastrum association was continuous in the 18th century  from Canada to
                                      2-1

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Oklahoma with tallgrass islands in Wisconsin and east to Ohio, Kentucky and
Tennessee.    The island prairies were undoubtedly successional stages, for fire
prevention in those areas invariably resulted in an increase in woody vegetation.
Because of its great agricultural value, little tallgrass prairie remains.   One
remaining tract, described by Risser,31 will serve to illustrate a typical
association of climatic, soil, and biological characteristics.  Mean annual
precipitation was 93 cm with 63 cm falling during the 205 day growing season.
Mean January temperature was 2.8°C and mean July temperature was 27.8°C.  Soils
were Brunizems with the A horizon extending to 40 cm and the B horizon to over
100 cm.  The list of common plants included the tallgrasses and forbs but did
not mention woody plants.  The list of common animals was comprised primarily
of herbivorous rodents and insects.

2.1.2  Mixedqrass Prairie
     The mixed or midgrass prairies are found to the west of the tallgrass
prairies in zones of generally lower precipitation.  Midgrass prairies average
60 to 120 cm in height.  They occur from Canada to northern Texas and the cli-
matic differences yield a variety of plant associations over the range.  Mid-
grasses predominate but both shortgrasses and tallgrasses may be important
components.  Lewis   described midgrass prairie in western South Dakota.  The
midgrasses Agropyron smithii and Stipa virdula predominated under relief from
grazing but there was an understory of shortgrasses, especially Bouteloua
gracilis and Buchloe dactyloides.  Increased grazing pressure led to a reduc-
tion of midgrasses and the formation of shortgrass sod.  Mean annual precipi-
tation was 38 cm of which 30 cm fell during a 126-day growing season.  Ten
year (1958-1967) average temperatures were -1°C (January) and 24°C (July).
Annual potential evaporation was high, about 140 cm from a free standing water
surface.

                                       39
    In a mixed grass prairie in Kansas,   tallgrasses  (Andropogon gerardi,
Sorghastrum nutans), midgrasses  (Andropogon scoparius), and shortgrasses
(Bouteloua curtipendula, B. gracilis, and B. hirsuta) all occurred in ungrazed
areas.  Grazing increased the frequency of shortgrasses.  Annual precipitation
was 58 cm with a 165-day growing season annually.
                                      2-2

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2.1.3  Shortgrass Prairie
     Shortgrass prairies average 15 to 45 cm in height and occur from Canada
to southeast New Mexico and west Texas.  A northern shortgrass prairie described
by Jameson   had Bouteloua gracilis and Buchloe dactyloides as dominant plant
species.  Annual precipitation ranged from 25 to 38 cm with 80 percent occurring
during the summer.  Mean January temperature was 4°C and mean July temperature
was 29°C.  Soils (A + B horizons) ranged from 35 to 76 cm deep.  Huddleston
described a shortgrass prairie near Amarillo, Texas.  Bouteloua gracilis pre-
dominated with various other shortgrasses present.  Prickly pear cactus (Opuntia
polycantha) was abundant with kochia (Kochia scoparia) occurring in disturbed
areas.  Mean annual precipitation was 53 cm but pan evaporation was nearly
225 cm per year.

2.1.4  Other Grasslands
     Outside of the midcontinent plains, major grasslands occurred in the in-
terior of California, as understory to conifers or as openings in the western
mountains, and as understory to arid-land shrubs in the interior northwest
and southwest.

     Kiichler   considered the native vegetation of the "California steppe" to
be perennial grasses of the genus Stipa.  Today, these grasslands plus portions
                                        45
of the surrounding, former oak woodlands   are dominated by introduced annual
                                             40
grasses, including Avena, Bromus, and Festuca.    Climatic data for the California
Agricultural Experiment Station's Hopland Field Station indicate great varia-
bility from year to year.    Mean annual precipitation for a ten-year period
was 94 cm, but  the range was 63 to more than 150 cm.  Summer droughts average
92 days in length and there are an average 70 days with frost each year.
Although the five unfavorable months divide the year into two separate growing
seasons, the dominance of annuals provides rapid response to community perturba-
tion.

     The palouse prairie (shrub steppe) of the Columbia plateau is dominated
by Artemesia tridentata, a shrub, and Agropyron spicatum, a bunchgrass.  The
area is characterized by hot, dry summers and cool, moist winters. '  Annual
precipitation is 25 cm or less.  Desert grasslands are superficially similar,
                                     2-3

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being associations of arid-land shrubs and grass understori.es.   Desert grass-
                                1 9
land near Las Cruces, New Mexico   is characterized by a black gramma climax
(Bouteloua eriopoda) with various combinations of desert shrubs, including
creosote bush (Larrea divaricata) and honey mesquite (Prosopis juliflora).
Mean annual precipitation is 23 cm with 55% coming between July 1 and
September 30.  Characteristic of desert regions, however, is wide variation
                                     9 1
and unpredictability of annual rains.    Several successive dry years reduces
perennial grass cover while a series of wet years can have the opposite effect.
Pan evaporation is approximately 236 cm annually and mean maximum temperatures
range from 13°C in January to 36°C in June.

     The vegetation of mountain grasslands varies with numerous factors, such
as latitude, altitude, slope and aspect.  Van Dyne*^ estimated a total area of
          2       ..       17
267,731 km  from Kuchler's   data, including that which occurs as understory
                                      2O f\
to ponderosa pine.  Site descriptions   '   indicate annual precipitation in
the range of 33 cm and mean annual temperatures in the range of 7°C.  Soils
(A + B horizons) may be fairly deep  (60 to 110 cm) with the grasses being
rooted to the full depth.  Agropyron and Festuca are the dominant grasses but
many other genera also are widespread.

     Many of the proposed cleanup procedures are qualitatively similar to pro-
cesses, either natural or man-induced, which have gone on previously in grass-
lands.  These have been divided into natural and man-made perturbations, those
activities which might be considered disruptive, and range improvement measures.

2.2  NATURAL PERTURBATIONS

2.2.1  Drought
     The distribution of plant communities in the central United States in
general conforms to the distribution of rainfall.  Any long-term changes in the
distributional pattern of rainfall would be expected to produce a general shift
in the distribution of plant communities.  There is evidence that such shifts
did, in fact, occur in the past.    A broad prairie "peninsula" extended into
Ohio during a warm, dry period following the last glaciation, but that prairie
was reduced to islands surrounded by forests by the time the first white settlers
reached the region.  Drought of a lesser extent is characteristic of the prairies
                                      2-4

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and, if of sufficient duration., affects the vegetational distribution.
Buffington and Herbel   reported that in 1858 over 90 percent of the Jornada
Experimental Range in New Mexico was "good grass" while by 1963 less than 25
percent was.  Located in a Bouteloua-Hilaria-Larrea association,17 a slight
shift in climate, with continued grazing, resulted in reduced grass cover and
                              1 2
an increase in desert shrubs.

     The drought of 1934-1936 permitted the invasion of shortgrass and midgrass
species into the tallgrass prairie zone.  Weaver and Bruner40 reported on an
Andropogon-Poa pasture which was converted to Sporobolus and Bouteloua.  Only
8 years were needed for recovery, however, once the drought had ended.

2.2.2  Flooding
     The effects of flooding are exactly opposite to those of drought.  Periodic
floods, as well as ground water percolation, produced flood plain forests well
into the shortgrass prairies of Montana and Colorado.-17
                     34
     Scifres and Mutz   reported on an area of coastal rangeland in Texas which
undergoes periodic flooding.  The native vegetation is mesquite-acacia savanna
in which the dominant grass is Setaria.  Low-lying areas (lagunas) may become
inundated with fresh water for as long as 5 to 10 years as a result of tropical
storms.  As the lagunas dry, a mesic sere is established which results in mid-
grass prairie, often dominated by spike dropseed (Sporobolus contractus).
Grazing capacity is doubled, relative to pre-flood stages, but long-term
grazing results in reversion to dominance by Setaria.

2.2.3  Fossorial Animals
     Fossorial (burrowing)  animals are characteristic of grasslands.  They include
ants and termites, as well as the more conspicuous vertebrates.  They all have
the net short term effect of setting back the development of both grassland
plant communities and soils.  This is accomplished through both the direct
consumption of vegetation and the burial of vegetation with soil brought up
from depths of two or three meters or more.
                                      2-5

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     Abandoned prairie dog towns have been valuable in the study of local succes-
sional patterns (seres).  Osborn and Allan' -reported on succession following
the decline of a prairie dog town in the Wichita Mountains of Oklahoma.   As
the colony declined over a 9-year period, it progressively abandoned the outer
perimeters of the town until there remained an 8-step representation of the
local sere in more or less concentric rings.  In the central, active portion of
the town, there remained barren soil with a few forbs.  On that portion which had
been abandoned the previous year grew an annual species of threeawn (Aristida).
The next stage was also annual threeawn and the next a mixture of annual three-
awn and forbs, indicating that the local sere requires three or more years in
the annual grass stage.  The next stage contained perennial grasses (Chloris,
Sporobolus) as well as threeawn.  That was followed by a shortgrass stage domi-
nated by blue gramma (Bouteloua gracilis) and buffalo grass (Buchloe dactyloides).
Next came what the authors called a subclimax midgrass stage, characterized by
silver bluestem (Andropogon saccharoides) and sideoats gamma (Bouteloua curti-
pendula).  The climax vegetation surrounding the abandoned prairie dog town was
a tallgrass prairie dominated by Panicum, Andropogon and Leptoloma species.

2.3  MAN-MADE PERTURBATIONS

2.3.1  Close Cropping and Grazing
     The nonselective removal of grasses, such as by mowing, produces results
which differ considerably from selective removal through grazing.  When species
composition and growing season biomass were studied in an Andropogon-Panicum-
Sorghastrum tallgrass prairie near Norman, Oklahoma,   it was found that denuda-
tion (close cropping and removal of mulch) had no significant effect on species
composition when compared to the control.  Net primary production  (NPP, biomass
produced during a single growing season) was greater in the denuded plots than
in controls, however.  Slightly different results were reported by Weaver and
Rowland   for tallgrass prairie in Nebraska.  They compared the prairie growing
on an abandoned dirt road with adjacent grazed or mowed fields.  Again they
found that yields (NPP) were 25 percent to 50 percent less in the  climax prairie
growing in the abandoned roadway than they were in the grazed or mowed fields.
However, they found a relative increase in the frequency of occurrence of
                                       2-6

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Andropogon in the roadway.  Since mowing is nonselective, they attributed the
increase in Andropogon to accumulation of natural mulch  (see Section 2.3).

     Grazing animals tend to select the plant species they consider to be most
palatable with the result being that intense grazing usually produces a shift
in species abundance.  In mixed grass prairies, grazing can result in shortgrass
                                   19 38
species replacing midgrass species,  *    and in a general decrease in canopy
        46
height.    In more arid regions, intense grazing pressure favors the establish-
ment of desert shrubs  and can interfere with reclamation attempts.
                                                                  13
2.3.2  Compaction
     The short-term effects of compaction are all negative.  The primary effect
is to increase bulk density of the soil (weight per unit volume) which decreases
infiltration of water, reduces water storage capacity, reduces aeration, inhibits
root penetration and restricts movement of soil animals.    These effects are
most severe in moderately wet soils and in those with a higher clay, but they
                                                              a
can be significant in coarse-textured, arid-land soils as well.

     The effects of compaction are not irreversible, however.  Stipa-bunchgrass
stands may be found growing on the streets of a Nevada ghost town   and climax
tallgrass prairie was reported to have been established 15 years after the
                                       42
abandonment of a dirt road in Nebraska.    Factors affecting the rate of recovery
from compaction include soil type, climate and presence or absence of surface
sealants.

2.3.3  Plowing
     The effects of plowing are in many ways similar to the activity of prairie
dogs.  Vegetation is killed and soil is turned over.  The major difference lies
in the fact that deep, organic-poor soil is not deposited on the surface by
plowing.  Most of our understanding of plant succession has come from the study
of abandoned agricultural land, most of which had been plowed for one or more
years.

2.3.4  Natural Succession
     Succession in tallgrass prairie can be extremely rapid, especially if a
                                                             27
suitable seed source is readily available.  Rice and Penfound   reported an
                                      2-7

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experiment carried out in an Andropogon-Sorghastrum^-Panicum prairie in Oklahoma.
In the first year after plowing, Ambrosia psilostachya (a ragweed) was the most
important dominant.  By the second year, the dominants in the control had
replaced the ragweed.  The authors concluded that "succession back to the
prairie stage was, therefore, extremely rapid under the conditions of the
experiment."

     The fruits of grasses tend to be windborne and the fruits of pioneer species
tend to be carried further than those of climax species.  Consequently, increasing
the size of the disturbance tends to lengthen the time required for succession.
             28
Rice, et al.,   indicated that the fruits of triple awn (Aristida oligantha)
are carried great distances and triple awn is typically the first invader in
disturbed tallgrass prairie.  Little bluestem (Andropogon scoparius) fruits
are windborne only about 2 meters and thus may take several generations to
reach the center of a large old field.
                                                                           25
     A typical tallgrass prairie succession was given by Perino and Risser.
Following abandonment of a cultivated field in Oklahoma, a weed stage is
established which persists for two or three years.  This pioneer stage is charac-
terized by Ambrosia, Sorghum, Bromus tectorum, and Rumex.  The weed stage is
followed by an annual grass stage lasting 9 to 13 years and is dominated by
Aristida oligantha, Aster sp., Ambrosia sp., and Andropogon saccharoides.
A perennial bunchgrass stage dominated by Andropogon scoparius follows and can
last 30 years or more.  Tallgrass prairie climax becomes established after 40
to 50 years and consists of Andropogon gerardi, A. Scoparius, and Panicum virgatum.
The weed stage is characterized by a predominance of live vegetation (51%) which
declines to 26 percent at climax.  Standing dead increases from 28 percent in the
weed stage to 32.5 percent in the bunchgrass stage and declines to 17 percent
in climax.  Litter increases throughout the sere from 21 percent to 57 percent.
Areal cover declines from the weed stage to the annual grass stage but increases
through the rest of the sere.
                                       2-8

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2.3.5  Range  Improvement

     2.3.5.1  Mulches--
     Mulches  increase soil moisture through increasing infiltration of precipi-
tation and reducing runoff and evaporation.  Soil moistures and temperatures are
                                                                          TO
stabilized and the conditions for germination of grass seeds are improved.
The effects of natural and synthetic mulcA^i are similar, but effectiveness may
                            1                              42                   -z
vary with the grass species,   growth stage of the grasses,   and local climate.
In desert grassland,   an increase in soil moisture of 20 percent, due to mulch,
increased forage production by 50 percent.  In climax tallgrass prairie, however,
naturally-occurring mulch was said to have reduced yields by 25 percent to 50
percent as compared to mowed or grazed fields where mulch did not accumulate.
In addition, application of mulch can reduce the frequency of less desirable
species, such as ragweed, by improving the conditions for emergence or growth
of the desired grass species.'
                             27,1
     2.3.5.2  Seeding--
     Seeding of desired grass species offers several advantages over dependence
on natural recovery.  First, it is often possible to bypass succession and seed
directly to climax.  Riegel, et al.,   seeded with climax species in west-central
Kansas and noted no differences in yields over a 17-year period when compared
to native grassland.  In other cases, selective seeding can actually improve
the range quality.  Rumsey   reported forage yield increases of up to 300 per-
cent in 7-8 years in an Agropyron/Arternesia association.  Seeding is not a simple
                                      2
proposition, however.  Bement, et al.,   were more successful with introduced
species than they were with native grammas, whereas Terwillinger and Jensen
had their greatest success with the grammas and other native species.  Seeding
success or failure depends upon a number of factors, many of which are beyond
direct control.  Terwillinger and Jensen   found seeding in shortgrass prairie
to be successful only when the precipitation to evaporation ratio was 0.3 or
greater.  Once the seed has germinated, sufficient ground cover must be achieved
before a periodic dry year to avoid wind erosion around the roots.  In drier
areas,.e.g., desert grassland and shrub steppe, probability of seeding success
declines unless extraordinary measures are taken, such as water entrapment,
reduction of competition from woody vegetation, delay of grazing, mulching, and
rigid seeding standards.
                                     2-9

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     2.3.5.3  Shrub Removal--              ,
     In 1858, over 90 percent of the Jornada Experimental Range in New Mexico
(Desert Grassland) was in good grassland range and by 1963 that figure had
declined to less than 25 percent.    Climatic change may have been partly
responsible but grazing pressure on the grasses certainly gave a competitive
advantage to the shrubs.  Range restoration   included plowing to 9 inches
to kill the shrubs, seeding, and nft-i'sture trapping.  In addition to range
restoration, new range has been created from shrubland by clearing of shrubs
                                     50
and seeding with appropriate grasses.

     2.3.5.4  Moisture Trapping--
     Twenty-five centimeters annual precipitation is generally considered to be
the minimum required for successful revegetation of disturbed lands; less
                                                                     9
requires intensive management including irrigation and fertilization.    Re-
clamation and improvement of desert grasslands is further impeded by generally
low infiltration rates so that much of the precipitation received is lost as
runoff.  Seeding success and production of herbage have been improved through
the construction of pits which trap runoff and allow a greater time for infiltra-
tion.  In southern Arizona where annual rainfall averages 15 to 20 cm, moisture
penetration averaged twice as deep and herbage production was five times greater
when pits were employed as compared to adjacent flats.    In a Utah salt desert,
Wein and West   found that moisture entrapment was essential to survival of
crested wheatgrass (Agropyron cristatum) seedlings even if there had been suf-
ficient rainfall to produce germination without entrapment.
2.4  EFFECTS OF CLEANUP PROCEDURES ON PRAIRIE
     This section describes the effects that imposition of certain contamina-
tion cleanup treatments produce on prairie ecosystems.  Qualitative descrip-
tions of the effects caused by each cleanup treatment are related in this sec-
tion; the quantitative assessment of the  impacts of cleanup on prairie ecosys-
tems is given  in Section  2.6 with estimates of the relative times for a return
to the native  ecosystem.   Recovery time projections are based upon the presump-
tion that,  if  man were restrained from interfering, plant succession would go
                                       2-10

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 forward under the vegetative potential at the site and climate to recreate
 a prairie.  Reclamation procedures and other "management" of prairie sites
 is discussed in Chapter 8.
      Three groupings of the cleanup procedures can be seen in this section.
 First is cleanup that provides temporary holding of a contaminant in place.
 Second are procedures that remove the physical contaminant and stabilize the
 site until renovation occurs, and third are alternatives to holding and
. removing the contaminant.

      (0-1) Natural Rehabilitation
      No significant impacts are expected to remain more than two or three years
 after manual cleanup.   Annual grasses will occupy the shoveled and scooped-out
 excavations during the next growing season and that may be the entire sere.
 No "area" effect is anticipated.   The extrapolation is one of a succession of
 "pock-marks."

      (1-1)   Chemioal Stabitization
      When vegetative cover is removed, soils become subject to accelerated
 erosion by both wind and water.   The various 'stabilization practices may tend
 to retard the initial  stages  of revegetation.   Chemical  stabilizers form a less
 permeable surface  layer which reduces infiltration of water and may also prove
 to be a physical barrier to seed  germination.   Further,  dark-colored emulsions
 may increase soil  temperatures above the range of tolerance for germinating
 seeds.   With time,  however, cracks tend to develop in stabilized areas  which
 both allow seeds to germinate and channel runoff to seeds sprouting in  the
 cracks.   As natural rainfall  decreases,  cracks in soil sealants can provide
 micro-habitats  which support  relatively vigorous growth.   In prairies,  however,
 sufficient  moisture to permit revegetation is  usually available and stabiliza-
 tion techniques  which  retard  revegetation must, be viewed as negative, long-term
 impacts.
      The properties of two groups of soil additives,  1)  chemical stabilizers
 and 2)  chemical  stabilizers with  mechanical properties,  are given in Appendix
 A,  Stabilizers.  Eleven of the chemical  stabilizers are  rated "preferred" for
                                      2-11

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prairie use, 10 of these require post-application site renovation for plant
regrowth; 7 of the 25 "preferred" chemical stabilizers with mechanical proper-
ties permit immediate natural regrowth of vegetation.   All eight of the pre-
ferred stabilizers are rated to break down in a year or less after application.

      (1-2)  Clear Cutting  Vegetation
     Clear cutting of grasses  (mowing) and removal is a common practice with
well-documented results  (Section 2.3).  Since the process is nonselective,
there are virtually no effects on species composition and, in the short term,
productivity is actually increased.  On shrub-free grasslands, effects of
mowing and removal would probably not be discernible with a single growing
season.  The presence of woody shrubs, however, increases the impact of clear
cutting.  Woody plants have their meristematic  (growth) tissues  located at the
tips of  branches  as opposed to at ground  level  in grasses.  Clear cutting thus
removes  the primary growth tissues resulting in longer recovery  times.  Most
woody plants do have the ability to form  stem tissue at the roots  (root-sprouting)
so that  clear  cutting may  have no profound effect on long-term community compo-
sition.  A  one-time clear-cut would allow woody plants to resprout using food
reserves stored in the roots but, as  farmers well know, repeated cuttings
deplete  stored reserves  and eliminate the woody component.

      (1-3)  Stump-ing and  Grubbing
      "Stumping and grubbing"  of grasses,  that  is, the  removal of a major portion
of the root system,  is not possible,  owing to  the diffuse  nature of  their root
systems. The  procedure  will prevent  root sprouting of shrubs and  will prolong
the  period  needed for  complete recovery.   Since reestablishment  of shrubs would
then depend on reseeding,  the  size  of the area treated would be  proportional
to recovery rate. A secondary impact would  be the  effect  of the treatment on
the  area's  attractiveness  to  wildlife.   Grasses,  generally, produce  a single
vertical stratum  which limits  the  number of  niches  available to bird species.
As  shrubs  and trees  are added to grasslands, the number  of strata increases
 resulting in  increases in bird species  diversity.   Removal of  shrubs, trees,
 or both could produce losses of bird species lasting decades  or more and could
                                       2-12

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possibly lead to the eradication of species already faced with limited habitat.
A detailed discussion is deferred to Chapter 10.
     Positive results of shrub removal would include improvement of pasture
for cattle.  Following the discussion above, it is apparent that improvements
would persist longer as size and severity of the treatment are increased.
Further, seeding success of shrubs would initially be reduced by the presence
of the grasses but, once established, shrubs are successful competitors of
grasses.  The presence of cattle yields a favorable competitive balance to
shrubs since cattle will selectively remove grasses, when they are available.

     (1-4) Sor aping and Grading
     Surface scraping and grading of the upper 5 cm of grass roots and soil
could reasonably be expected to have only a moderate effect on grassland eco-
systems.   In the prairies,  ground irregularities would preserve the meristematic
(growth)  tissues of a portion of the grass plants allowing relatively rapid
recovery.   Soil compaction,  if done with crawler tractors, could possibly have
a greater impact than the blading itself.   In mountain grasslands,  shrub steppe
and desert grasslands,  blading would remove the woody component yielding a
significant change in community structure.   Release from competition could
result in an increase in grass cover in arid zones with a corresponding
increase in animals utilizing grasses.   The number of niches would  be decreased,
however,  with a resultant displacement of the birds and insects which require
vertical heterogeneity in a plant community.  Taking the extreme examples,
       2          2
0.01 km  and 10 km  of blading, the lesser disruption would produce effects
probably too slight to measure while the larger could have significant effects.
The significant effects could be both detrimental,  such as long-term loss of
bird species, and beneficial,  such as range improvement for domestic livestock.

     (1-5)  Shallow Plowing
     Shallow plowing (<10 cm) will not penetrate the sod layer of most grasses
and would probably do no more than break off woody plants, allowing them to
resprout.  It is not likely to be used as a clean-up procedure and if used is
not likely to have much impact.
                                     2-13 '

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     (1-6)  Deep Plowing
     Deep plowing (up to 40 cm) would result in complete removal of the eco-
system with succession starting from bare ground.  This is the perturbation
that farming represents and is the best known event leading to secondary
succession (Section 2.3).

     (1-7)  Soil Cover Less Than 25 cm
     A number of factors can affect the outcome of adding soil cover to the
community.  With shallow coverage (<25 cm), quality of soil applied, actual
depth, and plant community would all affect impact level.  The more shallow
the soil cover the less disturbance would occur, generally.  In a mixed
plant community, woody vegetation would tend to be disturbed less than grasses.
In either case, grasses recover more quickly.  The addition of porous topsoil
would have less detrimental effect than adding subsoil, since the roots might
still receive sufficient aeration.

     (1-8)  Soil Cover 25 to 100 am
     There is probably no difference between adding 25 cm or less soil and up
                                                         2
to 100 cm.  Even the smallest area to be covered, 0.01 km , would require 2500
m  of soil for coverage to 25 cm.  Expediency would undoubtedly result in
coverage with any soil available with the result that effectively all of the
vegetation would be killed.  Thus, burial would result in a successional start-
ing point similar to scraping and grading (1-4), plowing (1-5, 1-6) or soil
removal (2-1, 2-2).

     (2-1)  Remove Plow Layer
     Soil removal is a radical perturbation to an ecosystem.  Removal of the
plow layer (^15 cm) would have an increasingly serious impact with decreasing
mean annual precipitation.  In tallgrass prairie, the effect could be no more
serious than plowing, for the A soil horizon extends well below that depth
(Section 2.1).  In shortgrass prairie, removal of the plowed layer could result
in virtual loss of the A and B soil horizons with long-term impairment of the
production capability of the soil.
                                      2-14

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     (2-2)  Remove Shallow Root lone
     Removal of the shallow root zone in tall- and midgrass prairies is
almost a contradiction of terms due to the depths to which grasses are rooted
(Section 2.1).  Shallower soils, such as some shortgrass prairies, desert grass-
lands and mountain grasslands, could be removed down to C-horizon material if
30 cm of soil or more were removed.  This would result in revegetation problems
analogous to deep cuts along roadways or spoil-bank reclamation.  Comparable
removals in tallgrass prairie might shorten the projected cultural lifetime
(i.e., number of centuries which the land might be tilled successfully) but
the short-term (e.g., decades) effect might be indistinguishable from the effects
of plow-layer removal.
     In either case, as with scraping and grading (1-4) and plowing (1-5, 1-6),
the complete removal of vegetation and exposure of soil would lead to predictable
erosional losses.  Water erosion potential is obviously greater under the higher
precipitations and storm-intensities found in the more eastern grasslands.  These
losses should not exceed normal agricultural losses on a scale of 0.01 to 0.1
  2                                               22
km  and, depending on locality, possibly over 1 km .  At the 10 km  scale,
however, significant increases in erosional losses may be anticipated, for it
would be hard to imagine landscape units of that magnitude which did not include
major drainages.  Thus, complete removal of the soil or its retaining vegeta-
tion would effectively prohibit sedimentation from occurring prior to entry
into major drains.
     Potential losses from wind erosion increase both with increases in the
size of the barren area arid with the reciprocal of the square root (l//r~) of
                      49
surface soil moisture.    Again losses would be comparable to normal agricultural
losses when the area disturbed was similar in size to agricultural fields.
Plowed fields are typically broken up with trees planted for windbreaks, the
removal of which would increase soil losses exponentially since the sheltered
zone is calculated as ten times the height of the trees.
     (2-3)  Remove Scraping and Grading* Medhanioally Stabilize
     Removing less than 5 cm of soil impacts prairie ecosystems less than
removing a shallow plow layer (2-1).  The mulch layer would be taken, with
                                      2-15

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a reduced impact on seed stores, soil tilth, and fertility, but wind erosion
effects could be approximately equal.  Wind erosion on bared, prairie soil is
precipitation dependent.  For prairie witn low precipitation (shortgrass) the
length of unobstructed wind run and soil particle aggregation at the exposed
surface become critical factors that determine the site wind erosion potential
in dry seasons of the year.  In tallgrass prairie climates, soil losses by
wind erosion are normally minimal.
     Stabilization is attempted to retard erosion, a desired result, but
carries with it a slowing of plant establishment, an undesired result.  Mechanical
and chemical stabilization perform differently.  Mechanical stabilization
compacts the soil while chemical stabilization binds soil particles together.
Either is accomplished by a number of methods or chemical agents, all with
qualitatively the same results relative to plant establishment and growth.
The properties of stabilizers are evaluated in Appendix A, Stabilizers.
     Few mechanical stabilizers are rated "prefe-red" for prairie soils in
Appendix A, including deflocculants, clays, and membranes.  Natural and
synthetic rubbers, polyethylene and vinyl membranes, paraffin wax, plus asphalt
emulsions exhaust that list, and only the asphalt emulsion permits regrowth
of plants the next season.
     One popular method of mechanical stabilization depends on soil clay and
physical compaction to make an impervious surface.  This may compress soil
sufficiently in making the physical barrier that it prevents subsequent seed
wetting and seedling emergence and revegetation.  Soil moisture input through
the compacted layer is decreased by two conditions.  Permeability to surface
water is seriously impaired by pore space reduction and a shortening of
infiltration opportunity occurs because of faster runoff from the smoothed
surfaces.  Runoff can readily become 70% of annual precipitation.  The
effects on revegetation, in principle, are similar among deflocculants, added
clays, and direct surface compaction.  Heavily treated areas are toxic to
plants but are likely to be breached in a few months by resident small rodents.
The composite effects of surface soil compaction are intermittantly visible
in reduced vegetative growth for decades afterwards (Section III).
     The use of meshes and mulches to reduce erosion are described in Sections 4.4
and 8.4 of Chapters 4 and 8.
                                      2-16

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                                          y Stabi lize
     Revegetation potential at the cleanup site will be partially reduced
compared to plowing (1-5, 1-6), by loss of seed sources, mulch layer and
the upper fertile A-horizon.  The significant revegetation impact is caused
from compaction by stabilization and its effect on water infiltration and
seed emergence.  The smoothed surface allows rapid runoff with the possibility
of water concentration leading to piping and gully development on long over-
land runs.  The high organic matter will make stabilization more difficult.
Physical retardation of seedling emergence limits early revegetation to shrub
crown sprouts.  Gradually frost heaving, aided by localized punctures of the
surface by shrubs and small rodents, will be effective in opening the surface
to serious erosion; runoff water erosion in tallgrass and eastern midgrasses
and wind erosion at western mixed grass and shortgrass sites.  This treatment
becomes a degraded version of 2-1.  Chemical stabilization is preferable in
the eastern prairie.

     (2-5)  Remove  Shallow Boot  lone, Mechanically Stabilize
     Treatment 2-2 has defined the ecological effects of removing 40 cm of
prairie soils and the mechanical effect of stabilizing was covered in Treat-
ments 2-3 and 2-4.   This cleanup has severe side effects on shortgrass soil
profiles because most of the B horizon will be removed and with it much of the
fertility needed for revegetation.  On these westside soils renovation is
required before succession toward grasses will begin.  This is next to the
most severe treatment on prairie.

     (2-6) Remove  Scraping and Grading,  Chemically  Stabilize
     This composite treatment appears similar to treatment 2-3 but is much
less drastic.  In some respects it has an impact equivalent to windrowing of
the surface which might be done in 1-4.  While there is a loss of surface
seed stores,  the potential for erosion is reduced by chemical stabilization
while revegetation is started.   Breakdown of chemical stabilizers occurs in
the next growing season if one of the preferred treatments from 1-1 is applied.
Revegetation  should have produced a crop of annuals  in the grasses and crown-
sprouting of shrubs should be well underway.  Because these stabilizers are
limited to relatively small areas (Appendix A) natural seeding should suffice.
                                      2-17

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     (2-7)  Remove Plow Layer*,  Chemically Stabilize
     The effects of removing 10 cm of surface sod present some problems to
cleanup crews.  Using a turf-cutter would be the most likely procedure but
its decontamination effectiveness would be limited by micro-depressions and
contamination inside burrow tunnels.  Plowing was described in Treatment 1-5
and those comments apply.  The net effect of removing the plow layer to 10 cm
would be quite similar to Treatment 2-6 just described and hav&;, the same
impact on soil fertility.  The impacts would be greater in shallow soils where
the plow layer is deeper than the A horizon.  The prospects for revegetation
would be impaired to a minor degree.

      (2-8) Remove Shallow Root Zone, Chemically Stabilize
     This is  a radical treatment because of the removal of the fertile, plant-
supporting medium on many sites and exposure of the  C horizon in shortgrass
prairie.  The application of chemical  stabilizer to  small areas as wind-erosion
protection can be tolerated but revegetation potential seems similar to 1-6,
starting from bare ground.  Severe wind erosion should be expected in  2 or 3
years.

      (3-1)  Barriers to Exclude People
     Fencing  of a contaminated area to restrict movement of man and other
animals has been proposed as an alternative to decontamination, at least temporarily.
Generally speaking, barriers can prevent direct contamination but can  be ineffec-
tive in preventing contamination by way of the food  web.

      (3-2  Exclude Large Animals)
     Fences designed to  exclude cattle and other large grazing mammals will
block one direct link in the food web  leading to man.  The release from grazing.
pressure will not necessarily be a desirable impact  on the grassland ecosystem,
for the resulting increase  in standing dead organic  matter and mulch will have
a  tendency to reduce primary production.  Large exclusion areas would  prove to
be an economic burden to the local population and  possibly a detriment to
                                       2-18

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migrating wildlifei  Otherwise, the species diversity and stability of the
ecosystems would not be significantly affected and will not be treated
further.
     (3-3)  Exclude Large and Small Animals

     The effect of barriers to exclude small mammals (rodents, etc.) will be
dependent, at least in part, on the size of the area fenced.  Small areas, on
                    2
the order of 0.01 km , may prove to be too small to support viable populations.
The resultant release from rodent, as well as large mammal, grazing pressure
could possibly begin to affect the rate of return of nutrients to the soil and
overall community stability.  Such a small area is not likely to be unique and,
if not, the loss cannot be considered to be significant.  Large areas, on the
order of 10 km , would contain self-supporting populations of small mammals
and would be largely unaffected by barrier erection.  Gene flow and genetic
plasticity could become affected, in time, but insufficient data exist to
evaluate this effect.

     Neither birds nor insects can be effectively controlled by barriers.  In
the case of upland game birds, such as ring-neck pheasants, feeding in the
contaminated area could lead to direct contamination of man.  However, insects
are sufficiently small and far removed from the human food web, so unless the
contaminant is extremely mobile, contamination by way of insects is unlikely,
although some insect vectored contaminents might prove toxic to migratory birds.
     (4-1)  Asphalt Hard-Surface Stabil-Lzat-Lon
     Decomposition of 3-inch-thick, unsupported hot mix asphalt requires more
than 10 years in the midgrass prairie on sandy soils when trampling by cattle
is prevented.  In the meantime, reinvasion by stands of grasses is blocked
until the asphalt fractures or the surface cracks.  The retardation of revegeta-
tion is absolute but if soil moisture conditions were right at .the time of
surfacing cold weather frost heaving can fracture the asphalt enough to allow
seed penetration, and germination and growth in the next season.
                                        2-19

-------
     Where shrubs intermingle with grasses the likelihood of puncture  by root-
or crown-sprouts is high.   Holes made by the sprouts and the new shrubs  act  as
collection points for debris, weed and grass seeds,  and soil.  Seeds germinating
in the drift piles speed breakup and weathering of the asphalt around  the
punctures.  Those local species that normally reproduce from seed should remain
at these breaks.
     Soil compaction by the tank trucks and heavy trailers needed for  asphalt
surfacing would be evident more than a century later as demonstrated by bison
wallows and trails.  Hydrological impacts generated by the hard surface would
equal those described for Treatments 2-3, 2-4, and 2-5, but the site prepara-
tion impacts are greater than those treatments cause.
     The gross effect of the asphalt hard surfacing is to delay for a decade or
more, beyond the delay caused by Treatment 2-5, the entry of the site into the
prairie sere.  The treatment might be tolerated in shortgrass prairie as a
secure, temporary cover to minimize redistribution of contamination, the
certainty of breakup in a few years makes that use highly questionable.   The
potential for gully creation in the relatively mesic tallgrass prairie precludes
use there anytime.


     (4-2)  Concrete Hard-Surface Stabilisation
     Covering a site with concrete deals the ultimate impact among those cleanup
treatments proposed.  All the disadvantages of asphalt surfacing plus the several
times greater durability of concrete chunks and blocks make  later uses contingent
on removal of the concrete.  This would be exceedingly expensive in either
transportation costs or onsite burial.
                                       2-20

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 2.5  RECOVERY  AFTER CLEANUP

 2.5.1  Irreversible Changes
      No  irreversible changes  are  anticipated with  scraping  and  grading, plowing,
 vegetation  removal  or flooding.   Each  falls within the  range of analogous
 perturbations  (discussed  in Sections 2.2  and 2.3 for which  successional informa-
 tion  exists.   Whether or  not  irreversible changes  (i.e.,  failure to reestablish
 a  similar community within  25 years or more) would occur  as the result of soil
 removal  or  buri,ai would depend upon local  conditions and  the extent of per-
 turbation.   In most  cases,  no irreversible changes would  be anticipated for
 removal  of  the plow  layer of soil or if suitable soil were  used for burial.
 In more  extreme cases, such as on shallow mountain soils, in the most arid
 margins  of  grassland  distribution or where burial  was with  particularly low
 quality  material, extraordinary reclamation procedures might be required for
 successful  reestablishment  of vegetation.  These might include  the land manage-
 ment practices (Chapter 8)  of water entrapment, irrigation  or addition of soil
 amendments.   It should be noted, however, that reestablishment  of vegetation
 on a site does not imply  lack of irreversible changes, nor  does irreversible
 change imply complete loss  of a resource.  The change may lower productivity
 and prevent recovery of climax by establishing an  entirely  different flora than
 the displaced grasses.

 2.5.2  Rates of Recovery  Following Cleanup
     Rates of recovery are affected by several factors, including severity of
perturbation, proximity to seed source, local climate and soil conditions.   In
general,  recovery will be most rapid the less severe the perturbation, the
smaller the area involved and the greater the normal rainfall.   In the dis-
cussion that follows, certain caveats are appropriate.   Conclusions will be
drawn for major plant associations such as tallgrass prairie,  which may cover
on the order of 10  km .   The data supporting those conclusions are drawn from
studies which represent small  samples from within the larger association and
typically do not begin to cover the range of possible seres.  In a few instances,
appropriate  seres simply have not been documented and it has been necessary to
extrapolate  from the most similar situations that could be identified.  It  is,
                                       2-21

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therefore, assumed .that this analysis will be useful in formulating policy
but that field-level decisions will require site-specific infoi-mation
     Idealized trend curves were developed as guides to illustrate the time
course of recovery to full productivity for some of the prairie ecosystem
parameters.  The o'rdinates are without, units either because they have no
dimensions (e.g., homostasis) or they are broad generalizations over the
array of heterogeneous prairie sites.  Representative cleanup treatments were
selected for the illustrations.  Assisted and unassisted recovery are shown in
Figure 2-1; recoveries of grasses and woody elements are illustrated in
Figure 2-2, and in Figure 2-3 the maximum contrasts in impact effects are shown.

     2.5.2.1  First Year  Following Cleanup--
     With at least two cleanup procedures, mowing and fencing (clear cutting
and barriers), prairies should attain complete recovery within one year.
        24
Penfound   reported that denudation resulted in no significant change in
species composition and actually resulted in an increase in biomass.  Since
"stumping and grubbing" are inappropriate for prairies, denudation would
consist only of mowing and removal of biomass.  Complete recovery can, there-
fore, be assumed after one year.  Size of area mowed would have no effect.
     If a suitable seedbed remains after cleanup, prairies may be seeded
directly to climax?0  thus providing for near recovery the first year.  This
would include scraping and grading, plowing, and most instances of soil re-
moval where some A horizon is left as a seed bed.  The addition of nitrogen
fertilizer can aid establishment of perennial grasses   especially if suffi-
                          q
cient moisture is present.   Size of area is unimportant.
     Assuming a suitable  seedbed remains but with reliance on natural revegeta-
                                                                           2 Q
tion, then the size of the area disturbed becomes important.  Rice, et al.,*°
reported that the seeds of a climax species were windborne only about 2 m while
the seeds of an early invader were carried a great distance.  Thus, assuming
seed sources completely surround the disturbed area and no differences exist
due to prevailing wind direction, in one year seeds of the climax species might
                            2
reach 7 percent of a 0.01 km  circular plot  (the configuration for maximum
potential  invasion under  the stated conditions).  The area invaded declines to
                                       2-22

-------
    0-t NATURAL RECOVERY
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                           2-23

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            12 CLEAR CUTTING
         13 STUMPING & GRUBBING Of

            WOODY COMPONENT
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   Figure  2-2.   Time course of change after mowing  (1-2) and  stumping

                 and grubbing (1-3)  of woody component of prairie.
                                     2-24

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   23
   2-4 MECHANICAL SOIL STABILIZATION
   2-5
                                                 3-1 BARRIERS (LARGE MAMMALS)
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Figure  2-3.  Recovery of  prairie  following  mechanical  soil stabili-
              zation and response  to the erection of  fencing.
                                    2-25

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                                                  2      ">           2
2 percent, 0.7 percent, and 0.2 percent for 0.1 km , 1 km ,  and 10 km  circular
plots, respectively.
     In areas not reached by seeds of the climax species, first-year invaders
are annual grasses and "weeds.
                              ,,4
                             27                23
include Ambrosia psilostachya   and Aristida sp.
In tallgrass prairie,  first-year  invaders
                 Russian thistle  (Salsola
kali) is a first-year invader of mixed prairie.    Launchbaugh   reported first-
year basal area cover of 20 percent to 60 percent in Texas mixed prairie with
the annual grass Panicum texanum providing 36 percent of the cover.  Other
annuals provided another 10 to 15 percent cover with the reminder due to non-
climax perennials.  First-year invaders of shortgrass prairie include Salsola
kali, Amaranthus retroflexus, and Chenopodium album.
     The annual weed stage persists for more than a year, typically.  In an
Oklahoma old-field studied by Perino and Risser   a weed stage comprised of
Ambrosia, Sorghum, Bromus, and Rumex persisted 2 to 3 years.  Characteristic of
the weed stage is the relatively large proportion of community biomass con-
tained in the living vegetation component, 51 percent as compared to 26 percent
in the tallgrass prairie climax for the area.
     To summarize first-year conditions in prairie natural successions, there
is little ground cover and that which is present is comprised of plants which
die at the end of the growing season.
     If the cleanup procedure has left the surface with a less than suitable
seedbed, such as might be the case when soil is added to the surface, then it
is entirely possible that no significant, invasion will occur during the first
year.  Stabilization would be required to prevent erosion and would result in
still further delays in vegetation establishment.  Improvement of the seedbed,
such as addition of fertilizer and mulching if precipitation averages less
                g
than about 7 cm   can lead to seeding success.  If the imported soil is of a
quality to encourage recovery, then it may also contain weed seeds which may
                                                 9
initially out-compete the local, desired species.

     2.5.2.2   Fifth Year  Following Cleanup--
                      41
     Weaver and Bruner   reported that 8 "normal" years, including 3 consecu-
tive "good" years restored a tallgrass climax which had been converted to
                                     L-26

-------
 midgrass by the drought  of 1934-1936.   It  is  assumed  that  5  normal  years  follow-
 ing a particularly wet year,  would operate on a similar time scale.
      Under  the  natural  revegetation  of circular  plots,  and  assuming  the  2
m
                                                         28
 movement  of climax  species  seeds  suggested  by Rice  et  al. "  continues  each
 year,  nearly one-third  of a 0.01  km  disturbed area would  be in  climax vege-
                                       •  2         '                - •   .
 tation.   Only about  1 percent  of  a 10  km disturbed area would be in climax.
     Areas  too far  from seed sources to  contain climax species would,  after
 5 years,  remain in  an earlier  successional  stage.   Osborn  and Allan ^ identi-
 fied 7 serai  stages  within  a 9-year succession;on an abandoned prairie dog
 town.  The  midpoint, after  about  5 years, was  characterized  by a  mixture
 of annual grasses (Aristida sp.)  and subclimax perennial grasses  (Chloris and
 Sporobolus).   In another abandoned prairie  dog town,    subclimax  perennial
 grasses dominated after 7 years.  Each area wa:; a tallgrass  prairie climax.
     After  5  years following plowing of  midgrass prairie,    it too was a
mixture of  annual grasses (Aristida) and subclimax,  perennial grasses
 (Paspa1urn and  Andropogon).   Climax grasses  had begun to appear but contributed
an insignificant amount of  the total cover, only 0.2 percent.  Total ground
cover  (basal  area) itself,  was less than half  that  of  the regional climax.
     Thus,  cleanup procedures which leave a suitable seedbed would most
likely remain  in subclimax  grassland following  5 years of natural succession.
Burial with soil could  yield similar results  if the  quality of the soil added
is similar.   Reliance on natural  succession on  poorer  quality soil material
would probably result in slower rates of succession with annual grasses and
forbs possibly predominating after 5 years.

     2.5.2.3  Tenth Year Following Cleanup--
     For each of the cleanup procedures which  leaves a plowed-fieldTlike
starting point, all  prairies should be in subclimax grassland after 10 years.
Tallgrass prairie regions may still be dominated by midgrasses and mixed
grass or shortgrass  prairies may be dominated by bunchgrasses.  The 9^-year-old
successional stage in the abandoned prairie dog town   was subclimax mid-
grasses,  silver bluestem (Andropogon  saccharoides)  and sideoats gamma  (Bouteloua
                                     2-27

-------
curtipendula).   Tallgrass prairie was the regional climax.  A.  saccharoides
still comprised 84 percent of cover after 14 years in Texas tallgrass prairie
                              I O
and 31 percent after 20 years.    Western wheatgrass (Agropyron smithii),
needle-and-thread (Stipa comata)  and feather bunchgrass (Stipa viridula)
                   	                                            47
dominated abandoned fields in western North Dakota within 10 years.     The
authors stated that these midgrasses were characterized by low total density
but that they nevertheless produced a relatively high yield of good quality
forage and were valuable hay land.
     Not all authors agree, however.  Booth   stated that annual grasses still
predominated after 10 years in southeastern Kansas and east-central Oklahoma.
     Few differences between cleanup procedures would be discernible after 10
years of prairie succession.  Prairie soils are sufficiently deep that scraping
and grading, deep or shallow plowing or removal of soil up to 30 cm would leave
a sufficient seedbed to produce comparable stands within a decade.  If burial
had been with particularly low quality soil, and no other treatments had been
performed, then succession would lag sufficiently that prairies might remain
in the annual grass or grass/forb stage after a decade.

     2.5.2.4  Climax--
     Tallgrass prairie apparently can return to climax very quickly if the
disturbed area is small and climax species are nearby.  Weaver and Rowland
reported that Andropogon-Sporobolus-Panicum prairie was established on a dirt
road only 15 years after abandonment.  Perino and Risser   reported a somewhat
longer .sere.  They described a 4-stage sere starting with (1) a weed stage
(Ambrosia, Sorghum, Bromus, Rumex) lasting 2 to 3 years,  (2) an annual grass
stage (Aristida oligantha, Andropogon saccaroides) lasting 9 to 13 years, and
(3) a perennial bunchgrass stage  (Andropogon scoparius) lasting 30 years or
more.  Equilibration or climax would not occur, therefore, for 40 to 50 years
following disturbance.  Climax was Andropogon gerardi, A. scoparius and
Panicum virgatum.
     Costello   described succession in northeastern Colorado mixed grass
prairie as  (1) an annual forb stage  (Salsola kali, Amaranthus retroflexus, Cheno-
podium album) lasting 2 to 5 years,  (2) a forb stage  lasting 3 to 6 years,
(3) a short-lived perennial grass stage  (Schedonnardus paniculatus, Hordeum
                                       2-28

-------
jubatum,  Sporobolus cryptandrus) lasting 4 to 10 years and (4) an Aristicla
stage (Ar ist ida 1ongi s e t a and A. purpurea) lasting 10 to 20 years.  Transi-
tion to climax was estimated to take another 10 to 20 years.   Thus, the sere
could be as short as 15 to as long as 60 years with drought cycles retarding
succession and wet years accelerating succession.
                18
     Launchbaugh   described the sere-of the San Antonio Prairie in Texas.
Following cultivation, an annual grass stage was established the first year
with Panicum texanum being the dominant.  Annuals gave 82 percent to 85 per-
cent of the cover and subclimax perennials gave the rest.  No climax species
were present the first year and cover (basal area) was low 20 to 60 percent.
After 5 years, annuals (Aristida supp.)  contributed only 46 percent of the
cover and subclimax perennials had increased to 47 percent (Paspalum and
Andropogon).  Climax species were represented (0.2%) and basal area had in-
creased to 2.1 percent.  After 14 years, annuals were only 7.2 percent of the
plants present and subclimax perennials (Andropogon saccharoides) had increased
to 84 percent.  Climax species  (Sporobolus and Stipa) had increased to 5 per-
cent and basal area had increased to 2.7 percent.  After 20 years, annuals were
3.5 percent and subclimax perennials 31 percent.  Climax species had increased
to 60 percent, most of which were Andropogon scoparius.  Basal area was up
to 3.3 percent.  No estimate of the additional time required to reach climax
was given.  A climax community was described, however, and the climax species
 (Andropogon and Bouteloua) were 94 percent of the vegetation and basal area
v;as up to 4.8 percent.  Both annuals and subclimax perennials were represented
in the climax community, 1.3 percent and 1.1 percent respectively.  Whitman,
       47
et al.,   estimated 40 to 60 years or more were required for succession to
climax in North Dakota mixed grass prairie.
     A shortgrass prairie in Colorado was still in the annual grass (Aristida)
                                         35
stage 21 years after abandonment.  Shantz   estimated to reach climax in  short-
grass (Bouteloua-Buchloe) prairie it would take 20 to 50 years following plowing.
                                     2-29

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2.6  QUANTITATIVE ASSESSMENT OF CLEANUP IMPACTS
     The boundless forests of the eastern U.S. are matched, in diversity by
the limitless span of grasslands reaching west up the Rockies from the eastern
forest's edge.  On high western plains removal of 40 cm of soil (2-2) leaves
an alkaline, frequently saline excavation in North Dakota, with 300 to 500 mm
annual precipitation-for short and mixed grasses to revegetate the Colorado
plains on intermittantly exposed parent material (A through upper B, horizons
removed).  On the excavated eastern prairie there may be no noticeable reduc-
tion in soil profile properties, plus 1800 mm of precipitation falls under
which tall grass revegetation will progress.  Assessments of cleanup impacts
and subsequent time to recover productivity are reduced to generalities that
address this range of site diversity.  Over their summer rain, wind, and
unshaded range, the grasses did maintain, with rare exceptions, an almost
permanently dry subsoil below the root zone.  This land has been appropriated
throughout for agriculture.  Recovery is treated in this chapter in the context
.of principles governing an unmanaged ecosystem; agriculture is examined in
Chapter 8.

2.6.1  Impact Assessment
     Mowing prairies (1-2) has no long-term effect.  The slight increase in
impact rating with increased area relates to reduced food availability to
herbivores and reduced cover for wildlife.  Scraping and grading (1-3), and
shallow plowing (1-5) have limited impact when localized but represent an
extension of the trend mentioned for mowing.  Deep plowing (1-6) requires
reinvasion of species from outside of the disturbed area, hence the greater
increase in impact level as area increases.  Soil burial (1-7, 1-8) requires
plant reinvasion and also has greater impact as area increases.  But since the
transported soil added is assumed to provide a seedbed inferior to the soil
covered up, impact is greater than for other treatments requiring reinvasion,
such as deep plowing.  Soil removal (2-1, 2-2) requires reinvasion also and
since deep plowing may leave seeds to germinate, the removal of seeds with
the soil results in a greater impact.  One intuitively feels that removal of
up to 40 cm of topsoil should be a greater impact than removal of 10 cm.  In
deep prairie soils, however, it is not entirely clear that it  is.  Hence, there
is just a slight increase in impact level.  Barriers to exclude people would have
                                      2-30

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essentially no impact on prairies.  Trees might invade the eastern prairie
remnants if man-made fires were excluded, but that is not considered a negative
impact.  Exclusion of animals by barriers (3-2, 3-3) should have little long-
term impact, since the grasses to support grazers would remain.  Animal popula-
tions are expected to quickly recover when permitted back in.  Paving represents
the ultimate loss with the area paved being the only qualifier.

2.6.2  Recovery Assessment
     Factors which affect the rate of recovery in prairies have been discussed
in Sections IV and V.  Because of the interactions of those factors, quantifica-
tion of the time required for recovery (Table 2-1) cannot be precise.  For
example, scraping and grading (1-4) of grassland may not result in death of
significant numbers of grass plants and recovery may be extremely rapid, two
or three years.  However, the potential exists for all of the grass plants to be
killed with the subsequent recovery taking as long as recovery from plowing,
up to 60 years.  Nor can a superficially more-destructive, cleanup procedure
be counted upon to require longer recovery times than a less destructive one;
hence, the overlapping ranges in time required to return to full productivity.
     Impact is also expected to increase as area increases, but with the
exception of more rapid revegetation of smaller areas, no clear relationship
between area and time-to-climax is apparent.  Succession on homogeneously
                           2
barren areas of up to 10 tar.  has not been documented and extrapolation from
smaller areas is dangerous.  The dividing point in time to recover seems to
                                    2                        2
be between areas smaller than 0.1 km  and larger than 0.01 km  where area
effects become discontinuous.  The discontinuities come with disturbance of
tKe seedbed and the general east to west decline in annual precipitation.  The
impacts increase and the time to recover climax increases along the east to
west precipitation gradient.
     Recovery from toxic constituents in chemical stabilizers (1-1) used for
temporary "paste down" is expected in two or three years.  Mowing (1-2) of
prairie leaves minimum impact and recovery would be expected within the next
growing season.
                                       2-31

-------
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                                                                 2-32

-------
     In considering treatments 1-4- through 2-2. those procedures which left
conditions similar to post-agricultural seedbeds (1-4, 1-5, 1-6, 2-1)  were
considered to have "typical" successions with the expected upper limit equivalent
for all treatments and the expected lower limit being varied according to per-
ceived potential for minimal impact.  Those which were considered to yield impact
in excess of agriculture (1-7, 1-8, 2-2) were assigned potentially longer
recovery periods.
     The various mechanical and chemical stabilizers used following cleanup
(2-3 through 2-8) may have significant impacts on early succession but are not
thought to be particularly significant in determining the ultimate length
of the sere.  That is, the maximum time to recovery may result from more basic
factors such as soil erosion and minimums in precipitation cycles.  The
initial effects of stabilization may become lost before climax vegetation is
established.  This is not to recommend for or against stabilization.  Stabiliza-
tion decisions should be made on a case-specific basis and based on local
range management, soil science, and road construction expertise and experience.
     Treatments 3-1 and 3-2 are essentially "no action" options and, conse-
quently, have no recovery time.  This does not imply that there will be no
effect on ecosystems, however (see Section 2.4).
     Hard-surface stabilization (4-1, 4-2) represents the greatest potential
impact with the longest recovery times even on the smaller areas to 0.10 km .
Its use is not recommended, therefore, and it is classed as "prohibited" on
prairie.
     In general, the smaller the area and the less radical the cleanup treat-
ment the quicker the recovery becomes.  The variations in soils, climate, and
local mixtures of plant and animal species make the return to full productivity
a highly site-specific process.
                                      2-33

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 2.7  CONCLUSIONS

      Among  the  several  "preferred"  cleanup  treatments,  in most instances, the
 "no action" options  (3-1,  3-2)  are  first  choice.  Their advantage  is  in allow-
 ing time  for careful  consideration  of possible  courses  of action with respect
 to  specific units of  landscape  that are contaminated.   Presumably, it would
 be  possible to  conduct  field-plot trials  to determine what combination of
 alternatives would be the  most  desirable  decontamination procedures.  Whether
 ,the barriers should exclude only people or  all  animals  cannot be completely
 defined as  a generality.   As  long as food chains  leading to man are isolated
 from the  contamination, there should be no  concern about non-game  wildlife
 crossing  the barriers.  Mowing  (1-2) represents the second level of ecological
 preference.
      It is  recognized that health and safety considerations may require immediate
 and effective action.   In  such  cases, preservation of a seedbed through plowing
 (1-5, 1-6)  is preferred, especially if the  area can be  reseeded instead of
 relying on  natural recovery.  Full  recovery with  reseeding may require fewer
 than  five years  as opposed to up to sixty to eighty years for bare ground
 after soil  removal.
     Soil removal (2-1, 2-2) or deep soil cover (1-7, 1-8) should be considered
 last-resort  options,  when followed  by reclamation to reduce recovery times.
The choice between these latter options should be made  by local professionals
 in  soils, range management, and highway construction.
     The "prohibited" cleanup treatments  in prairie are the variations of hard-
 surface stabilization, with asphalt  (4-1) or with concrete (4-2).  The 30-year
delays caused by their natural breakup require that they be removed bodily
eventually and reclamation procedures instituted.  Other contamination cleanup
methods are  available which are only moderately damaging to this land type.
                                     2-34

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 2.8  PRAIRIE  REFERENCES
 1.    Bement,  R.  E.,  D.  F.  Hervey,  A.  C.  Everson,  and L.  0.  Hylton, Jr.  Use
      of Asphalt-Emulsion Mulches to Hasten Grass-Seedling Establishment.
      Journal  of Range Management,  14:102-109,  196.1.

 2.    Bement,  R.  E.,  R.  D.  Barmington, A. C. Everson, L.  0.  Hylton, Jr., and
      E. E.  Remmanga.  Seeding of Abandoned Croplands in the Central Great
      Plains.   Journal of Range Management, 18:53-58, 1965.

 3.    Beutner, E. L.  and D. Anderson.   The Effect of Surface Mulches on Water
      Conservation and Forage Production in Some Semidesert Grassland Soils,
      Amer.  Soc.  Agron.  J.  35:393-400, 1943.

 4.    Booth, W.  E.  Revegetation of Abandoned Fields in Kansas and Oklahoma,
      Amer.  J. Bot.  28:415-422, 1941.                                '

 5.    Buffington, L.  C.  and C. H. Herbel.  Vegetational Changes on a Semi-desert
      Grassland Range from 1858 to 1963,  Ecol.  Monogr. 35:139-164, 1965.

 6.    Collins, D.  Comprehensive Network Site Description, Bridger, US/IBP
      Grassland Biome Tech Rep. No. 38, Colorado State University, Ft. .Collins,
      1970,  10 pp.                                               -.,-.:

 7.    Costello,  D. F.  Natural Revegetation of Abandoned Plowed Land in the Mixed
      Prairie Association of Northeastern Colorado, Ecology 25:312-326, 1944.

 8.    Davidson,  E. and M. Fox.  Effects of Off-Road Motorcycle Activity on Mojave
      Desert. Vegetation  and Soil, Madrono 22:381-412, 1974.

 9.    Environmental Studies Board.  Rehabilitation Potential of Western Coal Lands,
      Cambridge, Mass.,  Ballinger, 1974, 198 pp.

10.    Gleason, H. A.  and A. Cronquist. The Natural Geography of Plants.
      Columbia University Press, New York, 1964.

11.    Heady, H.  F.  Comprehensive Network Site Description, HOPLAND, US/IBP
      Grassland Biome Tech. Rep. No. 42, Colorado State University, Ft. Collins,
      1970,  11 pp.

12.    Herbel, C. H. and R. D. Pieper.  Comprehensive Network Site Description,
      JORNADA, US/IBP Grassland  Biome Tech. Rep. No. 43, Colorado State University,
      Ft. Collins, 1970, 21 pp.
                                       2-35

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13.  Herbel,  C.  H. ,  G.  H. Abernathy,  C.  C. Yarbrough,  and D,  K.  Gardner.   Root-
     plowing  and Seeding Arid Rangelands in the Southwest,   J.  of Range Manage-
     ment 26:193-197, 1973.

14.  Huddleston, E.  W.   Comprehensive Network Site Description,  PANTEX, US/IBP
     Grassland Biome Tech. Rep. No. 45,  Colorado State University, Ft.  Collins,
     1970, 12 pp.

15.  Jameson, D. A.   General Description of the Pawnee Site,  US/IBP Grassland
     Biome Tech Rep. No. 1,  Colorado State University, Ft.  Collins, 1969,
     32 pp.

16.  Koford,  C. B.  Prairie Dogs, White faces, and. Blue Grams.  Wildlife Monogr.
     3:1-78,  1958.

17.  Kuchler, A. W.  Potential Natural Vegetation of  the Conterminous United
     States,  Amer. Geog. Soc., New York,  Special Publ. No. 36, col. map,
     95x149 cm, and manual to accompany the map, 1964, 116 pp.

18.  Launchbaugh, J. L.  Vegetational Changes  in the  San Antonio  Prairie Asso-
     ciated with Grazing, Retirement from Grazing, and Abandonment from Cultiva-
     tion, Ecol. Monogr. 25:39-57, 1955.

19.  Lewis, J.  K.  Comprehensive Network  Site  Description, COTTONWOOD, US/IBP
     Grassland  Biome Tech. Rep. No. 39, Colorado State University, Ft. Collins,
     1970, 25 pp.

20.  Morris,  M. S.  Comprehensive Network Site Description, BISON, US/IBP
     Grassland  Biome Tech. Rep. No. 37, Colorado State University, Ft. Collins,
     1970, 23 pp.

21.  Noy-Meir,  I.  Desert Ecosystems:   Environment and Producers,  Annual Rev.
     Ecol. System 4:25-51, 1973.

22.  Odum, E. P.  Fundamentals of  Ecology, Saunders,  Philadelphia, 1971.

23.  Osborn,  B.  and  P.  F. Allan.  Vegetation of an Abandoned Prairie-Dog Town
     in  Tall  Grass  Prairie,  Ecology 30:322-332.

24.  Penfound,  W. T.   Effects  of Denudation on the Productivity  of Grassland,
     Ecology  45: 838-845, 1964.

25.  Perino,  J.  V. and P. G.  Risser.  Some Aspects of Structure  and  Function
     in  Oklahoma Old-Field  Succession,  B. Tor. Bot. C. 99:233-    , 1972.

26.  Reynolds,  H. G. and F.  E.  Packer.   Effects cf Trampling  on  Soil and Vege-
     tation,  U.S. Dept.  Agr.  Misc.  Publ.  940:117-122, 1963.

27.  Rice, E.  L.  and W.  T.  Penfound.   Plant  Succession and Yield of  Living Plant
     Material in a  Plowed Prairie  in  Central  Oklahoma, Ecology  35:174-180, 1954.
                                     2-36

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28.  Rice, E. L., W. T. Penfound, and L. M. Rohrbaugh.  Seed Dispersal and
     Mineral Nutrition in Succession in Abandoned Fields in Central Oklahoma,
     Ecology 41: 224-228, 1960.

29.  Rickard, W. H., and T. P. O'Farrell.  Comprehensive Network Site Descrip-
     tion, ALE, US/IBP Grassland Biome Tech. Rep. No. 36, Colorado State
     University, Ft. Collins, 5 p. 1970.

30.  Riegel, A., F. W. Albertson, G. W. Tomanek, and F. E. Kinsinger.  Effects
     of Grazing and Production on a Twenty Year Old Seeding, J. of Range Manage-
    . ment 16:60-63, 1963.

31.  Risser, P;. G.  Comprehensive Network Site Description, OSAGE, US/IBP
     Grassland' Biome Tech. Rep. No. 44, Colorado State University, Ft. Collins,
     1970, 5 pp.

32.  Roux, E. R. and M. Warren.  Plant Succession on Abandoned Fields in Central
     Oklahoma and in the Transvaal Highveld, Ecology 44:576-579, 1963.

33.  Rumsey, W. B.  Range Seedings versus Climax Vegetation on Three Sites in
     Idaho, J. Range Management 24:447-450, 1971.

34.  Scifres, C. J. and J. L. Mutz.  Secondary Succession Following Extended
     Inundation of Texas Coastal Rangeland, J. Range Management 28:279-282, 1975.

35.  Shantz, H. L.  Plant Succession on Abandoned Roads in Eastern Colorado,
     J. Ecol. 5:19-42, 1971.

36.  Slayback, R. D. and D. R. Cable.  Larger Pits Aid Reseeding of Semi-desert
     Rangeland, J. Range Management 23:333-335, 1970.

37.  Terwillinger,- C., Jr. and J.  E.  Jensen.  Analysis of Range Reseeding
     Results, Springfield Land Utilization Project,  Colorado Agr.  Exp.  Sta.,
     Colorado State University, Ft. Collins, General Ser. Paper 666,  1957,
     16 pp.

38.  Tomanek, G. W.  Dynamics of Mulch Layer in Grassland Ecosystems, p 225-240,
     in R. L. Dix and R.  G. Beidleman (ed.).  The Grassland Ecosystem:  A Pre-
     liminary Synthesis,  Range Sci. Dept. Sci. Ser.  No. 2, Colorado State
     University, Ft. Collins, 1969.

39.  Tomanek, G. W.  Comprehensive Network Site Description, HAYS, US/IBP
     Grassland Biome Tech. Rep. No. 41, Colorado State University, Ft.  Collins,
     1970, 6 pp.

40.  Van Dyne, G. M.  (Principal Investigator).  Analysis of Structure and Func-
     tion of Grassland Ecosystems, Colorado State University, Ft. Collins,
     2 vols., 1973, 622 pp.
                                      2-37

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41.  Weaver, J. E. and W. E.  Bruner.  A Seven-year Quantitative Study of Suc-
     cession in a Grassland,  Ecol. Monogr.  15:297-319,  1945.

42.  Weaver, J. E., and N. W. Rowland.  Effects of Excessive Natural Mulch on
     Development, Yield, and  Structure of Natural Grassland, Bot. Gaz.  114:
     1-19, 1952.

43.  Wein, R. W. and N. E. West.  Seedling  Survival on  Erosion Control  Treat-
     ments in a Salt Desert Area, J.  Range  Management 24:352-357, 1971.

44.  Wells, P. V. Succession  in Desert Vegetation on Streets of a Nevada Ghost
     Town, Science 134:670-671, 1961.
                                                      o
45.  White, K. L. Old-Field Succession on Hastings Reservation, California,
     Ecology 47:865-868, 1966.

46.  Whiteman, W. C.  Comprehensive Network Site Description, DICKINSON, US/IBP
     Grassland Biome Tech. Rep. No. 40, Colorado State  University, Ft.  Collins,
     1970, 15 pp.

47.  Whiteman, W. C., H. T. Hanson, and G.  Loder.  Natural Revegetation of
     Abandoned Fields in Western  North Dakota, North Dakota Agr. Exp. Sta. Bull.
     321, 1943, 18 pp.

48.  Whittaker, R. H.  Communities and Ecosystems, Macmillan, New York, 1975.

49.  Woodruff, N. P. and F. H. Siddoway.  "A  Wind Erosion Equation,  "Soil Sci.
     Soc. mer. Proceedings 29:602-608, 1965.

50.  Young, J. A. and R. A. Evans.  Downy Brome—Intruder in the Plant  Success-
     sion of Big Sagebrush Communities in the Great Basin, J. Range  Management
     26:410-415, 1973.
                                       2-38

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                                  CHAPTER 3
                              DECIDUOUS FOREST
3.1  OVERVIEW
     Temperate deciduous forest is a vegetation type in which broad-leaved
trees, the dominant growth form, exhibit an annual cycle of shedding their
leaves and becoming dormant as day length decreases and developing new leaves
and becoming photosynthetically active as day length increases.  Deciduous
forest is found in parts of some 33 states in the eastern half of the United
States, including the flood-plain forests which extend, finger-like, deeply
into the prairies.    Deciduous forest is bordered by prairie on its western
edge, which extends from Canada to Texas.  The border (ecotone) between decidu-
ous forest and prairie is typically savanna, grassland with scattered trees,
comprised of species contributed from each of the two major vegetations (e.g.
Andropogon-Quercus).  Moisture limits the western extension of deciduous forest.
The northern boundary is with the Canadian boreal forest with a broad ecotone
of deciduous trees and conifers extending across the great lakes region into
England.  The eastern and southern borders are effectively the Atlantic Ocean
and Gulf of Mexico, respectively.

     Regionally, precipitation ranges from approximately 76 cm to 152 cm,
annually, and is evenly distributed throughout the year.    Locally, such
factors as soil type, aspect, and topography may exert a greater influence on
                                                     a
forest type or distribution than gross precipitation.
     The deciduous forest of the eastern United States is by no means homoge-
               26                                           8
neous.  Kuchler   mapped 14 major forest associations, Braun  recognized nine
A great deal of variability is contained within either system under native,
undisturbed conditions.  Anthropogenic (man-made) changes in vegetation have
greatly increased the variability over native conditions.
                                     3-1

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3.1.1  Mixed Mesophytlc  Forest
     Mixed mesophytic forest is the prevalent  forest  of  the unglaciated
Appalachian Plateau Region of Pennsylvania, West Virginia, Ohio,  Kentucky  and
Tennessee.  Diversity characterizes the mixed  mesophytic forest,  both  in flora
and fauna.  The floral dominance is shared by  maple  (Acer saccharum),  buckeye
(Aesculus octandra), beech (Fagus grandifolia), yellow poplar  (Lirodendron
tulipifera), white oak (Quercus alba), northern red oak  (Q. rubra) and basswood
(Tilia heterophyla).  Kuchler   listed 26 other tree  species as major  compon-
ents.

3.1.2  Oak-Hickory Forests
     A wide-spread forest type in the central  United  States, oak-hickory forest
occurs in the drier regions of the deciduous forest biome.  Lying west of  the
mixed mesophytic forests, it extends in a discontinuous  distribution from  Michi-
gan to Alabama in the east, to Oklahoma and Texas to  the southwest and as
lowland forest into Nebraska and Iowa.  Dominant trees are various oaks  (Querus
alba, Q. rubra, Q. velutina) and hickories (Carya cordiformis, C. ovata) with
American elm (Ulmus americana), basswood  (Tilia americana), black walnut (Juglans
nxgra) and white ash (Fraxinus americana) being important components.

3.1.3  Appalachian Oak-Chestnut Forest
     Appalachian oak-chestnut forest includes  the Ridge  and Valley Province
and the Blue Ridge Province in the south and widens to include much of Ohio,
Pennsylvania and New Jersey, and the coastal plain north to southern Maine.
Since the loss of American chestnut (Castanea  dentata) to an introduced fungal
disease, the dominants are white oak (Quercus  alba) and  northern  red oak
(Q. rubra).  Maples (Acer rubrum, A. saccharum) and hickories  (Carya cordifor-
mis, C. glabra, C. tomentosa) are important, as are black birch (Betula lenta),
beech (Fagus grandifolia) and yellow poplar (Lidrodendron tulipifera).

3.1.4  Oak-Hickory-Pine  Forest
     Characteristic of the piedmont, this forest type extends west to  Texas.
Dominants include various hickories (Carya spp.), shortleaf pine  (Pinus echinata),
loblolly pine (Pinus taeda), white oak (Quercus alba) and post oak  (Q. stellata).
                      "o~/l
A rich forest (Kuchler"  listed 19 other components), the climatic climax  is
                                     3-2

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                    g
probably oak-hickory  but much of the region has been dominated  by  second-growth
pine forests since pre-settlement times.  The  erodable,  red  and  yellow  clay
soils of the region are well-known.

3.1.5  Southern Mixed Forest
     This forest type occupies the coastal plain from South  Carolina  to Louisiana
and into Texas.  Much of the region  is covered with pine,  especially .loblolly
(Pinus taeda) which some authors   have considered to be an  edaphic (soil
derived) climax.  Experimental data  have  shown, however,  that the pines yield
to hardwoods when fire is excluded.  Kuchler"  listed the  dominants as  beech
(Fagus grandifolia), sweet gum (Liquidambar styraciflua),  magnolia  (Magnolia
grandiflora), slash pine (Pinus elliottii), loblolly pine  (P. taeda), white oak
                                                     O
(Quercus alba) and laural oak (Q. laurifolia).  Braun  considered the forest
to be transitional to subtropical evergreen forest with  northern species drop-
ping out in central Florida and being replaced with more southerly  species.

3.1.6  Beech-Maple Forest
     The beech-maple forest is found from Indiana to New York, including parts
of Michigan.  Mature beech-maple forest presents almost  a  park-like appearance
with large trees forming a light-extinguishing canopy such that  little  under-
growth can survive.   Beech (^ajjs^jrandjUroHa)  and sugar  maple (Acer saccharum)
are the dominants with Ohio buckeye  (Aesculus  glabra), shagbark  hickory (Carya
ovata), white ash (Fraxinus americana), black  walnut (juglans nigra), yellow
poplar (lirodendron tulipifera),  wild black cherry (Prunus serotina), red oak
(Quercus rubra), basswood (Tilia americana), American elm  (Ulmus americana),
and slippery elm (U.  rubra) being locally important.

3.1.7  Maple-Basswood Forest
     Maple-basswood is a limited forest type in northern Illinois,  northeastern
Iowa, Wisconsin, and.Minnesota.   Sugar maple (Acer saccharum) and basswood
(Tilia americana) are the dominants with northern red oak  (Quercus  rubra) usu-
ally being present.   Other important species include box elder (Acer negundo),
bitternut hickory (Carya cordiformis), red ash (Fraxinus pennsylvanica), Hop-
hornbeam (Ostrya virginiana), bur oak (Quercus macrocarpa), American elm (Ulmus
americana)  and slippery elm (U.  rubra).
                                     3-3

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 3.1.8   Hemlock-Hardwood  Forest
     An ecotone  and  not  a  distinct  forest  type,  the  hemlock-hardwood  forest
 stretches  from Wisconsin to Maine with islands  at  higher  elevations of  the
 Appalachians south to Tennessee and North Carolina'.   It merits consideration
 on  size alone.   The  dominant trees  are beech (Fagus  grandifolia),  sugar maple
 (Acer  saccharum),  yellow birch  (Betula allegheniensis)  and  hemlock (Tsuga
 canadensis).

     The eight fore'st types described represent what is considered to be the
 potential  vegetation of  significantly large portions of their regions.  None
 of  them was  ever homogeneous over their ranges  and that is  certainly  true today.
 The vegetation of a  region has  always been a dynamic concept  with climate,  fire,
                                                         14
 and anthropogenic influences producing continuous  change

     Vegetational development on a  particular site has  varied with the  influ-
 ences  producing  change1  and as new perturbations  occur,  new  developmental
 sequences  and end points may result  .  Nevertheless, ecosystem development,
 either on  new substrate  (primary succession) or recovery following disturbance
 (secondary succession),  follows a  course which is  highly predictable  in gener-
 ality, if  not in specific  cases.  The generalities offer a  point of reference
 and will be discussed first.

 3.1.9   Theoretical Considerations
     As a  forest ecosystem developes, changes take place which convert  a  com-
 munity comprised primarily of small, short-lived,  opportunistic species having
 little effect on their environment to a community comprised of organisms  which
 tend to be larger, long lived,  and which often exert great  control over their
.                                                               T C
 own environment.  Some of those trends were summarized by Odum   from which
 Table 3-1  is adapted.

      A great deal of evidence has been accumulated which supports the generali-
 zations in Table 3-1.  That biomass accumulates is obvious to anyone who coin-
 pares a forest with an abandoned field.  Whittaker   described a succession on
 Long  Island, New York (oak-hickory-pine in  the system used here) in which
                                 fj
 biomass was approximately  1 kg/m   in  the earliest stages and  increased to
 between 30 and 40 kg/m2 in  the  mature forest.  Biomass increased  sigmoidally
 (Figure 3-2) with the result that  increasing metabolic demands reduced the
                                       3-4

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        Table 3-1.  Parameter trends during deciduous forest
                    succession  (adapted from Odum35).*
ECOSYSTEM ATTRIBUTE
Biomass
Gross production/respiration
Gross productl on/biomass
Net exosystem production
EARLY SUCCESSION
low
high
high
high
MATURE FOREST
high
low
low
low
  (potential yield)
Food chains

Species diversity
Stratification
Size of dominants
Life cycles
Niche relations

Nutrient cycling
Detritus

Overall homeostasis
Stability
 simple linear,
mainly grazing
     low
     little
     small
short, simple
Broad, oppor-
tunistic
     open
little,
unimportant
poorly developed
     low
complex, inter-
connected, detritus-
based
      high
      much
      large
long, complex
narrow, specialized

      closed
important

we 11-developed
      high
 *Terms in this table that are not in Glossary should follow
  definitions given by Odum.36
                                 3-5

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                                        46
energy available for incorporation into new biomass.   Consequently,  yield
declines with ecosystem development.

     With development in forest ecosystems, an organic layer accumulates on
the forest floor.  Prior to the accumulation of this detritus, animal food-
chains are limited to those organisms which can consume the living vegetation
(herbivores and their predators).  As the detritus increases, a complex of
microflora and small cryptozoa (literally "hidden animals") begin to exploit
it as a resource base.  In a beech forest in Denmark, Bornebusch  found an
average of 4424 cryptozoa/m  with a biomass of 37.8 g.

     There is consensus that species diversity increases during succession
although mature ecosystems tend to be less diverse than younger, transitional
stages.  Odum   gave an example of a forest which attained maximum diversity
at an age of almost 160 years with diversity declining beyond that.  Whittaker
gave as an example a forest which attained maximum diversity quickly, in about
8-10 years, and declined gradually as the ecosystem developed.  It is accepted
that maximum diversity is attained during tha transition from one more-or-less
discrete successional stage to another when species belonging to each state
coexist in the same area.  Consequently, in the example given by Odum   maximum
diversity apparently occurred during the transition to a mature forest, the
usual case, and  in the example given by Whittaker   maximum diversity occurred
during  the transition from the herb to shrub stages.

     Stratification, layering in  the forest, is a correlate of species  diver-
sity.   The generalized sequence of herb to  shrub to tree dominance is,  in
effect, the adding of layers which add species to the community.  Bird  species
reflect the effect of increasing  stratification perhaps most  clearly.   Johnston
and Odum21 reported two breeding  bird  species  in a three-year-old  field having
a grass-forb dominance, 13 species for the  local oak-hickory-pine climax.  The
size of dominants and their  life  history complexity  also are  correlated with
increased  diversity and stratification as  succession  proceeds to climax.
Bazzaz  reported that Solanum  carolinense,  Ambrosia  artemisiifolia,  and
Digitaria  sanguinales,  all  low-growing annuals (plants which  complete  their
 life  cycles  in  one  season),  were established  in  a  cornfield before  the first
winter after abandonment.  Climax for  the  area was  oak-hickory with  Quercus
velutina being  the  major  dominant.
3-6

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          Early successional stages are said to have open nutrient cycles in
which the nutrient elements are primarily extrabiotic (outside of organisms
and their products).  Mature stages are said to have closed cycles in which
detritus serves as a critical link between uptake and loss of nutrients from
vegetation.  Vitousek and Reiners   examined this hypothesis and found that
for elements which have atmospheric inputs to ecosystems, outputs from the
ecosystem in the form of stream discharges were low during the rapid growth of
early succession and increased with maturity to where element input and output
were approximately equal.  Thus, it may be concluded that uptake in mature
forests is in equilibrium with release of elements from organic matter.  Thus,
constancy characterizes mature ecosystems, and represents a measure of sta-
bility and homeostatic control.

     Two categories of perturbations have occurred during the history of
deciduous forests which may yield insight into the impacts of spill cleanup.
Natural perturbations and anthropogenic (man-induced) perturbations are not
always distinct from each other, however.   An example of where they overlap is
fire.   Fires have occurred naturally throughout the history of deciduous
forests   but, observing the changes that fire brought to deciduous forest
ecosystems or their utility as hunting tools, the American Indians would
                       12
deliberately set fires.    Thus, inclusion of fire as a "natural" perturbation
is somewhat arbitrary.
3.2  NATURAL PERTURBATIONS

3.2.1  Fire
     The role of fires in ecosystems has recently been summarized.    Lightning
has been the primary source of naturally occurring fires although man has been
setting fires in North America for an estimated 20,000 years.    The primary
difference between natural or lightning fires and set fires is the seasonality.
Electrical storms are essentially summertime phenomena, occurring when overall
combustibility is typically low.  Set fires can occur at any time and thus are
potentially more destructive.  It is probable that the grass fields of central
Kentucky described by Clark   were maintained by frequent fires set by Indians.

     Early succession following complete forest removal by fire in Finland
was qualitatively similar to succession following other massive perturbations.
                                     3-7

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The pioneer invaders were reselected, annual species with windborne seeds,
such as dandelion  (Taraxacum officinale) hawksweed  (Hieracium spp.). a"d fire-
weed (Chamaenerion angustifolium).  Other early invaders, such as raspberry
(Rubus idaeus), were carried by birds.  An herb stage was evident after 3 years
and grasses were dominant by the  sixth year.

     Henry and Swan   reconstructed a 300-year sere  (successional sequence) in
New Hampshire  from evidence contained in the soil and trees growing on the site.
From charcoal  and partially burned wood found in soil and from the ages of the
oldest trees in the forest, they  concluded that a massive fire had destroyed
the forest in  about 1665.  They were able to identify eastern white pine  (Pinus
strobus), white oak (Quercus alba), hemlock (Tsuga canadensis), spruce (Picea
sp.), red maple (Acer rubrum), and aspen (Populus sp.) as components of the
                    ~
destroyed forest, species found in the region today.    Herbaceous or short-
lived early invaders left no records, but the ages of extant trees allowed
them to reconstruct the succession of tree species.  White pine (Pinus strobus)
was the first tree invader, coming in between 1665 and 1687 and producing a
distinct pine forest stage.   Hemlock (Tsuga canadensis) invaded between 1684
and 1780, paper birch (Betula papyrifera) in 1742, 1770 and 1795, red oak
CQuercus rubra) between 1790 and  1860 and beech (Fagus grandifolia) began
entering slowly in 1815.  Thus, it took 150 years for the dominants of the new
climax forest to appear and possibly another 50 to 100 years for them to estab-
lish dominance.  Consequently, in New Hampshire, it may take up to 250 years
for a mature forest to reestablish itself following a massive perturbation,
such as complete consumption by fire.  Furthermore, minor perturbations,
such as wind-felling of trees during some 250 years, can open patches of forest
at different successional stages, and consequently different environmental con-
ditions, which permits the invasion of still further tree species which will
determine the ultimate composition of the forest.   Therefore, specific predic-
tions cannot be made about the ultimate consequences of a particular gross
perturbation.

     Other fires, which remove the understory of forests without seriously
injuring the dominant trees, have no correlate among the proposed clean-up
procedures and will not be treated.
                                     3-8

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 3.2.2  Primary Succession^

      Primary successions occur where no ecosystem has  previously existed,  such
 as on newly-created volcanic land.   Land masses within the eastern deciduous
 forest region have been remarkably  stable for thousands of years and,  conse-
 quently,  primary successions are poorly understood.  Surface  mining using  over-
 burden for reclamation, may produce a substrate which  can  lead  to essentially
 a primary succession.   Costly mandatory rehabilitation bonds, for contouring
 spoil banks to avoid instability and slope failure,  exert  economic pressure
 for "natural recovery."  Information on the probable years for  primary succes-
 sion,  on  surface-mine  spoil  banks,  becomes vital  to  predict the years  to com-
 plete rehabilitation.

      A case history of primary succession was developed by Morrison and
 Yarranton   '    for  sand dunes.   They have identified three stages in primary
 succession.   The  first stage or  colonizing stage  lasts  up  to  1600 years and is
 characterized by  beachgrass  (Ammophilia breviligulata),  balsam  poplar  (Populus
 balsamifera),  willow (Salix  glaucophylloides),  and sand cherry  (Prunus pumila).
 The  colonizing stage is  followed by  a transition  stage  lasting  another 1300
 years  and  characterized  by scattered trees without canopy  closure.   The typical
 species are hybrids of red and black oaks  (Quercus rubra x velutina),  fragrant
 sumac  (Rhus aromatica),  choke  cherry  (Prunus  virginiana),  a sedge  (Carex lan-
 guinosa) and  snowberry  (Symphoricarpos  racemosus).   That is followed by a
persistent  stage  lasting at  least 1900  years  and  comprised of white  oak (Quercus
alba), New Jersey tea  (Ceanothus americanus), black  cherry (Prunus  serotina)
and teaberry  (Gaultheria procumbens).

     The number of species apparently increases to a stability point approxi-
mately 2000 years after the dune is formed while  frequency continues to increase
throughout the 4800 years, which is too  long to wait.

3.3  MAN-MADE  PERTURBATIONS

3.3.1  Surface Mining
     Although not nearly as extensive as clearing for agriculture, surface
mining represents a massive perturbation which is both highly visible and
difficult to ameliorate.  The mine spoil which typically finds its way to the
                                     3-9

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surface is analogous to a new land surface and,  consequently,  natural  succes-
sions on mine spoil somewhat resembles primary successions.   Since no
4800-year-old mine spoils have been identified,  there is no  evidence that  the
two are directly parallel.  A further complication is the acidity problem
shared by the central and Appalachian coal fields.  In these areas, iron disul-
fide is exposed to air, oxidizes and produces sulfuric acid.  Spoil pH is  often
too low to support plant life and the low pH tends to increase the solubility
of a number of metal ions which reach toxic levels.  None of the proposed
cleanup procedures is likely to expose appreciable quantities of these acid-
forming disulfides.  Once the pH of surface mine spoils is adjusted, the plant
substrate is possibly quite similar to the product of cleanups, particularly
on shallow soils.  Therefore, examination of the revegetation history  of mine
spoils may provide a model of the consequences of some cleanup procedures.

     Surface mining in the eastern United States, especially in the rugged
topography of Appalachia, has created problems of water runoff, erosion, and
sedimentation which have led to extensive studies and actions directed toward
stabilizing spoil surfaces through soil amendments and revegetation.  Conse-
quently, there exists at least some data both on natural revegetation  and
reclamation.  In general, low pH inhibits both reclamation and natural recovery.
If pH is not limiting, planting can greatly accelerate early recovery.  One
study estimated that replanted spoil was as much as 10 years ahead of untreated
                          18
spoils after only 3 years.

     Untreated spoil often does revegetate naturally, however.  One of the
                                                         29
earliest reports of natural revegetation was by McDougall   who reported on
revegetation of surface-mined bottomlands in Illinois.  He concluded that
proximity to a seed source was an overriding factor in the invasion rate of
species.  He described a sere which began with annual weeds, such as knotweeds
(Polygonum aviculare and P. persicaria) with occasionally barnyard grass
(Echinochloa crusgalli) and giant ragweed (Ambrosia trifida) in furrows.  The
drier ridges contained sweet clover  (Melilotus alba), aster  (Aster ericodes),
sunflower (Helianthus hirsutus and H. decapetalus), ragweed  (Ambrosia artemi-
siifolia), evening primrose  (Oenothera biennis),  black mustard  (Brassica
nigra) and prickley lettuce  (Lactuca scanola).  Pioneer woody species included
willow  (alix nigra) and cottonwood  (Populus deltoides), if a seed source were
available.  They were  followed by seedlings of the forest-stage species:

                                     3-10

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silver maple (Acer saccharinum), elm (Ulmus aroericana) and sycamore (Platanus
occidentalis).   He stated that a 25-year-old strip mine was covered with "well-
established bottomland forest."

     Croxton   reported on revegetation of strip-mined lands in the same region
of Illinois and found evidence of the variability of results which have come
to characterize such areas.  He attributed the rapid recovery of the site
studied earlier by McDougall to the deposition of river alluvium over the spoil
and the creation of unusually favorable conditions.  The sere he reported was
essentially the same as that reported by McDougall, allowing for availability
of various weed seeds.  He indicated that recovery within 25 years was unusually
rapid and that areas with pH below 4.5 failed to revegetate.  He noted that the
old-field shrub stage of succession, which is characteristic of deciduous
forests, was poorly represented on mine spoil,,

     A distinct shrub stage was reported on mine spoil in southern Indiana.
Beginning approximately 7 years after abandonment of the spoils, the stage
contained sumac (Rhus sp.), honeysuckle (Lonicera japonica), trumpet vine
(Campsis radicans) and poison ivy (Rhus radicans).   Included in the.shrub
stage were saplings of cottonwood (Populus deltoides), river birch (Betula
nigra),  persimmon (Diospyros virginiana), sycamore (Platanus occidentalis),
sassafras (Sassafras albidum), slippery elm (Ulmus rubra), black cherry
(Prunus serotina), flowering dogwood (Cornus florida) and shingle oak (Quercus
imbricaria).  By 11 years after abandonment, a tree layer had developed and   .  ,
by 21 years pin oak (Quercus palustris) and persimmon were the dominant species.

     The conclusions to be drawn from these studies of early succession on
strip-mine spoils are that natural revegetation can occur if soil conditions
permit and that the rate and pattern of recovery is highly variable.  The
variability is primarily the result of the complexity of the plant growth
medium resulting from mining and the variability of the seed source in the
                 40
surrounding area.
     Revegetation of strip mine spoil has emphasized establishment of ground
cover and the prevention of erosion.  Species planted, such as sericea les-
pedeza,  have been selected for their ability to quickly establish ground cover
with the expectation that they will eventually be replaced by natural inva-
sions of local species.  For the most part, workers have been satisfied with
                                     3-11

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achieving their primary objective.  Long-term studies which seek to evaluate
the return of such disturbed lands to pre-mining ecosystems are virtually non-
existent, although "full-growth" of "high-grade" forests has been achieved
within 50 to 70 years.

3.3.2  Post-Agrlr iltural Successions
     Secondary succession following the abandonment of agricultural land is
the best-known, example of ecosystem development in deciduous forests.  Clearing
of unproductive land; changing markets, and loss of fertility has led to aban-
donment of land throughout the deciduous forest.  That abandonment began almost
as soon as settlement began and continues into the present.  Consequently,
virtually all aspects of succession have received at least some study.  For
convenience, a regional approach will be taken.

     3.3.2.1  Southeastern States—
     Succession on the Georgia piedmont has been studied by Nicholson and
Monk  '   who identified 5 major stages.  Their "early forb stage" occupied
the first 10 years following abandonment and was dominated by perennial grasses
(Andropogon scoparius, Aristida purpurascens, Eragrostis sp.) and forbs (Allium
vineale,  Erigeron canadensis, Haplopappus devaricatus, Cassia nictitans, Heter-
otheca subaxillaris, Aster pilosus, Solidago sp., Lespedeza sp.).  Chickasaw
plum fPrunus angustifolia) and brambles (Rubus spp.) formed a shrub layer along
with tree seedlings  (Pinus taeda, P. echinata, Diospyros virginiana, Celtis
occidentalis, Rhus copallina) and vines (Lonicera japonica, Smilax bona-nox,
Wisteria sinensis, Campsis radicans).  This is followed by what they called
a. "broomsedge stage" in which Andropogon scoparius increases its cover and
community richness declines.  The broomsedge stage lasted from the tenth to
the twentieth year following abandoment.  The old-field shrub stage replaced
the broomsedge stage and persisted up to approximately 30 years after aban-
donment.   Loblolly pine (Pinus taeda) and sweet gum (Liquidambar styraciflua)
increase as shading, soil moisture and soil organic matter increase.  Species
richness increases in all strata except the herb layer, which declines due to
shading and litter accumulation.  The end of the stage is identified by canopy
closure (approximately 30 years) and the reduction of the herb stratum to about
percent of the open-field level.
                                     3-12

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     Canopy closure* signals the start of the pine stage in which  loblolly
pine is the dominant.  The stage lasts approximately 70 years  (30  to 100 years
post-abandonment) and there is a slight decline  in total above-ground biomass
for the first 60 years.  Woody species increase  in the understory  as broad-
leaved deciduous species invade.  Maximum richness occurs as the species from
early succession overlap with the tree species of the later climax and subcli-
max forests, around 70 years post-abandonment.   Richness declines  as hardwoods
replace the pines (100 to 125 years) to increase again around  150  years as new
hardwood species appear.  The hardwood stage lasts from 100 years, post aban-
donment, to 200 years or more.
     Johnston and Odum   reported on breeding bird populations of  the Georgia-
piedmont sere.  They found that both density arid diversity increased with suc-
cession up to the pine stage where each declined sharply.  Only one species,
the pine warbler (Dendroica pinus), used the pine overstory, but other species
came in as the hardwood understory developed.  Approximately 12 species with
140 breeding pairs/40 ha (100 acres) were present before canopy closure and
this dropped to 10 and 17 at 20 years.  The maximum attained was 20 species
and 240 breeding pairs/40 ha in the transition forest with 23 and  220 in the
deciduous forest stage.  Only the cardinal (Ric.hmondena cardinalis) was present
in all stages with most bird species being stage-specific.
     On the North Carolina piedmont,  short-leaf pine (Pinus echinata) domin-
ates the pine stage with up to 7400 stems/ha (3000 stems/acre).  The first
oaks (Quercus spp.)  appear at about 20 years with the first hickories (Carya
spp.)  only a few years later.   The sequence during the first 3 years was given
by Keever.     Crabgrass (Digitaria sanguinalis)  is able to invade plowed fields
in the fall of the year of abandonment because of its drought resistance and
ability to germinate under cool soil temperatures.  Horseweed  (Leptilon cana-
dense)  may germinate at about the same time but  grows to maturity the follow-
ing summer.  Horseweed and ragweed (Ambrosia elatior) dominate one-year-old
fields with germination of new horseweed seeds being inhibited by the decay
products of the parent plants.   An aster (Aster pilosus) appears the first
year and becomes a dominant the second, along with ragweed and buttonweed
*See Glossary for definitions of terms.
                                     3-13

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(Diodia teres).   A few broomsedge (Andropogon virginicus) plants appear the
plants appear the first year but require 2 years to set seed.  They become
dominants by the third year.
     On the Virginia piedmont, Virginia pine (Pinus virginiana) dominates the
pine stage producing a closed canopy within 10 to 20 years.  They mature within
               19
50 to 70 years.
     Further inland, the old-field stage in middle Tennessee is characterized
by elm (Ulmus americana) and hackberry (Celtis occidentalis) with an under-
story of broomsedge (Andropogon virginicus), goldenrod  (Solidago altissima),
                                                    39
aster CAster pilosus) and panic-grass (Panicum sp.) .    Sassafras (Sassafras
albidum) may be a component of old-fields and, because  of allelopathy, may
persist in pure clones into the mature forest.
                                                                    17
     3.3.2.2  Northeastern States--
     Long-term succession in New England has been described earlier.*'  Bard'
described secondary succession on the New Jersey piedmont.  The first-year
dominants were ragweed (Ambrosia artemesiifolia) and evening primrose (Oeno-
thera parviflora) with later dominants represented.  They were replaced in the
second year by a goldenrod (Solidago nemoralis).  S. nemoralis remained impor-
tant for 15 years when it was replaced by S.. juncea which persisted for another
45 years or more.  By the fifth year, an aster  (Aster ericoides) became the
dominant herb and remained important for another 20 or more years.  Fifteen-
year-old fields were dominated by broomsedge  (Andropogon scoparius with A.
virginicus) which remained important for another 45 years.  Eastern red cedar
CJuniperus virginiana) is among the first woody invaders  (2- to 3-year-old
fields) .-and is the major arborescent species  for more than 60 years.  Dominant
shrubs are brambles (Rubus flagellaris) which reach their peak 25 years after
abandonment and poison ivy (Rhus radicans) which is most abundant 60  years
after abandonment.  The trees of the climax oak-hickory forest enter  before
the red cedar is mature and are well established in the understory  by the
sixtieth year after abandonment.  Recent evidence   indicates that  allelopathy
is important to the early replacement of species.  Aster pilosus, a second-
stage dominant, was shown to produce a chemical which inhibited germination
of first-stage dominants.
                                      3-14

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      There is a succession of animals which follows the plant succession
        25
 Kircher"   showed that bird diversity increased with each serai stage and that
 there was  a gradual shift during succession from species which used the area
 for feeding only to species which nested in the area.   Pearson37 reported that
 small mammals increased with early succession but declined as the forest be-
 came established.
      At  least occasionally,  the orderly replacement of species becomes delayed
 when one or more species establishes a stable, persistent community prior to
 the expression of climax.   Examples include   speckled alder (Alnus rugosa)
 for 20 years or more,  witch-hazel (Hamamelis. yirginiana)  for 40 years, nanny-
 berry (Viburnum lentago)  for 45 years,  and  meadowsweet (Spiraea latifolia),
 highbush blueberry (Vaccinium corymbosum),  lowbush blueberry (V.  angustifolium),
 arrowwood  (Viburnum recognitum),  sweetfern  (Comptonia  peregrina)  and common
 juniper  (Juniperus  communis)  for 47 years.   Thus,  the  typical succession cannot
 be  expected  in every instance.   Nor is  it possible to  predict the frequency  of
 occurrence  or  duration  of  stable  shrub  stages.
      3.3.2.3  Central  States--
      Early  succession  in southern Illinois  was described  by  Bazzaz.    Follow-
 ing  the harvest  of  corn  in August,  cover was provided  by  weeds  already estab-
 lished, including Solanum  carolinense,  Ambrosia  artemisiifolia  and  Digitaria
 sanguinalis.   During the first  growing  season  following abandonment,  annuals
 (plants which  complete their  life  cycle in  a single  season)  were  the dominant
vegetation and  included Alliumvineale,  Digitaria sanguinalis, Geranium maculatum
and Aster pilosus.  Sawbrier  (Smilax  glauca) was the first woody  plant  to be-
come established.  Total ground cover was approximately 65 percent.
     Perennials  (plants which live  for  several years) were the dominant vege-
tation by the second year of abandonment.   Erigeron annuus flowered  in  early
suBimer, when it v/as the conspicuous, dominant,  and Aster pilosus was  most con-
spicuous later in the summer.  Ground cover attained approximately  115 percent.
     By the third year, erosion had reduced ground cover  to  approximately 85
percent,  but the species replacement pattern continued.   Herbaceous  vegetation
had begun to develop strata with goldenrod  (Solidago nemoralis) dominating
the upper stratum and panic grass  (Panicum dichotomum)  and three-awn  (Aristida
                                     3-15

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dichotoma) codominant in the lower stratum.  Old-field shrubs began invading,
including black raspberries (Rubus occidental is) and persimmon (Diospyros
virginiana).
     Four-year-old fields had produced a stable herbaceous community, dominated
by broomsedge (Andropogon virginicus).   The developing shrub layer contained
persimmon, sassafras (Sassafras albidum).  elm [Ulmus alata), eastern red cedar
(Juniperus virginiana) and sumac (Rhus spp.).  Cover (all strata summed) had
increased to 119 percent, with 8 percent being contributed by shrubs.  Vegeta-
tion of 10- and 15-year-old fields remained similar in composition with the
shrubs growing to a cover value of approximately 16 percent.  By the 25th year,
the older sassafrass and persimmons had produced a tree layer with the composi-
tion of the shrub and herb layers as before.
     By 40 years after abandonment, the tree layer had reached a basal area of
about 15.6 and the shrub layer had increased to 21 percent.  Broom sedge still dom-
inated the herb layer.  Elm and sumac remained the dominants in the shrub layer
but a few seedlings of the climax oaks  (Quercus imbricaria and Q. velutina) had
appeared.  A total of 22 species occurred  in the tree layer with sassafras and
persimmon remaining the dominants.
     The rate of invasion of the climax oaks was considered to be dependent
on the proximity to mature forest,, since the seeds were dispersed by squirrels
which prefer the forest edge.  Diversity increased throughout the succession
to a maximum in the forest stage4 but may  be low when allelopathic species are
present.  Environmental heterogeneity produces a variety of seres within a
given area.
                                                                           42
     The animals which occupy serai  stages change with the  vegetation.  Sly
reported that deer mice  (Pereomyscus maniculatus) occurred  in the early, grass
stage of successions while the white-footed mouse  (P. leucopus)  occurred in
the later, forest stages.  The two species overlapped during the old-field or
grass-shrub stages.  Serai stage is  not the only determinant of  acceptability
to wildlife, however.  Beckwith5 concluded that the size of a tract  of  other-
wise suitable vegetation would influence whether or not  game  animals would be
found there.
                                      3-16

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 3.4  CLEAN-UP PROCEDURES, EFFECTS ON ECOSYSTEMS
      This section describes the effects that the proposed cleanup methods  can
 be predicted to have on deciduous forest ecosystems.   The description  is quali-
 tative for each treatment's impact in the ecosystem.   A quantitative assessment
 of all the cleanup methods is deferred to Section 3.6, after the impact is
 described and the likely time course of recovery is given (Section 3.5).   The
 cleanup treatments range in severity from a light spray,  of "tacky" chemicals
 over the vegetation and soils,  to severe impacts caused by removing vegetation
 and topsoil,  mixing the subsoil with caustic chemicals and compacting  the  mix-
 ture with cementing agents.

      (0-1)  Natural Rehabilitation
      For manual  cleanup of contamination,  no significant  impact  on the prairie
 is  anticipated to be evident  after 2 or 3  years.

      (2-1)  Chemical Stabilisation
      Properties  of the  two general classes  of chemical stabilizers are given
 in  Appendix A, Stabilizers.   Twenty-seven  are rated "preferred"  for reducing
 soil  erosion under normal  rainfall regimes  in the deciduous  forest.  Six allow
 seed  to  germinate in place but  they break  down  in a year.  Four  of the six
 chemical  stabilizers  are  safe to  handle  without  special equipment,  in  machine
 or  hand  sprayers.   Significant  leaf fall from shrubs and trees is  caused by
 the four  stabilizers  but  little damage to roots  is  expected.
     The  application  of stabilizers  that kill vegetation is acceptable when
vegetation to which they are  applied must be  removed in some of the cleanup
methods described  in  subsequent discussion  (treatment  1-3).  In general,  the
pi ant -damaging stabilizers leave a more weather-resistant and erosion-inhibiting
coating over soil  surfaces.

      (1-2)  Clear Cutting Vegetation
     Clear cutting deciduous forest is used in forest management.  Clear cutting
or block cutting permits reproduction from nearby forest trees, but public  ac-
ceptance has been a major obstacle to the practice.
     Clearcut forests revegetate in two ways.  First,  many species have the
ability to produce sprouts from the stumps and roots of the former trees.
                                      3-17

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Since the remaining root network is essentially that of a mature tree,  sprouts
typically show exceedingly rapid growth.  A coppice forest, which clear-cutting
produces, can produce canopy closure in a decade or two.  Since growth is from
the remains of the former forest, species composition is typically quite similar.
In addition to sprouts, the opening of a forest by clear cutting allows for
invasion of pioneer species and an abbreviated version of old-field succession.
The resultant, short-lived heterogeneity is attractive to game species.  Those
pioneer species which grow rapidly enough and can survive canopy closure add
to the diversity of the resulting forest.  Consequently, coppice forests may
differ in that respect from the original forest.

     (1-3)  Sturrping and Grubbing
     Removal of stumps and roots blocks the formation of a coppice forest and
results in longer recovery times.  A natural succession would be similar to
post-agricultural recovery and include the typical annual-perennial-shrub-tree
sequence of dominants.  The rate at which these stages replace each other will
depend on what seeds were present in the soil prior to cleanup, the size of the
affected area and erosion.  This treatment will differ from post-agricultural
land in that the seeds of species present when  the treatment began can be ex-
pected to remain behind.  The time-lag before the climax species appear as
seedlings would thus be reduced  to about a year and the total ecosystem de-
velopment reduced accordingly.   Thus, the up to 250 years  required for reaching
climax following agriculture might be reduced to  100 years or less.  Assuming
that the forest removed was not  climax  but an earlier successional stage, the
time required for recovery to that point would  likewise be shortened, with
the exception of early shrub stages.  Since woody shrubs appear very early  in
succession,  typically  the  first  or second year, and require  several years to
attain dominance, no shortening  of that interval  would  be  expected.

     The size of the affected area influences the invasion rate from outside
the  area.  Small  (i.e.,  0.1 km  )  areas  have  large perimeter  to  area ratios
compared to  large  areas  (i.e.,  10.0  km  ).  Since  squirrels prefer  forest
edge,3 acorns could be expected  to be buried  over the  smaller  areas more  quickly
than  the larger one with a proportional recovery  of oaks.
                                      3-18

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     Uncontrolled erosion can act as a recurring perturbation which continually
sets back recovery in the cleaned-up area to an earlier stage, and can expand
the perturbation beyond the  spill zone.  Thus, presence of erosion will result
in longer recovery times and larger perturbations.

     (1-4)  Sprccping and Grading
     In a forest, scraping and grading requires that stumps first be removed.
In addition to the effects of stumping and grubbing  (1-3), scraping and grading
(1-4) would remove the surface organic matter that remained.  That would result
in higher soil temperatures, decreased infiltration of water, increased runoff
and erosion and nutrient depletion.  As a result, recovery times could reason-
ably be expected to be longer than with stumping and grubbing (1-3) alone, but
not as long as required for  post-agricultural recovery since some seeds would
remain in the soil.  The pattern of recovery would be expected to remain the
same with the size of the area affecting the rate as well.  It has been found
in strip-mine reclamations that scraping and grading (1-4) delays recovery
relative to a rough surface, primarily because of a reduction in infiltration
and an increased risk of erosion.

     (1-5)  Shallow Plow-Crip
     Shallow plowing (<10 cm) following stumping and grubbing would probably
have no observable effect on ecosystem recovery beyond that of vegetation re-
moval.   The surface organic matter would be incorporated into the soil and
seeds redistributed,  but the long-term effects would not likely be discerible.
The effect would be less than soil removal because the seeds and organic matter
would remain and because the resulting pattern of ridges and furrows would trap
water and decrease erosion.

     (1-6)  Deep Plowing
     As recently as the early 20th century, farmers in the deciduous forest
zone cleared and planted "new ground."  Trees were killed by girdling and then
felled and usually burned.   The farmers then plowed their fields, although
cutting through the buried roots was punishing to both mule and man.  They
plowed partly out of tradition and partly to keep down weeds, that is, to pre-
vent natural succession.   Deep plowing as a cleanup procedure will do the same,
except being done only once the effect will be shorter-lived.  Thus, deep plow-
ing on deep soils may delay early succession a year or two.  Deep plowing on
                                     3-19

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shallow, hill soils can be expected to have a longer-lasting effect,  if it  can
be accomplished at all.  In either case, the effect will be less than grading
or soil removal, since the quality of the seed bed remaining should be superior
to that left by soil removal and the ridges and valleys will retain precipita-
tion.  The succession should be no slower than post-agricultural successions
on similar soils.

     (1-7)  Soil Cover Less than 25 cm
     The addition of,;'-uncontaminated soil to a forest floor has several potential
effects, not the least of which is the disruption of vegetation by the applica-
tion of the soil.  One acre-furrow-slice (the soil of one acre to a depth of 6
inches) weighs 2,000,000 pounds or more.    Therefore, covering 0.01 km  with
25 cm of soil would require at least 3.7 x 106 kg (8.2 x 106 Ibs or 4 x 10
tons) of soil and up to 3.7 x 10  kg for 10.0 km .  Such large masses of soil
require heavy earth-moving equipment which cannot be operated in a forest with-
out first removing or knocking down the trees.  It must be assumed, therefore,
that any soil additions will be done after the forest is removed.
     Twenty-five centimeters of soil or less would not cover the fallen boles
and stumps of mature deciduous trees, leaving the possibility that at least
some of the trees might resprout from unkilled tissues.  The severity of the
impact then would lie  somewhere between that of a clearcut  forest, assuming
a greater kill rate, and surface alterations.  Herbaceous material would be
buried below an effective recovery depth and the seeds present on the forest
floor would be too deep to germinate.  Consequently, recovery would consist
of a combination of resprouting of the former trees and invasion of pioneer
species, including the seeds carried in the uncontaminated  soil.  As such, re-
covery rate would depend upon the area disturbed, which affects the invasion
rate of trees, the kinds and amounts of seeds contained in  the  imported soil,
the seed-bed quality represented by the imported soil and sprouting rate of
the fallen trees.  All of these interact to produce a range of variables which
greatly diminishes predictability.

     (1-8)  Soil Cover 25 to 100 am
     Covering with additional soil primarily magnifies  the  problems  identified
in the previous  section.  As depth of added soil  increases, the probability of
resprouting of  fallen  trees decreases.  A  full  100  cm of  soil would  cover  most
                                      3-20

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 of  the  fallen boles,  and many of the uprooted stumps.  Resprouting cannot, be
 completely  ruled  out as a recovery factor, however.
      Since  noncontaminated  soil must be excavated elsewhere, it is safe to
 assume  that seed-bed quality will decline with the area and depth to be covered.
 That  is,  constraints on disturbing noncontaminated areas will require the de-
 contamination crews  to dig  deeper at the borrow site as volume demand goes up
 rather  than to increase the area disburbed.  In most regions, that translates
 as  a  lower  quality seedbed.  Thus, recovery time may be expected to be extended
 as  area treated and  burial  depth are increased.  Quality of the seedbed would
 be  the  primary factor affecting early recovery with the size of the area dis-
 turbed  affecting  later rates of invasion by trees.
      The  level of impact would be expected to be greater than that of vegeta-
 tion  removal, surface alteration, plowing, and possibly soil removal.  The one
 ameliorating factor  would be resprouting of fallen trees, if it were to occur.
      The  environmental costs of disturbance to the borrow sites must be factored
 into  any  cost-benefit analysis of burial procedures.  For;even the smallest area
                   23
 considered  (0.01  km  ), 2500 m  soil would be required for burial to 25 cm and
 10,000  m  soil would  be required for burial to 100 cm.   Because of the desire
 to minimize the area  affected, the impact on the borrow site would be greater
 than  that of any  of  the cleanup procedures considered,  with the exception of
 hard-surface stabilization.

      (2-1)  Remove Plow Layer                                   '-••...••
     The  effects of  removing the plow layer,  approximately 15 cm (6 inches)
 of soil, depend upon topography, soil type, and what other cleanup procedures
 are done  in conjunction.   Deciduous trees, growing in forests,  have roots in
 contact with the surface organic layer.   This is where the active exchange of
nutrients occurs.   Assuming it is possible to remove the top 15 cm (6 inches)
 of soil without first removing the trees,  it  is probable that no tree would
 survive the cleanup.   While the presence of standing,  dead trees would not be
 expected to interfere with recovery,  they would also not expedite it, leaving
no justification for not removing them.
     Assuming removal of the plow layer to follow stumping and  grubbing,  the
pattern or recovery would be that of,  at best,  a post-agricultural succession
or,  at worst, a strip-mine spoil.   All  plants would have to invade from outside
                                     3-21

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the area making the size of the affected area important.   If the cleanup were
to occur on nearly level topography having well-developed soils, the remaining
seed bed could be of high quality.  In steep terrain, however, forest soils
typically have a very thin (less than 15 cm) layer of topsoil which would be
removed entirely.  The resulting seed bed would resemble mine spoil and eco-
system recovery could be expected to be accordingly slow.  Subsequent chemical
and most types of mechanical subsoil stabilization have little added impact
but would minimize erosion in the short term recovery.

     (2-2)  Remove Shallow Root Zone
     In deciduous forest, shallow root-zone can be interpreted to be a plow
layer or less.  At any rate, soil removal is also seed removal and the early
colonizations must be from outside of the affected area.  Increasing the depth
of soil removal lowers the probability of leaving a suitable seed bed and in-
creases the time necessary for recovery.  Whereas canopy closures can occur
                                                 32 33
within 30 years in post-agricultural successions,  '   such rapid recovery is
                                13
unusual following surface mining   which is analogous to soil removal on shallow
soils.  Use of chemical and mechanical stabilizers to prevent erosion would
mimic post-agricultural recovery.

     (2-3)  Remove Scraping and Grading, Mechanically Stabilize
     As the sizes of stabilized areas increase more internal structures are
needed for overland water control.  These include dikes, berms, drainage
ditches, shaped waterways and overfall structures on steeper-grade channels
which are all beyond the scope of this presentation.
     The specific consequences of scraping and grading  (1-4) were presented
earlier and apply to the pre-stabilized deciduous forest.  Denuded areas-
depend on early reseeding by native plants.  A smoothed and compacted surface
having reduced water permeability is the medium represented after erosion
control by stabilization.
     Mechanical stabilization may involve compaction, meshes, mulches, defloc-
culants, and clays.  The effects of mechanical soil compactors remain evident
for many years.  Complete recovery will seldom occur by 100 years.  Simple
ground cover by plant invaders will take up to five years and succession may
be delayed 25 or 100 years compared to simple clear-cutting.  Heavily compacted

                                    3-22

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areas are subject to repeated regressive cycles following erosive denuding of
large open areas.  Infiltration can readily be reduced to an inch per hour or
less and offsite runoff is a serious problem at even one hectare of clearing
and surfacing.
     Non-compacting stabilization by meshes and mulches is indicated for the
cleared, deciduous forest and is the method rated in Table 3-2 (see Section
3.6).  This assumes that mesh is held down by pegs (non-metallic if mowed) on
steep slopes and anchored to prevent wind detaching or under-running sections.
Mulches are anchored by tractor disc or cleats in areas free of significant
water erosion.
     Deflocculants and clays have characteristics that produce impacts inter-
mediate among soil compactors and the various mulches.  They are subject to
frost heaving damage and are relatively short-lived since seeds can collect
and germinate in the breaks.  Deflocculants depress the early growth of plants
by salt effects in germination and rooting compared to clays.
     Significant damage by small rodents is probable in a few months for any
of the chemical and mechanical stabilizers used after soil removal.

     (2-4)  Remove PloD Layer, Mechanically Stabilize
     The ecological impacts were described in scraping and grading (1-4) and
the effects of stabilizing the exposed soil mechanically were defined in
treatment 2-3.  In general, natural recovery will be delayed compared to re-
moving 5 cm or less of soil, by removal of more seed sources and mechanical
stabilization will seriously retard revegetation compared to clear cutting.

     (2-5)  Remove Shallow Root Zone, MeahoLnicallij Stabilize
     This treatment has effects almost identical to plow layer removal  (2-1).
Soil fertility is reduced by deeper cuts and the potential for natural revege-
tation shifts to favor invaders instead of local pioneer species.  The subsoils
will tend to be more erosive than surface layers due to reduced organic matter
and so require heavier applications of stabilizers.  Higher clay content will
increase density under compaction and exacerbate water erosion.  Non-compacting
stabilizers are much superior in this case.
                                    3-23

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      (2-6)  Remove Scraping and Grading, Chemically Stabilise
     The physical effects and the ecosystem  impact of removal of scraping and
grading  (2-6) were described under treatments  1-4 and 2-3.  The effects of
chemical stabilizers are less durable than those of mechanically stabilized
soils and require prompt revegetation, usually by herbs 'and grasses in the
clearings made.  Either class of stabilizer  reduces surface erosion, increases
runoff, and has specific effects on water infiltration according to the spe-
cific stabilizer and its limits of use  (Appendix A, Stabilizers).
     Chemical stabilizers for soil stabilization control soil erosion while
seedlings become established then the "preferred" stabilizers break down.
Overland runoff is reduced by these compounds compared to soil compaction
treatments.  Stabilization with chemicals will reduce erosion of the exposed
soil horizons and should allow early revegetation of native pioneer species.

     (2-7)  Remove Plow Layer, Chemically Stabilize
     The effects of removal of the plow layer  (2-1) are combined with those of
treatment 2-6.  The deeper soil cut reduces  the seeded zone to those hidden by
small animals and exposes the infertile subsoil as the plant growth medium.
It presents a hostile environment to transplants and invader species and a
lengthening of the time for recovery.   Compared to the time required for re-
covery to climax the delay is probably negligible in the long term.  Chemical
stabilizers would be the method of choice for revegetating the cleanup zone.

     (2-8)  Remove Shallow Root Zone,  Chemically Stabilize
     The effects of removing the surface soil to a depth of 40 cm increase the
problems of revegetating in the infertile soil over treatment 2-7 and eliminate
revegetation by local pioneer species.  The  limited potential for recovery
favors exotic invaders.  Low organic matter  increases runoff to a serious ero-
sion threat and heavy applications of chemical stabilizers are called for,
including those that are not acceptable after other cleanup (Appendix A,
Stabilizers).  Chemical stabilizers of three to five year durability are
highly toxic and rehabilitation is required before revegetation will succeed.
This is one of the four deciduous forest cleanup treatments that require in-
tervention by reclaimers before it can start recovery towards the original
productivity.  If not reclaimed the area will be lost to erosion processes.
                                    3-24

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     (3-1)  Barriers to Exclude People
     Natural ecosystems can be benefited by excluding humans from the area
without any impact on the plants, soils, and wildlife.

     (S-2)  Exclude Large Animals
     Barriers which restrict large animals only will have a greater effect on
the animal populations themselves and not on ecosystem structure and function.
Large animals were once nearly exterminated from deciduous forests but several
species are now recovering.  White-tailed deer (Odocoileus virginianus) feed
in old fields and have increased their numbers as agricultural land has been
                                                    2
abandoned.  The fencing-off of small tracts (0.01 km ) would not represent a
                                                                           2
significant proportion of available habitat, but the maximum tract (10.0 km )
could seriously limit the habitat of a local population.  Even so, the effect
would be insignificant on a regional or state basis.

     (3-5)  Exclude Large and Small Animals
     The erection of barriers to prohibit animal crossings affects only ground-
dwelling vertebrates without impacting soil and plants.  Birds, insects and
squirrels are not likely to be restricted by any barrier which meets engineer-
ing and cost acceptability.  Nor are small mammals and reptiles likely to be
successfully removed with the enclosure of the area.  Thus, species composition
of an area would be virtually unaffected by the erection of barriers.  Restrict-
ing movement of animals into or out of the area would restrict gene flow but
only the smallest area of concern would likely be impacted and then only if
the barrier remained intact for several decades.  The effect on large mammals
is treated in the next paragraphs.
     Black bear (Ursus americanus) are also recovering in the deciduous forest
region.  Omnivorous animals which thrive on the absence of human contact are
showing the greatest recovery in back country forests of the eastern mountains.
One of the healthier populations exists in the Great Smokey Mountains National
                        2                                       2
Park, an area of 1865 km .  The maximum area considered, 10.0 km , is only
0.5 percent of that area, which could not be construed to be significant.
Fringe populations might be impacted more heaivily, however.
     The eastern cougar (Felis concolor cougar) is also recovering from former
population declines and is being sighted with increasing frequency.  Home
                                    3-25

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ranges are not well-known, but it appears certain that a viable population
requires areas many times  larger than the largest cleanup area considered.
Thus, habitat reduction  is not expected to be a factor.  Potentially more im-
portant is the effect that closure might have on migratory routes.  Large
predators must travel great distances hunting prey or risk depletion of their
food source.  In the eastern United States, that usually means passing through
frequent narrow corridors between heavily populated areas.  Closure of those
corridors could seriously restrict the home range of cougars and affect their
recovery.  Impact on the species could be serious.

     (4-1)  Asphalt Hard-Surface Stabilisation
     Paving a spill area with asphalt represents the most severe impact con-
sidered so far.  Any plant invasion or animal utilization of the area would be
delayed until the asphalt begins to decompose, possibly a decade after treat-
ment.  Establishment of  a community would require fairly complete decomposi-
tion of the asphalt which would require further decades.  The impact of an
asphalt surface over 0.01 km  might be acceptable if the area originally was
of low value ecologically, but not if the area has the potential for produc-
tion of a rich community.  It is not possible to consider acceptable a paving
               2
cover of 0.1 km  or more.  Even the most disruptive of the high priority tech-
niques, soil removal or  burial, would have significantly lower impact.

     (4-2)  Concrete Hard-Surface Stabilization
     The effects of paving with concrete are qualitatively the same as with
asphalt and the primary  evaluation is the same.  Since concrete decomposes
more slowly than asphalt, the effects would be longer lived and thus less
acceptable than those of asphalt.

     (5-0)  Application  of Sewage Sludge
     Application of sewage sludge can replace organic matter and plant nutri-
ents lost in vegetation  removal and help balance soil pH for better nutrient- •
availability.  '  '    The result is more rapid surface stabilization and
encouragement of plant growth.  The amendment is not without problems, however.
Municipal sewage commonly contains heavy metals which can be toxic, particu-
larly to higher organisms.  A potential exists for impacts on wildlife and
food-chains leading to man.  Secondly, a potential exists for saturation of

                                    3-26

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the soil cation exchange complex with excess ions leaching into streams.   This
                                                 38
problem has been demonstrated for liquid effluent   but could become a problem
with sludge, as well.   On graded land sludge could reduce runoff and erosion
by increasing infiltration, which would speed recovery.

     (6-1)  High Pressure Washing (
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                                                                 B
              0-1 NATURAL RECOVERY



            HERB i  SHRUB I  TREE STAGES
GENERALIZED TYPICAL RECLAMATION *
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processes are generalized and thus do not relate to a specific location.  The
major disruptions include severe vegetation removal, surface alteration, soil
removal, plowing and soil fill.  The time units are approximate with variability
resulting from local differences within treatments and between treatment differ-
ences.  The ordinate (Y-axis) is without units either because it is dimension-
less  (e.g., homeostasis) or site specific (e.g., primary productivity, species
diversity).  See Appendix B for further use.
     Species diversity increases from the bare-ground stage to some maximum
occurring during a transition from one major stage in succession to another.
In the example shown, the maximum occurs during transition from the herb stage
to the shrub stage, approximately 15 years after the sere begins. In other suc-
cessions, the maximum diversity might occur at the transition from the shrub
to tree stage (approximately 50 years) or as the climax forest replaces a sub-
climax forest (perhaps 150 years).  Reclamations seed a mixture of plants,
particularly legumes such as sericea Iespede2:a and black locust.  Seeding,
creates a diversity which may be greater than early serai stages but which,
through competition, do not yield to the waves of early invaders typical of
early successions.  Thus, species diversity may remain low for a number of
years.  The highly diverse old-field stage may be essentially bypassed with
the result that the maximum diversity obtained may be less than the maximum
attained by a natural sere.  The end point is; the same, however,, and a climax.
forest resulting from a reclamation-based sere is presumed to be similar to
the climax resulting from a natural sere.
     Cover increases gradually during natural successions, becoming more rapid
as trees replace the earlier stages.  Mature forests with their distinct lavers
produce the greatest cover of the sere.  Reclamations are similar except that
greater initial cover is possible by seeding, but cover may not increase until
trees are able to overcome the early cover species.
     Primary productivity generally increases with community age, reaching its
maximum in the mature forest.  The rate of change may not be constant, however,
but depend upon the rate of species replacement.  Thus, if a persistent serai
stage is established, the primary production rate may be essentially constant
for several years.                                     .
                                    3-29

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      In general, homeostasis increases with community development with the
climax forest  representing the most  stable state  (generalized typical reclama-
tion  curve).   In some instances, shrub stages attain a high state of homeostasis
(natural recovery curve) and persist  for  several  decades.
      Erodability increases sharply with a perturbation but declines as vegeta-
tive  cover protects the soil.  During natural successions, erodability remains
higher in early stages than the  later stages, although the most rapid decline
occurs during  the first few years.  The main point of reclamation is to quickly
reduce erosion.  By seeding directly  to a grass-shrub stage, the first several
years of succession are compressed into 2 or 3.   Consequently, erodability
drops sharply  as cover is established and declines in accordance with increased
cover thereafter.

3.5.3  Succession Stages Following Cleanup

     3.5.3.1   First Year—
     During the first year following  treatment, the clearcut forests would begin
to produce sprouts from the remaining stumps (Figure 3-2A).  The spring flowering
herbs of the former forest should reappear as usual.  The opening of the forest
would also permit the invasion of pioneer plant species from outside with rag-
weeds (Ambrosia spp.) and other annuals being among the first invaders.   Peren-
nial grasses,  such as broomsedge (Andropogon virginicus). and even woody plants
may also invade but typically do not become conspicuous.  With the exception of
the sprouts,  areas which have been stumped and grubbed (Figure 3-2B),  scraped,
graded,  plowed, or had soil added or removed should experience a similar first
year.   Cover would remain low on all treatments but especially on those leaving
the poorest seedbed, such as removal of the shallow root zone or burial with
up to 100 cm soil.   No plant invasion could be expected on soils with hard sur-
face stabilization.
     Animal use of first year successions would be limited.  Insect herbivores
could be expected and, consequently, avian insectivores.  The low productivity
could not support a large consumer biomass, however.  Cover on first year fields
is too low to  support resident bird populations and the small mammals found
there are transients, as well.   Large mammals would not find the area attrac-
tive.
                                    3-30

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     Areas around which barriers were  erected should not be visibly different
after one year.  Soils and plant cover have no visible impact following erec-
tion of barriers (Figure 3-3), or after flooding with a few cm of water.
     On denuded areas receiving sewage sludge, first year germination success
and growth would be expected to exceed that of bare ground.  The greater cover
would support a larger consumer biomass but no vertebrates would be expected
to become residents during the first year.
     3.5.3.2  Fifth Year--
     Five years following cleanup, most procedures should be represented by a
stable herbaceous community.  In central Tennessee,   similar aged fields were
dominated by broomsedge (Ahdropogon virginicus) and aster (Aster pilosus).  In
southern Illinois,   broomsedge was also dominant.  Woody vegetation invades by
the fifth year and includes persimmon  (Diospyros virginiana), sassafras (Sassa-
fras albidum), elm (Ulmus alata), eastern red cedar (Juniperus virginiana), and
sumac (Rhus spp.).   Ground cover is high, about 119 percent in the Illinois
example, but the woody vegetation contributes only a small fraction of the cover.
     Where disturbance was less than that represented by post-agricultural
successions, such as clear cutting, recovery would be more advanced.  Root and
stump sprouting could produce a dense  copse woodland in five years which might
prove to be attractive to deer and other forest-edge wildlife.  Herbaceous
groundcover should remain dense because canopy closure would not be expected
to occur within five years.   If the treatment had been to simply erect barriers,
no visible differences would be expected between treated and untreated areas.
     Soil stabilization by compaction,  binding agents, or flocculating agents
would probably no longer be distinguishable from non-stabilized cleanups which
left bare ground.   Hard surface stabilizations would not be expected to have
broken down or decomposed in five years and, consequently, there would be no
recovery (Figure 3-3).
     3.5.3.3  Tenth Year--
     For the cleanups which left bare  ground,  the tenth year would be quite
similar to the fifth year,  differing primarily in the growth of the woody
vegetation.   More individuals of the same shrub species might also be expected.
The characteristic  old-field/shrub stage is quite attractive to wildlife,  how-
ever.   The clear-cut forest might achieve canopy closure by the tenth year,

                                    3-31

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Figure 3-3.
     Recovery of deciduous forest following

     hard surface  stabilization.
               3-33

-------
if sprouting had been vigorous.,  and, if so, the herb stratum would be declining.
Hard surface stabilizations, particularly asphalt, could be starting to break
up with pioneer species starting to invade cracks.  Reclaimed land should have
a mixture of trees, shrubs, and herbaceous vegetation which is attractive to
wildlife.
     3.5.3.4  Fiftieth Year—
     In southern Illinois,  the local sere lacks a pine-forest stage.  Conse-
quently, 50 years of recovery would not likely produce a closed canopy.  After
30 years, 22 species of trees were present but so was a perennial grass (Andro-
pogon virginicus) layer, which indicates a high light level at the herb stratum.
Seedlings of the climax oaks (Quercus imbricaria and Q. velutina) had begun to
appear, indicating that a mature forest was less than 100 years away.
     In the southeastern states, a subclimax pine forest typically replaces
the shrub stage and can produce canopy closure within 30 years from the begin-
                   33
ning of succession.    When canopy closure by conifers occurs, light to the
forest floor is greatly diminished and the herb layer is largely eliminated.
Consumers do not utilize pine forests to any great extent and, consequently,
species diversity tends to be low.
     Stumping and grubbing, surface alterations, soil removals, plowing, stabi-
lizations, and soil fills should all be as described above.  Clear-cut forests
would likely have produced a closed-canopy, deciduous forest and be more ad-
vanced than the bare-ground treatments.  Hard surface stabilizations would not
be sufficiently decomposed to permit normal community development to progress
although individual plants might be doing well.  Reclaimed land could be ex-
                                    1                   40
pected to be in closed-canopy forest  but not in climax.
     3.5.3.5  100 Years After Cleanup--
     Extrapolating from conditions at 50 years, forests lacking a piae stage
should be approaching climax, although full growth and development would not
be expected.  In forests with a pine stage, 100 years marks the transition
from pine to deciduous forest.  In many seres, this is the point of maximum
diversity and productivity, both declining into the climax.  This point may
contain the greatest density of breeding birds, if not the greatest diversity.
This peak in diversity, density, and biomass extends even to the populations
                                    28
of decomposers in the forest floor.
                                     3-34

-------
     One-hundred-year-old reclamations are not known but it seems reasonable
to assume that the accelerated development during the first decade would no
longer be evident and reclamations would be similar to natural revegetations.
Neither are  100-year-old, abandoned pavements known.  It is assumed that decay
of either asphalt or concrete would be fairly complete after a century and re-
vegetation would be proceeding.  Vegetational composition and developmental
stage is not predictable, however, because of the spatial and temporal heter-
ogeneity which would result from the breakup pattern of the pavements.  Where
diverse microsites occur on mine spoils, the revegetational patterns do not
                             9
conform to theoretical seres.
     3.5.3.6  Climax--
     In deciduous forest, climax is more often a theoretical concept than an
observable fact.  Using the term loosely to mean forest dominated by a species
complex similar to the climatic potential, whether or not mature, climax forest
might be expected to occur 150 to 200 years following the disturbance.  Assuming
that the forest disturbed was climax, the new climax may or may not be the same.
        47
Woodwell   has suggested that man-made (anthropogenic) influences are changing
the basic physical and chemical properties of the earth and may interfere with
ecosystem development as we have understood it.   If so,  it is understood that
these influences, such as acid precipitation, will retard rather than accelerate
ecosystem recovery.
     Deciduous forest is an extremely diverse biome with numerous local seres
leading to a few climax types.   In generality, natural successions from bare
ground go through a series of defined stages:  annual weed, perennial herbs,
shrubs,  trees.  Often,  one or more subclimax forest stages precede climax
forest.   Occasionally,  metastable subclimax communities  apparently resist
invasion by trees,   possibly through allelopathy.    In other cases, periodic
perturbations, such as fire, lead to subclimax stages.    All of these extend
the full recovery time of ecosystems.
3.6  QUANTITATIVE ASSESSMENT OF CLEANUP IMPACTS
     Of the cleanup procedures specified, stumping and grubbing (1-3), scraping
and grading (1-4), soil removal (2-1 to 2-8), plowing (1-5, 1-6),  and cover
with uncontaminated soil (1-7, 1-8) are similar in that the rate and pattern
of recovery will be similar.  Differences which may be apparent during the
                                     3-35

-------
first few years should no longer be apparent after a decade or so.   Less
severe disturbances lead to more rapid recovei^y, more severe ones recover
more slowly.

     Because of favorable moisture and temperature conditions, deciduous
forests are reclaimed relatively easily.  The growth form of mature communities,
and their horaeostatic mechanisms, prevent revegetation of climax species, di-
rectly.  Trees of the climax forest typically do not do well on freshly re-
claimed surfaces and the forest floor, which retains nutrients and retards
erosion, requires years to develop.  Consequently, reclamations can only
shorten recovery time by about a decade, which represents only about 5 percent
of the time required to replace a "climax" forest.  However, reclamation can
provide early vegetative cover over the entire area immediately which amelio-
rates erosive degradation in the cleanup area and gullying outside the spill
zone.

     Early stages of natural successions are low in diversity and productivity.
Wildlife is not found on them.  Reclamations attempt to seed directly to the
grass-shrub stage which can establish valuable wildlife habitat within 5 years.
Consequently, the benefits gained from reclamations go beyond simply reducing
erosion or slightly shortening the sere.

3.6.1  Impact Assessment
     Cleanup procedures in deciduous forest are indexed (See Appendix B) in
Table 3-2 as impacts on ecosystems, with 0 equal to no impact and NA equal to
complete loss of the ecosystem.  The index estimates include consideration
of the physical, biological and sociological impacts of the treatments on the
nearby vicinity of the cleanup area.  There are several caveats which must be
observed.  First, the numerical rankings are highly subjective.  Secondly, as
explained below, most impact rankings for a given procedure in a given eco-
system increase as the area affected increases.  It is also likely that the
confidence decreases as the area increases.  Given enough.time, tens of years
to centuries depending on the treatment, recovery to a condition paralleling
that of surrounding untreated areas would occur due to natural recovery.
Thus the index values in Table 3-2 will tend toward 0 with time.  Since the
relative impact assessment is time dependent, the time selected for comparison
was the first growing season after cleanup treatment.

                                      3-36

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     The rationale for a particular index value is discussed in Section 3.4
and summarized here.  Intermediate impact rankings are explained in Appendix
B.  Impact of clear cutting (1-2) on deciduous forest is related to the time
required for succession, hence the possibility of root sprouting lowers the
impact relative to stumping and grubbing (.1-4)•  Impacts obviously increase
with area.  Scraping, burial, plowing and soil removal were all considered to
be impacts in addition to forest removal, for trees and shrubs would generally
have to be removed before the other procedures could be applied.  Scraping and
grading (1-4) are not considered to be any more disruptive than stumping and
grubbing  (1-3) since both preparation and the results are similar.  Shallow
plowing (1-5), over a large area, would be a slightly greater impact since
herbaceous plants and seeds would be buried.  Deep plowing  (1-6), if possible,
on many forest soils would bring lower quality subsoil to the surface and re-
sult in a degraded seed bed.  Removal of the top  10 cm  (2-4) would remove local
seeds and require plant invasion from outside of  the area.  Hence, resulting
in a greater impact and an increasing impact with areal increase.  Thinner
topsoils would also be removed.  Removal of up to 40 cm would remove virtually
all forest topsoils and leave poor  seed beds.  Similar  arguments apply to
burials.  Barriers  to exclude people  (3-1) would  have no  impact while barriers
to exclude animals  (3-2, 2-3) might have slight impact  over large areas.  The
impacts to animal populations themselves might be greater.  Hard-surface sta-
bilization (4-1, 4-2) is effectively  a complete,  permanent  loss.

3.6.2   Recovery assessment
     Deciduous trees require decades  to  reach canopy height.   Consequently,
any area  where trees are removed will not  be  soon restored  to  its  former  state.
Furthermore,  climax species  have habitat requirements which differ  significantly
from conditions prevailing  on bare  ground.  Climax  species  are not  early  in-
vaders  and often  cannot even be planted  on barren sites.  Table 3-2  is based
on estimates  of recovery times  following various  treatments and gives  Recovery
 Indices.  The ranges' of time for expected  recovery  are  quite  large  because
 the  factors  which affect them (e.g.,  soil  factors,  precipitation cycles,  etc.)
 have  potentially  greater  impact on recovery times than  do the differences
 between the  impacts of various  cleanup  treatments.   Consequently,  while  deep
 plowing (1-6)  has a greater perceived impact  than shallow plowing (1-5),  for
                                     3-38

-------
example, the seres are sufficiently long and local variability is sufficiently
great that climax recovery times cannot be effectively differentiated.

     Minimum time to recovery of climax appears to be around a century.  That
is the time required to pass through the various serai stages and create micro-
climatic conditions favorable to climax species.  The exception is where the
trees were clearcut but the forest was otherwise not disturbed (1-2).   Sprout-
ing may result in more rapid recovery, but even that is limited by the growth
rate of the trees and the degree of invasion by non-climax species.  Treatments
1-3, 1-4, 1-5, and 1-6 all require a full sere and the local variability is
probably greater than the differences between them.  Shallow soil cover (1-7)
and shallow soil removal (2-1) may result in conditions similar to the above
(optimally) or could possibly be more severe perturbations.  If unassisted,
natural revegetation is possible, time to climax should be similar to the above.
If not, reclamation may be indicated.

     Reclamation might be necessary where depth of soil applied is great (1-8)
or the depth of soil removed is great (2-2), even if stabilizers are used (2-5,
2-8).   If not reclaimed, decades could be added to the recovery times.  With
reclamation, time to climax should be within the range of natural seres on
more favorable sites (1-3, 1-4, 1-5, 1-6).  In general, stabilizers (2-3, 2-4,
2-5, 2-6, 2-7, 2-8) would be expected to greatly influence early succession
but their effects would not be expected to be discernible by the time climax
is approached.

     Hard-surface stabilization (4-1, 4-2) would significantly retard the onset
of succession and lengthen the potential minimum time for recovery.  It is not
clear if any effect would be discernible on a sere requiring 200 or more years.

     Barriers '(3-1, 3-2, 3-3) do not disturb vegetation in the system and'have
no recovery time associated with them.  Wildlife is discussed in Part III.

3.7  CONCLUSIONS
     The preferred treatment is the "no action" option of erecting barriers
(3-1,  3-2, 3-3).  The advantage is that it allows time for careful evaluation
                                    3-39

-------
of what further steps might really be required.   Particularly where large areas
might be contaminated, the effectiveness and impact of other treatments could
be evaluated experimentally.

     Hard-surface stabilization offers no apparent benefits and should not be
considered.

     As a generality, there are no significant advantages or disadvantages
obviously associated with any of the other treatments.  The decision to actively
reclaim or not will be "influenced by the area disturbed and location.  A small
        2
(0.01 km ), isolated area might not need to be reclaimed while a similar area
having significant population exposure probably would need to be.  Any 10.0 km
area disturbed would probably require reclamation of some kind.  Beyond these
considerations, local experience with road and other construction will influ-
ence decisions on need for stabilizers and/or reclamation.
                                     3-40

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10.
11,
12.
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 Bazzaz,  F. A.   Plant  Species Diversity in Old-Field Successional  Eco-
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 Billings, W. D.   The  Structure and Development of  Old-Field  Shortleaf
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 Bornebusch,  C. H.  The Fauna of Forest Soil,  Forst. ForsVaes, Danm.
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 Brewer, R. and E. D. Triner.   Vegetational Features of Some  Strip-Mined
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 Buckman, H.  0. and N. C. Brady.   The Nature and Properties of Soils,
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 Byrnes, W. R. and J. H. Miller.   Natural Revegetation and Cast Overburden
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Clark, T. D.   Kentucky, Land of Contrast.  Harper and Row, New York,
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Croxton, W.  C.   Revegetation of Illinois Coal Stripped Lands.  Ecology 9-
    155-175,  1928.
                                     3-41

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14.  Curtis, J. T.   The Vegetation of Wisconsin.   Univ.  Wisconsin Press,
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15.  Dickerson, J.  A. and W. E. Sopper.   The Effect of Irrigation with Munici-
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19.  Hosner, J. F.  and D. L. Graney.  The Relative Growth of Three Forest
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21.  Johnston, D. W. and E. P. Odum.  Breading Bird Populations in Relation
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23.  Komarek, E. V.  Effects of Fire on Temperate Forests and Related Eco-
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24.  Kozlowski, T.  T. and C. E. Ahlgren (eds.).  Fire and Ecosystems, New
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25.  Kricher, J. C.  Summer Bird Species Diversity in Relation to Secondary
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26.  Kuchler, A. W.  Potential Natural Vegetation of the Conterminous United
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         University Park, 1973.
                                     3-42

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28.  McBrayer, J. F., J. M. Ferris, L. J. Metz, C. S. Gist, B. W. Cornaby,
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         Succession on the Georgia Piedmont.  Ecology 55: 1075-1085, 1974.

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         teristics Associated with Forest Formation in Secondary Succession.
         Am. Midi. Nat. 93: 302-310, 1975.

34.  Niering, W. A. and R. H. Goodwin.  Creation of Relatively Stable Shrublands
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         Mew Jersey.  Ecology 40:249-255, 1959.

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         Discharge in Streamwaters Influenced by Sewage Effluent Spraying.
         Ecology 56:453-460, 1975.

39.  Quarterman, E.  Early Plant Succession on Abandoned Cropland in the
         Central Basin of Tennessee.  Ecology 38:300-309, 1957.

40.  Riley, C. V.  Ecosystem Development on Coal Surfaced-Mined Lands, 1918-75.
         In: J. Cairns and E. E. Herricks (eds.) Recovery and Restoration of
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         pp. 303-346.

41.  Scanlon, D. H., C. Duggan, and S. D. Bean.  Evaluation of Municipal
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                                    3-43

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44.  Viro, P. J.  Effects of Forest Fire on Soil.  In: T. T. Koslowski and
         C. E. Ahlgren (eds.), Fire and Ecosystems, Academic Press, New York,
         1974.  pp. 7-45.

45.  Vitousek, P. M. and W. A. Reiners.  Ecosystem Succession and Nutrient
         Retention:  A Hypothesis.  BioScience 25:376-381, 1975.

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         81-87, .1974.
                                     3-44

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                                   CHAPTER 4
                              CONIFEROUS  FORESTS
4.1  OVERVIEW                                                                  '
     The coniferous forests of the United States occur in all sections of the
Nation except for the Great Plains.  In the eastern portion of the country, the
distribution of conifers is considerably more continuous and less complex than
in the mountain and far western states.  In the East, zonation tends to be pri-
marily a function of latitude, while in the West, altitude and slope aspect
become major factors.  In the East, it is likely that cleanup procedures would
be limited to a single forest type, but in the West, one or more zones may be
involved if a spill occurs in a mountainous area.  It is not possible to con-
sider the coniferous forests apart from mountainous regions, so both will be
discussed here, as will the interface between the coniferous and tundra zones.
The primary purpose of the first section of this Chapter is to provide a rela-
tively detailed overview of the major types of coniferous forest in the United
States with respect to their distribution and major species associations.

     Costing   has reviewed the climax vegetation types of North America and
notes that there is considerable variation among vegetation maps with regard
to detail due to disagreement on the interpretations of climax relationships.
Examples of such vegetation maps may be found  ' 3>29.  More recent maps have
been published by Little   and Kuchler  .  Costing51 believes that studies of
local investigations of vegetation are necessary for a comprehensive understand-
ing of the bases for the differing interpretations found on vegetation maps.
This statement is no doubt also applicable to most descriptions of the distri-
bution of coniferous forest types, particularly those found in the more diverse
mountainous areas of the country.  It is also important to note that forest
types change in many areas due to shifts in land use and in natural succession
processes, dating older maps.  For example, the harvesting of Douglas fir has
resulted in the replacement of large stands of that tree by western hemlock and
various hardwoods with a resultant net increase of western hardwood forest types
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of nearly two million acres in the period of 1962-1970  .   The concept of
vegetational climax formations and their associations permits classification
on a regional basis; it assumes an acceptance of monoclimax theory which im-
plies the existence of pre and postclimax communities.  While this system is
dated, it has been widely used in various forms in the literature on North
American vegetation and it will provide a basis for the following description
of the coniferous forests of the United States.

     The coniferous forest has been divided into four climax formations in
North America:  Boreal, Subalpine, Montane, and Pacific Coastal.  There are
also large areas of coniferous forest that are considered to be sub or post-
climax by this system.  Costing51 has characterized the nature and distribu-
tion of these formations in some detail and the following descriptions are
largely adapted from his work.  Another system of nomenclature refers by the
major species associations and/or their geographical  location:  northern conif-
erous forest  (spruce —fir); northwestern coniferous forest (cedar— hemlock,
western larch —western white pine, Pacific Douglas fir— redwood); western pine
forest (ponderosa pine —sugar pine, ponderosa —Douglas fir, lodgepole pine);
northeastern pine forest (Jack, red and white pines); and southeastern pine
forest (longleaf, loblolly, and slash pines).  (See Figure 4-1.)

     The Boreal is the most continuous of the major forest formations with
respect to distribution.   In the western United States, the various coniferous
formations appear in vegetation zones which occur as  a function of altitude
and size of a mountain mass, the latter affecting the quantity of precipitation
which will occur on a given mountain range.  At a given latitude, an  isolated
mountain peak may not support stands of species having high moisture  require-
ments that may be satisfied on a nearby mountain range of lower elevation but
greater mass.  Due  to the  prevailing winds from the west, significant vegeta-
tion differences occur between the western and eastern slopes of  the  mountain
ranges.  The  character of  the communities within a given zone also differs  among
mountain ranges.  The  Rocky Mountain and Sierra Nevada forest complexes  differ
significantly and are discussed separately here.  The zonal  climaxes  occurring
within these  complexes include:  Tundra, Subalpine, Montane,  and  Foothill  (not
discussed).
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4.1.1  Boreal Formation
     The Boreal formation, sometimes referred to as "taiga" in its northern
areas, forms a broad band across the North American continent, lying to the
south of the Tundra formation; it occurs as far south as the New England
states.  The climate in the Boreal forest region is almost as severe as that
of the Tundra, being characterized by a cool, short growing season and moder-
ate precipitation that is heaviest near the East Coast (approximately 40 inches)
and lightest in the western region and the Alaskan interior (10 to 12 inches).
The topography characteristic of the Boreal formation is largely the result of
glaciation and abounds with lakes, bogs, and muskegs.  Thin residual soils
overlay rock masses, or deep moraine and outwash occur along the southern boun-
dary of the formation.

     The Boreal formation is characterized by climax growth of white spruce
(Picea glauca) and balsam fir (Abies balsamea); this climax is best developed
along the St. Lawrence River Valley.  White spruce and balsam fir are found
scattered throughout the range and they are associated with paper birch  (Betula
papyrifera) which may occur following fires in pure stands as a subclimax.
Black spruce  (Picea mariana) is frequently dominant north and west of Lake Su-
perior, and  it is frequently found associated with tamarac  (Larix laricina) as
climax species along the northern and far western transitions in high rocky
areas.  Further to the south, both species become associated  with bogs.  To
the west, paper birch and Jack pine  (Pinus banksiaiia) occur as climax species,
and are subclimax nearer the center  of the Boreal formation.  Jack pine  and
black spruce  form a subclimax in the western part of the range and Jack  pine
also occurs  extensively in areas of  sand plains and gravel  soils.

     The northern transition of the  Boreal formation into  the Tundra is  irregu-
lar with the coniferous forest extending far into the Tundra  region in  sheltered
valleys while the Tundra  is found on high ridges extending  into the forested
                                       26
area.   Indications were found by Griggs  , who  studied  the  reasons underlying
the positioning of the Arctic timberline, which suggested  that the timber  line
in Alaska  is advancing northward while it  is retreating  in portions of  Canada.
The  southern transition grades  into  grassland  in the west  and into deciduous
forest  in  the east.   Also,  in Alaska, the  Boreal coniferous forest merges  with
the  northwestern  coastal  forest.  The southern Boreal transition  zone  is marked
by pure stands  of white pine  (Pinus  strobus)  from  New England to  Minnesota and

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 and red pine  (Pinus resinosa.)  in the  Lake  States; Jack pine  also occurs  in
 less  favorable  sites  in the  Lake States area.   In the eastern  transition,
 spruce and fir  may mix with  hardwoods or grow  in alternating stands.   In the
 Rockies,  Picea  glauca is associated with Abies lasiocarpa.   The northern con-
 iferous forest  extends southward on the higher Appalachian mountains  as  far
 as the Great  Smoky Mountains of North Carolina,,  There, the  growth  form  and
 species associations  are similar to those  found throughout the Boreal  forma-
 tion, but red spruce  (Picea  rubens) tends  to replace white spruce from New
 Brunswick southward into New England.  Further south, balsam fir is replaced
 by Fraser fir (Abies  fraseri).  Therefore, the dominant species in  the south-
 ern Appalachians are  the ecological equivalent'; of those found elsewhere in
 the Boreal formation, but they may be distinguished taxonomically.  As the
 latitude decreases, the spruce-fir forest  is limited to increasingly higher
 elevations; this association may be found  virtually anywhere in the northern
 portions of the Boreal formation, but only above approximately 5,000 feet in
 the Great Smoky Mountains.   Spruce tends not to occur at the highest altitudes
 in the southern range and, in  its absence, fir becomes dominant

 4.1.2  Rocky  Mountain Forest Complex
     The Rocky Mountain forest complex contains several distinguishable  vege-
 tation zones  that extend as  far north as Alberta and southward into northern
Mexico, terminating at the southern end of the Sierra Madre  range;  this  zoaa-
 tion extends  westward to the eastern  foothills of the Sierra Nevada range and
 the eastern slopes of the Cascades, it also extends eastward into the  Black
Hills.  In addition to the major Rocky Mountain Ranges, the  complex encompasses
the basin and range physiographic province with its numerous north-south ranges
separated by desert basins.  The zones that occur are a discontinuous  alpine
 zone on the higher peaks, subalpine, montane arid woodland forest.   These zones
are discontinuous in their distribution from rasige to range  and the full com-
plement of zones is not necessarily present in each of the ranges.  For  exam-
ple,  in the northern portion of the complex, the upper zones exist  at  lower
altitudes and the lower zones may not be present; each zone  occurs  at  increas-
ing elevation as the latitude decreases.  As previously discussed,  there are
significant differences in zonation between north and south  exposures  and there
are marked differences in vegetation between the eastern and western slopes of
the individual ranges within the system and for the entire system as a whole.
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In mountain systems,  narrow valleys tend to allow the dominants  of a given
zone to extend downward into a lower zone while high dry ridges  permit  upward
finger-like projections of the dominants into continuous higher  zones.   Drain-
age of cold from higher elevations can significantly disrupt zonal distribu-
tion patterns.51  Whittaker and Niering83 have detailed the effects of  alti-
tude and slope aspect upon vegetation in the Santa Catalina Mountains of
southern Arizona.  (See Figure 4-2.)  A review and synthesis of  the factors
which produce and control the zonation of the vegetation in the  Rocky Mountains
by Daubenmire   may be of particular interest in the determination of the prob-
ability of reestablishing forest growth after implementation of  cleanup procedures.
     The zonal climaxes which occur within the Rocky Mountain coniferous forest
complex have been grouped by Costing   as follows:
          Alpine zone
              Tundra climax
          Subalpine zone
              Engelmann spruce —Alpine fir climax
          Montain zone
              Douglas fir climax
              Ponderosa pine climax
          Foothills (Woodland zone)
              Pinon —Juniper climax
              Oak—Mountain Mahogany climax
     The vertical range of full development of each of the zones is approxi-
mately 2,000 feet, with the foothill zone narrowing and disappearing at the
higher latitudes and each of the other zones being found at progressively
lower altitudes.  In the transitions between the zones, the species character-
istic of each zone become restricted to favorable habitats.  Near the upper
boundary, these species will be more common on ridges and south-facing slopes
where less moisture and higher temperatures occur; whereas in the lower tran-.
sition, the species characteristic of a given zone will tend to occur in the
relatively cool, moist sites.  Under these conditions, species of one zone
may extend into another zone.  Precipitation tends to increase with altitude;
a linear increase of 4.94 per 1,000 feet of elevation was found between the
                                                         45            51
sagebrush and alpine zones on the Wasatch Plateau of Utah   and Costing   notes
that similar observations have been made elsewhere.
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                3000-
                2500-
                2000
                                                                E^DAK^FQREST
                                                                                   .Mexican
                                                                                    •pinon .
                                                                      >AK "WOODLAND
                                                                 ?;:fj?™.'i^
                                                                 :Monzantta!l -•"
                                                    ChThubhuo pine
Wolnof~- --•'• ~- -'~"
,.  j-:.-;'"' cypress -f ;
-   CANYON -
 WOODLAND
                                                                               -•-'-Arizona
                                                          OPEN OAK WOODLAND^*-, osewood
                                                     RoseHe .shrubs
                                                                    DESERT-SCRUB^
                                      lower Slopes
                                            Open Slopes
                                        NE      N    NW
                1500
                1000
                            Vegetation chart for the Santa Catalina Mountains,  southeastern Ari-
                  zona. (The pattern above 9000 ft is for the nearby F'inaleno Mountains.) Four hun-
                  dred vegetation samples were plotted on the chart by their positions' in relation
                  to the elevation gradient, on the left,  and the topographic moisture gradient, on
                  the bottom. Boundary lines were drawn  to connect the mean positions at  which
                  one community-type, as these had been defined in this study, gave way to another.
                  Dominant species are indicated  in the parts of the pattern where they are most
                  important. [VVhittaker and Niering, 1965.]


Figure  4-2.   Vegetation chart for  the Santa Catalina  Mountains, southeastern
                 Arizona  (reproduced  from Whittaker82).
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     .4.1.2.1  Subalpine Spruce-Fir Climax —
     Engelmann spruce (Picea engelmannii) and alpine fir (Abies lasiocarpa)
are dominant in the subalpine zone.  The spruce tends to be larger, more
abundant, and longer-lived than the fir.  Variations in the dominant species
are found in different regions.  For example, in Arizona and New Mexico,
Abies lasiocarpa var. arizonica is as important as A. lasiocarpa is in other
ranges, while mountain hemlock (Tsuga mertensiana) frequently occurs in Mon-
tana and northern Idaho; still further north, Picea glauca and A. lasiocarpa
may be associated as the transition with the northern conifer forest is ap-
proached.  There is more variability among the subordinate species found in
the Rockies than among the dominants.  In the subalpine climax zone, lodge-
pole pine (Pinus contorta var. Murrayana), aspen  (Populus tremuloides), and
Douglas fir (Pseudotsuga menziesii) occur as climax stands following burns;
restoration of the original climax stand is quite slow.  The same situation
may obtain following cleanup procedures.  Lodgepole pine does not occur in
the southern Rockies, and in other areas, aspen frequently predominates over
the pine.  Aspen has the ability to regenerate from sprouts and this may pro-
vide a significant advantage over the pine after a burn.  This factor should
also be considered with respect to forest regeneration after cleanup.

     The subalpine forest grades gently into alpine tundra in the transition
zone with a gradual lessening of the density of t^ree stands.  Near the timber
line, dwarfing and distortion of the trees occur, producing a tree form re-
ferred to as "Kummholz."  The timber line region  is characterized by certain
tree species that are not adapted to conditions in the tundra zone and which
are unsuccessful competitors in the climax forest at lower elevations.  How-
ever, these species do occur on dry and windy ridges.  This is the niche oc-
cupied by the bristlecone pine (Pinus aristata) in the southern Rockies, limber
pine (P. flexilis) in the central Rockies, whitebark pine  (P. albicaulis), and
alpine larch (Larix lyallii) in the northern Rockies, with the exception of
the far northern areas where lodgepole pine is found at the timber line.

     4.1.2.2  Douglas Fir Climax --
     The Douglas fir climax zone lies at altitudes just below the  subalpine
spruce-fir  zone.  Douglas fir characteristically  occurs in such density that
few subordinate species are present.  There are north-south differences in
the Douglas fir forest.  In the south, white fir  (Abies concolor)  and blue
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 spruce  (Picea pungens) are present, but they are restricted to relatively
 small damp  sites.   In the north, the  subclimax species present differ with
 respect  to  the direction of the  slope face and the relationship of the site
 to the continental  divide.  Grand fir (Abies grandis) is found west of the
 divide and  characteristically occurs  on the western  slopes.  East of the
 divide Picea glauca, a representative of the northern conifer forest, exhib-
 its codominance with Douglas fir, and is found southward through the montane
 zone into the Black Hills.

     On  exposed ridges, open stands of pine which include species character-
 istic of timber line are found both in the montane and subalpine zones.  The
 species  found differ with the region:  P. fliexelis var. reflexa is found in
 the south;  P. aristata occurs in northern Arizona, southern Utah and Colo-
 rado; and P. flexilis occurs northward to the point where it is replaced by
 P. albicaulis.

     When stands of Douglas fir climax forest are burned, lodgepole pine or
 aspen replace it, exhibiting the same relationships as discussed for the sub-
 alpine zone.

     4.1.2.3  Ponderosa Pine Climax --
     Just below the altitude of the Douglas fir belt is the Ponderosa pine
 CPinus ponderosa) zone.  This species and its close relatives occur in rela-
 tively open forest that becomes increasingly like savannah as the altitude
 decreases.  Due to the open structure of the growth, grasses form a ground
 cover.   The Ponderosa climax is separated from the Douglas fir by a rather
broad transition where both species coexist in a shared dominance relation-
 ship.  The term Ponderosa climax is something of a misnomer as that species
 is truly dominant only in the northern Rockies west of the continental divide.
 In other regions, Ponderosa is replaced by or found in association with closely
related varieties, having similar ecological characteristics such as P. pon-
derosa var.  scopulorum on eastern slopes in the north; throughout the zone
 southward, P. ponderosa var.  arizonica,  P.  leiphylla var. chichuahana, and
 P. contorta var. latifolia,  all occur in the southern Rockies.  Along streams
 and drainage lines, narrow leak cottonwood (Populus augustifolia) will form
postclimax stands with P. acuminata and P.  sargentii.  Aspen (P.  tremuloides)
 and box elder (Acernegundo)  may also occur in moist areas.

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     Older Ponderosa trees are somewhat resistant to fire and are killed only
by severe burns.  Pondersoa seedlings are destroyed and saplings tend to oc-
cur in the understory in groupings of even age, representing growth of several
consecutive fire-free years.  Severe fires may result in stands of lodgepole
pine, while lumbering and overgrazing may result in dense growth of scrub
species found in the oak-mountain mahogany zone.

     4.1.2.4  Pinon-Juniper Climax —
     The lowest of the Rocky Mountain coniferous zones is characterized by the
pinon-juniper climax.  Typically, this is a zone of open vegetation with small
trees from 10 to 30 feet in height.  This vegetation zone also occurs on many
of the low ranges in the Great Basin as the only zone present.  The pinon-
juniper climax is typical of the intermountain region and forms a distinct
                            84
zone in the southern Rockies  .  The appearance and characteristics of the
vegetation within the pinon-juniper zone are relatively constant, although
it includes several species with restricted ranges and marked regional dif-
ferences with respect to taxonomic and sociologic considerations occur.  Among
the junipers present in the zone are Juniperus scopulorum, J. osteosperma,
J. monosperma, J. occidentalis, J. deppeana (this list is not all-inclusive);
the pinons, or nut pines, are variously referred to as species or varieties
and include Pinus cembroides (P. edulis, P. monophylla, and P. quadrifolia).

     This climax zone extends from northern Mexico along the western slope
of the Rockies to the Snake River in Idaho and into southern Alberta with the
pinon while the desert species of Juniper are replaced by J. occidentalis or
J. scopulorum.  On the eastern slope of the Rockies, the zone extends as far
as Fort Collins, Colorado, at which point pinon disappears and J. scopulorum
continues northward through Wyoming, frequently associated with sagebrush.
In the northern Sierras, pinon-juniper is not present with Jeffrey pine (Pinus
Jeffreyi) grading directly into Artemisia and Pushia; it does exist on the low
eastern slopes of the southern Sierras but tends to occur in mixed growth with
other species.  However, pinon-juniper does occur on every westernmost range
and mountain of the Great Basin, and frequently is separated from the Sierra
Nevada range by only a single valley.
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4.1.3  Sierra Nevada Forest Complex
     The following discussion of the Sierra Nevada Forest Complex will in-
clude the southern Cascade Mountains and the Sierra Nevada which extend from
Oregon southward along the California-Nevada border, including the innermost
ranges of the coastal mountain system.  The western slope of the Sierras is
gradual while the eastern slope is quite abrupt, dropping from peaks of more
than 14,000 feet to the floor of the Great Basin at an elevation of approxi-
mately 4,000 feet.  Due to this slope difference, the western slope encom-
passes a much greater land area than does the eastern.

     4.1.3.1. Western Slope —
     Due to the north-south axis of the Sierras, and the prevailing westerly
winds, the eastern slopes of the range are much drier than the western.  At
the base of the western slopes, 10 to 15 inches of precipitation fall annually
with a long, unbroken summer dry season.  As the altitude increases, the dry
season shortens, temperatures fall, and precipitation increases with a greater
proportion falling as snow.  Approximately 80 to 85 percent of the precipita-
tion occurs in the winter, with 35 to 75 feet of snow falling in the subalpine
zone.  The heaviest total precipitation is reported to occur between 5,000 and
7,000 feet41 where the mixed coniferous forest of the montane zone is found.
The subalpine zone coincides with that zone having the greatest snowfall,
and possibly  this is the zone or greatest precipitation since snow gauges
which are exposed to high winds tend to give low readings; spring snow sur-
veys indicate a greater water content of the accumulated snow than can be ac-
counted for by reported precipitation36.  This fact may have implications for
cleanup procedures.

     Subalpine Zone—The subalpine zone is usually found in a 1,000-foot ver-
tical range between 6,500 and 9,500 feet depending upon the latitude.  Typ-
ically, this  zone experiences cool, short growing seasons with wet winters
and dry summers.

     The major climax species found in the subalpine  zone in the Sierra Nevadas
is red fir  (Abies magnifica), which comprises 80 to 90 percent of the  forest
tree growth,  occurring in dense stands.  Other  species are associated, but of
minor importance  in the climax growth.  Western white pine  (Pinus monticola)
is usually present as a minor constituent.   Lodgepole pine  (Pinus contorta)

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is often present, at the edges of meadows, but in a successional role.  Ir-
regular growth of mountain hemlock  (Tsuga mertensiana) and white fir is
found in the zone, with the former  tending to occur at the higher elevations
of the zone and the latter at lower elevations.  Shrubs and herbs are found
throughout the zone and lichens occur on the trees.

     Timber line is often found at  lower elevations in the Sierras than in
the Rockies, ranging from 7,000 to  10,000 feet depending upon the latitude;
this is due to the more severe environmental conditions occurring in the
Sierras.  Pinus albicaulis, P. flexilis, and P. balfouriana are character-
istic of timber line growth in the  Sierras^0.  Juniperus occidentalis is also
common at timber line on exposed, rocky slopes; it is also found on the west-
ern slopes at lower altitudes.  Generally, red fir growth does not extend
to timber line, but instead grades  into a relatively narrow band of Pinus
contorta - Tsuga mertensiana dominance.  In this zone, P. contorta assumes
a climax role, although it is successional to Abies magnifica at lower alti-
tudes; hemlock also has climax characteristics at the upper limits of the
subalpine zone.

     Montane Zone—The montane zone occurs between 2,000 and 6,000 feet in
the Cascades,  between 4,000 and 7,000 feet in the central Sierras, and be-
tween 5,000 and 8,000 feet or more  in the south.  Five or six principal
species have climax characteristics in this zone and tend to occur in any
combination at any altitude, although the upper and lower margins of the
zone are likely to have consistent vegetational differences.  In the upper
part of the zone,  white fir is usually the important dominant, where it is
sometimes found in pure stands;  its numbers decrease at lower elevations.
Important species at lower elevations include sugar pine (P. lambertinana),
Jeffrey pine,  Ponderosa pine,  Douglas fir, and incense cedar which tends to
predominate on the most favorable sites.  Douglas fir is more frequent in the
north; sugar pine and Jeffrey pine are more abundant at higher elevations,
the latter being the most drought-resistant of the major species of the zone.

     4.1.3.2  Eastern Slope —
     The eastern slope of the Sierra Nevada range has the same vegetational
zones as those found on the western slopes.  However, the abruptness of the
eastern slope and its drier climate result in less favorable conditions and
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some differences in the distribution of vegetation from that found on the
western side.  The red fir forest is found in restricted areas such as the
Carson Range east of Lake Tahoe and in localized areas in the northern
Sierras.  The subalpine zone is generally represented by patches of lodge-
pole pine and those species of pine found at timber line on the western side.
The montane zone extends to high altitudes with poorly developed vegetation.
In this zone, Jeffrey pine is the most important species and it occurs in
open stands which differ in appearance from those on the western slope.
Pinon-juniper forest is restricted to a few eastward-extending high spurs
of the range, although it is well developed on the next range to the east
of the Sierras  .

4.1.4  Pacific Conifer Forest
     The coniferous forests of the Pacific coastal region parallel the coast
from the timber line in Alaska southward to central California.  Mountain
ranges of various altitudes are found within the range of this forest type.
The entire region from north to south is characterized by a mild climate
which is tempered by the presence of the Pacific Ocean.  Subzero temperatures
are rare on the Alaskan coastline and from Oregon southward, frosts are rare.
Precipitation ranges from 30 to 150 inches and the humidity tends to remain
high.  In the south, rainless summers tend to be compensated for by fog.
Snowfall increases with latitude where 50 to 60 feet may occur in some of
the higher mountain ranges in the north.

     The character of the coastal forest is primarily montane throughout its
altitude range from 0 to 5,000 feet.  In the northern portion of the Cascades
in the Washington-British Columbia border region, some subalpine forest oc-
curs, but  it contains dominant species derived from the Rocky Mountains
(Abies lasiocarpa), the Sierra Nevadas (Tsuga mertensiana) and the coastal
forest (Abies amabilis and A. procera).  Tundra exists on some of the higher
mountain peaks.

     The best development of coastal forest species occurs in the general
vicinity of Puget Sound, with the most luxuriant vegetation occurring in the
rain forest of the Olympic Peninsula where the ranges of all of the major
species overlap and most of the trees attain their maximum size.  The climax
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dominants are western hemlock  (Tsuga heterophylla), western arborvitae
(Thuja plicata) and grand fir  (Abies grandis).  Douglas fir is the most
abundant and widespread species; it tends to be found in the drier sites.
It is intolerant of shade and becomes the major dominant after fires and
is therefore subclimactic in its relation to the forest.

     North of Puget Sound, sitka spruce  (Picea sitchensis) becomes increas-
ingly abundant and is a climax dominant along with Tsuga heterophylla and
T. mertensiana in the northern extension of the forest.  In Alaska, where
the Boreal and Coastal forests interface with the tundra, P. sitchensis and
P. glauca occur at timber line.  Southward from Puget Sound, Douglas fir
becomes increasingly important and Port Orford cedar (Chamaecyparis lawsoniana)
becomes an added climax species.  Along the coast, redwood (Sequoia semper-
virens) replaces Sitka spruce.  The redwoods are generally limited to the
fog belt and their range extends irregularly for a number of miles south of
Monterey, California.  The species of the coastal forest extend eastward
along the Washington-British Columbia border, expanding to the north and to
the south on the western slop of the Rockies.  Species found in this exten-
sion include Tsuga heterophylla, Thuja plicata, and Pseudotsuga mensiesii
and occupy a zonal position between the Douglas fir and spruce fir zones of
the Rockies.  Western larch, white pine, and grand fir also occur in this
extension.  Daubenmire  noted that this extension follows a well developed
storm track and is frequented by winds which blow eastward from the coast
4.1.5  Coniferous Forests Occurring as
       Sub and Postalimaxes
     Extensive coniferous forests occur in the eastern portion of the Nation
as subclimaxes which are maintained by fires or swamps; in some regions these
forests are not considered to be climaxes.  The coastal plain from New Jersey
to Florida and along the Gulf States into Texas is a relatively flat area at
low altitude.  The soil is generally sandy and tends to have poor drainage
with many swamps.  Raised areas are usually dry for a portion of the year.
Dry seasons are accompanied by low water tables and relatively frequent fires.
In New Jersey, pitch pine forests occur and loblolly and slash pine are found
in the states further south.  These pine forests are generally open with
grass floors and are referred to as savannahs.  Frequent grass fires permit
survival of the relatively fire-resistant conifers at the expense of oak and

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hickory, which would replace the conifers if the area were given prolonged
                    811?
protection from fire  '   .   Some consider these areas to be a "pyric climax."
Whatever terminology is used, the presence of frequent fires in such areas
must be considered in the reestablishment of the original growth that pre-
ceded cleanup procedures.

     Coniferous forest may also be encountered within those regions generally
dominated by hardwoods.   Also, an association of hemlock and hardwoods occurs
in the transition between the northern coniferous forest and the deciduous
forest.  Hemlock (Tsuga canadensis) frequently occurs with beech and sugar
maple and less frequently with birch, white pine, and other hardwood species
from northwestern Minnesota through the Lake States into Nova Scotia.  Many
pure stands of pines (P. strobus and P. resirtosa) have been destroyed by fire
and lumbering.  White pine is found within the hardwood climax forests of the
region, but Costing   believes that these long-lived trees should be consid-
ered as relicts, although they do reproduce in open areas in the hardwood for-
est.  As such, their replacement following cleanup procedures may prove to be
difficult and might be considered to be optional, depending upon local circum-
stances.  Tamarack, black spruce, and white cedar (Thuja occidentalis) occur
in postclimax stands and occupy bogs throughout the region.  Aspen and pine ,
also occur in burned or logged out areas.

     Pitch pine (P. regida), Virginia pine (P. viginiana) and shortleaf pine
(P. echinata) occur from southern New England to Georgia in that region fre-
quented by an association of oak and chestnut, with the latter two species
becoming locally abundant in the southern part of the range.  In the south,
the occurrence tends to be limited to higher altitudes, but in the north, it
occurs at lower elevation and occurs as far east as Long Island.  Virginia
pine, shortleaf pine and loblolly pine also occur on abandoned land throughout
the region of the oak-hickory association on the Piedmont Plateau and on the
coastal plain of the Atlantic and Gulf States.  Virginia pine predominates
in the northern Piedmont with shortleaf and loblolly pine preceding climax
growth in the south, usually occurring in pure stands.
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4.2  NATURAL PERTURBATIONS
4.2.1  Fire
     4.2.1.1  Unassisted Recovery Sequence --
     Fossil records indicate that fire has probably always been a part of the
environment of forests on the surface of the earth.  Most of.the species of
conifers have a number of fire-adapted regenerative qualities which range from
a need for mineral seed beds to a requirement for high temperatures to permit
the opening of serotinous cones.  Thick bark, adventitious buds, and coppice
sprouting also enhance survival of fire.  Most coniferous species are also
tolerant of exposure to sunlight and open space  .  It seems likely that many
of these fire-adaptive qualities will serve to assist the recovery of the
coniferous forest from cleanup procedures, if those procedures are signifi-
cantly more disruptive of the forest than would be a severe fire.  However,
it is important to note that these characteristics are not universal among
coniferous trees.

     On a study plot in the Sierra Nevada mountains, which was established
after a severe fire in 1960, it was found that natural revegetation (un-
assisted) by Jeffrey pine seedlings greatly exceeded that by fir seedlings**.
This situation was reversed in data obtained from ten unburned control plots
where establishment and growth of fir seedlings exceeded the pine seedlings.
The pine seedlings were found to have high survival rates and demonstrated
an exponential rate of growth.  Some of the trees had attained heights of
250 cm at fourteen years of age (having germinated the summer of the burn).
It was also noted that pine seedling recruitment occurred at approximately
identical rates on burned and unburned plots.

     The sequence of events following a severe forest fire will differ for
each particular forest and location within that forest.  It is difficult to
generalize in this regard for all of the coniferous forests of North America.
At the site of the Donner Ridge test plots, the natural postfire reforestation
pattern appears to be:  pine > pine + fir > fir.   However, the stage of pure
fir forest is seldom reached in the region due to interference by fire, and
           D
Bock et al.  note that it is difficult for this fire-regulated successional
pattern to be reconciled in terms of classical ecological climax community
               O              Q
classifications  .  Bock et al.  suggest that Jeffrey pine is particularly
adapted to the fire environment, since the observed sustained exponential
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growth pattern would not be expected in the irregular climatic conditions
that have obtained in recent years in that area.

     Following a forest fire, the successional pattern is reset.   Fungi and
other microorganisms invade the area  , and the composition of wildlife popu-
lations  is  altered due to the drastic alterations in habitats produced by
the fire.  Lyon and Stickney   have examined the vegetal succession that fol-
lows large fires in the northern Rocky Mountains.  They found that succession
in the forest is not an autogenic process in which initial serai  plants modify
the site to their own exclusion and then subsequently permit the  establishment
of interseral and eventually climax species.  Instead, they note  that succes-
sion is a sequential development of vegetation in which the more  rapidly ma-
turing and often shade intolerant plants assume initial dominance and then in
turn are dominated by taller, slower growing, and often more shade tolerant
species.  They obtained data from three large wildfire burns that indicated
that a high percentage of plant species on a site at the time of  the fire
survive and reestablish themselves on the burned area.  The majority of recog-
nizable survival adaptations are on-site plant parts and seeds or fruits, and
these provide the major source of early serai vegetation.  They noted an ex-
ception to this rule in a few species that have both an on-site survival mech-
anism and airborne seeds.  They found that all of the dominants of early suc-
cession will be established in the initial postfire growing season, whether
                                                                        46
or not they are derived from on- or off-site sources.  Lyon and Stickney
believe that reliable estimates of the likely composition of the  early suc-
cessional forest can be derived from the composition of the prefire or the
first postfire year communities.  Further predictions may be possible based
upon the survival strategies and dominance potentials of the various plant
species in the community which will indicate the probable structural config-
urations of the early successional period.                           ,
                                      46
     The findings of Lyon and Stickney   suggest that in many areas, the
probable course of unassisted recovery from a cleanup operation in a conif-
erous forest might be predicted on the basis of  local data on fire recovery.

     4.2.1.2  Assisted  Recovery Sequence --
     Shearer   has compared the effects of unassisted fire recovery with as-
sisted recovery in coniferous forests  in the Rocky Mountains.  He notes that

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historically coniferous forests of the northern Rockies have been returned
to early stages of succession by fire  .   This is largely a consequence of
heavy accumulations of litter and other flammable debris accumulated over
many years.  Pioneer species such as western larch (Larix occidentalis) and
lodgepole pine (Pinus contorta) require an early successional stage, and
they rarely become established in the absence of a major disturbance of for-
est.  Frequently, land managers utilize mechanical scarification on slopes
of less than 30 percent in order to enhance the formation of a seed bed.
Shearer   describes experiments designed to obtain quantitative data con-
cerning the effects of varying intensities of burning on natural regeneration
in western larch/Douglas fir forest.  It was found that early establishment
of coniferous forest regeneration following prescribed broadcast burning of
clearcuts was influenced by the interaction of several factors, the most im-
portant of which were  (1) seed bed condition, (2) seed supply, and  (3) en-
vironmental characteristics affecting seedling survival.

     Shearer   noted that even under the most extreme conditions of fire, the
soil temperature remained at 66°C at a depth of 29 mm while the surface temp-
erature was 260°C; therefore, the underground systems of the plants receive
relatively little damage, and most species were able to reestablish them-
selves by vegetative reproduction.

     It was observed that most of the seeds that fell on the clearcuts came
from adjacent growth, although some were from unidentified sources, perhaps
miles distant.  Most of the natural seeding occurred during periods of tur-
bulence associated with frontal weather systems.  The actual distribution of
the seeds on the large clearcuts decreased rapidly with increased distance
from the edge of the adjacent timber stand surrounding the burn, but there
was a low, relatively constant concentration of seeds throughout the central
section of the burned area.   Possibly a higher proportion of the total seed
in the central area was derived from unidentified distant sources, rather than
from the adjacent timber stand.

     Germination of seeds was adequate on treated and untreated seedbeds,
but was greater on bare mineral soil  (burned or scarified) than on scorched
or unburned duff.  It was found that germination began sooner on clearcut test
beds possibly due to higher soil temperatures than obtained beneath residual
timber.  It was also found that the establishment of seedlings could be increased
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by burning the residual duff on clearcuts.  Burned clearcuts facing from
300 degrees to 90 degrees azimuth (west-northwest to east) regenerated well.
Clearcuts with the least amount of regrowth were judged to have poor seed
sources.  Regeneration was reduced on less favorable aspects where high sur-
face temperatures and low soil water limited seedling establishment.  Smaller
burned areas having three or four adjacent timber edges tended to have in-
creased regeneration due to a better seed supply and possibly better shading
from the adjacent forest.

     Shearer   also notes that successful regeneration was so strongly asso-
ciated with the type of habitat.  Growth was particularly successful under
shade cast by either living or dead trees on burned seedbed.  Growth was
sparse on poorly burned seedbeds and on hot open slopes with little or no
shade.  In general, moist habitats regenerated well, while drier areas were
understocked.  Large clearcuts received insufficient seed fall and the upper
soil was soon depleted of available water by heavy vegetative competition.

     Shearer   concluded that clearcutting coupled with prescribed broadcast
burning on north- and east-facing slopes usually leaves the cutover area re-
ceptive to natural regeneration if sufficient seed is present.  On hot, dry,
and steep south- and west-facing slopes, shelterwood or very small clearcuts
(group selections) offer a better chance for regeneration by leaving a greater
seed source and better protection for th? site.  Clearcuts without seedbed
preparation, regardless of the aspect,  restock slowly.

4.2.2  Other Natural  Perturbations
     Other than fire,  major natural  perturbations to coniferous forests in-
clude earthquakes, land and snow slides and flooding.   The severity of the
damage depends upon the intensity of the initial disturbance and the location
of the affected forest; prospects for recovery from these events are subject
to the same variables. In some instances, permanent alteration of the land-
scape will result with attendant changes in the biota of the area.

4.3  MAN-MADE PERTURBATIONS
     Probably the most obvious of the man-made perturbations to the conifer-
ous forest of the United States are logging and land clearing for agricul-
tural purposes, construction, and mining.  Only in the cases of logging and,

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recently, strip mining is reforestation contemplated after the clearing or
clearcutting of the land.  Clearcutting for the purpose of harvesting usually
does not entail the processes of stumping, grubbing, and soil importation
that would probably occur in the case of a cleanup operation.  Clearing for
agriculture is generally intended to be a permanent treatment.  Therefore,
neither of these examples is strictly analogous to the sequence of events
that might be involved in the cleanup process.  In some respects, the restora-
tion of a forest after a strip mining operation would resemble the cleanup
operation, but there is little historic precedence of sufficient age for this
to provide prognostic information.

4.3.1  Clearcutting
     In addition to the loss of vegetation and disruption of animal habitats,
clearcutting has a number of additional effects.  The ecological balance of
the forest flora and fauna is affected at all biological levels.  For exam-
ple, the loss of habitats from the destruction of the trees may change the
bird population in the cle'arcut area, which in turn may affect the insect
population.  The slash remaining after clearcutting will offer new habitats
for new species, and there may be increased damage to young trees in the
regenerating area from diseases and pests  .  Water quality in a forested
area is generally decreased after clearcutting due to increased sediment in
the water  .  Hibbert   has reviewed the historical effects of forest treat-
ment on water yield.  Generally, he found that removal of forest increases
water yield, but he notes that the results of individual treatments were
highly variable and were, for the most part, unpredictable.  Hibbert also
found evidence that the increase in streamflow was proportional to the amount
of reduction of the forest.  Surface runoff and streamflow were also shown to
be increased in the Hubbard Brook experiment.   (See discussion by Horwitz  .)
Soil erosion is greatly increased in clearcut mountainous areas.  Disruption
of the soil and increased insolation alter the microbiological populations
after clearcutting.  Soil nutrients are  leached from  the  soil  in clearcut
areas .

4.3.2  Strip Mining
     Strip raining operations in forested  areas represent  a widespread  source
of severe perturbation.  Only in recent years have  there  been significant

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attempts at reclamation of mined areas, and the technology for doing so is
still in a developmental stage.  May and Striffler   have addressed the water-
shed aspects of stabilization and restoration of strip mined lands.  They
found that erosion and sedimentation from disturbed watersheds are attribu-
table to three main sources:  slides from sidecast overburden, haul roads,
and the mined area itself.  Proper spoil placement to ensure bank stability
by drainage control will serve to minimize disturbance.  Studies of replant-
ing of strip mined areas may be found in Boyce and Neebe   and Sindelar,
                             64
Atkinson, Majarus and Proctor  .  Many of the efforts at replanting of strip
mined lands have not attempted to reproduce the original forest, but rather
to stabilize the land with rapidly growing (often imported) species.
4.3.3  Controlled Burning
     Fire has been used as a tool in the forest for centuries.
In is com-
monly used now in forest management as a means of decreasing fire potential,
for removal of debris after logging operations, etc.  Stark   has studied the
effects of controlled burning of forest understory material upon soil nutri-
                    /• o
ent content.  Steele   has examined various aspects of smoke management from
such fires in relation to atmospheric conditions.  A discussion of the envi-
                                                                       20
ronmental aspects of prescribed burning may be found in Fillmore et al.

     In the consideration of methods for reforestation after cleanup proce-
dures, assisting recovery through the planting of seedlings seems essential.
     74
Tinus   has noted that in order to survive, the species and seed source used
must be adapted to the particular site, the seedlings must be in the proper
physiological state to meet the new environment, and root contact with the
soil must be quickly established.  When compared with outdoor grown bare root
seedlings, containerized seedlings can be more precisely controlled and will
not lose root contact with the soil in the planting process.  It may also be
of interest to consider mychorrhizal inoculation of the soil in conjunction
with replanting, if the soil is imported and alien to the forest which is
destroyed in cleanup procedures.  Mychorrhizal inoculation in afforestation
has been .reviewed by Milola
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4.4  EFFECTS OF CLEANUP PROCEDURES ON CONIFEROUS FORESTS
     This section will discuss the effect on coniferous forest ecosystems of
a number of possible cleanup procedures.

     (0-1)  Natttral Rehab-Lli,ta.ti,on
     The coniferous forest is not always pure but frequently occurs in mixed
stands with varying proportions of hardwood pioneers which become established
mostly on small bare patches, brush patches, or other non-grassy patches in
the disturbed area.  An example of primary succession following complete de-
struction of a conifer forest is that of the six stages of a red spruce forest
on mineral soil  .  The successional stages are:
          1.  Moss meadow
          2.  Aster-fireweed meadow
          3.  Hair grass-sedge meadow
          4.  Wetlow-birch thicket
          5.  Aspen forest
          6.  Spruce forest.

     In the north, gray and paper birch, pin and black cherry, and big tooth
and trembling aspen are the typical hardwood pioneers.  In the south, sweet
gum, red maple, and many other hardwoods become established following clear-
cutting.

     Along the east slope of the Rockies, severely disturbed areas, such as
those resulting from fires, tend to be  colonized first with lichens, moss,
and fireweed.  Lodgepole pine reseeds concurrently, either in pure pine  stands
or in association with Englemann spruce in clearings at the upper edge of the
coniferous forest.  However, cleared areas may be characterized by such  harsh
climatic conditions near the ground that conifers cannot  reseed in the area.
Many mountain meadows of the western American ranges may  have originated in
this manner.

     If natural rehabilitation  is  to be relied upon for the clearcut areas,
the major  source of seed will be the surrounding forest.  Areas with dimen-
sions greater than five tree heights  (of the  surrounding  forest) will not
receive  adequate coverage.   If  the treatment  is carried out on a fire species
such as  lodgepole pine or Jack  pine, cones  will not open  and  reseeding may
not occur.
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     Although the site may' be replanted with coniferous species, hardwoods
may soon invade, and subsequent possibilities for variations in the pattern
of succession of various sites then become too numerous for generalizations.
      (1-1)  Chemical Stabilization
     Appendix A lists the characteristics of 23 "chemical" and "chemical with
mechanical characteristics" stabilizers which are preferred for coniferous
forests.  These soil sealers and stabilizers mainly include cementitipus cal-
cium compounds and mixtures, organic bituminous products, waterproofing agents,
and emulsified binders.

     The use of emulsifiers is a temporary treatment for stabilizing a soil
until vegetation is established.  Its effective life is not much beyond 2
years.  It would only be useful on sloping areas.  It could, to some extent
on most treated sites, enhance succession and the development of wildlife
habitat by retarding erosion until plants became established.  It would not
adversely affect any site over and above the primary treatment.

     Deflocculants such as salt, sodium hydroxide, and commercial materials
such as Calgon, when present on the soil exchange complex in sufficient quan-
tity can virtually render certain soils impervious to water.  The degree to
which this can be accomplished depends upon soil texture, structure, and the
type and concentrations of ions already present in the soil.  However, it is
assumed the soils of the treated areas would be appreciably affected by the
chemical treatment.  Accordingly, infiltration would be reduced, and surface
runoff increased.   Thus, less water would be available for vegetation that
might invade or be planted on the site.  Erosion on-site and sedimentation
off-site would be increased as a result of both increased runoff and the de-
flocculated soil which would go into suspension more readily.

     (1-2)  Cteareutting Vegetation
     Clearcutting of coniferous forest has been suggested as a possible tech-
nique for cleanup of spilled hazardous materials.   Precedent for this proce-
dure and many associated problems may be found in the commercial harvesting
of Douglas fir in the Pacific Northwest, western white pine in northern Idaho,
Jack pine in the Lake States, loblolly pine in the south, and lodgepole pine
in the Rocky Mountains.  Revegetation in these cases may be achieved through

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growth of previously established seedlings, natural seeding prior to cutting,
artificial seeding after cutting and plant programs.  However,  it is assumed
that in the case of clearcutting for purposes of spill cleanup,  the clearcut
areas will be replanted or reseeded.

     Technically, artificial rehabilitation is applicable to any kind of for-
est.  It contrasts sharply with the seemingly closely related method of clear-
cutting combined with rehabilitation by natural means which has much greater
limitations and gives satisfactory results only under favorable conditions.
                                                                  19
     Some of the 'general effects of clearcutting can be summarized   as
follows:
          1.  Clearcutting eliminates the danger of wind damage or
              disease infection to residual trees in the cutover area,
              but increases the risk of windthrow or heat damage to
              trees bordering on the cutover area.
          2.  Clearcutting improves forage for game animals such as
              deer, elk, and provides habitats for certain animals that
              were not present before logging.  However, streams may be
              adversely affected by clearcutting with increased temper-
              atures, debris jams, and sedimentation, all of which are
              detrimental to fish populations.  The procedure will also
              reduce habitats of some of the smaller animals such as
              woodpeckers, and tree squirrels.
          3.  Water yields during low-flow periods will be increased
              by clearcutting; snow catch may also be increased.  In
              swampy areas, the water table may be elevated by the
              procedure.
          4.  Clearcutting will permit the use of genetically improved
              tree planting stock, but growing conditions will be also
              enhanced for many unwanted brush species, which will com-
             . pete with the young conifer  seedlings.
          5.  Good growing conditions for  shade-intolerant tree  species
              such as Douglas fir and noble fir will  be created  by clear-
              cutting but seedlings will be exposed to  injury from cli-
              matic extremes.
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     Effects of Clearcutting on  Climate  and Hydrology—Small  clearings within
 forest  stands  can  create  extreme effects on the microclimate,  and  larger
 clearings  significantly affect hydrological factors.  As an illustration of
 these effects, Table  4-1  was taken  from  Geiger:25
                                             I '
                Table 4-1.  Measurements  on forest clearings.
Measurement item
Size index D:H*
Outgoing radiation
of open land)
Diameter D (meters)
0 12 22 24 38 47 87

(percent
Rain (percent of open land)
Temperature (excess
land midday July)
over open
0 0.46 0.85
0 11 31
87
0 0.7 2.0
0.93 1.47
33 52
105
2.0 5.2
1.82 3.36
66 87
- . 102
5.4 4.1
 *D = diameter of the clearing, H = height of forest trees, and tree height
  averages approximately 20 meters.
     (a)  Temperature:  Temperature excesses (temperature increases over those
found in the forest surrounding the clearcut) increase with the size of cleared
openings in the forest up to a size index of about 1.8 because of solar heat-
ing.  However, beyond this size temperature again decreases because of wind
action.  It has been found that size indices less than 1.25 can provide com-
plete frost protection while frost damage will be considerable at indices of
1.50 or greater.  In colder regions, air temperatures decrease linearly to
about 5°C below the temperature obtained in a closed stand as the diameter
of the clearing increases from 0 to 80 meters.   Extrapolation of the data in
Table 4-1 indicates that the excesses would be minimal (except for the dif-
ferences in cooling by transpiration) in clearings 180 meters in diameter.

     Soil temperatures within clearings will increase by 2°C to 3°C over
those temperatures found in soil beneath a closed stand.   In colder climates,
spring snow thaws in clearings may occur as much as 4 weeks earlier than in
closed stands.
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     Cb)   Radiation:  Incidented radiation will,  or course,  be greater in
clearings.  Albedos will be higher in the clearings and net  radiation in
clearings may vary between 70 and 90 percent of that in the  forest stand.

     Cc)   Soil Moisture:  In general, the forest bordering a clearing will
deplete soil moisture in the clearing to the extent of their root systems
during the summer, while soil moisture within the clearing beyond the forest
root zone will remain high throughout the year.76  Soil moisture within the
clearings in mixed conifer forests can be expected to be 5 to 40 percent
                                     1. 31, 34, 57
above that of the surrounding forest.

     Cd)  Precipitation:  Although small clearings will, because of wind
eddys, tend to increase  in rainfall, their greatest effect  is upon snow
catch.  During periods of snowfall in small clearings,  incoming snow  at  one
time or another  comes from all  directions.  The ultimate pattern of snow
accumulation, however, will  most  strongly reflect  the  average velocity and
direction of  air flow.   The  zone  of  maximum snow accumulation will generally
be  near the center  of the clearing.24'29  Snow catch in small clearings
within coniferous forests can be  expected to be  20 to  40 percent higher  than
that found within the forest.24'54   It  should  also be  pointed out that  the
total quantity of snow  in the forest area will not be  increased.  Clearings
will have the effect of reducing  snow catch downwind  in the forest.

      (el  Runoff:  Numerous  experiments have  demonstrated that  clearing a
 coniferous  forest will  increase runoff30 because of reduced transpiration
 and interception.  The  amount  of additional  runoff will vary with the climate
 of the  area,  the forest type,  soils, slope and aspect. The increase will be
 greatest during the first year or two after cutting.   As  the area is invaded
 by herbaceous vegetation and broad leaf species or as planted stock develops,
 the effects of clearcutting will decrease (see Section 4.5).

      Erosion and sedimentation will not be greatly affected if the forest
 floor is not severely disturbed by the clearcutting process.

      Effects of Clearcutting upon Wildlife-The impacts of clearcutting upon
 the existing and potential  wildlife habitats  wihtin coniferous forests may
 be categorized  as:  direct  alterations to the habitat  including obvious damage
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to the structural and functional aspects of the area;  and indirect altera-
tions and changes within the habitat and its surrounding area through inter-
ferences with the processes normally provided within the larger natural bio-
logical system of the forest.  While the true quantitative and qualitative
impacts on wildlife generated by clearcutting in terms of ecological recov-
ery and stabilization are subject to debate, some generalizations may be made.
          1.  The structural alterations resulting from clearcutting
              obviously influence the mature trees.  In the moist cool
              transcontinental coniferous forest biome between the
              45th and 57th latitudes (north), the coniferous forests
              modify and temper the environment such that the lesser
              plant species and codominant species are dependent upon
              them.  The removal of the dominant species is equivalent
              to forcing plant succession back to a more primitive state
              near the pioneer or early second stage of succession.
          2.  Habitats are defined by the plant community both struc-
              turally and functionally;  direct utilization of the three-
              dimensional space formerly occupied by the clearcut forest
              for reproduction, food and shelter is no longer possible.
          3.  The ground plane, depending upon its condition after treat-
              ment will redevelop a plant cover of some type.  Erosion,
              drying and heating, and general physical exposure will
              make this a harsh environment for rapid  development.
          4.  Plant succession will in most cases start anew unless  the
              area is planted.   Migration of animal and plant species
              from adjacent areas will participate in  setting the char-
              acter of redevelopment.  If the image and statistical
              character of this area is  to be similar  to its surround-
           -'"  ings,  it must be supported by management activities that
              recognize the needs of the area in terms of specific habi-
              tat requirements.    *
          5.  Reutilization of the area by the native  mammal, bird,  rep-
              tile,  and insect populations is a function of how well
              and how fast the former habitat begins to simulate the
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              the functions of the surrounding area for the support
              of wildlife, and of the relative adaptability of those
              species that are able to find niches within the treated
              area.

     The reestablishraent of plant stages represents a new-found supply of
food and shelter for the wildlife.  Competition and simultaneous resource
use will prevent this space from developing immediately into its former
character.

     To bring treated areas back to their former wildlife habitat requires
judicious replanting and management.  How well and how much these practices
are employed will greatly influence the degree and amount of recovery.

     (1-3)  Stumping and Grubbing
     The removal of stumps and roots creates depressions and scarifies the
treatment area.  The net effect of this treatment would be modification of
the effects of simple clearcutting in several ways:
          1.  Surface runoff would either remain unchanged or possibly
              be decreased.  The additional water storage in depressions
              created by the treatment would tend to offset the addi-
              tional runoff that would be caused by antecedent soil
              moisture.
          2.  The surface runoff would carry greater sediment loads
              because of the additional scarification caused in the
              cutting process.
          3.  The depressions and scars produced by the treatment would
              occur at a slower rate after use of clearcutting as a
              treatment procedure followed by stumping and grubbing,
              than in the case of simple clearcutting for harvesting
              due to the absence of roots and stumps for coppice
              stumping.
          5.  Small mammal burrows would be destroyed and/or damaged.
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     (1-4)  Scraping and Grading- .....
     Scraping of coniferous forest areas would require prior clearcuttlng
and removal of stumps from the treatment area.  The litter layer and or-
ganic soil layers would be removed in the process of scraping.  Accordingly,
infiltration rates would be greatly reduced,, surface runoff would increase,
and detention and retention storage of water would be reduced, resulting in
unchecked soil erosion.  Further, the residual seed pool in the soil would
be greatly diminished and nutrient levels drastically lowered.  Depletion
of populations of soil-building microfauna and flora would also take place.

     Grading of coniferous forest would result in an amplification of all of
the effects of scraping treatment; erosion in particular would be increased
since smooth grading would eliminate detention and retention storage.  The
grading equipment, would also tend to compact the soil, thereby increasing
runoff.  Runoff efficiencies, even on slopes as low as 2 percent, might be
expected to exceed 60 to 70 percent.

     (1-5)  Shallow Plowing
     This treatment would in ,most instances require some smoothing of the
site following stumping and grubbing.  Over the long term, the effects of
shallow plowing would probably not differ greatly from simple clearcutting.
Over the short term, this treatment would be superior to stumping and grub-
bing.  Essentially, on areas with soils stone-free enough for plowing, and
of adequate depth, the area would be tilled as an agricultural field.  Sur-
face organic matter would be incorporated into the soil, and the soil loos-
ened, thus creating a good seed bed, and favorable conditions for root
development.

     The infiltration potential would be increased by the loosened soil re-
sulting from shallow plowing and be enhanced by the creation of a uniform
depression storage for water.  Assuming that the area will be quickly reveg-
etated, the potential for surface runoff and erosion would be minimized.
Such areas would not be unlike abandoned fields.  The overall effects upon
infiltration created by the shallow plowing would be greater than those re-
sulting from simple clearcutting but not excessively so.

     On steep shallow soils which are underlain by shallow bedrock the plow-
ing treatment could create a potential hazard for land slips and slides.  By
                                    4-29

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          retaining water and with no  vegetation to  remove  the  excess water,  the  soil
          could become saturated and slip.   This would probably be  true  of  soils  with
          low shearing indices,  such as those developed  from shale  materials.

               (1-6)  Deep Plowing
               It is assumed that this treatment would be accomplished either with rip-
          pers, root plows or counter-disk  plows, all  of which  can  cultivate  to a depth
          of 12 to 18 inches.  The deepest  depth would be no greater than 24  inches,
          unless specialized equipment were used. Generally, plowing will  have simi-
          lar effects to those produced by  shallow plowing.  The  treatment  would  of
          necessity be restricted to the deeper soils.  Infiltration would  be improved
          over shallow plowing,  and a greater kill of  herbaceous  species would be
          achieved.  The natural succession from coppice sprouting  and residual seeds
          in the soil would be delayed for  longer periods than  in the case  of simple
          clearcutting.  The hazard of slips and slides  would be  increased  in moun-
          tainous areas.  Small  animal habitat, burrows, runs,  etc., would  be largely
          destroyed.

               Plow pans are common on old  oil field soils.  They hinder deep infil-
          tration, increase interflow   and impair root  development.  Fragipans and
          hardpans on these often previously eroded  soils are also  at shallow depths.
          Deep plowing would break the pans if present.   In addition, for those soils
          where nutrients have leached to lower levels,  deep plowing would  implement
          turnover and mixing of the soil.   Growth and development  of invading species
          or planted species would be enhanced.
.
              •' (1-7)   Soil Cover less tfian 25 cm
               Soil fill to even these shallow depths would require large quantities
          of soil material and the use of heavy equipment for hauling and spreading.
          The forest  floor would be buried, effectively smothering much of the life
          that it fosters and the biological/physical interactions that occur in and ..
          near the surface of coniferous forest soils.  Small animal populations would
          suffer loss of habitat and the food supply found upon the forest floor.

               Surface runoff will increase and subsequent erosion of the loose dress-
          ing material would be severe.  On steeply sloping land, off-site sedimenta-
          tion rates would be high.  The effects of the treatment would be comparable
                                              4-30

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                                    •t A '"} "Z 1C
to the construction of logging roads  '   *   but more severe since larger
expanses of area would be involved, and there would be no provisions for
compaction and drainage as in the case of road construction.

     The low growing plants of the forest floor would be buried and killed.
The roots of the taller, herbaceous plants would also be buried and the less
hardy of these should be expected to die due to lack of soil aeration.
                   •
     Since the soil-covering material must be imported, it is likely that it
will not have come from a coniferous forest, and that it will probably be a
mixture of topsoil and subsoil, or be alluvial material and, as such, it is
likely that it will contain low levels of nutrients.  In any event, the ma-
terial will be inferior to the native soil underneath.  It will be loose and
could provide a good physical seed bed for germination and establishment.
The residual seed pool and nutrient level will be low.  There is also the
possibility of importing plant and animal species with the material that would
compete with the natural species.  The quality of the imported soil material
would be the primary factor affecting early recovery by natural means.  If
the area is artificially rehabilitated,  there should be no appreciable delay
beyond that induced by simple clearcutting, unless the covering material is
of very poor, quality.

      (1-8)  Soil Cover 25 to 100 am
     The use of deep soil burial would as a treatment tend to magnify the
effects mentioned under shallow soil burial.  In addition, nearly all of the
lower growing herbaceous species would be killed, and the root systems of
larger broad leaf species would be effectively buried and smothered.  This
soil material would contain lower proportions of seeds and organic matter.
The potentials for erosion on-site and sedimentation off-site would be in-
creased because of the greater volume of loose material.

     The destructive effect on small animal habitats would be complete.  De-
velopment of herbaceous and broad leaf species would be delayed, particularly
on the larger treated areas; this would affect both large and small animals
for an extended period.
                                    4-31

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      (2-1)  Remove Plow Layer
      Logically, removal of the "plow layer"  (uppermost 10 cm of soil) would
follow stumping and grubbing.  In old forest soils this would remove humus
layers and most or all of the A horizon.  Many coniferous stands, particularly
in the East and Midwest, are fire or old field subclimax forests.  Loblolly,
shortleaf and slash pine exist in the South as the result of fire or previous
clearing and cultivation as do Jack pine in the Midwest and lodgepole pine in
the West.  The forests of white pine in the Northeast and Virginia pine in
the Southeast are classic examples of old field subclimaxes which developed
on soils with only B or C horizons remaining.  Removal of an additional six
inches would, except in soils with deep C horizons such as those found in
the eastern and southern coastal plains, essentially "sterilize" the areas
for long periods.  This would be particularly true of coniferous forests
located on their characteristically shallow and/or rocky soils in areas of
steep terrain.  Surface runoff and consequential erosion would be accelerated.
The reestablishment of the forest, either naturally or by planting, would be
impaired and in some cases impossible.

     The effects of this treatment would be less drastic on deep soils.  The
deeper layers of many coniferous forest soils have a higher nutrient content
than the surface material.  If the forest is artificially rehabilitated on
these treated areas, production should not be greatly impaired.
     (2-2)  Remove Shallow Root Zone
     It is assumed that the depth of this zone is somewhat greater than that
of the plow layer.  Essentially, the effects of the removal of the described
plow layer above would be applicable to removal of the Shallow Root Zone.
Both treatments would not leave suitable seed beds for natural rehabilitation
and would delay natural succession.

     (2-3)  Remove Scraping and Grading, Meohanioally Stabilize
     The effects of scraping and grading have been described in treatment 1-4
above.  Mechanical treatment in addition to the scraping and grading is as-
sumed to involve compacting of the area with mechanical equipment (e.g.,
rollers, vibrators, rams, etc.).  Thus, it would first be necessary to clear-
cut the trees, remove slash, stump and grub roots, and smooth the area.
                                    4-32

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     The smoothing treatments could involve grading, scraping, soil removal
and burial with imported soil.  In any case, the degree of compaction will
be affected more by the nature of the soil material, the soil moisture con-
tent, and the compaction treatment than by the particular smoothing treat-.
nsent.  Therefore, it is assumed that those areas to be mechanically treated
will essentially exhibit similar enviornmental effects and recovery rates,
regardless of the smoothing treatment used.

     The average depths of compaction by various types of machines are given
in Table 4-2.  The actual depth for a specific site will vary with soil char-
acteristics.  Generally, at optimum moisture contents, compaction potential
will increase in the order:  heavy clay, silty clay, sandy clay, sand, and
gravel-sand-clay.
             Table 4-2.  Average possible depth of compaction to
                         10 percent soil voids (from Armstrong4).
                Equipment
Depth Compacted (in.)
          2 3/4-ton smooth-wheel roller
          8-ton smooth-wheel roller
          2 1/2-ton vibrating roller
          2-ton vibrating plate compactor
          D-8 crawler tractor
          Ram (portable)
       5
       6
       5
      12
       6
       6
     Footed rollers, either sheeps foot or taper foot, comprise a special
class of compactor for cohesive soils.  At least 64 passes are required to
completely cover a given area.  Depth of compaction can reach 18 inches or
more.

     The effects on microclimate of mechanical treatment will not differ
from those of clearcut areas.  Wildlife should find little interest in the
treated areas since it will not support appreciable amounts of vegetation
for several years.
                                    4-33

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     (2-4)  Eemove Plow Layer, Mechanically Stabilize
     The effects of this treatment are essentially the same as those de-
scribed in treatment 2-3 above.

     (2-5)  Remove Shallow Root Zone., Mechanically Stabilize
     The effects of this treatment are essentially the same as those de-
scribed in treatment 2-3 above.

     (2-6)  Remove Scraping and Grading, Chemically Stabilize
     The result of the addition of a chemical stabilizer to stumped and
grubbed land which has been smoothed would depend on the type of chemical
treatment.  Chemical emulsifiers will counteract the effects of scraping
and grading by stabilizing the soil bed until vegetation is established.
They could speed succession by retarding erosion until plants became es-
tablished.   Chemical deflocculants will intensify the effects of the me-
chanical disturbance.  They will reduce infiltration and increase surface
runoff.  Less water will be available for vegetation that might invade the
site, thus succession will be retarded.

     (2-7)  Remove Plow Layer, Chemioally Stabilize
     The effects of this treatment are essentially the same as those de-
scribed in treatment 2-6 above.

     (2-8)  Remove Shallow Root Zone, Chemically Stabilize
     The effects of this treatment are essentially the same as those de-
scribed in treatment 2-6 above.

     (3-1)  Barriers to Exclude People
     The exclusion of humans  would have no negative effects on the natural
processes within the exclosure, and  could be beneficial, especially in areas
of high population density.
      (3-2)  Exlude Large Animals
      Barriers that exclude  large browsers, grazers, and predators will affect
the succession within  the exclosure.  With the exclusion of browsing and
grazing animals, a greater  density  and  diversity of herbaceous  species will
                                     4-34

-------
 develop  whether  or  not  the  coniferous  forest  cover  is  removed.   If  the  trees
 are  removed,  the early  stages  of  succession will  be extended  and the  develop-
 ment of  the climax  forest will be prolonged.

      The presence of more herbaceous plant species  results  in making  avail-
 able more energy to the small  herbivores.  In addition, herbivore population
 should increase  due to  the  absence of  some of their predators.   Small preda-
 tors not limited by the exclosure (slumber weasel,  etc.) will increase  due to
 the  additional food supply  and absence of competitive  predators.

      The elimination of the soil  compaction produced by the larger  mammals
 may  favor the rehabilitation of the forest floor  and the reestablishment of
 its  ecological processes.

      The large biota mammal habitat would be  minimally influenced by small
                                    2
 exclosures.  Large  exclosures  (10  km ) in areas of  limited forest could have
 serious  negative  impacts upon  the  local area.  Home  ranges of the larger ani-
 mals  (deer, elk,  bear,  cougar,  etc.) are invariably  larger than the largest
 treated  areas proposed.  In the densely populated forest areas of the eastern
 United States, and  to a  lesser  extent  in the more sparsely populated western
 states,  large exclosures could  interfere with animal movement.

      Barriers that  exclude  large browsers, grazers,  and large predators will
ultimately influence the dynamics of succession within the exclosure.   An
 immediate reduction in browsing and grazing will favor the development of
plant species subject to these processes.  These plant species,  which usually
 include  the grasses, forbes, shrubs and palatable tree seedlings, will exper-
 ience a measurable  increase in growth, an increased  density and therefore
higher measurable productivity  (accumulated biomass).  These  (r-strategy)*
plant species tend to dominate the earlier stages of plant succession when
moisture, available nutrients and light quality are  favorable..  Their removal
favors those less palatable tree species (k-strategy) typical of later succes-
sional stages.  Therefore browsing and grazing can foreshorten plant succession
and create conditions which favor faster rates of development toward climax.
''Using the terminology of growth equations where r is the intrinsic rate of
 increase, and k is the upper asymptote or equilibrium population size,  r
 selection predominates in early colonization with k-selection prevailing
 as more and more species and individuals attempt to colonize.50
                                    4-35

-------
If trees are removed, the early stages of succession will be extended,  ulti-
mately prolonging the development of a climax forest.

     (3-2)  Exclude Large and Small Animals
     This treatment would benefit birds and tree-dwelling animals because of
the resultant additional availability of protection and food.  The effects on
the density and diversity of herbaceous vegetation within the enclosure and
the subsequent effects on microclimate, soil compaction and succession would
be amplified over those resulting from the exclusion of large animals.

     It is also expected that any small animals trapped within the exclosure
would benefit, particularly if a source of water were available.  Gene flow
would be restricted, but this effect would not be significant unless the ex-
closure remained effective for many reproductive cycles.

     (4-1)  Asphalt Hard Surface Stabilization
     Paving a contaminated area represents a severe  impact.  Asphalt may be
laid either between the trees or after trees have been removed and the site
smoothed.  Asphalt laid between the trees will result in the gradual (1 to 3
years) death of the trees in the treated area.  Coniferous trees have rela-
tively shallow roots and depend on the infiltration  of surface water for
moisture and nutrients.  Paving the surface will block infiltration, and
runoff efficiency will be 90 to 98 percent of the rainfall.  Plant or animal
invasion of the area would be delayed until the asphalt begins to decompose.
The existence of decaying trees on the site would speed the process of as-
phalt breakup by mechanically disturbing the surface as the trees fell.

     (4-2)  Conerete Hard Surfaee Stabilization
     The effects of  this treatment are very severe and are  essentially the
same as described in treatment 4-1 above.  Infiltration of  surface water
would be stopped.  Runoff would be virtually 100 percent of  rainfall leading
to extensive off-site  erosion.  Establishment of a community would require
complete breakup of  the  concrete, a process that would required  decades to
centuries.
                                     4-36

-------
1,
2,
3.
     (5-0)  Application of Sewage Sludge
     Sewage Sludge Application Without Clearcutting—The effects upon conif-
erous forests and their associated wildlife of applying sewage sludge to the
forest soils are dependent upon the characteristics of individual wastewaters.
Chemical contaminants in wastewater may be classified as either inorganic
(heavy metals) or organic including PCBs, pesticides and other synthetic ma-
terials.  Pathogenic biological pollutants include a wide variety of bacter-
ial, protozoan, parasitic helminth and viral forms.  Wastewater treatment
processes can provide significant reductions in the levels of these contami-
nants,  but conventional treatment processes are not adequate to remove certain
chemical and biological pollutants.

     In general, based upon studies in Douglas fir stands17'55'69 the appli-
cation of sewage sludge may be predicted to have the following effects:
              An increase in the rate of forest floor decomposition
              An increase in the rate of tree and ground cover growth
              A possible initial decrease in surface water infiltration
              in the short run due to .the presence of fine sediment in
              the sludge,  but a net long-term effect of increased infil-
              tration due to enhanced ground cover growth
              A decrease in anaerobiosis in the upper soil profile
              An increase in coliform bacteria which will move through
              the soil profile with the soil solution
          6.   An increase in the flow of nitrates through the soil sys-
              tem accompanied by the stripping of cations from the soil
              complex
          7.   An increase  in carbon dioxide production resulting  from
              organic decomposition processes in the soil
          8.   An increase  in cationic losses due to increased mobile
              anion  pools
          9.   An increase  in heavy metals in soils and animal tissues
              (see also  Peterson et al.   )
         10.   An increase  in microbial aerosols,  depending upon the
              method of  application of the  sewage sludge.
                                    4-37
4,
5,

-------
     Phosphorus may also increase, particularly in those soils having high
exchange capacities; however, it is most likely that such accumulation will
                                         27 78
occur primarily in the upper soil layers.  '     Soluble salts of soil ex-
tracts, notably chlorides, sulfates and calcium, will also be increased.'
In general, animal viruses have not been detected following sewage sludge
   . .  „.   43,69
application.
32
     Accumulation of heavy metals in plants grown on sludge-amended soil has
been found to be greater than that found in plants grown on untreated soil,
although toxic levels have not been detected.    Similarly, dangerous levels
of heavy metals in the tissues of birds and small herbivorous mammals sampled
                                               3 18 21
in sludge-amended areas have not been detected. '  '

     It may also be expected that populations of larger browsing mammals
would increase due to the availability of additional forage.  The effects
of sewage sludge application upon invertebrates will vary from species to
species.  Earthworms and other invertebrates will probably tend to increase
due to the higher nutrient levels provided by the applied effluent.  If the
area is heavily irrigated, the diversity and numbers of most soil microar-
thropods will decrease.    Song birds may increase because of greater food
availability.

     Sewage Sludge Application Combined With Clearcutting—The combined ef-
fects of clearcutting and sewage sludge application on soils will be similar
to those produced by sludge treatment alone.  In addition, the growth of
ground cover, particularly that of broad leaf species will increase.  Ac-
cordingly, the return to a coniferous forest will be delayed or possibly
prevented entirely unless the area is artificially rehabilitated.  The ef-
fects on wildlife will be essentially those discussed in the clearcutting
treatment 1-2 above, but with the additional enhancement of food supply.

4.5  RECOVERY AFTER CLEANUP
4.5.1   Irreversible Changes
     Over the very long run  (thousands of years) the consequences of all of
the treatments discussed here are theoretically reversible, assuming that no
major climatic changes occur and that the requisite sequence of events and
conditions obtain for the successional reestablishment of  the original
                                     4-38

-------
 coniferous forest.   Over a period of a hundred years or less,  hard surface
 stabilization,  particularly in the case of concrete treatment,  may be  con-
 sidered as virtually irreversible.  Other treatments such as  removal of the
 plow layer,  if  done on a shallow soil on a steep hillside,  might  also  be ir-
 reversible if no supplemental  remedial treatments are applied.

 4.5.2  Rates of Recovery
      The perturbations discussed in this chapter on cleanup procedures do not
 have a  great deal of precedence.   The only common analogous situations are
 clearcutting, fire,  surface mining,  and abandoned fields.   Even under  these
 situations natural  successions will  not necessarily lead to the same sub-
 climax  or climax coniferous forest that existed prior to the disturbance.
 For  example,  Douglas fir in the west seldom reestablishes  itself  naturally
 following clearcutting.   Longleaf pine,  an important  species in the south,
 does  not  always  reseed itself  on  burned areas,,   Loblolly pine,  an old  field
 species,  may not become  reestablished  on adjacent  old fields that are  first
 invaded by hardwood  species  and then protected  from fire.

      If it is desirable  to have the  treated area return  to  its  former  pro-
 ductivity as soon as possible,  then  artificial  planting  is  the  restorative
 method of choice.  Seedlings of nearly  all of the  important conifer species
 are grown in State or  Federal nurseries.   The largest  treatment area consid-
 ered, 10  km  , would  require only  about  250,000  seedlings, well  within  the
 production capabilities  of any  large nursery.   In northwestern Mississippi,
 a planting schedule  of 50,000,000  loblolly pines annually was maintained for
many years.

     Table 4-3 summarizes the successional associations of some major conif-
 erous forest types.   Recovery sequences over future time are shown graphically
to demonstrate the duration of treatment effects, assuming no retrogression
occurs.   The endpoint for the curves in Figures 4-3 through 4-5 is restoration
of productivity to the extent that a layman would view it as similar to the
productivity of undisturbed areas.  Representative cleanup treatments were
 illustrated in the figures and the application of that information in evalu-
ation of the impact  of cleanup on coniferous forest is demonstrated in some
detail in Appendix B.
                                    4-39

-------
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   Figure  4-3.   Sequence of ecological  recovery following cleanup.
                                        4-42

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          2-1 REMOVAL OF PLOW LAYER
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        Figure 4-4.   Sequence of ecological recovery following cleanup.
                                         4-43

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           3-2 LARGE ANIMAL BARRIERS
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     Figure 4-5.   Sequence of ecological recovery  following  cleanup.
                                        4-44

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     4.5.2.1  First Year —
     During the first year after a clearcut treatment, the remains of the
understory hardwoods would sprout, and the released herbaceous plants and
grasses would develop rapidly.  Pioneer plants, primarily annuals, would
begin to invade the area, and conifer seedlings present on the area would
develop.

     Natural reseeding from the trees bordering the clearcutting could pos-
sibly occur if the treatment was performed during a seed year.  Otherwise
the area would have to wait, and during this time the competitive understory
will have had an opportunity for greater development.  If the particular
conifer species does not reestablish well (e.g., Douglas fir) or is unable
to compete with understory hardwoods (e.g., Virginia pine) it is possible
that the stand will retrogress to brush or hardwoods.

     If the area were replanted, the original stand density could, for most
conifers, be reestablished in the first year, and complete crown cover could
be obtained in 5 to 20 years depending upon the species.

     The use of the area by animals, mainly transient herbivores, during
the first year would tend to increase because of the development of additional
ground cover.  This would continue to a peak use at the beginning of crown
closure of the conifers.

     Areas which have been stumped and grubbed and subsequently graded,
scraped, plowed, or had topsoil removed, or areas which have been dressed
with imported soil material will show less development than the clearcut
treatment.  Grading, scraping, and topsoil removal will produce the poorest
conditions for rehabilitation and the areas will be vegetated primarily with
pioneer species during the first year.  Stumping and grubbing and plowing
treatments will produce good seed bed and moisture conditions and will not
be greatly inferior to the clearcut treatment.

     Runoff will be increased the first year on the clearcut areas (Figure
4-6).  Runoff rates will be highest for topsoil removal, scraping. and grad-
ing treatments and will carry higher sediment loads from erosion.  Runoff
may also be higher from areas stumped and grubbed, plowed or covered with
                                 4-45

-------
             20
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                              YEARS AFTER CLEARCUT
    Figure 4-6.  Decrease in runoff following clearcutting coniferous forests
                 (after Swane and Mines72).
imported soil material, depending upon depression storage and infiltration
characteristics, but it will carry heavier sediment loads than expected from
the simple clearcut treatment.

     The effects of chemical and mechanical stabilizers combined with other
treatments would be greatest for the soil removal, soil burial and scraped
treatments, and least for the stumping and grubbing and simple clearcut treat-
ment.  Recovery of the area would be delayed until leaching occurred and soil
structure could re-form.  Treatments which left the most organic matter would
recover more rapidly, but succession on the site should be expected to be
delayed at least 5 years by the treatment.

     With the exception of the chemical emulsions, the application of stabi-
lizers will require:  (1) breaking up and tilth forming; (2) application and
mixing in of the stabilizer; (3) application of water to, or its part removed
from, the soil to achieve moisture control; and (4) compaction.  Thus, the
treated area must first be clearcut, stumped and grubbed, slash removed,
                                     4-46

-------
smoothed and plowed.  The stabilizing treatment would show effects far in
excess of those between the additional treatments of topsoil removal and
burial with imported soil.  It is therefore assumed that all treatments (e.g.,
stumping and grubbing, grading, smoothing, burial, soil removal and plowing)
will have very similar effects and responses after stabilization.

     Generally, the effects on wildlife succession and hydrology will be
greater than those of simple mechanical stabilization.  Succession and wild-
life habitat will be retarded for at least an additional 5 to 10 years, and
runoff efficiency will increase to above 70 percent.  However, erosion and
sedimentation will be considerably less than for the mechanical treatments,
but structures to handle the excess runoff will have to be installed to mini-
mize offsite damage from runoff.

     Complete recovery of a site subjected to a combined treatment, in some
cases, may take centuries.  Soil with high proportions of montmorillonite clay
and soil in areas subject to heavy frosts will loosen within a few years.  Soils
in the sub-humid areas where rainfall is high and plant invasion occurs at
higher rates may require up to 5 years for the establishment of a complete
ground cover of pioneer species.  It is assumed that the area would not be
suitable for planting.  Thus, depending upon location, soil characteristics
and degree of compaction, succession will be delayed over that which might
occur on the simple clearcut area by 25 to 100 years.  Of course, heavily
compacted areas would be very prone to retrogression.

     This tendency would be amplified by the increased surface runoff and
erosion that would result from treatment.  A compacted area, even if compacted
by a sheeps foot roller, and devoid of vegetation and depression storage, will
present little friction to flowing water.  Infiltration, particularly in soils
with clay and silt components, will be reduced at least to 1 inch per hour or
less.  It is expected that runoff efficiency will be on the order of 70 per-
cent or more.

     The damage from offsite runoff, even from areas of 1 hectare, could be
considerable and would require the construction of diversions, lined channels,
or dams for water storage and desilting.
                                    4-47

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     4.5.2.2   Fifth  Year  —
     Three years after treatment, assuming  successful rehabilitation of the
conifer,  if erosion  has not been severe and if the site  is of good to medium
quality,  the forest  growing conifer  species (e.g., loblolly, short leaf,
slash, etc.) will have attained heights of  20 to 60  inches.    The slower
growing species, such as  Douglas fir, will  have reached  15 to 20 inches.
At ten years,  heights of  the faster  growing species  will be on the order of
20 to 30  feet, and those  of the slower species will  have attained heights of
            28 71
4 to 5 feet.   '    In the moist temperate zones, crowns will have started to
close and stratification  will have begun.   In colder regions, there will still
be heavy  competition between hardwood brush and coniferous species.

     If natural rehabilitation  (0-1) were relied upon and had been success-
ful the density of the new reproduction might appear as  shown in Figure 4-7,
to dense  near  the seed source and sparse or absent at greater distances.

     The  plowed areas will probably  exhibit the best reproduction followed
in order  by stumping and  grubbing (1-3), simple clearcut (1-2), soil burial
(1-7), scraping and  grading (1-4), and soil removal  (2-1 through 2-8).  In
stands with associated  hardwoods, the effects of sludge treatment may be
evident in a greater development of  hardwood competition.
                             YOUNG TIMBER
YOUNG TIMBER
        CLEARCUT AREA  . .
TIMBER OF
SEED-BEARING AGE
       Figure 4-7.
                        TIMBER OF SEED-BEARING AGE
                                \
                                                   WIND AT TIME
                                                   OF SEED FALL
Clearcutting the whole stand, with reproduction
secured by seed disseminated from seed trees lo-
cated outside the cut stand.  The density of the
reproduction 5 years after the cutting is indi-
cated by the dots (from
                                     4-48

-------
     The effects of forest removal on surface runoff will have diminished
as  indicated  in Figure 4-4.  Runoff from the concrete and asphalt areas will
noi. be appreciably diminished  since these materials will not have deteriorated
greatly.

     In those forests with associated hardwoods, the crown cover of hardwoods
within clearcut areas will have developed in some stands to the point of clo-
sure and will provide cover and food for wildlife.  Use of the area will be
enhanced by the border created by the clearing.

     Within the exclosure, competition of hardwood and herbaceous species may
have delayed conifer growth.

     4.5.2.3  Fiftieth Year --
     On clearcut areas (1-2) with or without supplemental treatment (e.g.,
stumping and grubbing, plowing, etc.) which were successfully restocked,
either naturally or artificially, complete crown cover will have been ob-
tained and the herbaceous and hardwood understory will have been suppressed.
Stratification of the forest into dominants, codominants, intermediates, and
suppressed trees will have developed.  The number of trees per unit area,
except in the boreal forests, where such processes occur at slower rates,
will have decreased due to suppression by larger trees as indicated for rep-
resentative tree age in conifer forests in Table 4-4.

       Table 4-4.   Approximate age of representative coniferous
                   forests where number of trees per acre is re-
                   duced by suppression.
       Eastern Forests
         White - red Jack pine
         Lobloily-short!eaf pine
         Spruce-fir
       Western Forests
         Douglas fir
         Ponderosa pine
         Hemlock-sitka spruce
Approximate age (years)

     20 to 30
     20 to 25
     30 to 40

     30 to 40
     20 to 30
    110 to 120
                                     4-49

-------
     The effects of the clearing treatments on wildlife, runoff and erosion
will not be evident.  The wildlife habitat will have been essentially stabi-
lized to that of the surrounding forest.  It is possible, but not likely, that
the exclosures could remain 100 percent effective, even if maintained, over
this long a period.

     Asphalt treated surfaces C4-1), if not maintained, will appear as do
abandoned World War II air strips today, heavily cracked and buckled and
invaded by grasses and pioneer species.  The concrete treated areas (4-2)
will, of course, be weathered but still intact except for plant invasions in
cracks or expansion joints.  Offsite scouring and gullying by concentrated
runoff from the areas will still be active, assuming that any structures in-
stalled to prevent this have not been maintained.  The areas treated by
sludge C5-0) will show no significant effects of treatment by this point
in time.

     It is not possible to make general predictions for those sites that may
have retrogressed as a result of the treatment applied.  The effects could
range from exposure of bedrock to the development of a permanent meadow, de-
pending upon the particular site and treatment.

     4.5.2.4  100 Years After Treatment --
     In all cases except the boreal forest, assuming that artificial rehabi-
litation or successful natural rehabilitation of clearcut areas has occurred,
the new coniferous forest will be approaching maturity.  The forests .of the
southeast will have passed the point of commercial maturity.  The dominant
trees will have attained heights equivalent to the representative data in
Table 4-5.  Basal area development will be on the order of data presented
in Table 4-6.

     On areas treated by scraping, grading, topsoil removal and burial, a
maximum depth of litter will have accumulated on the forest floor.  An F
horizon will have begun to develop, but otherwise the rest of the soil pro-
file will show no appreciable development.  The soils of the other treatments
will show no significant change.

     Wildlife habitat 100 years after treatment will not be discernible from
the surrounding habitat, assuming that no additional perturbations have occurred

                                   4-50

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       Table 4-5.  Height of dominants in a fully stocked stand at
                   100 years - good to medium site fully stocked.
                                              Height (feet)
       Eastern Forests
           White - red Jack pine
           Loblolly-shortleaf pine
           Spruce-fir
       Western Forest
           Douglas fir
           Ponderosa pine
           Hemlock-sitka spruce
 80 to 100
 80 to 90
 50 to 60

120 to 140
 90 to 100
 40 to 120
Table 4-6.  Approximate basal  area (m2/ha) of representative conifer species -
            good to medium site, fully stocked (after Forbes22).
Eastern Forests
Age
(yrs)
20
30
40
50
60
70
80
90
100
110
120
130
140
150
Eastern
Loblolly Slash white
pine pine pine
29 32
35 36 41
37 37 48
38.5 37.5 53
39.5 38 55.5
57.5
59
60.5
61
61.5
62



Red
spruce


29.5
44
38.5
49
53.5
57
58.5
59.5




Jack
pine
29
32
33
33
32.5
31.7
29







Western Forests
Ponderosa
pine
19
35
45
48.5
49
49
49
49
49





Douglas
fir
21
32
40.5
47
52
56
59.5
62.5
65
67
69
71
73
74.5
Sitka spruce
and
western
hemlock
25.5
43
50.5
56.5
62
66
69
72
74
76
77.5
78.5
80
81
                                     4-51

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to either the naturally rehabilitated or treated forest areas.   However,  it
is unlikely that the exclosures will have been maintained for this long a
period.  Thus, evidence of the exclosures and their effects would not be
apparent.

     There is no precedent for predicting the effects on succession of the
concrete and asphalt treatments.  It is reasonable that natural succession
will have been delayed for at least 50 years by the asphalt treatment and
more than 100 years for the concrete treatment.  Even after such a long
period, the spatial: patterns of the process would be controlled by the
breakup pattern of the covering.

     The succession processes on the clearcut treatments will be approach-
ing maturity.  In areas where hardwoods are the climax species, broad leaves
will begin to dominate.  For other climaxes (Ponderosa pine in Arizona, for
example) the area will support a pure (unmixed) mature stand.  However, the
surrounding stand will have become over-mature and have begun to retrogress.

4.6  QUANTITATIVE ASSESSMENT OF CLEANUP IMPACTS
     The relative severity of the different cleanup treatments on various
environmental parameters 'is shown in Figures 4-3 and 4-5 and Appendix B,
Table B-3.  It is apparent that the most severe cleanup techniques are hard
surface stabilization  (4-0) and soil removal (2-1 through 2-8), while the
least severe treatments are exclusion by barrier (3-1 and 3-2) and applica-
tion of sludge (5-0).  This reflects the unfortunate fact that there is an
inverse relationship between a treatment's effectiveness in contaminant de-
mobilization and its destructive environmental impact.

     Lawrence   has described the hypothetical development of a spruce-
hemlock forest following glacial retreat.  He estimated that climax could
be reached within 130  to 200 years, at a median of 170 years.  Other authors
agree that the duration of sere from bare mineral soil to climax coniferous
forest is about 200 years.  Using this generalization, and noting the dura-
tion of successional periods in the development of mature forest given by
Lawrence,   a series of index numbers from zero to nine  (not measurable to
irreversible) can be imposed on the set of successional periods.  These index
numbers can then be applied to  the  cleanup treatments  performed over different
                                    4-52

-------
areas, the index numbers representing the approximate point in the sere to
which the cleanup treatment retrogresses the climax forest.  The result serves
as an indication of the relative severity of the treatments.  Table 4-7
presents this analysis for different sizes of disturbed areas and the details
are given in Appendix B.

     As expected from consideration of Table 4-7, the most severe treatments
over all areas are mechanical soil stabilization after soil removal (2-3 to
2-5) and hard surface stabilization (4-0).  In consideration of treatments
2-3 through 2-5, it must be realized that erosion of the land after scraping
and compaction is a very important factor in the indicated severity of these
treatments.  With treatment 2-3, the removal of only the upper five centi-
meters of soil will assure that some roots remain, from which vegetation
will emerge to check erosion during the first season after treatment.   How-
ever, as deeper soil layers are removed through treatments 2-4 and 2-5, lit-
tle or no rhizomal material will remain to sprout erosion-inhibiting vegeta-
tion.  Because of the compaction of the soil, seeds blown in from surrounding
areas will not find germination sites until rills and gullies have started
to form, particularly on sites with greater slope.  In almost all conceivable
situations, human intervention, in the form of gully control and artificial
seeding and planting, will be required to ensure recovery of the coniferous
association within half a millenium.

     Hard surface stabilization, treatment 4-0, also represents serious de-
structive impact to the coniferous forest.  Asphalt will decompose at rates
determined by climate, slope aspect, asphalt composition, and vigor of me-
chanical pavement destruction by vegetation and frost.  However, concrete,
due to its inorganic nature and resultant resistance to decomposition, will
have consistently higher durability than asphalt in various biomes.  If the
earth is compacted or any exotic subgrade is used below the concrete,  vege-
tative recovery will be further inhibited to the point where human interven-
tion will be required to ensure recovery of the coniferous association.  Small
areas of high-level contamination may be served best through this treatment,
since it is the most effective and provides the greatest public safety.
However, for areas larger than Q.I km2, this treatment can be considered
unacceptable.
                                     4-53

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     Other treatments have serious impacts when applied over large areas.
Removal of the plow layer  (treatment 2-1) or  shallow root zone  (treatment
2-2) has serious effects over the larger areas.  First, because the best
s.oil is removed by the treatment, new topsoil must be formed before most
species can return.  Second, the effects of erosion will be much more severe
over the large areas than over the small areas.  That is, over areas of from
10 to 100 km2 erosion will proceed almost as  rapidly as soil formation and
                                                     2
vegetation recovery, while over areas of 0.01 to 1 km  vegetative recovery
will occur much faster than erosion.  This Is because the turbulent currents
which produce accelerated water erosion and the high surface wind velocities
which produce accelerated wind erosion rarely occur over small areas, while
they are common over large, barren tracts.  An exception would be the case
of a small area of high slope, where water erosion would be quite severe.

     Finally, chemical soil stabilization (treatment 1-1) and soil cover
(treatments 1-7 and 1-8) would have serious impacts at the scale of 100 km2.
In the case of chemical stabilization this is because, over such a large
area, erosion would probably overwhelm the stabilization effect of the com-
pound,  thus pushing vegetative recovery to or beyond the maximum natural
recovery span.  The importance of erosion over larger areas is also the
reason why soil cover is considered a drastic treatment at the scale of
100 km2.  Natural reseedir.g and sprouting from stumps and rhizomes simply
will not occur fast enough at this areal scaile to counter the destructive
impacts of erosion and mass wasting.   The vulnerability to erosion from these
treatments also makes them undesirable for contaminant demobilization; it
makes little sense to use a treatment which is ineffective and causes great
environmental damage.

     Three treatments are benign,  or perhaps beneficial, to coniferous for-
est:  barriers (treatments 3-1 and 3-2)  and application of sewage sludge
(treatment 5-0).   Sludge application may be effective in demobilizing a con-
taminant,  and therefore is a preferred treatment, especially in sensitive
areas where low-level  contamination has occurred; however,  the possibility
of contaminant entry into the food chain must be evaluated prior to its use.

     The next group of relatively benign treatments includes clearcutting
(treatment 1-2),  stumping and grubbing (treatment 1-3),  and shallow and deep

                                    4-55

-------
plowing (treatments 1-5 and 1-6).   Deep plowing and stumping and grubbing have
greater impact at the scale of 100 km2 for the same reason as chemical stabil-
ization, namely that colonizing vegetation is usually overwhelmed by erosion
in the first few seasons after treatment.  Surface scraping and grading (treat-
ment 1-4) has greater impact at the 10- and 100-km2 scales than over smaller
areas because the treatment accelerates erosion while, through topsoil removal,
intrinsically decreasing the rate of revegetation.

     Finally, the group of treatments which involve chemical stabilization and
soil removal, treatments 2-6 and 2-8, have serious, though not drastic, impacts
on coniferous forest associations.  Quantitatively and qualitatively, their
short-terra effects and effectiveness are identical to their counterparts
(treatments 2-3 through 2-5) which involve mechanical, rather than chemical,
stabilization.  The difference  is that most chemical stabilizers do not com-
pact the soil to produce an environment hostile to seedling growth, but they
do effectively retard erosion while vegetation establishes itself.  By the
time the stabilizer breaks down, in one to five growing seasons, vegetation
will be firmly established and  will continue to retard erosion as the chemical
stabilizers decompose.  This is true,  in most cases, even over large areas,
although more durable stabilizers should be chosen to give plants more than
one season to become established over  large areas.

4.7  CONCLUSIONS
     The treatments which will  have the  least, and approximately equal, effect
will be exclusion by barrier  (treatment  3-1 and 3-2) and  sewage sludge appli-
cation  (treatment 5-0).  These  treatments may have a beneficial effect on the
development and perpetuation of the climax association.   Among the treatments
which require the removal of the forest, recovery would be most rapid with
clearcutting  (treatment  1-2) and shallow plowing  (treatment  1-5), with stump-
ing and grubbing  (treatment 1-3) and  deep plowing (treatment  1-6) having
slightly longer recovery periods only at the  100-km2  scale.
     All of these  treatments would be acceptable.  In cases  other than low-
level  contamination,  restriction by barriers  should be used  only  in  remote
areas,  because barriers  provide no significant,  immediate demobilization to
a contaminant.
                                     4-56

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     Treatments involving mechanical compaction (treatments 2-3 through 2-5)
and paving (treatment 4-0) would have severe impacts over all areas.  These
treatments should be prohibited at all scales greater than 1 km2, and should
be used over smaller areas only in the case of contamination severe enough
to prohibit the use of less damaging., thoxigh highly effective, techniques
such as those involving chemical stabilization (treatments 1-1, 2-6, 2-7, and
2-8).  Soil cover (treatments 1-7 and 1-8) should be used only for contami-
nants which would naturally degrade before natural erosion removes the soil
cover.  The exact determination of the proper treatment must be made consid-
ering the quantity and quality of released contamination, as well as the
proximity of the site to human populations and activities.
                                     4-57

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4.8  CONIFEROUS FOREST REFERENCES
     1.  Anderson, H. W., and C. H. Gleason.  Logging Effects on Snow, Soil
             Moisture, and Water Losses Western Snow Conference, Proceedings
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     2.  Anonymous, Forest Cover Types of North America.  Report of the Committee
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     3.  Anthony, Robert A., and C. W. Wood.  Effects on Municipal Wastewater
             Irrigation on Wildlife Habitat.  Symposium on Municipal Wastewater
             and Sludge Recycling on Forest Land and Disturbed Land.  Penn.
             State University, School of Forest Resources, Philadelphia, Penn.
             1977.

     4.  Armstrong, C. F.  Soil Mechanics in Road Construction.  E. Arnold,
             London, England, 1961.

     5.  Avery, C. C., and L. J. Fritschen.  Hydrologic and Energy Budgets of
             Stocked and Non-stocked Douglas-fir Sites as Calculated by Meteo-
             rological Methods, 1971.

     6.  Berndt, H. W.  Some Influences of Timber Cutting on Snow Accumulation
             in the Colorado Front Range.  Rocky Mountain Forest and Range
             Experiment Station, Research Notes 58, 1961.  3 pp.

     7.  Bock, J. H., and C. E. Bock.  Natural Reforestation in the Northern
             Sierra Nevada—Donner Ridge Burn.  Proc. Annual Tall Timbers Fire
             Ecology Conference 9:119-126, 1969.

     8.  Bock, J. H., C. E. Bock, and V. E. Hawthorne.  Further Studies of
             Natural Reforestation in the Donner Ridge Burn.  Proc. Annual
             Tall Timbers Fire Ecology Conference 14:195-200, 1974.

     9.  Bormann, Frank, Likens, Fisher, and Pierce.  Nutrient Loss Accelerated
             by Clearcutting of a Forest Ecosystem.  Science 159:882-884, 1968.

    10.  Boyce, S. J., and D. J. Neebe.  Trees for Planting on Strip Mined Land
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             33 pp.

    11.  Campbell, T. E., and W. F. Mann, Jr.  Regenerating Loblolly Pine by
             Direct Seeding, Natural Seeding, and Planting.  U. S.  Department
             of Agriculture Forest Service Research Paper SO-84,  1973.

    12.  Chapman, H.  H.  Is the Longleaf Type a Climax? • Ecology  13:328-34,  1932.

    13.  Cluff, B.   Engineering Aspects of Water Harvesting Research.   Univ.  of
             Arizona  Proceedings of the Water Harvesting Symposium,  1975.

    14.  Copeland, 0. L.   Forest Service Research  in  Erosion Control.   Vol.  12(1)
             75-79  (reprint"),  1969.
                                       4-58

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 15.  Daubenmire, R. F.  Vegetational  Zonation  in  the  Rocky Mountains.
         Botanical Review  9:325-93,  1943,,    •

 16.  Dindal, D.  L.  Effects  of Municipal Wastewater Irrigation  on Community
         Ecology of Soil Invertebrates.  Symposium on Municipal Wastewater
         and Sludge Recycling on  Forest  Land and  Disturbed Land.   Penn.
         State University, School of Forest  Resources,  Philadelphia,  Penn.,
         .1977.

 17.  Edmonds, R. L.  Microbiological  Characteristics  of Dewatered Sludge
         Following Application to Forest Soils and Clearcut Areas.  Symposium
         on Municipal Wastewater  and  Sludge  Recycling on Forest Land  and  Dis-
         turbed  land.  Penn. State University, School of Forest Resources,
         Philadelphia, Penn., 1977.

 18.  Ellertson,  R., and G. R. Geoffrey.  On  Uplake of Redwinged Blackbirds
         Nesting on Sludge-Treated Soils.  Symposium  on Municipal  Waste-
         water and Sludge  Recycling on Forest  Land and Disturbed  Land, Penn.
         State University, School of  Forest  Resources,  Philadelphia,  Penn.,
         1977.

 19.  EPA.  Processes, Procedures and  Methods to Control  Pollution  Resulting
         from Silvicultural Activities.  EPA 430/9.73-010  Office  of Air and
         Water Programs, 1973.  pp. 91.  ]

20.  Fillmore, W. J., D. I. Aldrich,  J. S. Barrows, R.  B.  Perry,  and  B. F.
         Wake.  Is Prescribed Burning Compatible with  Environmental Quality?
         In:  Proc.  Tall Timbers Fire Ecology Conference  14:627-44, 1974.

21.  Fitzgerald, R.   Recovery and Utilization of Strip-Mined Land  by  Appli-
         cation of Anaerobically Digested Sludge and  Livestock  Grazing.
         Symposium on Municipal Wastewater and Sludge Recycling on Forest
         Land and Disturbed Land, Penn. State University,  School  of Forest
         Resources,  Philadelphia, Penn., 1977.

22.  Forbes, R.  D.  (editor).   Forestry Handbook.   Ronald Press Co., New York,
         1961.

23.  Fredrickson, R.  L.   Sedimentation After Logging  Road  Construction in a
         Small Western Oregon Watershed.  USDA Misc.   Publ.  970, No. 8, 1965.

24.  Gary,  H.  L.   Snow Accumulation and Snowmelt as Influenced by  a Small
         Clearing in a Lodgepole Pine Forest.  Water Resources Research 10(2):
         348-353, 1974.

25.  Geiger, R.   The Climate Near the Ground.  Oxford University Press,
         1961.  pp.  611.                .

26.  Griggs, R.  F.   The Edge of the Forest in Alaska  and the Reasons for its
         Position.   Ecology,  15:80-96, 1934.
                                4-59

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26,  Harris, A. R.  Physical and Chemical Changes in Forested Michigan Sand
         Soils with Effluent and Sludge Fertilization.  Symposium on Munici-
         pal Wastewater and Sludge Recycling on Forest Land and Disturbed
         Land.  Penn. State University, School of Forest Resources, Phila-
         delphia, Penn., 1977.

28.  Harris, A. S.  Clearcutting Reforestation and Stand Development.  Journal
         of Forestry 6(330), 1974.

29,  Haupt, H. J.  Relation of Wind Exposure and Forest Cutting to Changes
         in Snow Accumulation.  In:  International Symposia on the Role of
         Snow and Ice in Hydrology, Banff, Alberta, 1972.

30.  Hibbert, R.  Forest Treatment Effects on Water Yield.  In:  International
         Symposium on Forest Hydrology.   (Sopper and Lull, ed.)  Pergamon
         Piess, New York, 1967.  pp. 813.

31.  Hoover, M. D.  Effect of Removal of  Forest Vegetation Upon Water Yields.
         American Geophysical Union, Transactions 25 969-975,  1944.

32.  Hornbeck, J. W., M. T.  Katerba, and  R. S. Pierce.  Effects of Sludge
         Application in a Northern Hardwood Forest on Soil Water Chemistry
         and California Population.  Symposium on Municipal Wastewater and
         Sludge Recycling on Forest Land  and Disturbed Land.   Penn. State
         University, School of Forest Resources, Philadelphia, Penn., 1977.

33.  Horwitz, E. C. J. .Clearcutting:  A  View from the Top.  Washington, D.C.:
         Acropolis Books Ltd., 1974.

34.  Johnston, R. S.  Soil Water Depletion by Lodgepole Pine on Glacial Till,
         U.S. Forest Service, Intermountain Forest and Range Experiment Sta-
         tion, Ogden, Utah, Research Note INT-199, 1975.  8 pp.

35.  Kidd, :*. J., Jr.  Soil Erosion Control Structures on Skid Trails.  USFS
         Research Paper INT-1, 1963.  8 pp.

36.  Kittredge, J.  Forests and Water Aspects Which Have Received  Little
         Attention.  J. For., 34:417-19,  1936.

37.  Komarek, E. V., Sr.  Fire Ecology Review.  Proc. Annual Tall Timbers
         Fire Ecology Conf. 14:201-16, 1974.

38.  Kuchler, A. W.  Potential Natural Vegetation of the Coterminous United
         States.  American Geographical Society Special Publication No. 36.
         New York:  American Geographical Society, 1964.  144  pp.

39.  Larsen, J'. A.  Fires and Forest Succession in the Bitterroot  Mountains
         of Northern Idaho.  Ecology 10:67-76,  1929.

40.  Lawrence, D. R.  The Glaciers and Vegetation in Southeastern  Alaska.
         American Scientist, Summer, 1958.  pp. 89-122.
                              4-60

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41.  Lee, C. H.  Total  Evaporation  for  Sierra  Nevada  Watersheds  by  the
         Method of Precipitation  and  Runoff  Differences.   Trans.  Araer.
         Geophys. Union,  Pt.  I.   (Cited from Costing,  1956),  1941,  pp.50-66.

42.  Little, L., Jr.  Atlas of United States Trees:   Volume  1. Conifers  and
         Important Hardwoods.  U. S.  Dept. of  Agriculture.   Misc. Publica-
         tions No. 1146 (undated).

43.  Lui-Hing, C., and  S. J.  Sedita.  Viral  and  Bacterial  Levels Resulting
         from the Land  Application  of Digested Sludge.  Symposium on  Munici-
         pal Wastewater and Sludge  Recycling on  Forest  Land  and  Disturbed
         Land, Penn. State University,  School  of Forest Resources,  Philadel-
         phia, Penn., 1977.

44.  Lull, H. W.  Soil  Compaction on  Forest  and  Range  Land.  U.S.  Forest
         Service, USDA  Misc.  Pub. #768,  1959.

45.  Lull, H. W., and L.  Ellison.   Precipitation in Relation  to  Altitude in
         Central Utah.   Ecology 31:479-484,  1950.

46.  Lyon, L. J,, and P.  F. Stickney.   Early Vegetal  Succession  Following
         Large Northern  Rocky Mountain  Wildfires.  Proc. Tall Timbers Fire
         Ecology Conference 14:355-75,  1974.

47.  Martinelli, M., Jr.  Watershed Management in the Rocky Mountain Alpine
         and Subalpine  Zones.  Rocky  Mountain  Forest  and Range Experiment
         Station Research Note RM-36, 1964.  7 pp.

48.  May, R. F. , and W.  D. Striffler.   Watershed Aspects of Stabilization
         and Restoration of Strip-Mined Areas.   In:   International  Symposium
         on Forest Hydrology.  Ed. Sopper and  Lull.  Pergamon Press, New
         York, 1967.   pp. 663-71.

49.  Mikola, P.  Mychorrhizal Inoculation in Afforestation.   In:  International
         Review of Forestry Research.   Ed. J.  RomBerger and P. Mikola.   Volume
         3,  New York, Academic Press, 1970.  pp. 123-196.

50.  Odum.   Fundamentals of Ecology,  Saunders, Philadelphia,  1971.

51.  Costing, H. J.  The Study of Plant Communities:  An Introduction to
         Plant Ecology.  Second Edition.  San  Francisco; W. H. Freeman and
         Company, 1956.  440 pp.

52.  Packer, P. E.   Forest Treatment  Effects -on  Water Quality.   In:   Interna-
         tional Symposium on Forest Hydrology.   Ed. Sopper and Lull.  Per-
         g'amon Press, New York, 1967.   pp. 687-99.

53.  Peterson, J. R., R. I. Pietz, and  C. Lui-Hing.  Crop Production on
         Illinois Coal Mine Spoils Amended with  Digested Sewage Sludge.
         .Symposium on Municipal Wastewater and Sludge Recycling on  Forest
         Land and Disturbed Land, Penn.  State  University, School of Forest
         Resources, Philadelphia, Penn., 1977.
                                   4-61

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54.   Rich, L. R.,  and J. R. Thompson..  Watershed Management in Arizona's
         Mixed Conifer Forests:  The Status of Our Knowledge.   U.S. Forest
         Service,  Rocky Mountain Forest and Range Experiment Station, Ft.
         Collins,  Colorado.  Research Paper RM-130, 1974.  15 p.

55.   Riekenk, H.,  and R. J. Zasoski.  Effects of Dewatered Sludge Applica-
         tion to a Douglas Fir Forest Soil on the Ground Water and Soil
         Solution Compositions.  Symposium on Municipal Wastewater and
         Sludge Recycling on Forest Land and Disturbed Land, Penn. State
         University, School of Forest Resources, Philadelphia, Penn., 1977.

56.   Roth, P. L.,  and G. T. Weaver.  Survival, growth and heavy metal uptake
         of Woody Plant Species on Sludge-Treated Spoils in the Palzo Mine.
         Symposium on Municipal Wastewater and Sludge Recycling on Forest
         Land and Disturbed Land, Penn. State University, School of Forest
         Resources, Philadelphia, Penn., 1977.

57.   Russel, W. L., and J. L. Thames.  Water Use and Management of Ponderosa
         Pine in Northern Arizona.  Progressive Agriculture in Arizona 20(5):
         10-11, SWRA W70-01829, 1968.

58.   Shantz, H. L., and R. Zon.  The Physical Basis of Agriculture:  Natural
         Vegetation.  In:  Atlas of American Agriculture (Pt. 1, Sect. E).
         U.S. Dept. of Agriculture, Washington, D.C., 1924.  29 pp.

59.   Sharpe, G. W., C. W. Hendee, and S. "W. Allen.  Introduction to Forestry,
         4th ed.  McGraw Hill Book Company, New York, 1976.

60.   Shearer, R. C.  Early Establishment of Conifers Following Prescribed
         Broadcast Burning in Western Larch/Douglas Fir Forests.   Proc. Tall
         Timbers Fire Ecology Conf.  14:481-99, 1974.

61.   Shapherd, J.   The Forest Killers:  The Destruction of the American
         Wilderness.  Weybright and Talley, New York, 1975.

62.   Shigo, A. L.   Successions of Organisms in Discoloration and Decay of
         Wood.  Intl. Review of Forestry Research, Vol. 2.  Ed. J. A.
         Romberger and  P. Mikola.  New York:  Academic Press, 1967.

63.  "' Shreve, F.  A Map  of the Vegetation of the United States.  Geog. Rev.,
         3:119-125, 1917.

64.   Sindelar, W., R. Atkinson, M. Majarus, and K. Proctor.  Surface-Mined
         Land Reclamation Research at Col strip, Montana.   Res.  Report No.  69,
         Montana AES  Bozeman, Mont.,  1974.  98 pp.

65.  Smiley, F. J.  A Report Upon  the  Boreal  Flora of the  Sierra  Nevada  of
         California.  University of  California  Publication in Botany  9,  1921.
         423 pp.

66.  Smith,  D.  M.  The  Practice  of Silviculture.   John Wiley  §  Sons,  Inc.,
         New York,  1962.   578  pp.
                                  4-62

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 Steele, R.   Smoke Considerations Associated with Understory Burning
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     Ecology Conference, Missouja/ Montana, 1974.

 Stendnick,  J.  D., and Woodridge.  Effects of Liquid Digested Sludge
     Irrigation on a Second Growth Douglas. Fir Stand.  Symposium on
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     turbed  Land,  Penn.  State University,  School of Forest Resources,
     Philadelphia, Penn.

 Strothmann,  R. 0.  Douglas-Fir Survival and Growth in Response to Spring
     Planting dta  and Depth.  USDA Forest  Service Research Note PSW-228
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     467 pp.

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     Note NE-120,  1970.   8 pp.
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     USFS Forest Resource  Report  No.  20, 1974.

 Urie, D. H.  Nutrient Recycling  in  Forests Under Effluent and  Sludge
     Treatments  in Michigan.  Symposium on  Municipal  Wastewater  and
     Sludge Recycling of Forest Land  and Disturbed  Land,  Penn.  State
     University, School  of Forest  Resources,  Philadelphia. Penn.,  1977.

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                                  4-63

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80.  Weaver, J. E., and F. E. Clements.  Plant Ecology,  McGraw Hill 2nd
         Edition, 1938.  pp. 601...

81.  Wells, B. W.  Plant' Communities of the Coastal Plain of North Carolina
         and Their Successional Relations.  Ecology, 9:230-242, 1928.

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83.  Whittaker, R. H., and W. A. Niering.  Vegetation of the Santa Catalina
         Mountains, Arizona.  (II) A Gradient Analysis of the South Slope.
         Ecology 46:429-452, 1965.

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         Arizona.  Ecology 35:473-489, 1947.
                                   4-64

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                                 CHAPTER 5
                           AEOLIAN MOUNTAIN PEAKS
 5.1  OVERVIEW                                      •           ,'
     The discussion in this chapter will largely be restricted to high mountain
 regions and peaks that lie above the tundra life zone, but much of the material
 may be applicable to desert mountains of much lower elevation arid the barren'
 peaks and outcroppings of forested mountain ranges.  Generally, the environ-
 ments to be considered herein consist of steep slopes and barren rock; depend-
 ing upon the altitude and latitude, ice and snow and harsh meteorological
 conditions may be present, unmitigated by the protection of vegetative cover.
 Depending upon geographic location, tundra, desert and various forest life
 zones surround the mountain peaks at lower elevations, frequently in close
 proximity.  Because of the fact that the surrounding life zones are a priori
 "downstream," it is likely that cleanup operations may ultimately involve more
 than the primary site of a spill, if such is a mountain peak.  If containment
 or stabilization of a spill on a mountain top is not effected by the cleanup
 procedures implemented, the discussions in the reports for other life zones
 will become applicable at lower elevations.  It should also be noted at the
 outset of this discussion that probably few, if any, of the cleanup procedures
 covered in this series of reports will be either effective or logistically
 possible on many mountain peaks due to the severity of the physiographic and
meteorological components of the environment.

 5.1.1  The High Mountain Peak Environment
     The vegetational zonation found in mountain ranges varies largely with
 the latitude, altitude, slope aspect,  mass of the mountain range, prevailing
wind patterns and the location of the range with respect to land and oceanic
masses.   These factors are discussed in some detail in the coniferous forest
 chapter.
                                     5-1

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     Life zones in the uppermost mountain regions of the world have been
described by Whittaker   as arctic-alpine desert and semidesert.   The semi-
desert occurs in arid regions above the timberline.  In temperate zones, sparse
communities of low shrubs and/or cushion plants may occur.  In the arctic, the
semiarid areas are generally considered to be part of the tundra zone, but with
respect to physiognomy, plant adaptations, soil characteristics and sparseness
of animal life, they are desert-like.  Arctic-alpine deserts tend to have very
low plant cover, dominated by snow, ice or rock which may support growth of
bacteria, algae and lichens.  Vascular plants may occur in irregularly scattered
pockets having less extreme microclimates.  These deserts occur in Greenland,
Antarctica, and above timberline on high mountains all over the world.  Alpine
deserts occur in the lower alpine zone in arid mountain ranges.  At lower
latitudes, permanent ice and snow are not necessarily present, and the presence
and nature of vegetation will vary with the amount of moisture present.
         TO
     Swan   notes that the alpine regions of the world are delimited by timber-
lines extending from latitudes 72°N to 56°S with a maximum altitudinal extension
to approximately 14,000 ft.  Figure 5-1 depicts the worldwide distribution of
timberlines and the arctic and aeolian zones.  The upper edge of the alpine
zone is usually defined as the upper limit of the range of vascular plants.
Here too occurs an upward transition from autotrophic to heterotrophic life
forms.  The characteristics of this boundary identify three basic types of alpine
regions:  high-latitude, low-latitude and a depressed equatorial alpine region.
In the low latitude alpine environment, vascular plants are found above 20,000
ft.  (6,100 M) and a long growing season is typical.
                        4
     Above the alpine zone lies the aeolian zone which Swan   has divided  into
terrestrial, nival and aquatic phases.  In the aeolian zone,  autotrophic  algae,
lichens, mosses and a variety of heterotrophic animals and plants occur,  but
vascular plants are entirely absent except in  isolated instances where micro-
habitats exist which provide more  favorable circumstances.  The aeolian zone
extends  in altitude to include the summit area of Mount Everest where bacteria,
fungi and yeasts are found.  Figure  5-2 illustrates alpine-aeolian  zonation  in
the  eastern Himalaya.
                                      5-2

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LIMIT OF VASCULAR PLANTS
HIQICST MAXIMUM TIMBERLINE
UWEST MAXIMUM TIMBERLINE
ISOTHERM OF 21'f. OVER OCEAN
"• AMERICA, S. AMERICA,  ANTARCTICA

JU«OPE. ». ASIA, AFRICA

ASIA, AUSTRALIA
                                                                                                N. PACIFIC, JULT MEAN
                                                                                                t, PACIFIC, JANUARY MEAN
                                                                                                (CALCULATED FROM SEA LEVEL
                                                                                                LAKE RATE: 1*F.-J20 n.
                Figure  5-1.    Alpine and aeolian regions  of  the  world
                                   (from  Swan38).
                                                     5-3

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                                          3PtCT«8iU5  ."r
                                       R (IOOOSOMII    M
                                       Romuc
                                       BtTjm UTILIS
Figure  5-2.  Alpine-aeolian zonation in  the eastern
              Himalaya  (from Swan38).
                            5-4

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      Most  of the work  on  high-mountain  ecology  has  been done  in  Europe and  in
 North America;  a considerable  amount  of work  hass also  been  done  in  the Soviet
             38
 Union.   Swan   notes that unifying  concepts need to be developed in order to
 link the ecological characteristics of  the widely spread  treeless mountain  zones
 throughout the  world that are  commonly  lumped under the category of "alpine."
 For  example,  in the eastern Himalaya, the life  found above  the level of the
 highest  vascular plants forms  a distinct category.

 5.1.2 The Aeolian Life Zone
      In  the  aeolian zone,  nutrients are  supplied by the atmosphere  (carried in
 by wind).  Swan  has  distinguished between the aeolian and alpine  regions  by
 contrasting  the sources of nutrition:  alpine biota are dependent upon local
 autotrophic  flowering  plants,  whereas aeolian organisms are basically supplied
 by air-transported nutrients that are rarely of local  origin.  Hutchinson19 con-
 siders the aeolian region  to be roughly equivalent  to  the hyperallobiosphere
 or that  portion of the eubiosphere  at high altitudes where heterotrophic
 organisms are dominant.
     The aeolian and alpine regions may be defined  geographically as well as
 nutritionally and include  some portions of the high alpine zone and the nival
 zone described  by European researchers. 3  Swan38 believes that the aeolian
 region is most  easily recognized where established  or  semipermanent organisms
 exist in the absence of flowering plants.  Vascular plants may be absent at
 lower altitudes  in particular  localities or seasons, and when the ground is
 covered with snow and organisms dependent upon snow and wide-blown nutrients,
 the distinction may become blurred.   Swan37 suggests that the picture may be
 simplified if the aeolian region is arbitrarily defined as being near or above
 the upper limits of flowering plants.
     Nutritional patterns in the aeolian zone are still not completely under-
 stood.  Animals are sometimes found at altitudes far above the highest vascular
plants; in such instances, wind-blown nutrition is ascribed.  Also,  insects and
 crustaceans occur in temporary glacial pools,  and it may be inferred that those
organic nutrients present  are probably of atmospheric origin,  falling on old
 snow fields and eventually being released from melting ice.   Arthropods and
birds that  feed upon wind-blown insects are obviously aeolian, but they may be
                                       5-5

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transient visitors to the zone.   In many,  perhaps most',  instances the type  and
quality of nutrients involved in the support of aeolian  life and the degree
to which animals and plants are dependent upon atmospheric nutrition are un-
known.  Gregory   has reviewed various organic particles carried by the atmo-
sphere such as pollen, bacteria, fungi and insects.  Luty and Hoshaw   have
                                                     38
examined airborne dissemination of green algae.  Swan   has reviewed the ecology
of the three phases of the aeolian zone (nival, aquatic  and terrestrial); a
brief adaptation thereof follows.

     5.1.2.1  The Nival Phase of the Aeolian Zone--
     Descending air over snow fields may have the effect of concentrating
particles suspended in the atmosphere; hence, analysis of snow fields may pro-
vide an exaggerated impression of the distribution of airborne debris.  Wind-
blown particles tend to blow on and off of most surfaces, but remain upon snow.
Osburn   studied the phenomenon of the accumulation of radioactive fallout
contamination of snow; he found that the particles concentrate in a snow patch
as it melts, presumably as a function of adsorption of the particles to surfaces
within the snow.  Interestingly, radioactive debris was held to a large extent
within a shrinking snow patch and was released in reduced quantities in the melt
water.  He also noted that radioactive particles tend to concentrate in soil
depi-essions beneath melting snow.  These observations may be of potential signifi-
cance in the design of alternative cleanup procedures for implementation in the
high mountain environment.
     Autotrophic green and bluegreen algae may be considered to be of an aeolian
nature in the high mountain environment in that nitrogen and other nutrients must
be derived from the atmosphere.  Bettler  has  suggested the existence of a  food
chain consisting of pollen > bacteria > algae  > annelids for the green  snow worm
Mesenchytraeus solieugus that occurs on a British Columbian glacier.  These
aeolian annelids are  found in the mountains  of the northwestern United  States,
Western Canada and Alaska.
     There has been  some work suggesting the possibility of organic precipitates
and proteinoid materials of oceanic origin being deposited  upon  high mountains,
         ? Q
but Swan   believes  that further study  is necessary  on  this topic.   Accumulations
of dead  insects are  occasionally found  at high elevations,  and'these  are
scavenged by certain  species of birds.  As previously mentioned,  Osburn   found
                                      5-6

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 that radioactive particles concentrate.in soil  depressions beneath melting
 snow; it is also possible that this is true for organic materials.

      5.1.2.2  The Aquatic Phase of the Aeolian  Zone--
      The organisms that inhabit the pools and torrents of the aquatic  phase
 of the aeolian zone are considered to be aeolian by virtue of the fact that
 the organic materials upon which they subsist are assumed to be originally of
 atmospheric derivation.   Torrential fauna include turbellarians,  crustaceans,
 hydracarinids,  and various insects that  inhabit areas primarily or solely near
 the sources of torrents  or those whose primary  nutritional source is closely
 linked with organic materials  released from snow or ice.   Large populations of
 fairy shrimp (Branchinecia sp.)  are found in temporary glacial  pools at  altitudes
 up to 19,000 ft.  in the  eastern  Himalaya.   Examination of their intestinal
 contents  has revealed mostly fine granular  glacial  dust mixed with traces of an
 unidentifiable  organic material;  algae have not been  found.   That algae  are found
 in more permanent  ponds  suggests the  existence  of nutrients  derived from auto-
 trophic plants, but  if,  in fact,  the  primary algae  are green algae, the  presence
 of nitrogenous  material  derived  from  the organic debris of snow may be inferred.
 Swan   believes that  many lakes  classified  as alpine  are,- in fact, aeolian.

      5.1.2.3  The  Terrestrial  Phase of the  Aeolian  Zone--
      The  organic and  other  particulate matter that  is  deposited upon high
 altitude  snow and  ice  surfaces also deposits  and  collects  upon  snowless  areas,.
 the particles being trapped within cracks and crevices where  air  turbulence is
 reduced and  the particulate contents of  the air  can fall out.  Such accumula-
 tions of  the terrestrial phase are frequently obvious  and  largely account for
 collected dust under rocks on mountainsides.  Rock  slopes  free of snow harbor
more  scattered and thicker accumulations of debris  than snow-covered slopes;
 such concentrations serve to sustain aeolian organisms.   It is likely that such
 sites will also trap spilled materials that are not blown off rocky mountain
top surfaces.
     Terrestrial aeolian animals are frequently found at lower altitudes on rock-
covered glaciers.  Various spiders, mites, and insects have been found in this
environment in the Himalaya.  Mites, collembolans and flies live in the absence
of plants on the snow free slopes on the sides of glaciers; their nutrition is
aeolian in nature.  Salticid spiders (Europhrys  sp.) have been found at 22,000
                                     5-7

-------
ft. (6700 m) in the Himalaya and are presumed to feed upon collembola,  anthomyid
flies and possibly wind-blown insects.  An example of this aeolian food source
may be seen on the peak of Citlaltepetl (Pico de Orizaba) in Mexico where July
winds are from the east with a sweeping uplift of air from the tropical valleys
of Vera Cruz onto the mountain peak; many insects are transported to the peak
by these winds.  The lizard Sceloporus microlepidotus Wiegmann is relatively
abundant on rocky slopes above timberline   and is found at 15,800 ft.  of
elevation (700 ft. above the highest flowering plants).  The lizard colonies
are visited by ravens (Corvus corax sinuatus Wagler) and sparrow hawks  (Falco
sparverius sparverius Linn.).  Salamanders (Pseudoeurycea gadovii) were collected
at 15,000 ft. and rattlesnakes (Crotalus triseriatus) at 14,850 ft.  Swan
suggests that all of these organisms  exist, at least partially upon the aeolian
food chain.  Lizards have also been found at extreme elevations in Peru and
      •10
Nepal.
     The upper limit of the terrestrial phase of the aeolian region is  uncertain.
Swan38 notes that sun/shade temperature differentials of 43°C (78°F) are found be-
tween shade and sun near the ground at altitudes of 15,500 ft.  He suggests that
it is at least plausible for such differentials to exist at higher altitudes,
perhaps even near the summit of Mount Everest, in micro habitats sheltered from
high wind velocities.  Assuming a lapse rate of approximately 3°F per thousand
foot increase in elevation, minimum shade temperatures near the summit  of
Mount Everest would approximate -9°F  (-23°C), and maximum shade temperatures
would approach 20°F (-7°C).  Based upon data from free-air temperatures and
comparative temperatures between snowless valleys and snow-covered slopes,
Swan38 suggests that actual shade temperatures near the  summit of Mount Everest
are somewhat colder, but even if shade temperatures approximate -30°F  (-33°C),
it is conceivable that on calm days,  surface sun temperatures may approach
50°F (10°C).  The fact that icicles exist where snow overlies dark vertical
rocks at extreme altitudes indicates  the occurrence of above freezing tempera-
tures.  Figure 5-3 indicates the sun/shade temperature ranges occurring at
15,500 ft. of elevation for soil and  air in a valley in  eastern Nepal.
     Swan38 lists a number of bacteria, fungi and yeasts that were collected
by the 1963 American Mount Everest  expedition.  He  suggests that periodic equable
temperatures and water are available  at high altitudes;  the fact that  the
organisms obtained on Mount Everest represent soil microflora rather than a
                                      5-8

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                                        18
miscellany of air-borne organisms supports the thesis that living organisms
do exist and grow on very high mountains..
     Lichens are widespread in the alpine zone and are often found at higher
altitudes than are local vascular plants, but they are relatively scarce in
extremely arid environments or on surfaces recently uncovered by permanent
snow.  In eastern Nepal, certain vascular plants that can obtain water from the
soil exist at higher elevations than do the noticeable lichens.  That lichens
can grow upon glass and smooth rock surfaces without leaving any trace of etch-
ing is suggestive of their aeolian nutritional status.  Lichens are known to be
                                                         31 38
sensitive to smog and to concentrate radioactive fallout.  '
     Although lichens are scarce -at the high elevations of the aeolian mountain
zone, they do constitute the most visible of the plant life forms in this zone;
therefore, it is of interest to consider their ecology in greater detail.  Hale"1
states that lichens occur in virtually every pioneer terrestrial habitat from
antarctic and arctic to tropical areas.  Their ability to adapt to xeric en-
vironments permits them to dominate in certain habitats that are devoid of
other plant life forms.  Generally, lichens have a high light requirement and
they are succeeded by bryophytes and higher plants where they are shaded and other
conditions permit such successional growth.  However, in habitats where condi-
tions are relatively stable as in the Arctic and Antarctic, in deserts, and rock
outcrops, lichen communities can persist for centuries.  Hale notes that various
lichens tend to be specific for certain rock types.  Mattick   states that lichens
                                                     14
have been found as high as 6200 m (20,341 ft.).  Gams   has reported lichens at
7000 m (22,965 ft.) on K-2 in Karakonm.  Kappen   states that lichens are often
the predominant form of vegetation in mountains of northern regions such as
Scandanavia, but many species demonstrate reduced vitality above 5200 m  (17,000
ft.)-
         38
     Swan   ascribes the scarcity of lichens at high elevations to lack of surface
water from snowmelt, or possibly to snowblast.  Below 5750 m  (18,864 ft.), sub-
surface liquid water from snowmelt permits the development of small "oases" of
                             8
vascular plants in the scree.   Here (in what  is, strictly speaking in view of
our working definition of the aeolian  zone, an upward extension of tundra),
lichens are found entangled with small herbaceous plants.  The relative  aridity
of the area confines the vascular plants to portions of  scree  slopes with under-
                                                 Q
ground meltwater sources, or to rock-base niches.    Lichens,  lacking a vascular
5-10

-------
system and roots, are unable to utilize subsurface water, and therefore are limited
                                                                20
by the degree of aridity of the particular mountain environment.
         TO
     Swan   has noted that studies of barren areas of the world,  notably those of
the antarctic, give little consideration to airborne nutrition.   Llano   has
discussed the contribution of wind-blown guano to populations of collembola and
mites found within a few hundred miles of the South Pole.
     In order to provide a basis for estimation of time to recovery from a clean-
up operation, it is of interest to briefly consider the nature of lichen growth.
         2
Armstrong  has reviewed studies on the growth rates of lichens.   Lichen colonies
do not have a steady growth rate; initial growth is slow, until  a diameter of
approximately 1-1.5 cm is reached at which time the rate increases and becomes
nearly linear until a diameter of 12 cm is attained and then the rate slows, be-
coming non-linear.  Studies under more ideal growth conditions than those obtain-
ing in the aeolian mountain peak environment indicate thallus (plant body) dia-
meter growth rates (in the rapid linear growth phase) ranging from 1.5 to 3.0 mm
per year for the lichen Parmelia gfabratula.  A study of maximum thallus dia-
meter versus thallus age indicates that nearly 25 years are required for the
lichen to attain, a diameter of one centimeter, then (at an increased rate of
                                                                       2
growth) a diameter of 7 cm may be reached after fifty years.  Armstrong  suggests
that there is considerable variation in the growth rate on an individual plant
                                                                    18
and that the rate is quite sensitive to environmental factors.  Hale   notes
that while lichens with diameters of 30-40 cm have been reported in the Arctic
and are reputed to be several thousand years old, only direct and continuous
observation can establish the true age of a lichen thallus.  Hale lists growth
rates for several species; one is reported to have an annual radial growth
rate of 25 mm and another ranges from 11 to 90 mm.  Growth rates for a given
species increase with the temperature of the local climate.  Hale believes that
the average life span of a given lichen thallus may range from 20 to 40 years,
depending upon species and conditions.  In the foliose lichen Parmelia con-
spersa, growth slows after a thallus diameter of 9-10 cm is reached, following
which the center decays and is overgrown by crustose lichens.  These crustose
lichens also overgrow freshly exposed rock surfaces where the centers of the
thalli have fallen away.  Hale is of the opinion that such "recycling" of a
lichen community can continue until the micro-environment is  so altered that
                                       5-11

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other plant forms succeed the lichens.  Since the last glaciation of North
America and Europe some 10,000 years ago, such recycling of lichen communities
may have occurred hundreds or thousands of times.
     There are several methods of measuring and expressing lichen growth rates,
none or which are entirely satisfactory.  Armstrong  suggests that when the
problems of such measurements are solved, the science of lichen ecology will be
able to progress rapidly.  If the diameter and radial growth rate can be accurately
determined, it "becomes possible to estimate the age of a colony, but, according
to Armstrong, there are currently several problems with such determinations.
This "state of the art" probably partially explains the absence of growth data
on lichens in the aeolian mountain zone.
     Bailey  states that there have been few studies in which the germination and
development of lichen propagules (bodies containing the algal and/or fungal
spores which are disseminated by wind, water, animals, etc.), on substrates
conducive to lichen growth.  Lichens are structures composed of both fungi and
algae in a symbiotic relationship.   They produce propagules containing either
or both symbiotics, but only the latter type can reproduce the lichen structure.
Propagules are dispersed by wind and Bailey cites studies indicating that the
propagule content of the wind is proportional to the regional abundance of lichens.
    9
Bond  found that glacial ice in Colorado contains arctic-alpine lichen spores
that are presumably aeolian in derivation.  Once a spore has been deposited on
a suitable substrate, it must germinate and then attach itself to the substrate
by the formation of a "holdfast."  Thallus fragments of preexisting plants can
also become established on a new site by the formation of a holdfast.  Different
species of lichens vary in the types of spores that are formed.
     Bailey  notes that little is known of the nature of colonization of newly
exposed surfaces, partially due to the relative scarcity of such areas.  It was
found that the island of Krakatau was colonized some 3 years after the volcanic
eruption, which removed all plant cover, by blue-green algae; lichens followed
at a later stage.  Studies on Surtsey, a volcanic island which appeared off the
southwest coast of Iceland in 1963, indicated the presence of three species of
lichens by 1970 and 11 species by 1973.  Four of the species were widespread
and evenly distributed over the island.  Aeolian transport is ascribed to these
botanic colonists.  The lichens first became established in and around holes in
the lava, suggesting that surface texture was important in providing a "foothold"
for the holdfasts of the plants.
                                       5-12

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     Based upon the foregoing discussions, it would appear that lichens are
able to colonize a new area within a 10 year period of the first exposure of
the substrate surface, but development of the plants is a slow process, requir-
ing 50 years to attain a diameter of 7 cm and perhaps 80 to 100 years to "mature"
to a diameter of 12 cm.  These estimates are based upon the results of studies
in more temperate environments than that which obtains in the aeolian mountain
peak zone; here, conditions are more severe, and the time to recovery may be
markedly increased.
     The time required for recolonization of a treated area will depend upon the
extent and nature of the treatment, and the abundance of lichens surrounding the
treatment area.  If viable fragments of lichen thalli survive treatment which
includes the removal of the lichens, the rate of recolonization may be relatively
rapid and independent of the size of the treatment area.  If no viable thalli
fragments or propagules survive a treatment, colonization will have to come from
outside, and will probably be slower for a large treatment area than for a
small area.  It should be emphasized that this brief review only skimmed the
surface of lichen biology and ecology, and that many important aspects of their
developmental patterns were not discussed.  Further, no data were found for-
environmental conditions comparable to the aeolian mountain zone.
     Swan suggests that the reestablishment of life forms in areas uncovered
by permanent snow may require considerable time and that aeolian forms are
successional to alpine flora and fauna in environments capable of supporting
alpine life forms.

5.2  NATURAL PERTURBATIONS
     Only aeolian life, as discussed earlier in this chapter, will be considered
here.  There is little precedence for intentional perturbation of high mountain
peaks and relatively little literature concerning either natural or intentional
perturbations.  Also, in the discussions of other life zones, steep slopes per
se were considered only incidentally.
     The lack of vegetation and the steep slopes characteristic of high mountain
peaks make them particularly vulnerable to the erosive forces of earthquakes,
wind, water, ice and associated debris.  Meltwa.ters and rainfall wash soil away,
leaving rills behind.  The steepness and shape of a slope strongly influence
the velocity and destructive force of water runoff.  High mountains tend to have
                                       5-13

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steep slopes with an average gradient of 25° or more.   The gradient is a func-
tion of various factors, including the type of rock present, the age of the
mountains, their tectonics, climate, etc.  Soil destruction also is a function
of the shape of the slope, the relative positions of sections with different
gradients and the nature of the soil formation; for example, podzolic soils,
formerly under forest, are particularly vulnerable to erosion.1  Animal grazing
activities also serve to erode mountain slopes as well as enhance conditions
for water and wind erosion.
     The hydrographic networks of mountainous regions are complicated systems
composed of rivers and streams of various sizes, gullies and ravine type
gorges, all of which usually terminate in larger mountain rivers.  Al'benskii
and Nikitin  have discussed these systems with respect to various aspects of
mountain system erosion.  They note that the conditions of headwaters of rivers
serve to determine the role of rainfall in feeding the rivers.  In high mountains,
the role of rainfall is negligible; snow is the major source of runoff.  Ground-
water provides approximately one third to one half of the water of mountain
rivers.  Rivers originating from glaciers and. snowfields have fairly regular
rates of flow, whereas those originating below the snowline frequently run dry
in the summer.  Where forestation is light or absent, the rate of runoff in-
creases rapidly and the rate of decrease is only slightly less; heavily forested
areas usually do not have sharp runoff peaks. "
5.2.1  Erosion and Mudflow Phenomena
     Al'benskii and Nikitin  observe that the greatest force of linear erosion
in mountains is exerted by small rivers and streams, and temporary torrents,
particularly in periods subject to strong showers and/or intensive snowmelt.
Such torrents are known as mudflows (or mud-stone flows) and are loaded with
silt, sand, debris, stones and other solid material.  The character of the
flow is influenced by the degree of solid material loading; if there is little
solid material present (a fluid or turbulent mudflow), the flow resembles a
freshet, but if the water is heavily loaded (a cohesive or structural mudflow)',
the movement of the flow may be greatly slowed.
     Cohesive mudflows have a high specific gravity and tremendous destructive
force derived from flow pressure and shocks from stones carried by the flow.
Such flows tend to congeal, forming a wave-like elevation when their movement
stops.  Fluid flows tend to be contained within the action section of the

                                       5-14

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stream bed, depositing and, to some extent, sorting their solid contents,  Mud-
flows may also be classified according to their origin, e.g., fed by slope
erosion and weathering products, fed from linear sources, etc.  In arid mountains,
the drainage areas of mudflows may contain great reserves of solid material and
strong showers may produce highly destructive mudflows.
     Mudflows may reach volumes exceeding those of freshets by a factor of 30
or more.  Table 5-1 provides data from mudflows in the Soviet Union.   Mudflows
have been known to carry rocks of 100 cubic meter volume for considerable dis-
tances.  Mudflows are characterized by episodic activity, being common in some
regions and irregular in others.  Mudflow velocities vary from 3-7 m per second
and tend to proceed in waves of varying height and frequency.  Waves are caused
by obstructions in the path of flow.  Erosion by mudflow is a widespread phe-
nomenon on mountains, but flows are rare in densely forested areas.   Owens
has studied the morphology of alpine mudflows.
     Should an uncontained or unstabilized spill be washed from the primary site,
the inclusion of radioactive material in a mudflow is a possibility.
5.2.2  Snow Avalanches
                         .  1
     Al'benskii and Nikitin  note that snow avalanches are most frequent in
high mountains, but they do occur occasionally on medium and low ranges.  Ava-
lanches tend to form where large masses of snow accumulate on steep slopes or
along ravines.  Three types of avalanches may be distinguished on the basis of
their formation:  surface, bottom and jumping.  Surface avalanches are actually
snowslides coming off an entire surface of a steep slope; they are common on
smooth grassy slopes and are more frequent on slopes facing the sun.  Bottom or
trough avalanches form in ravines and hollows and slide in the shape of a talus
fan.  Jumping avalanches differ in that they'form in ravines or other surfaces
terminating in high escarpments from which the sliding snow "jumps."  Avalanches
are capable of producing severe destruction, averaging 50-60,000 tons in weight
and slides of 1.5 to 2 million cubic meters have been observed.  Avalanches
tend to flow from slopes of 30° gradient or more, although some have been ob-
served on slopes of 15-18°.  Generally, avalanches do not form in densely
forested stands.  Schaerer   discusses the effects of terrain and vegetation
upon avalanche sites.  An excellent reference to the physics, ecololy and
management research of avalanches may be found in Perla and Martinelli.
                                       5-15

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 5.2.3  Landslides
                29            .......
     O'Loughlin  has  studied  factors affecting the  incidence of landslides.
 He  found that a combination of steep slopes, heavy seasonal rainfall and an
 impermeable till substratum predisposes a site to catastrophic failure.  The
 occurrence of springs  at the heads of landslide scars suggests the importance
 of  groundwater  in the  release  of materials for slides.
     Dingwall   has found that  erosive overland flow of debris and,fine sedi-
 ments from bare debris surfaces is greatest during summer months.  This process
 is  limited: to  those months when the debris is snowfree and unfrozen; to those
 surfaces unprotected by vegetation and coarse debris; and to finer fractions of
 the debris.

 5.2.4  Overgrazing
     Overgrazing is a cause of soil destruction on mountain slopes; while there
 is no forage in the aeolian zone, the topic is included here as a perturbation
 affecting high mountain slopes.  Animal grazing trails criscross in increasing
 density with time,  resulting in vegetation removal and soil destruction.
 Continued use of the trails inhibits regrowth of vegetation.  Where the trails
merge, sheet erosion can reach proportions of as much as 100 cubic meters of
 soil per hectare per year.

 5.2,5  Recovery
     Recovery,  either unassisted or assisted,  from perturbations in the mountain-
top environment  does not have the same meaning as in the sense of the discussions
covering other life zones.   In cases where perturbations such as rock,  mud,
snow,  or ice slides erode barren mountain peaks or slopes,  devoid of higher
forms  of vegetation, the term "recovery" seems to have little meaning.   In lower
life zones, recovery refers to restoration of the original  life forms such as
forests or grasslands,  but  in the aeolian environment where the only life forms
are microorganisms,  lichens,  insects,  and a few incidental  animals, there is
little to restore.   Erosion,  either violent or gradual,  must be considered as
a natural process of wearing down mountain ranges.   At lower elevations where
 life zones other than aeolian are present, the term recovery regains its signifi-
cance  and the reader is referred to the appropriate chapters of this series.
                                     5-17

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      However,  while recovery is not an applicable term,  prevention or  reduction
 of the severity of certain perturbations of mountain environments  may  be both
 possible and desirable.  With respect to transuranic spills and cleanup, certain
 preventative measures may aid to reduce spread of the spilled material.   This
 concept will be discussed at greater length in a later section.  It is of in-
 terest here, however, to note that some success has been encountered in the re-
 duction of the incidence and/or severity of avalanches,  erosion and mud flows
 through afforestation.  Afforestation is certainly not a short-term procedure,
 but it may have some applicability with respect to treatment of transuranic
 spills.  Discussions of afforestation at lower elevations in the aforementioned
                                                  1               24          4
 context may be found in:  Al'benskii and Nikitin;  Margaropoulos;    Aulitzky;
 Martinelli;   and De Quervian and Der Gand.
      Al'benskii and Nikitin  discuss the topic of afforestation as a possible
                                                     4
 means of reducing mudflows and avalanches.  Aulitzky  notes that in many cases,
 timberlines lie below altitudes where tree growth is climatically possible and
 he discusses the possibility of afforestation above present timberlines.  Mar-
        26
 tinelli   lists possible methods of snowpack and avalanche control:  weather
 modification by cloud seeding; intentional avalanching for the purpose of stor-
 ing snow in shaded valleys at high elevations; reshaping of natural terrain to
 improve show trapping efficiency and capacity; control of snowraelt by addition
 of materials to the snow surface; and the erection of snow fences and other
                                                                    12
 barriers to increase snow accumulation in desired areas.  Dortignac   discusses
 the possibility of increasing the melt rate of glaciers and packed snow by
 scattering dark materials over the surface.

 5.3  MAN-MADE PERTURBATIONS
      No precedents were found in the literature for intentional perturbations
 of mountain peaks in the aeolian life zone; however, perturbations of mountain
 peaks and slopes at lower elevations are common in the form of plowing  and re-
 contouring for strip raining and agricultural purposes; these perturbations may
 occur in desert mountains which have certain similarities to the aeolian zone
 with respect to the absence of vegetation.

5.3.1  Regrading and Replanting
                      28
     May and Striffler   discuss regrading and revegetation of mountain watersheds
                                        5-18

-------
sustaining severe mechanical and hydrological disturbances due to strip mining
operations.  Al'benskii and Nikitin  discuss increased erosion due to agricul-
tural efforts on mountain slopes, and methods of afforestation of these damaged
slopes by terracing and replanting.           i

5.3.2  Alternative Techniques
     The aeolian mountaintop environment presents unique logistical problems for
cleanup that are not present in other terrestrial environments.  As discussed
earlier, the potential for immediate and possibly widespread dissemination of
spilled material by wind and water is great.  Possibly, the first problem to be
addressed will be that of containment rather than cleanup.  As noted in the fore-
going section, most of the treatments considered for other terrestrial environ-
ments will not be applicable to mountain peak spills.  They might, however,
become applicable if an uncontained spill spreads; the contamination of streams,
lakes, and mudflows presents a definite hazard.  The derivation of possible
substitute treatments is beyond the scope of this report, but certain observa-
tions are pertinent.
     It is important to note that wind is an important component of the high
mountain macroenvironment in the aeolian zone.  Life forms that are adapted to
an existence based upon the providence of the windfall most likely will be more
abundant in sheltered microhabitats where windborne debris can settle out of
suspension.  This precipitation process will include atmospheric contaminants.
Osburn   has noted that lichens collected in areas adjacent to the Greenland
"Broken Arrow" incident contained higher than background contamination.
     Various aspects of the physics and management of snow and ice are discussed
in Martinelli,   Dyunin,13, Gary,15 Shiotani and Arai,35 Tabler,39'40 Tabler and
        41                          33
Schmidt,   and Perla and Martinelli.    An important factor in the treatment of
a spill in the aeolian zone will be whether the spill occurs on a snow-covered
surface, soil surface, or rock surface.  The observation of Osburn   that snow
adsorbs and concentrates particulate matter can be of extreme importance for the
design of effective containment and cleanup procedures.  The combined actions of
water and gravity, which present the immediate danger of spread of the spill to
lower levels on the mountain, might also make possible the utilization of the
properties of an affected watershed to concentrate and contain a spill.
                                       5-19

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     Similarly, the effects of wind barriers, serving to concentrate organic
and particulate matter in the aeolian environment, might also provide additional
possibilities for treatment.  Devised techniques embodying these and similar
factors might also be environmentally compatible and offer comparatively short
recovery times.
     The possibility of controlling snow surface temperatures by dusting with
various materials has been studied by Arnold,  Grove et al.,    and Williams and
Gold.44
     It is likely that there will be a degree of similarity between the responses
of the aeolian and alpine environments to cleanup procedures.  Swan   primarily
distinguishes between the biological components of the two zones on the basis
of nutrition; with respect to the physical phase of the environment, there probably
will be a number of similarities in the response of terrain in the two zones  to
cleanup operations.  It should be realized that mountains, particularly the
peaks, present a dynamically unstable condition rather than the dynamic equilibria
presented by biological systems.  Geologically speaking, all  mountains are doomed
to destruction by erosion; therefore, "recovery" of the physical component of the
mountain ecosystem does not have the same meaning that it does in more horizontal
situations.  At best, "recovery" will imply a return to the pre-treatment dynamic
state, or rate of erosion.-

5.4  EFFECTS OF CLEANUP PROCEDURES ON AEOLIAN MOUNTAIN PEAKS

5.4.1  Proposed Treatment Techniques
     As discussed previously in the section on recovery from natural perturba-
tions, the high mountain peak environment presents a totally different situation
from those discussed in reports on other life zones.  First,  the very nature of
what is meant by the term "recovery" is open to question.  There are few life
froms present to be significantly affected by possible cleanup procedures..
There are no flowering plants in the aeolian life zone; life forms present on
the high peaks are limited to bacteria, fungi, algae, lichens, insects, nema-
todes, and a few species of birds and reptiles.  Second, the nature of the moun-
tain peak terrain, combined with the lack of flowering plants will make questions
concerning recovery from most of the treatments considered in other reports
moot:  there is virtually no plant life to "recover" and such treatments as
                                      5-20

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vegetation removal, surface alteration, soil removal, plowing, soil fill,
sludge application and flooding are either not applicable or, if logistically
possible, impractical.  It appears likely that alternative and innovative
treatment procedures will be necessary to treat primary spill sites, while
conventional treatments may be necessary at points below the spill if it is not
contained.
     While it is true that there is little variety or abundance of life in the
aeolian environment, the ecosystem that exists may be considered quite fragile.
As previously discussed, it has been observed that lichens are slow to become
established on high mountain surfaces that have been uncovered from permanent
snow.  Those life forms that have become established in the aeolian system are
dependent upon accumulations of nutrients that: are ultimately derived from the
winds; it is likely that the time required for such accumulations to form is
rather long.  There are very little data on this subject.
     An important consideration in the design of cleanup techniques for the
mountain peak environment is the accessibility of this zone to men and equip-
ment.  The operation of helicopters may not be feasible at higher elevations;
ground access to many sites by heavy equipment may be impossible, and the severity
of mountain physiognomy may preclude its ure.  Equipment used in cleanup opera-
tions may be restricted to that which can be packed in or parachuted.  Air removal
of contaminated materials may be the only feasible method.  For these reasons,
methods based upon (or partially utilizing) the management and manipulation of
natural features and phenomena (see discussion of the Nival Phase of the Aeolian
Zone) at the site, such as snow cover and water runoff, may be desirable from
the standpoints of logistics,  economics and ecology.   The impact of devices to
manage wind, snow drift and water runoff would, be variable with their design
construction and placement.   It is expected that their major impact would be upon
the abiotic phase of the environment (erosion, etc.)  and that the impact of
such devices upon the life forms of the aeolian zone would be minimal.
     The following discussion  of suggested cleanup techniques will  be generally
limited to the aeolian life zone.   Some of the comments might also  have limited
application to steep mountain  slopes and peaks in lower life zones  or in a
desert environment.
                                     5-21

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     (0-1)   Uati&al Rehabilitation
     Little has been published on the topic of natural rehabilitation of per-
turbations to the aeolian mountain peak environment, making the estimation of
recovery time from a spill cleanup operation rather difficult.   "Natural re-
habilitation" would depend largely upon the rates of two processes:   dispersion
of spilled material by wind and water and the rate of decay of spilled material
that becomes trapped in rock crevices, snow and ice.  These processes could be
quite rapid or very slow, depending upon the properties of the spilled material
and climatic conditions at the site.
     (1-1)  Chemical Stabilization
     Soil stabilization by the addition of chemical stabilizers to the surface
is probably not a viable treatment in the aeolian mountaintop environment.

     (1-2)  Clear Cutting Vegetation ("Removal")
     This technique, applicable in many life zones, will be generally inapplicable
in the aeolian environment.  With the exception of lichens, fungi, and certain
algal species, there is no vegetation present.   The removal of lichens from rock
surfaces or algae from cliff faces, snow, or ponds probably will have little
lasting impact upon the ecosystem, with the exception that lichens probably
will be very slow to become reestablished.  It  is unlikely that the removal of
lichens will have measurable effects upon temperature, radiation, soil moisture,
precipitation, or surface runoff.  Removal of algae from snow or ice may increase
surface albedo, thereby decreasing surface temperatures and runoff; this treat-
ment might possibly affect the microclimate.  The possibility of controlling snow
surface temperatures by dusting with various materials has been studied.  Removal
of algae from cliff surfaces can increase surface erosion.

     (1-3)  Stumping and Grubbing
     Not applicable to this land type.

     (1-4)  Scraping and Grading
     Whether surface alteration techniques, such as scraping and grading with
"air-dropped" equipment, will be logistically possible on mountain peaks in the
aeolian environment is highly questionable.  Surfaces are likely to be snow, ice,

                                      5-22

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rock, and debris with little soil accumulation on steep slopes; some surfaces
might be almost vertical.  High winds, precipitation, or dense cloud cover might
be present.  The potential for an avalanche must be considered in some areas.
Under these conditions, manual labor might be the only effective resource,
as was largely the case in the Greenland "Broken Arrow" incident.
     Removal of surface snow and ice can be expected to produce minimal lasting
impact.  Surface scraping and grading of rock, soil, or debris will tend to
accelerate erosive action, the severity of which will depend upon the composi-
tion and slope of the surface.  If the treatment increases the smoothness of the
surface, the potential for a snow avalanche will be increased.  Severe altera-
tion of mountain peaks will produce a strong visual or aesthetic impact.  Post-
treatment measures might be required to reduce the potential for erosion and
avalanches.  Methods of afforestation and terra.cing might be considered for these
purposes.  Depending upon the location of the spill, climatic conditions might
permit some degree of afforestation or vegetation above the timberline.  Without
such measures, recovery, or return to the pre-treatment conditions, could be
quite slow.  In fact, the net effect of the treatment might be to potentiate the
pre-treatment erosive condition.   Erosive processes could be accelerated and
recovery might never occur.

     (1-5)   Shallow Plowing
     Not applicable to this land  type.

     (1-6)   Deep Plowing
     Not applicable to this land  type.

     (1-7)   Sail Cover Less than  25  am
     Application  of soil as a coverup type of treatment would not seem to be
applicable in the  mountain environment because of steep slopes and rapid erosion.
Construction of mechanical retaining structures probably would be required.   This
treatment might be possible behind glacial moraines and in small valleys but
contamination of  ground water and subsequent flow to streams would appear to
render such treatments ineffective.   Because of the absence of plant cover growth
in the aeolian environment, stabilization of such soil fill would be quite diffi-
cult.
                                       5-23

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     (1-8)   Soil Cover 25 to 100 cm    ,  ;,                  	
     Mot applicable to this land type.

     (2-1)   Remove Plow Layer
     Removal of soil (if present) will increase exfoliation and erosion of the
underlying rock surfaces by making them accessible to temperature extremes and
alternation between freezing and thawing.  As discussed in Section 5.1.2.3, the
daytime sun and shade temperature differential on a mountain peak can exceed
70°F.  Snow removal would be expected to produce similar effects.  Reference to
the particulate adsorptive properties of snow was made earlier in Section 5.1.2.1,

     (2-2)   Remove Shallow Root Zone
     A "root zone" in the sense used in other ecological zones does not exist in
the aeolian mountain peak environment.  The comments in 2-1 will apply to
soil removal to depths usually thought of as the root zone.

     (2-3)   Remove by Scraping and Grading,  Mechanically Stabilize
     Removal of soil and rock by scraping and grading, if logistically possible,
would probably serve to increase erosive processes.  Mechanical stabilization in
the sense of soil compaction would probably not be applicable to many sites in
this zone.   Partial stabilization by methods analogous to those used in trail
maintenance may be possible, but their long-term effectiveness is questionable.

     (2-4)   Remove Plow Layer., Mechanically Stabilize
     The mechanisms for thermal fractures of newly exposed surface rock were
described earlier in treatment 2-1.  For this land type, the feasible mechanical
stabilization would be the temporary system of rock-weighted mesh and drilled
pins in lead anchors or the use of "rock-bolts."  Mechanical stabilization of
soil patches by a soil compaction process would be quickly exfoliated by frost
heaving and cannot be recommended here.  Large areas would be prohibitive to
cleanup, and "recovery" in this context would be an indefinable term.
                                       5-24

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      (2-5)   Remove Shallow Root Zone,  Mechanically Stabilize
      This combined treatment is inappropriate for the aeolian mountain peak
 environment.

      (2-6)   Remove by Scraping and Grading,  Chemically Stabilize
      Soil removal followed by chemical stabilization would mitigate some of the
 consequences of rill  and gravitational creep erosion caused by slope steepness
 until the chemicals break down under ultra light exposure.  This breakdown is an
 indeterminate result  and highly dependent  upon the cumulative duration of snow
 and ice  cover,  and particularly dependent  upon slope aspect.
      The removal  of spilled material by scraping and grading of hard surfaces
 is  subject  to those points discussed in treatments 2-1  through 2-3.   The effec-
 tiveness and consequences of chemical  stabilization would  depend upon the nature
 of  the site and the properties  of  the  stabilizing material.   The use of these
 methods  in  areas  subject  to severe erosive forces is questionable.

      (2-7)  Remove Plow Layer., Chemiaallii Stabilize
      This treatment is inappropriate for the  same reasons  as  treatment 1-4.
 Chemical  stabilization would  be  less effective than  weighted  mesh upon those
 patches  where some  soil has  collected.

      (2-8)  Remove Shallow Root Zone, Chemically Stabilize
      This treatment is not appropriate.

      (3-1)  Barriers toExclude People
      If the  supporting posts can be  bolted into rock to support the  ice during
snow melt, this might be the most realistic temporary procedure while cleanup
is carried out.  Access barriers might be necessary at greater distances from
the primary  spill site than for other life zones.  Because of the absence of
protective vegetative cover, rapid transport of spilled material by water and
dissemination by wind can occur immediately after the spill; the spread of con-
tamination to locations remote from the primary site is a definite possibility.
                                      5-25

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     Due to the high danger of spreading of spilled material  by wind  (in  the
absence of protective plant cover)  and water to sites downslope and/or possibly
remote from the primary location, erection of barriers some distance  from the  spill
may be necessary.  It may be necessary to restrict access to lakes and streams at
lower elevations in the watershed.   Valleys at the base of a mountain peak spill
site may be subject to wind contamination.  Assessment of the dangers of such
spread will have to depend upon local evaluation of the site and consideration
of the properties of the spilled materials.
     (3-2)  Exclude Large Animals
     The erection of animal access barriers might or might not be necessary,
depending upon the site location and altitude.  Barriers excluding large animals
probably would not be necessary for spills in the aeolian environment since it is
far above their normal range.  It is unlikely that animals will interfere with
the recovery of a treated area, however, they can act as a vector for direct
dissemination of radioactive materials.

     (3-3)  Exclude Large and Small Animals
     Small animals in the lower portion of the aeolian zone are generally
limited to a few reptiles and insects; these are discussed in  the first part of
this chapter.  Birds, which are occasional visitors  to this life  zone  (also
discussed  earlier in this report), can be problematical.

     (4-1)  Asphalt Hard-Surface Stabilization
     Outside the  scope of work of this  study.

      (4-2)  Concrete Hard-Surface Stabilization
      Outside the scope of  work of this  study.

      (5-0)  Application of Sewage Sludge
      Outside the scope  of  work  of  this  study.

      (6-1)  High-Pressure  Washing  (<3 mm)
      Not applicable to this land type due to logistics and recontamination
 problems.

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     (6-2)  Flooding to 30 am
     Not applicable to this land type.

     (7-0)  Soil Amendments Added
     Outside the scope of work of this study.

5.4.2  Alternative Treatment Techniques
     Severe climate is characteristic of this zone with high velocity winds
and severely eroding steep slopes at those seasons free water occurs.  Snow
blasting can redistribute contaminants impacted on high vertical surfaces
without interference but horizontal movement can be influenced by diverting
melt water with structures, and snow may be managed or directed while in
motion.

     (8-1) . Snowfences and Wind Barriers
     These structures can be of temporary benefit in reducing snow accumula-
tion at one small area by holding it in another site.  The wind shadow extends
leeward 10-15 times the height of permeable barriers.  By rule of thumb, a
solid wall 0.75 meters high protects the adjacent surface from snowblast and
wind erosion to 10 meters downwind and a snowfence 1.2 meters high and of
about 50% frontal area casts a wind shadow 12 meters downwind.  The most
effect is obtained with a rough edge.  Wind velocity is least near the ground
at 3 to 5 barrier heights on the downwind side of both solid and penetrable
barriers.  Effectiveness of the barriers and snowfences seems independent
of wind speeds, at even high velocity if the barrier is vertical.  The principal-
problem with barriers is that of determining the perpendicular to the direction
from which the prevailing high winds scour a given area consistently.

     (8-2)  Watershed Control Devices Constructed
     The usual operations of shaping by clearing (1-2) , scraping and grading
(1.-4, 2-3, 2-6), and revegetation are not viable in this ecosystem as ways of
controlling movement of contamination in water.  Streams are torrential and
mudflows scour deeply in above-freezing weather.  The high kinetic energy
                                    5-27

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requires that manual construction methods or small air-freighted equipment
of limited capability be used for the diversion structures.  These can include
stone riprap and diversion dikes and stone gabions across rills and smaller
channels.  Contoured terraces, stone walls and check dams, and rock outfalls
may be feasible as aids in containment when the contaminated area is snow-free.
Grade stabilizing structures such as chutes and stone drop spillways can be
supplemented by stone levees to modify smaller stream channels and reduce
erosive cutting into contaminated "soils" and snowbanks.  None of these appear
to be effective controls in areas with landslides, avalanches, and even severe
snow blast.

     (8-3)  Snow and Ice Additives
     The application of dusts to snow and ice to retard or enhance melting
can be useful.  Experience with dusting charcoal dusts and lamp black powders
over snow and ice showed significant increases in melt rates.  That observation,
when taken with the observation that deposits of solid particulates are captured
while melting occurs, suggests a unique procedure for reducing the volume of
              i
snow to be cleaned up.  The transportation requirements for dusting material
are modest enough to be handled by backpackers, small fixed-wing aircraft,
or even avalanche-prevention artillery rifles.  Subsequent snow cover cancels
the effectiveness of the dusting, but it can be renewed again repeatedly.  On
the other hand,  the potential of reducing melt rates by foamed polyurethane
insulation blankets seems not to have been tested experimentally in snowfields
as a containment technique.  In thoery it would be an effective method for
isolating small  areas of contamination from heat and winds.

     (8-4)  Removal of Contaminated Snow and Ice
     The logistics of travel in the area seem the most likely source of environ-
mental damage.  Melting ice and packed snow requires heat, but given air support,
fuel tanks can be supplied and the contamination concentrated by melting the
snow and ice carrier.  The characteristics of the contamination would control
the selection of resin column adsorbers, or using alcohol gels or thixotropic
mixtures for containerizing the contamination prior to transportation.  Reflec-
tive surface solar stills would also be effective as concentrators where sunlight
is available because of the high light intensity at high elevations.
                                     5-28

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5.5   RECOVERY AFTER CLEANUP     ,     ••.>-.••
      The applicability of the term "recovery" to both the biotic and abiotic
components of the aeolian zone and mouritaihtop environment was discussed at
the beginning of Section 5.4 on cleanup procedures.  The following discussion
is subject to the same reservation's.

5.5.1  Irreversible Changes
      Any treatment that drastically  alters the shape or surface of the mountain
peaks or slopes or greatly increases the rate of erosion in the barren ecosystem
under discussion, can for all practical purposes be considered as irreversible.
Destruction of habitats or extremely slow-growing life forms as lichens might
be considered to be irreversible from the standpoint of the human lifespan.  There
is little data on the growth rate of these organisms in the aeolian environment.

5.5.2 Rates of Recovery
      There is insufficient data available from cleanup procedures to provide a
meaningful discussion of recovery rates of the aeolian mountaintccp environment.
The abiotic components of the ecosystem might not recover, per se, but will
instead establish new rates of erosion which incorporate changes brought about by
the cleanup procedures.  The degree of the effect will depend largely upon the
severity of the severity of the treatment implemented.
     With respect to the biotic components of the aeolian system, it can be
inferred from observations on the establishment of lichens in areas uncovered from
permanent snow that recovery for these organisms will be extremely slow.  Algae,
if removed from cliff surfaces, or with snowpack, probably will be able to be-
come reestablished in a relatively short period of time.  If food sources for
zoological components of the aeolian environment are removed from the spill
area, it can be expected that their reestablishment (dependent upon buildup
of concentrations of organic materials of aeolian derivation)  will be slow in
some  cases and rapid in others.  Lizards that depend upon windblown insects
might be able to become reestablished in a treated area within a few generations;
aeolian insects, dependent upon collected organic materials in cracks and crevices,
might require many years to become reestablished.  There is insufficient data to
speculate upon the recovery rate of snowworm populations that might be depleted
or eliminated with the removal of contaminated snow during the cleanup process.
                                      5-29

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5.5.3  Successional Stages               -
     The "recovery" events that occur within arbitrary "successional stages" will
vary greatly depending upon the location, situation, season of the spill, 'and the
treatment applied.  The discussion here will apply only to the biotic phase of the
environment.  It is emphasized that there is little data or precedence for  these
estimates, and that they are essentially educated guesses.  Deterioration can be
expected for the abiotic phase of the system; the rate will depend upon the loca-
tion of the spill and the nature of the treatment.  Since lichens are the most
visible biotic component of the aeolian mountain environment, their recovery
will be assumed to essentially signal the "recovery" of the biotic component.

     5.5.3.1  First Year—
     In the first year, regeneration of disturbed, removed, or destroyed microbial
forms, including algae on cliffs and snow fields, probably will be well underway.
It is assumed that these organisms are reasonably well adapted to the environment
and enjoy relatively short generation times.  Higher forms of animal life that
are mobile and can subsist on windblown insect.s might have begun to reinvade
the treated area.

     5.5.3.2  Fifth Year—
     By the end of the fifth year, the microbial  lifeforms will be well established
and the higher animal life forms probably will have recolonized the niches able to
provide sufficient food.  If algal forms were removed from cliff faces during
the treatment, they also probably will be reestablished,  although the thickness
of their  "mat" probably will not be  fully developed.

      5.5.3.3  Tenth Year—
      By the end of the tenth year, there should be  sufficient accumulation  of
windblown organic  debris  in cracks and crevices to  permit survival  of small
populations of those  species of  spiders, mites, etc., that utilize  this nutri-
tional  source.  Algal mats  should  be well developed on  cliff faces  (if there is..
a favorable habitat in the  cleanup area).   Vertebrate populations  (lizards)
probably  will have attained equilibrium  by  this time.   With  the  exception  of the
slow-developing  lichens,  the biological  climax populations of the  aeolian  life
                                       5-30

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 zone should be well  on the way to recovery in the treatment  zone,  assuming  that
 the treatment did not leave residual  chemicals or mechanical structures.  By  the •
 tenth year, small lichen colonies may be reestablished over  the  treatment area,.
 if lichen growth preexisted the treatment and lichen  growth  was  completely  removed
 during the treatment.

      Speculation beyond this time period seem:; meaningless because,  in  the  absence
 of protective vegetation sufficient to provide stable microhabitats,  changes  in
 climatic  patterns might occur that are great  enough in magnitude to  alter the
 environment and its  biota.   If lichen growth  preexisted.the  treatment,  it should
 be reasonably recovered by the 100th  (or perhaps  by the 50th)  year,  subject to   ."'
 the factors discussed  earlier in  this section.                                   .  '

 5.6  QUANTITATIVE ASSESSMENT OF CLEANUP IMPACTS '
      Environmental forces  are  asserted  differentially  in the aeolian mountain
 from  "normal"  zones, and the effects  of recovery  from  cleanup  are evaluated
 differently.   Lack of  soil cover  throughout and the absence of flowering
 plants lends a restricted meaning  to  recovery.  In the  following discussion,
 recovery means that the rate of erosion  of surface features has been slowed to
 the rate of  loss  that  existed  before  contamination.  The eroding surfaces
may be snow  fields, snow banks, aeolian  mineral drifts  from rock, ice features,
 rock  faces,  or other surfaces,  including patches of frozen and unfrozen "soils."
 Life  forms that exist  year  'round  are sophisticated, such as lichens and
 snow  worms or primitive bacteria and  algae.  Transient populations of insects
 attract scavenger birds temporarily into the aeolian peaks.
      Wind-drifted mineral deposits collected around rocks and  ice features
and on and in  snowbanks form the sites  for "soil" accumulation.  Soils and
vegetation in the normal sense are absent.  In their place are patches of
rock-weathering products combined with wind-drifted solids to  form mineral  •
pockets of a few  square meters in area.  Continuous areas of soil patch as
 large as 0.01 km  are rare, and for discussion of larger areas to 0.1 and 10 km2
of cleanup, the effects must be imagined as imposed upon an  increasing number of
patches scattered around one or several mountain peaks.  Consequently, the
 impacts from the effects of cleanup are  those registered upon  small mineral
patches whether it is one patch or large numbers of "soil" patches among
bare rock and snow and ice fields.
                                     5-31

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     The majority of the cleanup treatments evaluated in the report  are  in-
appropriate in this zone, especially those which involve the redistribution
of soils (1-3, 1-6, I-?, and especially 1-8).
     Use of stabilizers is judged ineffective without there being precedent  to
judge from.  This area is considered significantly different from spoil  banks
at lower elevations.  At those sites particle size ranges exist, and the surface
dries off after precipitation.  In the mountain, piles of aeolian debris are
intermittantly soaked or ice sheathed where chemical stabilizers are unlikely
to stick, and it is not likely that sublimation is an effective drying agent.
Single-grain coarser material is filled with rock fragments or covered with
rock too large to hold in place with sprayed solution.  No effective use can
be projected for treatments 1-1, and 2-3 through 2-8.  Thermal problems with
chemical stabilizers are extreme at these heights.
     Five groups of time to recover are shown in Table 5-2.  These rank
as groups from most destructive but acceptable at some sites (1-4, 2-1, and
2-2); through less destructive, if considered to apply only to lichens  (1-2
and 1-5); then, potentially destructive, but not required to be  (8-2).  These
are the cleanup techniques that can take a century or more to repair.
     Impacts only fractionally as retrogressive are  imposed by Treatments 8-1
and 8-3 and mainly on solid precipitation.   Removal  of contaminated ice or
snow is ranked in this same time span.  The  non-impact cleanups  are the
barriers (3-1, 3-2, and 3-3).
     In Table 5-2 the operations of clear  cutting  (1-2)  and shallow plowing  (1-5)
are restricted to scraping  lichens from their support.   In  this  snow-blasted
and windy  zone, ten years may pass before  recplonization occurs,  and  one or
several centuries are  likely to pass before  a full-standing crop is established
again.  This  is a drastic cleanup and  has  the longest recovery  time of  the
likely treatments on vegetated  sites.  Similar  effects  and  recovery are
attributed to treatment  1-5 when applied  to  lichens.
     The most drastic  cleanup  after-effects  upon  the environment derive from
removal of the aeolian "soils" in  treatments 1-4,  2-1,  and 2-2.   Replacement
with additional  aeolian debris to  an  equivalent depth is postulated  to  take
one  to  several centuries.   If treatment  8-2  were  to be  constructed  of these
                                      5-32

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                                                            5-33

-------
"soil" materials it would be rated equally damaging.   The recommended con-
struction materials are rock fragments for the structures proposed to divert
snow melt.
     Stone filled diversions created from tatus (8-2) are expected to be
restored in a few years by natural rock-falls.  Except for the potential for
misuse of soils, this technique would be rated as little impact, as are
Treatments 8-1 and 8-3.  Installation of fences (8-1) to create drifts and
melting of snow and ice (8-3) are rated benign as is removal of contaminated
snow and ice (8-4).  High pressure hosing down with water (6-1) has little
impact if the logistics of obtaining the required water is met by an environ-
mentally benign way.
     The procedures judged least destructive are shown in Table 5-2 as
barriers, mainly barriers to keep people out  (3-1) and a few transient animals
that may pass through  (3-2, 3-3).  Damage during barrier installation is pre-
sumed minimized and remedied by solid precipitation cover in a few months.
     The effect of increasing the area of cleanup can only be visualized as
including additional numbers of discrete and overall cleanup sites because
of the terrain being limited in area.  The impacts and the times to recover
are area independent due to frequent transitions from ice to rock to snow
cover.

5.7  CONCLUSIONS
     Because of the complete lack of vegetative cover and the extreme severity of
physiographic and climatic factors in the aeolian mountain peak environment,
most of the conventional cleanup procedures considered for other terrestrial life
zones and environments appear to be either inapplicable or logistically impracticable,
and probably would be minimally effective.  For these reasons, and the  fact  that
precedents for perturbations of this environment and recovery therefrom are  ex-
tremely rare in the literature, accurate quantitative estimation of the impacts
of these treatments would be difficult.  It might appear that alternative treat-
ments that are applicable to the aeolian mountain peak  situation  should be
devised as a separate  study, and their  impacts then  considered.   Possible alterna-
tive avenues of approach have been mentioned  in this  report.   With  respect  to
"conventional" cleanup procedures, those  involving  surface  alteration  and hard-
                                      5-34

-------
 surface  stabilization  appear  to  have  the most  lasting  impacts.  The  severity of
 impact and the  amount  of time required  for  "recovery"  varys depending upon the
 location and precise situation of the spill and the exact nature of  the treat-
 ment  imposed.

      It  is suggested that alternative techniques for immediate containment
 and subsequent  cleanup which  are suited to the aeolian mountain peak situation
 be devised.  These techniques would be more effective  and less detrimental than
 those methods devised for other environments.
     The preferred treatments are those involving barriers (3-1, 3-2, 3-3) and
 removing contaminated snow or ice (8-4).  The least suitable treatments are
 those which strip the lichens from surfaces, and defined this way are Treat-
ments 1-2 and 1-5, although they are not physically the most destructive.
                                    5-35

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5.8  AEOLIAN MOUNTAIN PEAK  REFERENCES
 1.  Al'benskii, A. V.  and  P. D. Nikitin.  Handbook  of Afforestation  and  Soil
        Melioration. 3rd ed.  (Gosudarstvennoe  Izdatel'stvo Sel'skokhozyais-
        tvennoi Literatury, Moscow:  1956.) Translated from Russian by  Israel
        Program for Scientific Translations. Jerusalem,  1967.

 2.  Armstrong, R. A/-   Studies on  the Growth  Rates of Lichens.   In: Lichenology:
        Progress and Problems.  D. H.  Brown, D.  L.  Hallsworth  and R. H.  Bailey,
        eds.  London: Academic Press, 1976.

 3.  Arnold,  K. C.  An  Investigation  into  Methods of Accelerating the Melting
        Ice  and Snow by Artificial Dusting.  In:  Geology of the Arctic.
        G. D. Raasch,  ed.   University of  Toronto Press.  11:198-1013, 1961.

 4.  Aulitzky, H.  Forest Hydrology Research  in Austria.   In: Forest  Hydrology.
        W. E. Sopper and H. W.  Lull  eds.  Oxford: Permagon Press, 1967.

 5.  Aulitzky, H.  Significance  of Small Climate Differences  for the  Proper
        Afforestation  of Highlands in Austria.  W.  E.  soppef and H.  W.  Lull
        eds.  Oxford:  Permagon  Press, 1967.

 6.  Bailey,  R. H.  Ecological Aspects of  Dispersal  and  Establishment in Lichens,
        In:  Lichenology: Progress and Problems.  D.  H.  Brown, D. L. Hallsworth
        and  R. H. Bailey,  eds.  London: Academic Press,  1976.

 7.  Bettler,  G. T.  The Plant Ecology of  the Drakensberg Range. Nat'l  Museum
        Ann., v.  3, pp. 511-565,  1964.

 8.  Billings, D.  W.  Arctic and Alpine Vegetation:  Plant Adaptations to Cold
        Summer Climates.  In:  Arctic  and Alpine Environments. J. D.  Ives and
        R.  G. Barry,  eds.  London: Metheuen $ Co.,  Ltd., pp.  403-443, 1974.

 9.  Bond,  E.  K.   Plant Disseminules  in Wind  Blown  Debris from  a Glacier in
        Colorado.   Arctic  Alpine Res. 1,  165-169,  1969.

10.  DeQuervain, M.  R.  and H.  R. Der Gand.  Distribution of Snow Deposit in a
        Test Area for Alpine Reforestation.    In: Forest Hydrology.   W. E.
         Sopper  and  H.  W.  Lull eds.  Oxford: Permagon Press,  1967.

11.   Dingwall, P.  R.   Erosion by Overland Flow on an Alpine Debris Slope. In:-
         Mountain  Geomorphology. Slaymaker, 0.  and McPherson, H. J.,  eds.
         Vancouver:  Tantalus Research, 1972.

12.   Dortignac,  E. J.   Forest Water  Yield Management Opportunities.  In: Forest
         Hydrology,  W.  E.  Sopper and H. W. Lull, eds.  Oxford: Permagon Press,
         1967.
                                     5-36

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 13.   Dyunin,  A.  K.   Fundamentals of the Mechanics of Snow Storms.  In:  Physics
          of Snow and Ice.  International Conference on Low Temperature  Science
          Proceedings.  Sapparo,  Japan, pp.  1065-1073, August 1966.

 14.   Gams,  H.   Die  Herkunft der Hochalpinen Moose und Flechten.  Jahrb.  Ver.
          Schutre Alpenpflanz.  Munchen 25,  1-11,  1960.

 15.   Gary,  K.  L.  Airflow  Patterns and Snow Accumulation in a Forest Clearing.
          West.  Snow Conference  Proc.  43:106-113,  1975.

 16.   Gregory,  P.  H.  The Microbiology of the Atmosphere.   New York:  Wiley
          (Interscience), 1961.
                         *   ,

 17.   Grove,  C.  S.,  Jr.,  S.  T.  Grove,  and A. R, Aidun.  The Theory  and  Use of
          Aqueous  Foams for  Protection of Ice Surfaces.   In:  Ice  and  Snow Pro-
          perties, Processes and Applications. W.  D.  Kingery,  ed. Cambridge-
          M.I.T.  Press, pp.  666-684,  1963.

 18.   Hale, M.  E.  Jr.   The Biology of  Lichens. London: Edward  Arnold  (Publishers!
          Ltd.,  1967.   176 pp.

 19.   Hutchinson,  G.  E.   The Ecological  Theater and the  Evolutionary  Plan.  New
          Haven: Yale University Press,  1965.

 20.   Kappen, L.   Response to Extreme  Environments.   In: The Lichens. V.  Ahmndjian
          and M. E. Hale, eds. pp.  289-400.    New York: Academic Press, 1973.  697 pp,
21.
Llano, G. A.  The Terrestrial Life of the Antarctic. Sci. Am. 297-212-230
    1962.                                                                '
22.  Luty, E. T. and R. W. Hoshaw.  Airborne Algae of the Tucson and Santa
         Catalina Mountain Areas.  Journal of the Arizona Academy of Science
         pp. 179-182, 1967.

23.  Mani, M. S.  Introduction, to High Altitude Entomology. London: Methuen,


24.  Margaropoulos, P.  Woody Revegetation as a Pioneer Action Towards Restor-
         ing of Totally Eroded Alopes in Mountainous Watersheds. In: Forest
         Hydrology. W. E. Sopper and H. W. Lull, eds. Oxford: Permagon Press,


25.  Martinelli, M. Jr.   Snow Fences for Influencing Snow Accumulation. In:
         The Role of Snow and Ice in Hydrology. Syrap. on Measurement and Fore-
         casting Proceedings. Banff, Alberta.  1972.  Handout, pp. 1394-1398.

26.  Martinelli, M. Jr.   Possibilities of Snowpack Management in Alpine Areas.
         In:  Forest Hydrology.  W. E.  Sopper and H.  W.  Lull, eds.  Oxford:
         Permagon Press, 1967.

27.  Mattick, F.  Die Flechten als Ausserste Vorposten des Lebans in Gebirge.
         Montagne e Uomini, 2, 494-6,  1950.
                                     5-37

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28.  May, R. F. and W. D. Striffler.  Watershed Aspects of Stabilization and
         Restoration of Strip-Mined Areas.  In: Forest Hydrology.  W.  E.  Sopper
         and H. W. Lull, eds. Oxford: Permagon Press, 1967.

29.  O'Loughlin, C. L.  A Preliminary Study of Landslides in the Coast Mountains
         of Southwestern British Columbia. In: Mountain Geomorphology.  0.  Slay-
         maker and H. J. McPherspn, eds. Vancouver: Tantalus Research Ltd.

30.  Osburn, W. S.  The Dynamics of Fallout Distribution in a Colorado Alpine
         Tundra Snow Accumulation Ecosystem.  In: Radioecology. V. Schultz  and
         A. W. Klement eds. M.Y.: Reinhold and Am. Inst. Biol. Sci. Publ.,  1963.

31.  Osburn, W. S. Jr.  The Impact of Technology: Large Scale Examples.  In:
         Arctic and Alpine Environments.  Ives, J. D., ed. London: Methuen,
         1974.

32.  Owens, I. F.  Morphological Characteristics of Alpine Mudflows in the
         Nigel Pass Area. In: Mountain Geomorphology. 0. Slaymaker and H. J.
         McPherson, eds. Vancouver: Tantalus Research Ltd., 1972.

33.  Perla, B. I. and M. Martinelli, Jr,  Avalanche Handbook.  USDA Forest
         Service. Agriculture Handbook 489, 1976.  238 pp.

34.  Schaerer, P. A.  Terrain and Vegetation of Snow Avalanche Sites at Rogers
         Pass, British Columbia.  In: Mountain Geomorphology.  0.  Slaymaker
         and H. J. McPherson, eds. Vancouver: Tantalus Research Ltd., 1972.

35.  Shiotani, M. and H. Arai.  On the Vertical Distribution of Blowing Snow.
         In: The Physics of Snow and Ice. pp.  1075-1083,  1967.

36.  Swan, L. W.  Some Environmental Conditions Influencing Life at High Alti-
         tudes. Ecology 33:109-111,  1952.

37.  Swan, L. W.  Aeolian Zone. Science 140:77-78, 1963.

38.  Swan, L. W.  Alpine and Aeolian Regions of the World. In: Arctic and Alpine
         Environments.  H. E. Wright, Jr. and W. H. Osburn, eds. Indiana
         University Press, 1967.

59.  Tabler, R. D.  Predicting  Profiles of Snowdrifts in  Topographic Catchments.
         West. Snow Conference  Proc. 43:87-97, 1975.

40.  Tabler, R. D.  Evaporation Losses of Windblown Snow, and  the  Potential  for
         Recovery. West. Snow Conference  Proc. 41:75-79,  1973.

41.  Tabler, R. D. and  R. A. Schmidt.  Weather Conditions that Determine Snow
         Transport Distances at a Site  in Wyoming.. In: The Role of Snow  and  Ice
         in Hydrology,  pp. 118-126,  1973.

42.  Wangersky,  P. J.   The Organic  Chemistry  of Sea  Water. Am. Scientist.  53:
         358-374,  1965.
                                      5-38

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43,
44,
45,
46.
Whittaker,.Robert A.  Communities and Ecosystems. Macmillan Publishing
    Co., Inc. 1970.  385 pp.


Williams, G. P. and L. W. Gold.  The Use of Dust to Advance the. Breakup
    of Ice on Lakes and Rivers.  East. Snow Conference Proc. 1963. pp 31-60.
    (Also available as: Tech. Paper 165. Division of Building Res. Nat. Res.
    Council of Canada, Ottawa.)

Wilson, A. T.  Organic Nitrogen in New Zealand Snows. Nature 183:318-319
    1959.


Wilson, A. T.  Surface on the Ocean as a Source of Airborne Nitrogenous
    Material and Other Plant Nutrients. Nature. 184:99-101, 1959.
                                     5-39

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                                   CHAPTER 6
                                    TUNDRA
6.1  OVERVIEW
     Tundra, which in Russian-Finnish usage referred to the treeless zone of
northern Eurasia, especially Finland, was subsequently applied to its counter-
part in the Arctic and Alpine North America.  The Soil Conservation Society of
America defines tundra as "the treeless land in arctic and alpine regions;
varying from bare area to various types of vegetation consisting of grasses,
sedges, forbs, dwarf shrubs, mosses and lichens."  It is generally considered
that the tundra vegetational life-form represents the integrated effect of
primary climatic parameters.  From a practical point of view, tundra should be
defined by combinations of physiognomy and environment.    In this definition
the tundras are the grassless arctic plains, the vegetation of which may form
varied and often complex patterns of dominance by dwarf-shrubs, sedges and
grasses, mosses, and lichens.  The tundras of North America and Eurasia are
quite similar; their principal herbivorous mammals include the musk ox, cari-
bou, arctic hare, and lemming.  Longspurs, plovers, snow bunting, and horned
larks are characteristic birds; reptiles and amphibians are few or absent, as
in alpine grasslands.  In many tundras the deeper layers of soil are perma-
nently frozen, and only the surface soil is thawed and becomes biologically
active during the summer.  The semi-arid areas of the Arctic are generally
considered as part of the tundra.
     Dagon  stated that the variety of definitions and the resultant misunder-
standing accompanying the application of the term tundra have been far too
numerous.  He lists numerous definitions for the term and points out that there
is a great deal of ambiguousness associated with the use of the word tundra.
For the purpose of this report, the term tundra defined on the basis of its
physiognomy and environment is more appropriate.
                                      6-1

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6.1.1  Geographical Distribution
     Tundra lies between the northern limit of trees and the area of perpetual
ice and snow in the far north, or above timber line in high mountains.  In
North America, it forms a broad band completely across the continent, and it
also occupies the narrow low coastal area around most of the periphery of
Greenland.  It occurs on mountains as far south as Mexico if their elevation
is sufficient to produce a timber line.  Thus it is limited in its northern
or upward extent by ice and bounded on the southern or lower margin by boreal
or subalpine conifer forest.  The tundra is essentially an arctic grassland.
It is the cold polar area beyond the treeline in the northern circumpolar lands
of North America and Eurasia.  The tundra vegetation and environment continues
southward along mountain alignments in western North America and Siberia.  The
term tundra is further subdivided into Arctic and alpine.  Alpine and Arctic
tundra are discussed in detail in the vegetation section (6.1.3) of this
chapter.

6.1.2  Environment
     Low temperatures and a short growing season (about 60 days) are the main
characteristics of tundra environment.  The ground remains frozen except for
the upper few inches during the growing season.  The dominant factors which
shape the tundra environment   are:  the character of the solar energy input,
the nature of the immediate and adjacent surfaces, weather systems, and topog-
raphy.  The annual and daily cycling of solar energy received on a unit surface
in the arctic tundra is quite different from that experienced at lower lati-
tudes.  In general, tundra summer is limited to the three months of June, July,
and August; winter occupies the remainder of the year.  Daily air temperatures
are generally below 10°C in summer but may rise occasionally to 20°C during
brief sunny spells.  The mean daily range of temperature in summer is about 6°C.
The coldest months are December through April; the mean daily temperature in
tundra areas in February is about -30°C and the mean daily range varies from
about 10 degrees in continental areas to about 6 degrees elsewhere.  Extreme
low temperatures of about -50°C occur, in the exposed tundra.  Topography and
vegetative cover are probably important factors in the temperature regimes of
tundra environments.
                                      6-2

-------
     The tundra is often termed a "polar desert."  Annual precipitation in this
area is indeed light.  However, thawing of the active layer each summer causes
vast tracts of wet lands.  By and large the annual rainfall is equal to the
water equivalent of snowfall.  Normally there is adequate precipitation for
vegetative growth; deficiencies in moisture supply become critical only briefly
during the occasional summer droughts.  Droughts have been sufficiently severe
to permit serious tundra fires to occur.  Low evapotranspiration rates and the
presence of permafrost result in a large percentage of the precipitation run-
ning off into the tundra's poorly developed streams and stagnant ponds.  It is
difficult to overemphasize the importance of the snow cover on the tundra
during the eight to ten months of the year.  Snow is essential to the survival
of many plants and animals.  In addition to being a source of water, snow acts
as a protective blanket to many plants and animals.
     Wind plays a dominant role in the tundra.  Strong winds are usually the
most critical.
     Both plant and animal life exist precariously, mainly by taking refuge in
a particular microclimate environment and thereby escaping the rigors of gen-
eral climate.  The microclimatic environment is  in a delicate state of balance,
and alteration of this balance either naturally, or unnaturally, such as through
vegetative modification, may have serious consequences.   For example, the alter-
ation of albedo can upset the energy balance at  the soil  surface and result in
thermokarst conditions.  The removal of tall vegetation will result in increased
winds and shallower  snow cover which may also significantly change  the thermal
regime near and in the ground.

6.1.3  Vegetation
     Tundra vegetation  is  low, dwarfed, and  often matlike, and  includes a  high
proportion of grasses and  sedges.  Even the  woody plants, including the willows
and birches,  are  usually prostrate.   The herbs  are mostly perennial and of a
rosette  type, producing  relatively  large flowers,  often  with  conspicuous  colors.
Mosses  and  lichens may  grow anywhere  and  in  favorable  habitats  form a thick
 carpet  with  the  low  herbs.   The  number of  species  is small compared with  floras
 of temperate  climates;  and, even within the  tundra,  the  number  decreases  north-
 ward.   Most  of the  genera  and many of the  species  are  to be  found  throughout
 the Northern Hemisphere wherever tundra occurs.

                                       6-3

-------
      The  uniformity of the  flora is  undoubtedly  related  to  the peculiarities
 of environment.   The growing  season  is  short  and its  temperatures  are relatively
 low.   Permafrost  in the ground  and its  depth  of  thawing  in  summer  is of great
 importance  as  is  the extreme  instability of soil,  related to  the frost action.
 Light is  continuous throughout  the growing season  in  the arctic tundra, and is
 intense and high  in the ultraviolet  rays in alpine tundra.  Local  marked dif-
 ferences  in vegetation are  commonly  related to minor  variations in topography
 and differences they"produce  in drainage and  retention of snow.
      The  tundra ecosystem can be divided into (1)  Arctic Tundra, and (2) Alpine
 Tundra.
     6.1.3.1  Arctic Tundra--
     The circura-artic tundra can be regarded as comprising a simple formation-
type composed of Eurasian and North American formations.  Even within the same
formation, however, in spite of superficial similarities, considerable con-
trasts are evident in both life-form and general appearance.  Although flower-
ing herbaceous plants, particularly grasses and sedges, are almost universal
throughout all communities, dwarf shrubs, mosses and lichens compete successfully
in most places.  Furthermore, there is a great contrast between the almost
closed-cover tundra communities near the forest margins and the scattered,
sparse communities on almost bare ground in the most inhospitable parts of
north Greenland and Spitzbergen.-  It is clear also that not all the extensive
tundra communities are to be regarded as true climatic climax.
     In the climatically more favored areas of the tundra, the true climatic
climax communities are probably those in which grasses and sedges are dominant
with a substantial understory of lichens and mosses.  Communities of this
nature are found on undulating areas with a considerable range of slope, aspect
and lithology.  The dominants in the American formation are various species of
sedge (Carex spp.), cotton grass (Eriophorum spp.), and woodrush (Luzula spp.),
along with species of many genera of grasses such as the bents (Agrostis spp.),
foxtail grasses (Alopecurus spp.), fescues (Festuca spp.), and timothy (Phleum
spp.) which are also of common occurrence in middle latitudes.  The commonest
associated lichens belong to the genera Stereocaulon, Alectoria, Cetraria, and
Cladonia, while mosses of the genus Polytrichum are most frequently encountered.
Along with these are a great variety of plants with showy flowers belonging to

                                      6-4

-------
genera which are also distributed throughout the woodlands and meadows of mid-
dle latitudes such as the anemones  (Anemone spp.)» marsh marigolds  (Caltha spp.),
buttercups  (Ranunculus spp.), avens (Beumspp.), cinquefoils  (Potentilla spp.),
campions  (Lychnis spp.), catchflies (Silene sp>p,)j> a*«d primroses  (Primula spp.)'
These are accompanied by flowers which are more typically associated with high
latitudes and high altitudes such as the mountain avens (Dryas spp.)> saxifrages
(Saxifraga spp.), and gentians (Gentiana spp.)-  A varied cover of predominantly
herbaceous vegetation thus forms an almost complete turf over the ground.
     Over very large areas, however, the grasses and sedges are much less im-
portant and dominance is assumed by foliose lichens and mosses, particularly
the former.  This cover of cryptogams, if ungrazed, may be anything from four
to ten inches high and, in the more southern parts of the tundra, may be almost
continuous.  Further north communities similar to the two already described
are much more discontinuous and a great deal of bare ground is found between
individual plants or plant aggregates.  This type of vegetation has been most
vividly described in the Taimyr Peninsula by Middendorf.  Here, in many places,
the ground is only about half covered by plants, permafrost is not more than
three inches beneath the surface in many places, and a varied patchwork of com-
munities is found.  In places mosses (Polytrichum spp.) dominate; elsewhere
sedges or lichens (Cladonia spp.).  Throughout all these communities, however,
there is an admixture of flowering plants, creeping shrubs such as the dwarf
willow (Salix lapponum) and xerophytic, heath-like shrubs such as the crowberry
(Empetrum nigrum).  Even at the height of summer, when many species are in
flower, these communities give the landscape a drab or yellowish aspect.  This
is partly due to the colors of the mosses and lichens, but partly to the fact
that many of the grasses and other flowering plants, as an adaptation to reduce
transpiration,  retain the dead remains of last year's growth.  Ultimately,
around the very fringes of ice caps and on some exposed sea coasts, the vegeta-
tion dwindles and only an occasional tussock of sedge or cushion-shaped plant
is to be found.
     Dwarf shrubs occur sporadically throughout the communities already de-
scribed but locally shrubs become dominant.  Usually, however, the shrubs, which
are subordinate elements in predominantly herbaceous communities, belong to
different species from those which form arctic heath and arctic scrub communi-
ties.  In arctic heath the species are low growing, the Canadian communities

                                      6-5

-------
being dominated by small shrubs such as the arctic bell-heather (Cassiope
tetragona), crowberry (Empetrum nigrum), and alpine bearberry (Arctostaphylos
alpina).   In arctic scrub, on the other hand, quite a busy growth is attained
which may reach a height of several feet.  It is dominated by broad-leaved
shrubs such as the narrow-leaved Labrador tea (Ledum palustre), Lapland rose-
bay (Rhododendron lapponicum), alder (Alnus sinuata), scrub birch (Betula
glandulosa), and numerous species of willow (Salix spp.)-  Many communities are
found containing both these types of shrub, however.
     Usually the arctic shrub communities are found on sheltered slopes, par-
ticularly where the soil thaws unusually deeply in summer and where it is rich
and moist.  It seems probable that they constitute a zone of ecotone between
the more typical tundra communities on the interfluves and the outliers of the
forest on the lowest slopes.  There is some evidence that, where trees are
nearby, invasion takes place sporadically in a series of favorable years only
to be rebuffed in a subsequent unfavorable period.
     Finally, there is another suite of communities, covering extensive areas
in the tundra, which cannot be regarded as climatic climax; these are the tundra
bogs and moors.  They are very similar in appearance and species-content to the
bogs or "muskegs" which occupy ill-drained localities within the general area of
the boreal forest.  Very often in both Europe and America, they are dominated
by cotton grass (Briophorum vaginaturn) along with many other species of sedge
and some grasses.  Usually also various species of moss, particularly bog moss
(Sphagnum spp.), compose a sub-dominant understory.  The surface of these bogs
is usually "tussocky" and the tussocks of cotton grass and moss are frequently
invaded by dwarf willows.  Indeed, at an advanced stage of development, when
the peat has achieved considerable thickness, the vegetation may become quite
luxuriant, similar in many ways to that of the better-drained arctic heaths.
These "heath moors,"-as they have been called, ensure a copious supply of
available moisture throughout the growing season and, at the same time, thaw
out to a sufficient depth to accommodate the rooting systems of shrubs.  Apart
from the heathy shrubs, some broad-leaved, deciduous shrubs also invade this
kind of surface.  In Canada, for instance, several species of birch (Betula)
and many of willow (Salix) are of frequent occurrence.  It seems likely that
soil conditions here would be quite suitable for those species of tree which
regularly invade drying-out muskegs within the boreal forest areas—species

                                      6-6

-------
like the black spruce (Picea mariana) and the Canadian larch or tamarack
(Larix laricina).  Indeed, if these species of tree were able to advance un-
interruptedly, along a solid front, across bogs in the southern parts of the
Canadian tundra, they would probably demonstrate their ability to survive the
climatic rigors there.  Individual tree seeds which have been carried by the
wind have been observed to germinate here quite satisfactorily but have sub-
sequently been incapable of surviving the desiccating blizzards of winter.
Isolated saplings cannot survive but if they had the partial shelter of nearby
parent trees, they would probably be able to do so; the forest would thus en-
croach gradually.  This cannot take place, however, since the deep peat areas
are separated from the forest edge by less favorable types of terrain.
     The intense physiological drought of the winter months should be stressed
as a limiting factor in the tundra far more than mere low temperatures.  If the
air always remained still, many of the northern trees could probably withstand
even lower temperatures than they do.  Strong winds, even at very low tempera-
tures, are able to abstract water quite quickly from living plant tissues; if
this proceeds beyond a critical point, death ensues, since no replacements are
obtainable from the completely frozen soil.  The plants of the tundra minimize
the danger of this in several distinct ways.  On the most exposed areas, all
are very low-growing; many die down completely in winter and survive as under-
ground rhizomes, root stocks, corms and bulbs.  Those herbaceous plants which
do maintain organs above ground level in winter do so in the form of very tight-
packed rosettes or cushions; many species of saxifrage do this very success-
fully.  As a group, the lichens are noted for their ability to survive in an
almost desiccated state for protracted periods.  It is understandable therefore
that they should form such an important element in the vegetation of many of
the bleakest and baldest arctic interfluves.  The arctic shrubs are also low-
growing except in the most sheltered valleys.  They have adopted different de-
vices to prevent over-rapid transpiration.  Many of the broad-leaved ones are
deciduous (Salix, Alnus, Betula) while the heaths all have the characteristic
small leaves with rolled-back margins.
     The shortness of the growing season also imposes great restrictions on
plant growth.  It is mainly because of this factor that the flowering herbs of
the tundra fall into two classes; there are those which flower at the beginning
of the growing season and those which flower towards the end of it.  The

                                      6-7

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early-flowering species are typically plants with substantial underground food-
storage organs; they use the stored energy from the preceding year to flower
and produce seed and then utilize the remainder of the growing season to build
up food for the following year.  The late-flowering species use the first part
of the season to build up a store of energy and then use most of it in produc-
ing seed; they then pass the winter as inconspicuous underground organs or,  if
annuals, survive merely as seeds.
     The factors of winter frost, winter winds, short growing season and perma-
frost are responsible, collectively or separately, for precluding trees from
the tundra.  Because of contrasts in relief and aspect the relative importance
of these different factors varies greatly and an evaluation of the exact reasons
for the absence of trees in a particular place is usually obscure.  However,
the complex inter-digitation of the southern edge of the tundra with the north-
ern edge of the forest indicates that, generally speaking, wind force along
with shallowness of unfrozen soil are the operative factors in the southern
parts of the tundra.  Here, forests occupy the valleys while the interfluves
are tundra.  Wind force is obviously important on these interfluves but,
whether forest would extend further up the slopes if the depth of the thawed
layer in summer were deeper is not clear.  The existence of permafrost, as
such, does not preclude forest since vast areas of the northernmost parts of
the boreal forest are underlain by it both in Siberia and Canada; northern
species such as the Dahurian larch (Larix dahurica) and Siberian dwarf-pine
(Pinus pumila) are adapted to this soil condition in that they develop a root
system which is entirely spreading with no tap root whatsoever.  In the north-
ern archipelago of Canada and the arctic peninsulas and islands of the U.S.S.R.,
as well as in the Spitzbergen and the north of Greenland, it appears probable
that trees cannot possibly regenerate regardless of wind and soil depth.  Though
increase in the length of the season with continuous daylight does, to a cer-
tain extent, compensate for increased latitude, it is doubtful if the growing
season here is sufficiently long for trees.  Even if trees could survive the
winter, it is very doubtful if they would be able, to flower and produce seed.
In these fringing areas, so near to perennial ice, there is no recognizable
frost-free season.  Everywhere in the tundra the mean length of the frost-free
season is  less than fifty days but here, in spite of continuous daylight, air
frosts occur frequently in all the summer months.  Returning to the southern
                                      6-8

-------
fringes of the'tundra, however, it is doubtful whether the length of, the frost-
free season has any bearing on the position of the limits of the, forest.  Prob-
ably the length of the frost-free season is sufficient here to permit forest
regeneration but,wind speed in winter and extreme shallowness of soil in summer
prevent the spread of trees.                                      •
     Fluctuations in the position of the northern edge of the boreal forest
have occurred during the past few millennia.  Locally, in European Russia, a
distinctive fringing zone of ."tundra moor" has been described.  Here, hummocks
of bog moss (Sphagnum spp.) peat, each several yards in diameter, with narrow,
marshy channels between them, cover the. landscape.  The mosses on the hummocks
;are often still growing but the cores of the hummocks are permanently frozen.
This permanently frozen peat contains the stumps of both birches and conifers,
many of which are in position of growth.  Clearly these areas were forested
not so very long ago but the reason for forest recession is not altogether
clear.  Possibly a deterioration in climate was responsible; possibly, the
activities of reindeer herders along the former forest margins caused the sap-
lings to be grazed off and thus prevented regeneration; possibly both climatic
change and human activity played some part in the changes that occurred.
     Although the flora of the tundra is fairly well known, its communities and
their successional relationships have not been sufficiently studied.  In con-
trast with temperate vegetation, many species may occur in any type of habitat,
and several that appear to be climax may also be pioneers in the newest of
habitats.  Even climax is not agreed upon, possibly because observations have
been made in widely separated areas.  Variations do exist, as has been shown
for eastern Canada.  It is also possible that the climax criteria used for
temperate climates are not always applicable in the arctic.  Interpreted in
terms of Greenland vegetation, Cassiope heath appears to be climax, and a Sedge-
Dryas dominated community, of equal extent but on drier sites, is preclimax.
Two subclimaxes are frequent.  Any habitat with sufficient moisture, whether it
be pond margin, seepage area, or boggy ground, eventually is covered with a
thick moss mat supporting several herbs, of which cotton grass (Eriophorum spp.)
is most conspicuous.  Xerarch succession on rock exposures eventually results
in a lichen-moss mat, which may continue almost indefinitely.  ,
     Important climax dominants are Cassiope tetragona, one or more species of
Vaccinium, Archtostaphyloas alpina, Empetrum nigrum, Andromeda polifolia,

                                      6-9

-------
 Ledum palustre, Phododendron  lapponicum, and species of Betula and Salix.
 These and other species occur in varying combinations and degrees of importance.
     Practically all habitats support some of the many species of Carex, of
 which the commonest include C. capillaris, C. nardina, and C. rupestris.  The
 preclimax sedge community  invariably includes Elyna bellardi in abundance.
 Some grow mats, some are in clumps, but all are dwarfed.  The same can be said
 for the grasses, which, although relatively abundant and widespread, are re-
 stricted to a few genera,  of which Festuca and Poa are especially well repre-
 sented.  Many of the conspicuous herbs previously mentioned are included in the
 numerous species of one of the following genera:  Saxifraga, Potentilia, Ranun-
 culus, Draba, Cerastium, Selene, Lychnis, Stellaria, and Pedicularis.  Conspic-
 uous and widespread species typical of tundra are Oxyria digyna, Papaver spp.,
 Dryas octopetala, and Epilobium latifolium.

     6.1.3.2  Alpine Tundra-
     Mountains high enough to have timber line support tundra, whose upward
 extent is limited by the snow line.  In the east, as a consequence, tundra is
 found only on a few high peaks in New England.  Farther south, the Appalachians
 are not of sufficient height to support tundra.  That on Mt. Washington is
 representative of the type and is essentially similar to the not far distant
 arctic vegetation.
     Alpine tundra in the  western mountains mostly lies far to the south of the
 arctic and, consequently,  is found at high altitudes only.  In the Canadian
mountains, it is found as  low as 6,000 feet, but southward its lowest elevation
 steadily increases some 360 feet per degree of latitude to 30° north latitude,
 and then declines very gradually to the equator.  In the central Rocky Moun-
 tains, tundra is well developed between 11,000 and 14,000 feet.  In the Sierra
 Nevada, where the snow line is lower, tundra lies mostly between 10,500 and
 13,000 feet.  In general,  it is lower on coastal than interior ranges and on
 the wetter sides of mountains.
     When climate changed  arid terminated the glacial period, vegetation similar
 to modern tundra must have followed the ice as it receded northward.  This left
 only these high peaks and  ridges where tundra could survive as relicts.  The
 relict vegetation obviously belongs to the Tundra Formation because of the
                                     6-10

-------
growth form and the duplication of characteristic genera as well as many species.
The greater importance of grasses and the presence of numerous endemics in the
western mountains suggest that these alpine tundras might be classed as asso-
ciations of the Tundra Formation.
           23
     Webber   compared the composition and production of the vegetation at
Point Barrow (Alaska) and Niwot Ridge (Colorado).  The apline tundra vegetation
on Niwot Ridge is twice as productive as arctic tundra (Point Barrow) but only
because of higher incoming solar radiation (Table 6-1).

6.1.4  Animal Life
     The animal life in the tundra biome consists of caribou, musk ox, arctic
hare, lemming, longspurs, plovers, snow bunting, and horned larks.  There are
very few, if any, reptiles and amphibians in the tundra environment.  Though
vertebrate animals inhabiting arctic and alpine tundra environments are faced
with many similar environmental problems, such as low temperatures and scarce
cover, important differences between arctic arid alpine environments exist in
day-length and solar radiation patterns, topography and moisture, and other
physical factors of the environment.  These differences in environment are
reflected in the distribution of animal life in the arctic and alpine tundra.
The differences occurring between arctic and alpine faunas are due not only
to real differences in the habitats available as a result of physical environ-
mental differences, but also to the much patchier "island" distribution of
alpine habitats in contrast to those of the more continuous circumpolar arctic.

6.1.5  Soils
     Low temperatures and, in most places, the presence of an impermeable
perennially frozen substratum, are the dominant factors affecting the develop-
ment of soils of the arctic and alpine tundra,,  The cold environment modifies
soil-forming processes to such an extent that it overshadows, and may even
completely obliterate, the effects of relief and time on soil characteristics.
Tundra soils are wet nearly continuously during the thaw period.  In general,
the tundra soils can be divided into two groups:  (1) poorly drained soils that
are usually saturated, and (2) well drained soils.
                                     6-11

-------
   Table 6-1.  Comparison of arctic and alpine environments  and vegetation.
Component
Latitude
Altitude (meters)
Average July solar radiation
(cal/cm2/min)
Maximum photoperiod
Maximum air temperature (°C)
Maximum soil temperature (°C)
Annual mean precipitation (mm)
Permafrost
Average length of growing period
(days)
Number of common vascular plants
Average area! vascular production
Arctic tundra
71°N
7
0.30
84 days
3.9
2.5
107
Universal
55
40
100
Alpine tundra
40°N
3749
0.56
15 hours
8.5
13.3
1021
Sporadic
90
100
200
  (grams/m2/yr)
Average ratio of above- to
  below-ground biomass
Average area! net photosynthetic
  efficiency (percent)
1:8

0.5
1:12

 0.5
                                    6-12

-------
     Poorly drained mineral soils of the tundra all have essentially the same
sequence of horizons.  They consist, typically, of a mat of organic materials
at the surface; a grey, greyish brown, or bluish mineral layer which may be
mottled in whole or in part with colors ranging from olive or olive brown to
reddish brown and which may contain patches or streaks of organic matter; and
a grey perennially frozen layer which may have patches of organic matter in its
upper part.  The description in Table 6-2 of a soil in northwestern Alaska
is representative.  (Color and Munsell color notations are for moist conditions
unless otherwise noted.  Depths are measured up and down from the surface of
the mineral soil.)
     Well drained soils occur throughout tundra areas, but are of relatively
small total extent except in arid regions near the northern limits of vegeta-
tion.  South of those regions they occur almost exclusively in stony, gravelly,
or coarse sandy materials on steep slopes, high narrow ridges, escarpment edges,
stabilized dunes and beach ridges, and elevated portions of flood plains.  The
combination of coarse-grained materials and exceptionally good surface drainage
is, with rare exceptions, an essential condition for their existence.  Either
bedrock or dry permafrost underlies these soils; where they are developed in
thick unconsolidated materials, solid permafrost may occur at greater depths.
     The well drained soils differ from most soils of the tundra in that excess
moisture is able to escape..  As a resultj oxidizing rather than reducing
processes are dominant, and soluble products of weathering are redistributed or
removed from the soil.  The rate of weathering, decomposition or organic mate-
rials, and movement of materials (that is, the intensity of soil development)
depend on temperature and the amount of moisture available.  In the cold and
relatively arid arctic environment, these processes go on at a much slower rate
than in forested areas to the south.  As a consequence, the soils that are
formed may have the same sequence of horizons as in comparable well drained
soils of taiga areas, but have much thinner hcirizons.  In nearly all cases,
physical and chemical properties of the soils reflect those of the parent
materials.
     The well drained soils vary in the kinds of horizons that develop, and in
the thickness and degree of development of the horizons.  The soil described in
                                    18
Table 6-3, from southwestern Alaska,   is representative of the most extensive
of these soils.  Colors are for moist conditions.

                                     6-13

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6-15

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     The principal horizons in this soil are the dark upper horizon and the
yellower subsoil horizon, which grades into the shaly parent material.   The
soil is acid and low in exchangeable bases throughout.  Chemical analyses in-
dicate the A12 horizon is slightly higher in free iron than both the All hori-
zon above it and the B horizon below it.  A similar distribution of iron has
been noted in other soils of this kind,9'  indicating that there is a tendency
in these soils toward the development of an iron-rich subsurface horizon.  The
process of podsolization, in which iron, aluminum, and organic carbon are moved
in solution from the upper mineral horizon and reprecipitated in a lower hori-
zon, is common in soils of cool, moist, forested regions.  In a few places in
tundra regions just north of the treeline where large quantities of water move
through coarse-grained soils, as in micro-depressions in uplands or protected
areas where snow accumulates, the process is also intensive.  There the soils
have bleached upper horizons over thin horizons of iron accumulation.   Soils
of this kind are more common in tundra areas immediately above treeline in sub-
arctic regions.
     Soils developed in materials derived from basic rocks,  such as basalt,
limestone, and calcareous shales, are similar in appearance  to the acid soils
described above, but pH values and base  saturation are high.  In some places,
calcium carbonate has accumulated in the  lower part of the  soil.
     With increasing distance from the  treeline, the  amount  of organic matter
added to the soil decreases and, because  of  lower temperatures and lower pre-
cipitation, chemical and biological processes such as oxidation and huraifica-
tion proceed at a slower rate.  Well drained soils in the  colder tundra  areas
may have only very  thin  or no dark upper horizons and thin brown B horizons.
In the far north, where precipitation rates  are very  low and the vegetative
cover is sparse, well drained soils that have no discernible horizon develop-
ment are dominant.  Other  soils with no horizon development are the young  sandy
soils of active dunes bordering some major  rivers    and  the very gravelly  soils
of  flood plains,  low terraces,  and  steep colluvial slopes.

6.2   NATURAL  PERTURBATIONS
6.2.1   Fire
      Little  is known  of the  role  of fires in tundra  ecosystem,  yet they do oc-
cur.   Fire removes  most of the insulating layer of live vegetation and litter,
                                      6-16

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 damages or destroys the peat, and greatly changes the albedo of the surface.
 The result is a potential rapid increase in thermal erosion with increased
 runoff.  A general account of vegetation recovery following a major fire in
 the tundra is given by Cody.6  Nine years after the fire, grasses, sedges,
 and forbs recovered fairly well but lichens and mosses showed little recovery.
 With lichens playing an important role in the diet of caribou and reindeer, it
 is evident that burned areas will be lost to grazing for many years.

 6.2.2  Drought
      The tundra ecosystem is subjected to frequent droughts.   Droughts have
 been sufficiently severe to permit serious tundra fires  to occur.   Any long
 term drought  patterns  are expected to affect the structure and productivity of
 an ecosystem.

 6.2.3   Grazing

     Overgrazing  by the  caribou and reindeer is  quite  common  in the tundra eco-
 system.  These animals  lead to  selective  removal of  lichens through grazing.
 Vegetation composition and  density are affected  considerably.   In  the  tundra,
 intense  grazing activities  tend  to result in more woody  and hardy  shrubs.

 6.3  MAN-MADE  PERTURBATIONS
     Disturbances to tundra vegetation due to activities  of man derive from
 both winter and summer roads, pipelines,  seismic  lines, drill  sites, crude oil
 spillage, tundra fires,  living sites,  and waste disposal.
     The discovery of oil on July  18,  1968 near Prudhoe Bay on Alaska's arctic
 coastal plain  (the North Slope) and subsequent flurry of  oil and gas explora-
 tion and development have already had a pronounced impact on the tundra environ-
ment over a large area.  In addition to the direct effects of oil development
on the North Slope, there will be subsidiary effects in other parts of arctic
tundra.  Klein   described the impact of oil development in Alaska.  Detailed
descriptions of human impact of tundra are also given by Watson, Bayfield, and
Moyes22 and by Walker.21
     Bliss and Wein  examined 25 seismic trail sites in the Low Arctic.  By
using control plots in adjacent vegetation, they were able to characterize

                                     6-17

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the disturbance (Table 6-4).   They concluded that wherever viable  roots  and
rhizomes of shrubs, sedges, or grasses remained in the disturbed substrate,  a
30 to 50 percent recovery in natural plant cover will occur in 3 to 5 years.
Subsidence will occur in areas of high ice content.  To date,  there is little
evidence that immediate reseeding can prevent ground ice melt  and subsidence.
Less detrimental effects from surface rutting and scraping were measured in
the High Arctic.

         Table 6-4.  Change in conditions caused by seismic lines and
                     winter roads with paired control plots in 1970
                      (adapted from Bliss and Wein3).


Community type
Shrub-sedge-heath
hummock
Hummocks
Wet sedge meadows
Spruce-alder
Upland winter road

Year
disturbed
1965

1967
1969
1969
1969
Increased
active
layer (cm)
26

8
1
10
7
Increased
bare soil
(percent)
63

25
5
98
100
Decreased
plant cover
(percent)
65

34
7
169
99
      Revegetative studies  are  underway in several  locations.   Bliss  and  Wein
 reported trails with 16 species seeded in 1970.  At the  rate  of 20 kg  per  ha,
 Festuca rubra,  Poa pratensis,  Poa compressa,  and Phieuro  alpinum have the best
 results in establishment and winter survival  on  mineral  and peat soils.
 Alopecurus pratensis grew better on mineral soil.   Fertilizer treatment  with
 100 kg per ha actual N and P205 doubled culm height over nitrogen fertilizer
 alone.  The authors recommend  sowing seeds with  snowmelt in the spring or  be-
 fore snowfall in the autumn.
      Experiments with oil spillage on terrestrial  vegetation are few.   Bliss
 and Wein3 reported that oil poured directly on the foliage killed those leaves
 in contact with the oil in a few days.  Some regrowth was evident in late  sum-
 mer from June treatment, but none from July treatment.  Greater damage was

                                      6-18

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evident in wet sedge and cotton grass tussock communities than in shrub com-
munities.  Microbial activity in the soil may increase tenfold, but the impli-
cations of this activity for the nutritional status of the community are not
yet established.  McCown and Brown   applied oil to the soil surface (avoiding
foliage contact) and observed little immediate damage.  Shoot growth response
of Dupontia through the summer was not suppressed, except at the heaviest
treatment of 12 liters per square meter, but root biomass seems to have been
reduced.  Observations in the second growing season showed reductions in stems
per plot and in growth per stem.  Carex aquatilis and Eriopjiorum angustifolium
seemed less sensitive than Dupontia.  To the extent that effects of oil spillage
are manifest through limited root growth, vegetative response may not be appar-
ent in aboveground tissue for one or more years.
     A study of the effect of an air cushion vehicle (SK-5) on tundra vegeta-
tion '   was measured quantitatively.  The results clearly show that the exhaust
air blows the litter and loosens organic matter, but principal damage was
caused by dragging of the vehicle skirt on the surface.  Although such effects
change the albedo, the direct visible damage by the air cushion vehicle after
25 passes was often less than that of a single weasel pass.
     In general, any disturbance which eliminates or greatly reduces plant
growth, vegetative cover, or the organic litter or peat layer by any cause will
increase thaw depth as a result of increased solar heat flux.   Greater under-
standing of response to disturbance in different landscape units is needed for
regulating land use and for providing design criteria for land vehicles.

6.4  EFFECTS OF CLEANUP PROCEDURES ON TUNDRA
     The concept of the fragility of the tundra has probably been too uncriti-
cally accepted as a convenient shibboleth by conservationists, in order to
totally exclude resource development from the tundra.  Undoubtedly, wet tundra,
which may contain frozen water up to five or six times in excess of dry soil
weight within the upper 40 meters, is fragile.   This problem is rare in alpine
tundra.  Degree of disturbance potential could be mapped on a regional scale
according to water content, grain size and vegetation physiognomy.  However,
there are other reasons behind the concept of the fragile tundra that relate
specifically to plant adaptation and community structure and primary productivity
                                     6-19

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considered both as daily rates and total season's production.  Bliss" has argued
that the very limited number of plant species in the Arctic is a real indica-
tion of fragility of the ecosystem since adverse impact on a very few species
may damage the whole:  the potential for recovery may be proportional to plant
                              Q
community variability.  Dunbar  emphasizes that a proper consideration of
"fragility" hinges on one's definition of stability.  A steady-state situation,
which may pertain to. arctic lakes and perhaps also to tundra vegetation, is
vulnerable to excessive disturbance since the system cannot adapt.  Another
type of stability is represented by a system which can absorb disturbance and
return to its previous state.  Tundra animal populations undergo drastic fluc-
tuations but recover, perhaps as a result of their ability to draw on outside
areas.  Dunbar concludes that simplicity of an ecosystem, coupled with slow
growth rates, leads to vulnerability to disturbance which can be tolerated only
if the spatial scale is large (as in the Arctic) and the time scale is suffi-
ciently long.

     (0-1)  Natural Rehabilitation
     Natural rehabilitation after a contamination of land in the tundra environ-
ment is suggested as a high priority treatment for cleanup.  Ecosystem recovery
tends to follow ecologically normal and predictable successional trends, i.e.,
patterns following daaage from most postulated contaminants are sinilar to those
following fire, logging, or shipping of top soil and other natural catastrophic
              2
events.  Bliss  reported that nine years after a fire, grasses, sedges and forbs
recovered fairly well but lichens and mosses showed little recovery.  It is as-
sumed that in case of a contamination of an area in the tundra environment,
ecological recovery will follow a different pattern.  The area would still have
its litter and organic cover and will not be subjected to a deeper thaw during
summer.  The vegetation in a tundra ecosystem has a higher below-ground biomass
production and would provide better soil binding against water erosion during
the summer thaws.
     (1-1)  Chemical Stabilization
     The cleanup by chemical stabilization is to reduce the infiltration rate
and thereby reduce the mobility of contaminants into the vadose zone.  The
chemical stabilization will not be practical in the tundra environment.
                                     6-20

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      (.1-2)   Clear-cutting  Vegetation ,
      Removal of woody shrubs  by clearcutting  can  be used  as  a possible technique
 for cleanup.   Along  the Alaska pipeline  route,  the tundra vegetation was removed
 by clearcutting of woody  plant species and  shrubs.  In  arctic and  alpine envi-
 ronments  the plants  are small,  close to  the ground, and often widely separated
 by bare soil or rock.  Unlike the  situation within a  forest, the modification
 of microclimate by vegetation is minimal and  the  physical environment dominates
 the vegetation.   In  such  open and  windy  places, the effects  of microenvironment
 are pronounced.   Even a few centimeters  difference in microtopography makes a
 marked difference in soil temperature, depth  of thaw, wind effects, snow drift-
 ing and resultant protection  to vegetation.   The  microtopographic  effects may
 be caused by a rock,  a soil polygon rim  or  by another plant  itself.  The re-
 moval of  larger vegetation plants  would  result  in an  uneven  distribution of
 snow and  thus  differential distribution  of  soil moisture, heat exchange, and
 protection from windblast.
     It is assumed that the clearcut areas  will not be  disturbed as far as the
 litter and organic horizons of  the tundra soils,  and  that the clearcut areas
 will be replanted or reseeded.
     General effects of clearcutting are described in the coniferous forest
 land type (see Chapter 4).  Clearcutting of the woody shrubs in a  small area
 within the tundra ecosystem can have extreme  effects on the microclimate and
 the hydrological  factors,  since  so much  of the alpine or  arctic landscape is
 characterized  by  scattered woody shrubs  and forbs.  Removal of the vegetation
 will affect the snow and  soil moisture distribution due to microtopographical
 changes created by the removal of  larger shrubs.  Soil  temperature within the
 clearing will  increase and there would probably be a deeper and earlier thaw
 during the summer.  The effects  of clearcutting on heat balance, soil moisture,
precipitation, runoff, and on wildlife have been described in the coniferous
 forest land type  (Chapter  4).  These effects of clearcutting in tundra environ-
ment would be  somewhat different in magnitude but there are no data available
 on these effects of clearcutting in a tundra environment.

     (1-3)  Stumping and  Grubbing
     Removal of roots  and stumps in a tundra  environment  would cause considerable
 disturbances.  The practice would  create depressions and  other microtopographical
                                     6-21

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disturbances in the treatment area.  As mentioned earlier, the effects of micro-
topographical changes in a tundra environment are quite drastic and would af-
fect snow distribution, heat exchange, depth of thaw, soil moisture, soil
temperature, and surface runoff.  Surface litter and the organic layers on the
surface would also be disturbed.
     Due to the drastic nature of disturbances such as increased potential
hazards for soil erosion and sediment losses and deeper thawing and freezing
that would be caused by a stumping and grubbing operation, the practice of
vegetation removal by stumping and grubbing should not be used as a contaminant
cleanup technique in the tundra environment.

     (1-4)  Scraping and Grading
     The surface alteration through scraping and grading  in the tundra environ-
ment would require some prior clearcutting and removal of stumps from the treat-
ment area.  Surface litter and some organic.matter would  be removed in the
process of scraping.  Grading processes may even expose some mineral soil hori-
zons.  The insulative effects of vegetation, surface litter and organic matter
would be destroyed and therefore the  heatflow would not be insulated.  Soil
thawing and freezing would be relatively faster and deeper.
     Infiltration rates would decrease with an increase in surface  runoff and
water erosion.  The frequent freeze-thaw cycles at the soil surface coupled
with the common presence of permafrost not far beneath the surface  results in
physical frost-thrusting of soil,  rocks and plants wherever water is abundant.
Surface scraping and grading would enhance such soil frost activity which
produces various kinds of polygons, stone nets, and  solifluction terraces.
These disturbances would make the  edaphic environment unstable.  Such wide-
spread soil frost activity, combined  with the  frequent presence of  permafrost
not  far below  the soil surface, would have a  significant  effect on  getting the
vegetation  reestablished  in the treatment area.  Vegetational  patterns  in
arctic and  alpine tundra  are  strongly shaped  by  such soil frost activity.
     Other  effects  of  surface alteration  in  the  tundra  environment  would be
similar to  those described  in the  coniferous  forest  land  type (see Chapter  4).
                                      6-22

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      CJ.-5) • Shallow Plowing •       • >
      Shallow plowing  operations  for contaminant  cleanup  would  not  be practical
for  the  tundra  land type.

      (1-6)  Deep Plowing                                          '     .
      Deep plowing operations for contaminant  cleanup would  not be  practical  for
the  tundra land type.

      (1-7)  Soil Cover Less Than 25 am.
      Top soil dressing the treatment area would  cover up the surface litter  and
organic matter  horizons.  Ecological impacts  of  the treatment  would vary accord-
ing  to the depth of top soil application.  The treated areas should be reseeded
or replanted for getting vegetation reestablished.
      Beneficial effects of top soil dressing  would be in terms  of  better in-
sulation against heatflow, thus  slowing soil  thawing and freezing.  Infiltration
rates would also increase.  However, lack of  vegetative  cover  would make the
soil  surface vulnerable to the soil losses due to wind and  water erosion.

      (1-8)  Soil Cover to 25 to  100
      Same as for treatment 1-7.

      (2-1)  Remove Plow Layer
      Removal of surface soil (10 cm) from a contamination area  in the tundra
environment would be similar to  scraping and  grading practices.  Surface litter
and organic matter layers would be disturbed.  Ecological impacts of this opera-
tion  would be similar to those described under Scraping  and Grading (1-4).

      (2-2)  Remove Shallow Root Zone
      Removal of shallow root zone soil (<40 cm) would also  be similar to the
operations for surface alterations.  The ecological disturbance and impact are
very  similar to those described under Scraping and Grading  (1-4).
                                     6-23

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     (2-3)  Remove Scraping and Grading, Mechanically Stabilize
     Surface scraping and removal of a shallow layer  (<5 cm) from a contami-
nated area in the tundra environment would be impractical.  Tundra soils have
thick layers of litter and organic horizons on the surface.  Moreover, the re-
moval of a shallow layer from soil surface would disturb the area and would
result in loss of insulative layer against heat flow.  The operation would
cause increased frost action and unstable surface conditions.  Exposed surface
would not be suitable for mechanical stabilization.

     (2-4)  Remove Plow Layer3 Mechanically Stabilize
     The technique would not be applicable for the same reasons described above
(2-3).

     (2-5)  Remove Shallow Root Zone* Mechanically Stabilize
     Would not be practical.

     (2-6)  Remove Scraping and Grading, Chemically Stabilize
     Chemical stabilization is not practical in the tundra environment.

     (2-7)  Rerxove Plena Layer^ Chemically Stabilize
     Chemical stabilization would not be practical.

     (2-8)  Remove Shallow Root Zone, Chemically Stabilize^
     Chemical stabilization would not be practical.

     (3-1)  Barriers to Exolude People
     Exclusion of people from the treatment area would not affect  the  ecology
of tundra.

     (3-2)  Exclude Large Animals
     Exclusion of large herbivores such as reindeer,  caribou or musk oxen
would reduce local grazing pressure  and result  in  increased  surface biomass,
increased insulation by organic material and a  gradual change  in permafrost

                                      6-24

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 depth.  Since large herbivores can cause a decrease in lichens and in increase
 in woody shrubs, continued exclusion might lead to a shift in relative abundance
 of some species, but otherwise would not affect the ecology of the area.
      Herding arctic animals follow set migration,paths;  however,  unless the
 exclusion fence blocked a natural barrier such as a mountain pass or  river  ford,
 even the largest fenced area should have little effect on gross animal movement.

      (3-3)   Exclude Large and Small Animals
      Exclusion of the small and large animals  from the treatment  area would
 help the process of natural restoration.   There would  be no disturbances  caused
 by browsers  and grazers.   Large animals like reindeer,  caribou and musk oxen,
 and small animals like  lemmings,  have quite a  grazing  impact on the ecology of
 the tundra environment.   The other  impacts are due to  compaction,  surface soil
 disturbances and physical  damage  to the vegetation.

      (4-1)  Asphalt Hard Surface Stabilization
     This treatment is outside  the  scope of work of  this  study.  However, ex-
perience  in construction of  arctic  roadways and air  strips  suggests that changes
in  the insulation properties of the  surface and the  resultant  change in the
depth of permafrost would be the major  effect.  Lachenbruch  has detailed the
procedures for calculating the proper thickness of gravel fill for different
surface materials and climatic conditions that will minimize the effect on the
permafrost layer.

     (4-2)  Concrete Hard Surface Stabilization
     This treatment is outside the scope of work of this study.

     (5-0)  Application of Sewage Sludge
     This treatment is outside the scope of work of this study.

     (6-1)  High Pressure Washing
     This treatment is outside the scope of work of this study.
                                     6-25

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     (6-2)  Flooding to 30 am
     This treatment is outside the scope of work of this study.

     (7-0)  So£l Amendments Added
     This treatment is outside the scope of work of this study.

6.5  RECOVERY AFTER CLEANUP
6.5.1  Irreversible Changes
     The cleanup techniques described earlier for the tundra environment would
not have irreversible impact on the ecology.  However, the harsh nature of the
tundra environment, relatively short growing season and low temperatures during
the growing season would make the vegetative regeneration, ecological succession
and animal recovery very slow processes.

6.5.2  Rates of Recovery
     The sensitive nature of the tundra ecology to disturbances has led to the
concept of "fragile" tundra.  Figure 6-1 illustrates the series of events which
follow the damage of tundra vegetation.  The altered plant cover reduces both
surface insulation and albedo, and more heat is absorbed by the soil with the
result that there is a greater depth of thaw and both subsidence and erosion
may ensue.  Such disturbance will ultimately recover due to the natural homeo-
static mechanisms in ecosystems which bring about new equilibrium.  Unfortu-
nately little is known about the time factor in these recoveries; it may range
from a few to hundreds of years.  In Figure 6-1, well drained sites where the
ground contains little ice show slight changes and recovery to a new, little
altered equilibrium is rapid.  However, on wet sites containing much ground ice
greater damage is caused, and recovery will be slow and may result in a different
vegetation when equilibrium is regained.
     One of the greatest concerns of ecologists is the degree to which tundra
vegetation can be disturbed and yet reestablish a turf within three to five
                                                                   A
years prior to therniokarst development.  According to Brown et al.,  even the
replacement of mulch results in nearly as deep a thaw as does the removal of
total plant cover, 61 cm versus 75. cm, respectively.  The control plots averaged
                                      6-26

-------






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32 cm for maximum summer thaw.  The changed albedo is probably the major factor
even though an insulative layer was returned in the one treatment.
     The rates of vegetative recovery and seedling establishment in the tundra
environment are very slow, thus increasing the potential for permafrost melt
and thermokarst development.

6.5.3  Succession Stages Following Cleanup
     6.5.3.1  First Year--
     During the first growing season after the cleanup the ecological succes-
sion would depend upon the nature of treatment and the degree of disturbances
associated with it.  In the natural restoration areas there would be no signi-
ficant disturbances in the surface litter and organic horizons.  Some of the
woody shrubs which have quite an extensive and well insulated rooting system
will start sprouting.  Grasses, sedges and forbs would also regenerate fairly
well.  Lichens and mosses would not show much of regeneration.  Cleanup pro-
cedures such as stumping and grubbing, surface alterations, and removal of sur-
face soil layers would cause major surface disturbance and thus the treated
area would be subjected to severe frost action.

     6.5.3.2  Fifth Year—
     In the natural regeneration area, and  in the  areas which were fenced out
to keep the people or large and small animals out, the surface disturbances
and  frost action were minimum.  The vegetative recovery for grasses, woody
shrubs and forbs should be quite normal.  Again the  lichens and mosses would
have a relatively  slow recovery.  The seeds  from  the  nearby sources, and sprout-
ing  of shrubs and  grasses, which have an  extensive rooting system, would get
the  vegetative establishment  started.  In the areas  where  surface litter and
organic horizons were removed or disturbed,  there would be a  considerable in-
crease in the frost  action  and microtopographic changes.   Erosion rates would
be quite high.  There would be very poor  vegetative  recovery  and  succession.

      6.5.3.3  Tenth  Year--
     Vegetative  succession  after  ten  years  from  cleanup treatment of an area in
the  tundra  environment  would  have a near  normal  vegetative cover  recovery
                                      6-28

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 except for lichens  and mosses.   This  is based  on  an assumption  that  there were
 no major disturbances  to the surface  litter  and the organic  horizons.  The
 situation would  be  different in areas where  the cleanup  operation disturbed the
 insulating layers of litter  and organic matter and  changed the  albedo  con-
 siderably.  The  vegetative establishment would have a very slow start  in the
 disturbed areas.  However, during  the first  ten years after  the treatment, most
 of the frost  action induced  disturbances and land subsidence would have already
 taken  place and  natural  or man  induced revegetation would start taking place
 on a new surface.

     6.5.3.4  Climax--
     It  would be very difficult  to evaluate  the post cleanup treatment effects
 on vegetative recovery and succession to a climax stage.  Differences  in eco-
 logical  conditions  after fifty or  100 years  after different  cleanup  treatment
 are not  expected.   In terms  of geological time, there would  be  no differences
 due to different cleanup treatments reflected  in  the climax  vegetation.

 6.6 QUANTITATIVE ASSESSMENT OF CLEANUP  IMPACTS
     The proceeding sections of this  chapter have clearly shown that any cleanup
procedure  (except the benign exclusion by barrier)  involves  major perturbation
of the tundra biome that will result  in  long lasting environmental effects.
Quantitative assessment of the ecological differences among  the various pro-
cedures is meaningless since any procedure which  would result in removing a
hazardous material will result in approximately the same ecosystem desruption.

6.7  CONCLUSIONS
     Cleanup techniques result in changes in albedo, in microclimate, in thermo-
equilibrium, and in the relationships between unfrozen ground and permafrost.
To  a large extent homeostasis is maintained by the mosses and lichens.   During
the short summer growing period when the sun is the warmest,  there is an
abundance of standing melt water on the tundra.  Moss has a very high evapo-
transpiration rate that tends to keep the air layers closest to the ground
cool.  The lichens prevent the direct rays of the sun from striking the ground
surface.  The interaction of cool air, cool water and no direct sunlight permits
                                     6-29

-------
only a minimum melting of the permafrost and leads to the formation of a shal-
low active area where plant growth takes place.
     If the cover material of the tundra is disturbed in any way the active
layer becomes thicker while the permafrost table is lowered.  The thicker
active layer collects additional water from surrounding areas.  This additional
water leads to formation of frost heave structures, thermokarsts and soil move-
                            *
ment through solifluction.
     All cleanup techniques alter the cover material and are therefore delete-
rious to the tundra.
                                      6-30

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6.8  TUNDRA REFERENCES
 1.   Abale, G./W.  H.  Parrott, and D.  M. Atwood.   Effects of SK-5 Air Cushion
     Vehicle Operations on Organic Terrain.  CRREL Report, 1972.  141 pp.

 2.   Bliss, L.  C.   Primary Production  within Arctic Tundra Ecosystems.  In:
     Productivity and  Conservation in  Northern Circumpolar Lands, 77-84.
     IUNC.  Pub. 16. Merger, Switzerland, 1970.

 3.   Bliss, L.  C.,  and R.  W.  Wein.  Plant Community Response to Disturbances in
     the Western Canadian Arctic.  Can. J. Bot., 50:1097-1109, 1972.

 4.   Brown, J., W.  E.  Richard, and E.  Victor.  The Effect of Disturbance on
     Permafrost Terrain.  CRREL Special Report 138, 1969.  13 pp.

 5.   Brown, J., and J. C.  F.  Tedrow.   Soils of the Northern Brooks Range, Alaska,
     4:  Well-Drained Soils of the  Glaciated Valleys.   Soil Sci. 97:187-195,  1964.

 6.   Cody,  W.  J.  Reindeer Range Survey.  Plant Res.  Inst., Canada Dept. of
     Agric., Ottawa, 1964.  17 pp.

 7.   Dagon, R.  R.   Tundra - A Definition and Structural Description.  Polar
     Notes. 6:22-34, 1966.

 8.   Dunbar, M. J.   Stability and  Fragibility in Arctic Ecosystems.   Arctic,
     26:179-185, 1973.

 9.   Hill,  D.  E.,  and  J. C. F. Tedrow.  Weathering and Soil Formation in the
     Arctic Environment.  Amer. J. Sci.  259:84-101,  1965.

10.   Holowaychuk,  N.,  J. H. Petro, H.  R. Finney,  R. S. Farnham, and P. L. Gersper.
     Soils  of Ogotoruk Creek Watershed.  In: Environment of the Cape Thompson
     Region Alaska (N. J.  Wilimovsky,  and J. N. Wolfe, eds.), 1966.  pp.  221-273.


11.   Johnson,  P. L. and W. D. Billings.  The Alpine Vegetation of the Beartooth
     Plateau in Relation to Cryopedogenic Process and Patterns.  Ecological.
     Monographs, 32:105-135,  1962.

12.   Klein, D.  R.   The Impact of Oil  Development in Alaska.  In:  Productivity and
     Conservation in Northern Circumpolar Lands,  209-242. IUCN. Pub. 16. Merges,
     Switzerland,  1970.

13.   McCown, B. H.  and J.  Brown. Ecological Effects of Oil Spills and Seepages in
     Cold-Dominated Environments,  In:  1971 Tundra Biome Symposium Proceedings,
     61-65, 1971.
                                     6-31

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14.  McKay, G.  A., B. F. Findlay, and H.  A.  Thompson.   A Climatic Perspective of
     Tundra Areas. In: Productivity and Conservation in Northern Circumpolar Lands,
     10-33.  IUCN Pub. 16. Morges, Switzerland, 1970.

15.  Osburn, W. S. Jr.  Radioecology.  In: Arctic and Alpine Environments (J. D.
     Ives and R. G. Barry, Eds.), 875-903. Methuen, London, 1974.

16.  Richard, W. E.  Ecological Evaluation of Air Cushion Vehicle Tests on Arctic
     Terrain.  CRREL Tech. Report, 1971.   30 pp.

17.  Rickert, D. A. and J. C. F. Tedrow.   Pedological Investigations on Some
     Aeolian Deposits of Northern Alaska.  Soil Sci. 104:250-262, 1967.

18.  Rieger, S.  Dark Well-Drained Soils of Tundra Regions in Western Alaska.
     J. Soil Sci. 17:264-273, 1966.

19.  Sigafoos,  R. S.  Frost Action as a Primary Physical Factor in Tundra Plant
     Communities.  Ecology.  33:480-487,  1952.

20.  Vuilleumir, F.  Insular Biogeography in Continental Regions.  The Northern
     Andes of South America.  Amer. Nat.  104:373-388, 1970.

21.  Walker, J.  The Influence of Man on Vegetation at Churchill.  In:  Pro-
     ductivity and Conservation in Northern Circumpolar Lands, 266-269.  IUCN.
     Pub. 16. Morges, Switzerland, 1970.

22.  Watson, A., N. Bayfield, and S. M. Moyes.  Research on Human Pressures  in
     Scottish Mountain Tundra, Soils, and Animals.  In: Productivity and Con-
     servation in Northern Circumpolar Lands, 256-265. IUCN. Pub. 16. Morges,
     Switzerland, 1970.

23.  Webber, P. J.  Tundra Primary Productivity.   In: Arctic and Alpine Environ-
     ments  [j.  E. Ives and R. G. Barry, eds.), 445-473, Methuen, London, 1974.

24.  Whittaker, R. H.  Communities and Ecosystems.  Macmillan Publishing Company,
     New York, 1975.  385 pp.
                                    6-32

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                                  CHAPTER  7
                        COASTAL  INTER-TIDAL MARSHES
.7.1   OVERVIEW
     Heavy vegetational development takes place where the soil is waterlogged
or  covered by  shallow standing water for all or most of the year.  Wher.e this
vegetation is  dominated by grasses, reeds, sedges, and other non-woody types
the development  is referred to as a marsh.  If the vegetation is largely
bushes and trees, it is called a swamp.  Coastal marshes and swamps represent
some of the highest zones of primary productivity in the world.  Some marshes
exhibit a  net  primary productivity of greater than 3,000 g/m2/yr (Table 7-1).
In  coastal marshes, however, less than 10 percent of the net production of the
ecosystem  is consumed by grazing herbivores, mostly insects in this case, and
at  least 90 percent follows the detritus path of energy flow.  The bulk of
the aninals in the coastal marsh such as shellfish, snails, and small crabs,
seem to obtain their energy directly or indirectly from detritus.
     The five mechanisms and conditions that maintain this biological energy
flow at rates  far superior to the adjacent ecosystems are:  (1) Tidal action
promotes a rapid circulation of nutrients and food, and aids in the rapid re-
moval of the waste products of metabolism.  (2) A diversity of plant species
and life forms provides a continuous photosynthetic carpet despite variable
physical conditions.   The three major life forms of autotrophs that work to-
gether to maintain a high gross production rate are:   (a)  phytoplankton; (b)
benthic microflora—algae living in and on mud, sand, rocks, or other hard
surfaces, and bodies or shells of animals; (c)  large attached plants—the sea-
weeds,  submerged eel grasses,  and emergent marsh grasses.   (3)  A coastal marsh
is often an efficient-nutrient trap that is partly physical (differences in
salinities cause vertical as well as horizontal stratification of water masses)
and partly biological.   (4)  A year-round primary production by a succession of
"crops," even ,in northern regions.   (5) Close contact between autotrophic and
heterotrophic  layers.
                                     7-1

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     Coastal marshes develop on relatively flat terrain between the limits of
normal high and low tide of protected bays, estuaries, and lagoons.  They are
dominated by a few species of tall emergent reed-like vegetation which are
tolerant of rhythmic submergence and saline conditions.  The water may be nearly
fresh or nearly marine or highly variable in salinity, and flushing occurs with
each tidal cycle.  Within saltwater marshes there is a gradual build-up of organic
peat deposited by the vegetation itself.  Highly dendritic tidal creeks dissect
the marshes and serve as avenues of entrance and egress of the tidal waters
which alternately flood and drain the marshes.  Because of their adaptations to
the intertidal zone, salt marshes are highly sensitive to even minor change
in water levels.
     The coastal marsh ecosystem lies from a few feet above sea level to a
few feet below it.  Hence, it is subject to the ebb and flow sweeping action of
tidal currents, and all must be tolerant of some salinity change.  All trap
suspended nutrients by slowing down the water currents, and they all provide
shelter and food for a variety of small brackish water and marine animals.  These
are among the most productive ecosystems of the world with annual production
rates running around five tons per acre.  Much of this plant production becomes
available as organic detritus which provides the chief food base for the coastal
fish and shellfish populations of commercial importance.  Without these important
production and nursery areas, our coastal seafood resources would suffer severe
decline.
     Although tolerant of short-term inundations with fresher or more saline
waters and even short-term exposure to the air, these systems cannot tolerate
long-term changes in these environmental factors.  Drying of the habitat or
major intrusion of fresh- or saltwater has been shown to change the composi-
tion of the dominant vegetation with long-term erosion of the productivity of
these systems.
     The marsh vegetation is dominated by several species of the tall Spartina
grass and to lesser extents by other emergent species such as Distichlis, Juncus,
and Salicornia.  Around the bases of these plants and on the surfaces of old
leaves grow a variety of filamentous algae including blue-green, brown, and red
algal types.  On the mud flats between the bases of the plants grow a variety of
                                     7-3

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diatoms and blue-green algae.  Plant production of the marsh is dependent upon
all three groups of producers, the tall emergent species, the filamentous attached
forms, and the mud flat inhabitants.
     Only grasshoppers and a few birds such as seaside sparrows may be found among
the tall Spartina grass, but the water and mud flats are teeming with animal
life.  This includes snails, mussels, and oysters, as well as a variety of worms,
crabs, shrimp, and small fishes.  Many of the crabs, shrimp, and fishes are juve-
niles of species which support the commercial catch as adults.  Large numbers
of shore and wading birds forage in these marshes at low tide.
     Studies have shown that there is a regular export of decomposing organic
matter through the tidal creeks to the estuaries, but the major export occurs
when storms inundate the marshes with high water and flush out great quantities
of organic matter to the estuaries and the continental shelves.

7.1.1   Occurrence of Coastal Marshes
     Coastal marshes (or intertidal emergent wetlands) are recognized as an eco-
logical class within the Estuarine System of a wetland classification (Figure
7-1).  There are nearly 70 million acres of natural wetlands in the continental
United States of which coastal marshes total about 17.5 million acres.

7.1.2   Related Land Tyj)es_
     Coastal marshes as an ecosystem type are very similar to coastal swamps
and grass flats.  All are emergent wetland ecosystems (Figure 7-1).
     A coastal swamp is an association of mangrove trees which grows in the sea
or in the water of sheltered bays and estuaries of subtropical regions.  The
average water depth may be from a few inches to about four feet.  Extensive prop
root systems reduce the action of waves and tidal currents and produce a charac-
teristic set of internal environmental conditions.  Water flow is greatly reduced.
Sedimentation is high, and much organic matter accumulates.  Oxygen levels are
low, and the environment is in many respects similar to that of anaerobic sub-
merged soils.  Strong gradients in oxygen content and other factors exist from
the periphery to the interior of the swamp.  In some cases, saltwater swamps
grade inland into saltwater marshes.
                                     7-5

-------
     Coastal swamps are dominated by the low, bush-like red. black, and white
mangrove trees.  A few other shrubs and vines may also be present.  The exten-
sive root systems developed by the mangroves provide surfaces for attachment of
filamentous algae, and the surface muds may support large and productive diatom
floras.  Large numbers of oysters are often found attached  to the mangrove roots;
a variety of small crabs, shrimp, and fishes feed on the organic forage around
the roots and mud flats at low tide; and birds nest in the  branches of the man-
groves.
     Grass flats or submarine meadows consist of a few species of grasses which
are tolerant of continual submergence in salt and brackish waters.  They are
normally found from the low water line to a depth of about three feet, but they
may extend considerably deeper in very clear waters.  Although seldom found in
very strong current, they are most luxuriant where there is moderate flushing.
The long flat blades of the dense beds protect the bottom from erosion, and
extensive deposition creates a substratum of finely particulate, high organic
muds.  Sufficient water penetrates the beds to-maintain high oxygen levels in
the water above the bottom.
     The grass flats are dominated by eelgrass (Zostera spp) in northern lati-
tudes or by turtle grass (Thalassia spp) or manatee grass (Cymodocea spp) in
the more tropical areas.  The long grass blades are often clothed with a layer
of attached filamentous algae which produce organic matter and which also act
as brushes to remove suspended matter from the flowing water above.  Many small
animals live among the stems and roots of the grass beds, and larger fishes and
birds forage there.

7.2   NATURAL PERTURBATIONS
     Coastal marshes are generally considered to represent a serai stage in the
succession of water to dry land.   In areas with relatively stable climatic
conditions, succession is extremely slow and the marsh maintains the same appearance
year after year.   In other areas, violent climatic fluctuations cause coastal
marshes to revert to an open water phase in some years and the concept of succes-
sion in the normal sense of the word has little meaning.  Fire has been shown to
play an important role in maintaining coastal marshes.  Coastal marshes can
recover from fires in a couple of years if the fire does not burn down to the
bare soil and thereby permit excessive erosion.
                                    7-6

-------
     Large storm systems  (e.g., hurricanes) can cause extensive damage to coas-
;tal wetlands due to erosion and excessive freshwater runoff.  Erosion physically
disrupts  the marsh while  the freshwater inflow may temporarily upset biota
adapted to marine or estuarine conditions.  These effects are generally short
term and  marsh recovery would be expected within a few years.  Studies of natu-
ral perturbation show  effects on primary and  'secondary productivity but these
perturbations are well within the range of homeostatis within the marsh ecosystem.
 7.3   MAN-MADE  PERTURBATIONS

 7.3.1   Impact on  Baseline  Ecosystem  Components
     The  coastal  marsh  is  a semi-aquatic  system  in equilibrium with the prevail-
 ing  climatic, hydrographic, geological, and biological forces of the coast.
 Even slight modification in the  level of  the water table or the rate of surface
 freshwater flow greatly modifies the biological  characteristics of the system.
 Although  the coastal marshes vary greatly in detail, a more or less typical
 marsh has freshwater vegetation  at the  landward  side, saltwater vegetation at
 the  marsh is drained by highly dendritic  tidal creeks which empty into the bay
 or estuary.  Freshwater entering along  the upper edges of  the marsh drain across
 the  surface and enter the  tidal  creeks.
     Many of the  marshes of the  Atlantic  and Gulf coasts have undergone great
 attrition in recent years, primarily as a result of  levee  and canal construction.
 A levee placed  across the  upper  end  of  a  coastal marsh has the following primary
 effects:
      — cuts off  all distributaries  feeding the  marsh
      — prevents  freshwater flooding
      — prevents  annual flushing
      — prevents  annual renewal  of  sediments and nutrients
      — ends  foi-mation  of  new  marshes.
      Canals  which lace  the coastal  marshes for navigation, pipelines,  or mosquito
 control have  the  following primary  effects:
      —  intercept and  carry off freshwater drainage
      —  block  freshwater from  flowing  across  the portion  of  the  marsh that
         is  seaward of  the  first canal
      —  rapidly carry  off  freshwater to the bay  or estuary

                                      7-7

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     — lower the water table
     — permit saltwater intrusion well into the marsh proper.

 7.3.2   Unassisted  Recovery  Sequence
     The biological consequences are clear.  On the Atlantic coast where sub-
sidence rates are fairly slow, the marsh vegetation gives way to dry land vege-
tation with accompanying changes in the animal populations.  Bourn and Cottam
reported on a detailed 10-year study of the fate of a drained coastal marsh in
Delaware.   Prior to canalization, 90 percent of the marsh vegetation was salt-
marsh cordgrass (Spartina alterniflora) with smaller amounts of other marsh
species, especially at higher elevations.  A few open water areas supported
luxuriant growths of widgeongrass (Ruppia maritima) and other submerged aquatic
species.
     Ten years after ditching had taken place the wetland plants had been reduced
to small groups in the remaining low spots and along canal margins.  Groundsel-
bush (Baccharis halimifolia)  dominated the plant community which now was made up
largely of dry land species such as asters, goldenrods, terrestrial grasses, and
young trees (pine, juniper, sweetgum, maple, and hawthorn).  Aquatic animal
populations of the ditched areas had been greatly reduced in areal extent and in
density, even in the wetland habitat which still remained (Table 7-2).   The
density of the total invertebrate population was reduced from 39 to 97 percent
in the various samples, and the mollusks and crustaceans, which make up important
food items for many fishes and shore birds, were reduced 32 to 100 percent.  Open
aquatic areas, which formerly supported widgeongrass and other important duck foods,
had been reduced to mud flats and dry land.  Thus, the wetland habitat, important
in the production of fishes,  shellfishes, ducks, and wading birds, had given way
to land with its low wildlife values.

     On a subsiding coast, such as occurs  in southern Louisiana, elimination of
the normal freshwater and sediment input upsets the land-water equilibrium, and.
the subsiding marsh tends to become an open water area.  This tendency is intensi-
fied by canals which drain the marshes, enhancing compaction.  These canals tend
to grow wider as a result of marginal  subsidence, wave erosion, and disturbance
from boat traffic.  Plant production by marsh grasses of the Gulf coast is very
high, exceeding 10 tons per acre per year  and a great deal of additional plant
production occurs in the marshes due to attached algae, mud flat diatoms, and

                                      7-8

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   Table 7-2.   Effects  of ditching  a  Delaware  tidewater marsh  on  the  aquatic
               invertebrate  populations.   Vegetational zones are  characterized
               by the dominant  plant  species.   Six-foot square quadrants were
               sampled  for comparison of  invertebrate  density  in  the  drained
               and undrained sections of  the marsh,  and they represent  three
               consecutive years  of sampling during  the months of April-December
               (from U.S.  Environmental Protection Agency^)-
   Vegetation  Zones
 Feet above mean
sea level (for the
undisturbed marsh)
                                                      Percent  reduction of the
                                                      invertebrate  populations
    Total
invertebrates
Mollusks and
crustaceans
Saltmarsh cordgrass
(Spartina alterniflora)
Saltgrass
(Distich! is spicata)
Saltmeadow cordgrass
(Spartina patens)
Saltmarsh bulrush
(Scirpus robestus)
1.88-2.93
2.35-2.90
2.58-3.32
2.75
39-82
64-88
41-97
50-97
32-95
82-94
55-100
58-98
phytoplankton in the shallow waters.  A large fraction of this organic matter

is exported through tidal creeks to nearby bays and estuaries.  When the marsh

becomes an open water area, however, production is apparently reduced, and

instead of exporting organic matter, the area becomes a nutrient sink.  Birds

and mammals no longer find food and refuge among the marsh grasses, and canals

create migrational barriers to terrestrial and semi-terrestrial animals which

utilize the marsh.  Complete shifts in vegetation accompany increased salinity

and subsidence.
     Saltwater intrusion increases the salinity of the marshes,  eliminating

the broad mixing zone so important as nursery grounds for juvenile fishes,

shrimp, and crabs.  In deeper channels where reducing conditions prevail,

large quantities of hydrogen sulfide are produced which are toxic to the marsh
       o
grasses  and to the aquatic animals.  Acid conditions of the canals may also

result in release of heavy metals from the sediments.  As a result of habitat

loss, decreased food supply, increased salinity, and increased hydrogen sulfide,


                                      7-9

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populations of aquatic animals are adversely affected.  Moore and Trent  compared
oyster production  in natural and canalized marshes.  They found that in the
altered marsh the  set of young oysters was reduced by over 90 percent, juvenile
growth was slowed, average length was reduced by 36 percent, weight was reduced
by  27 percent, and mortality was increased by 39 percent.  As a result of these
and other studies, St. Amant (unpublished) has concluded that lack of freshwater
has drastically modified the ecology of coastal marshes and severely damaged
production of valuable oysters, shrimp, fur animals, and waterfowl.
     In areas of eroding shorelines where dredged spoil has been used to sup-
port vegetation, both seeding and transplanting methods have been used to re-
develop the flora.  Both methods have been highly successful and after two grow-
ing seasons, little or no difference existed in appearance and primary produc-
tivity between these new marshes and long established natural marshes.
     The methods of soil removal are dependent on the depth and characteristics
of the unstable material as well as upon the nature of the underlying stable
substrate (Figure  7-2).  Where depths of unstable material do not exceed about 10
feet a dragline, shovel, or dredge may be used to excavate the unstable material
to sufficient width.  The excavated material handled by dragline or shovel is
usually side cast beyond the excavation, forming a spoil bank, and it must be
removed a sufficient distance to prevent lateral displacement back into the
excavation.
     Where deeper unstable deposits are encountered (about 10 to 25 feet), dis-
placement methods are commonly used.  In such methods the fill is advanced by
end-dumping and placement with a bulldozer in a V-shape (i.e., highest along the
central crest).  Fill height is increased until the load is sufficient to produce
failure in the underlying unstable materials, displacing them laterally.  Dis-
placement may be accelerated by jetting with water prior to, during, and after
displacement of the fill.  As the fill settles,  additional material must be
placed to maintain the grade.  The weight of the fill  will cause lateral compres-
sion in the displaced materials which may result in settling and horizontal
movement of the shoulders for several years.
     Displacement of unstable materials under the fill may also be accomplished
by blasting.   In the "underfill" technique the surface layers are broken with
equipment or light charges, the fill is placed,  and explosives are then positioned
through the fill in jet holes or casings.  Usually one to three rows of explosives

                                     7-10

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are placed along the center line about midway between the fill bottom and the top
of the underlying solid substratum.  In addition, at each edge of the fill two
or three rows of charges are placed 4 to 5 feet below the surface.  The explo-
sion displaces the soft materials, creating a cavity under the fill which then
settles rapidly.  In the "toe-shooting" technique the soft material is displaced
by blasting ahead of the advancing fill.  Added fill material is pushed into the
cavity left by the blast, and the fill is advanced with a V-poir.t which displaces
the soft material and', develops a wave in front of the fill.  In the process, the
front face of the fill is overburdened, and the explosive charges are placed
around the toes of the fill near the bottom of the soft material.
     The cutting and digging action of the dredging operation breaks through
the thin oxidized layer of the submerged soil and exposes the deeper unoxidized
layer.  Furthermore, most of the sediments placed in suspension are removed from
this layer and, hence, are in the chemically reduced state.  Such materials have
very high chemical and biological oxygen demands.  Frankenberg and Westerfield
calculated that some dredge spoils require 535 times their own volume of oxygen
for complete oxidation, and Brown and Clark  reported oxygen levels near dredges
18-83 percent below normal.  Both the sedimentary particles and the interstitial
waters released contain immediately toxic materials such as hydrogen sulfide,
methane, and a variety of organic acids, ketones, aldehydes, etc., as well as
heavy metals and pesticides which exhibit persistent toxic effects.  Turbidity,
per se, reduces light penetration and interferes with photosynthetic production
of oxygen, and it tends to elevate water temperatures.  Eventually the suspended
material settles to the bottom either near the dredging site or far downstream.
Thus, there is a redistribution of sediments together with whatever nutrients
and chemical pollutants which they may contain, and this may result in modified
bottom topography and altered patterns of water circulation.  Such sedimentation
problems are greatly accentuated when dredge spoil is placed back into the water.
General and immediate effects of dredging and spoil placement are listed in
Table 7-3.
     In coastal marshes the matter is complex because of the adjacency of salt-
water and the natural process of coastal subsidence.  Coastal marshes, in the
undisturbed state, represent vast drainage systems.  Freshwater enters on one
side, generally from the floodwaters of annual river overflow, and it gradually
works down to the coast in a broad, flat surface sheet.  Occasional creeks and
bayous aid in the runoff.  Near the estuaries the marshes are dissected by

                                     7-12

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                                                                  7-13

-------
dendritic tidal creeks.  Thus, through the marsh there is naturally a gradual
salinity gradient from freshwater to the more brackish waters of the estuary.
Marshes overlie deep layers of unconsolidated river deposits which gradually
undergo compaction as the water is squeezed out.  Such marshes would gradually
subside, but sediment input through river overflow and buildup of organic matter
through plant growth counteracts this tendency and maintains the delicate land-
sea, and freshwater-saltwater balances.
     Soil removal (including denuding) from marshes accelerates the rate of
freshwater runoff, and it may lower the water table of the soil, drying out the
higher areas of the marsh.  Artificially denuded areas do not correspond to nat-
ural coastal meandering tidal streams.  They may, however, erode to form open
canals.  Once opened, such canals tend to widen due to tidal and other natural
action or due to the effects of boat traffic.  Land loss from canal erosion has
reached serious proportions in Louisiana and elsewhere.
     In addition to draining away the freshwater, the canals offer paths for
saltwater penetration of the marshlands, and this is especially prominent in
the deeper canals.  Since rivers no longer are permitted to flood the upper
reaches of the marshes, they are now deprived of both the annual freshwater
and the annual sediment load.  Thus, as compaction and subsidence proceed, and
as saltwater penetrates through the canals, the effect of saltwater is being
felt further and further inland.  Vehicular traffic over the marshlands (mud-
boats, marsh buggies, and heavy equipment) associated with restoration activities
accentuates this problem.

     Marsh canals have very high contents  of organic matter and high oxygen
demands.  Yet water  circulation is often poor,  and this  leads to reducing or
near reducing conditions, especially  in the bottom water.  Saltwater is rich  in
sulfates, and when the sulfates enter  the  reducing conditions,  they are con-
verted to sulfides,  which are very potent  biotoxins.   Precipitated iron sulfide
is  a common marsh deposit.
     Spoil banks are often cast up alongside the  canals  creating a surface dam
effect.  Such banks  impound waters on  both sides  and  seriously  interfere  with
normal surface  drainage patterns.  The spoil banks directly cover  vast acreages
of  marshland, and erosion from  the  spoil banks  tends  to  drain back  into the
canal, on one side,  and  into  the marshland,  on  the other.   Since the  sediment

                                     7-14

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itself is mostly in the chemically reduced state, it tends to lower the oxygen

concentration of the canal waters when it flows back.  Erosion of spoil banks

and shallowing of canals require redredging in a never-ending cycle.  Effects

of soil removal and spoil placement in marshlands are listed in Table 7-4.
          Table 7-4.   Effects of soil  removal  and placement of dredge
                      spoil  in marshlands (modified from U.S.  Environ-
                      mental  Protection Agencyll).
              Interference with surface drainage patterns

                  Acceleration of surface drainage by canals

                  Damming of surface drainage by spoil  banks

                  General acceleration of freshwater runoff


              Loss of marshland habitat

                  Loss due to canalization

                  Loss due to water table lowering
                  Loss due to erosion and widening of canals

                  Loss due to spoil coverage
                  Loss due to acceleration of marsh subsidence


              Acceleration of saltwater penetration


              Conversion of sulfates (of saltwater) to sulfides in the
                  canals and precipitation of iron sulfide in the
                  canals

              Erosion of spoil banks and distribution of chemically
                  reduced sediment into canals and open marsh
7.4  EFFECTS OF CLEAN-UP PROCEDURES
     ON COASTAL MARSHES

    Clean-up procedures considered for marsh land types include temporary con-

tainment, contaminant removal and barrier exclusion.  The following subsections

discuss the effects of these treatments on the marsh ecosystem.

    The first techniques considered are those which may be applicable for pre-

venting further spread of contaminants across the marsh until contaminant removal
                                     7-15

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by clean-up can be accomplished.  The various alternative methods are considered
to be appropriate for coastal marshes if they might pre/ent further redistri-
bution.  The techniques discussed in this subsection include chemical stabili-
zation, clear cutting, stumping and grubbing, plowing, and application of un-
contaminated soil cover.
    (1-1)  Chemical Stabilization
    Chemical stabilizers are materials employed to bind soil particles together
as an aid to preventing erosion.  Chemicals may also be applied to mulch mater-
ials to act as a binding agent.
    The effect of chemical stabilizers is usually temporary and in the water-
logged soils of the marsh environment may be very transitory.  Because of this
characteristic, chemical stabilization may not be an appropriate treatment for
large areas.  However, for small plots, this approach may be of some use.  Since
chemical application is commonly a part of revegetation programs, little eco-
logical impact would be expected from application in marsh areas.
    Certain chemical stabilizers are designed to reduce the rate of infiltration
In a coastal marsh environment, with the frequent flooding associated with high
tides, infiltration reduction has little meaning.  Use of this treatment is
therefore inappropriate for this land type.
    (1-2)  Clear Cutting Vegetation
    Clear cutting would be an appropriate treatment for relatively upland por-
tions of coastal marshes which support significant populations of trees and
to large emergent stands such as found in mangrove swamps.  Since root systems
would not be removed, erosion potential will clearly be appreciably diminished
relative to root layer removal techniques discussed in subsequent sections.
Root and/or stump sprouting is likely to occur and recovery would thus be ac-
celerated relative to total clearing treatments.

     (1-3)   Stumping and Grubbing
     Stumping and grubbing involves the removal of all surface vegetation and
major root systems.  Disposal of vegetation may be by natural decomposition or
by burning, depending on the volume of organic material and the properties of
the contaminant.
                                     7-16

-------
      The  clearing  of  the  land removes the vegetative cover and permits the rain-
 fall  to strike  the bare land surface.  These processes  lead to increased surface
 runoff and  severe  erosion.  The  effects will be accentuated in rainy weather.
 In  dry weather  considerable quantities of soil in relatively upland areas may be
 raised as dust  clods  which will  be transported at a later date when the rains
 fall.  Runoff and  erosion will add a great deal of soil solids to the marsh re-
 sulting in  greater water  turbidity and increased sedimentation in tidal creeks.

    Denuded areas  have been shown to lose large quantities of dissolved min-
 erals, particularly sodium, potassium, calcium, magnesium, nitrates, and phos-
phates.   In some cases increased groundwater and springflow has been noted
 immediately following removal of phreatophytes (which normally pump water up
through the roots  to be lost via transpiration), but the springflow may even-
tually diminish as the water table is lowered through lack of recharge.
    If the brush cleared from the land is burned in the flood plain the ashes,
which are highly alkaline, may enter tidal creeks and cause an immediate in-
crease in the pH of the water (in one study the pH jumped almost immediately
from 7.8 to 11.3 and remained high for some time).   In addition,  heat  from
the fire can elevate the marsh water temperature quickly and keep it high for
some hours.
    Denuding equipment in operation as well  as spills in maintenance yards can
result in the passage of petroleum products into the water courses.
    The net result may be summarized in the  following points:
        — loss of habitat  from devegetation  of the  area
        — loss of land fertility from surface erosion and subsurface flow
        — increased erosion from denuding  site activities
        — lowered groundwater level  from  devegetation
        — greatly increased fluctuation  in water level  due to  faster runoff
          following rains  and decreased  flow during  dry periods  because  of
          loss of groundwater
       — greatly increased marsh sediment load due  to  erosion and
          runoff
       — greatly increased marsh turbidity  due to  erosion and runoff
                                     7-17

-------
        — modified chemical composition of the water due to increased
          sedimentation and runoff,  turbidity, leaching of soil
          nutrients.
    As a result of these influences, the coastal marsh will undergo a number
of changes.  The violent fluctuation in water level will result  in greater
freshwater flow rate during wet weather.  The creek beds may be  cut deeper,
the banks will be undercut, and the open water sections will be  widened.   Rif-
fles may disappear and pool areas fill.  Marsh areas may be swept clear by
flood waters.
    Increased sediment loads clog the interstices of riffles, fill the pools,
and cover the bottom generally with a layer of inorganic silt.  Bottom habitat
diversity would be significantly diminished.  Accompanying the increased run-
off, there would be an increase in water turbidity.  This lowers the light
penetration of the water, increases oxygen demand, and modifies  the chemical
characteristics of the water in other ways.  Loss of vegetative  cover and in-
crease in turbidity both serve to elevate the temperature of the water (as
much as 10°F).5
    During dry weather freshwater flow may slack off or it may cease entirely,
since the marsh now receives less groundwater inflow than before.  As pointed
out by Bayly and Williams,  land clearing may so alter the local hydrological
regime that formerly perennial streams may approach or become intermittent.
Since open water pools tend to be reduced or lost, the aquatic habitat may be-
come severely restricted or dried up between floods.  Any water that remains is
now subjected to more rapid and estreme temperature fluctuation in response to
prevailing atmospheric conditions.
    The long-term results will depend greatly upon local circumstances but,
in general, they would include the following:
        — permanent loss of natural land habitat — If the topsoil is
          eroded away, a native ecosystem will not return for many years
        — increased surface runoff and  reduced groundwater  flow — The
          denuded surfaces will continue to yield rapid and  complete runoff
        — persistent chemical changes — The high level of sedimentation
          and turbidity may eventually  taper off.
                                      7-18

-------
     Recovery after stumping and grubbing would be  dependent  upon several  fac-
 tors including
         — size  of area  denuded (the  magnitude  of the  effects outlined
           above would be  increased with  increasing area)
         — location of disturbed area relative  to open water  (areas
           adjacent to open  water would be subject  to  runoff  effects
           as well as the  erosional influence of tidal currents  and
           wave  action)
         — weather following cleanup  (heavy rains would magnify  runoff
           impacts and extended dry periods would delay recovery by
           possibly drying exposed muds).

     (1-4)    Scrap-ing and  Grading
     Surface  alteration  such as scraping  and grading of a marsh  area would
 have environmental  consequences  similar  to those discussed above for vegeta-
 tion removal.   However, more complete removal  of the  surface layer organic
 matter would result with  this  type of treatment.   In  addition,  epibenthic
 and  burrowing animals would be more  directly affected by surface alteration.
     Because  of  the  relatively  flat characteristics of marsh  lands, grading
 for  containment would not entail  leveling  as may be the case  in  more upland
 ecosystems.  Grading in coastal marshlands  would probably include banking
 of materials so that drainage  patterns would be  from the edges of the af-
 fected area  inward  (the reverse of the normal  drainage pattern).  This could
 alter the  fresh -  salt water gradients within  the marsh and  ultimately modify
 the  biological  character of the marsh.  However, the slight  gradients in-
volved here would undoubtedly  be overcome by tidal and wave  action and flood
 events and eventually more-or-less normal gradients would prevail and con-
 tainment would be temporary.

    (1-5)   Shallow Plowing
    Plowing is not felt to be  an appropriate treatment for a coastal marsh.
 Bottom sediments  in marshes  are continually in a state of flux in response
to tides, waves and runoff events.  Plowing would be not only destructive to
the marsh habitat but would  also probably enhance contaminant mobility by dis-
rupting the hydrologic regime and creating new flow routes.
                                     7-19

-------
     (1-6)   Deep Plowing
     See treatment 1-5;  this technique is not appropriate for this land type.

     (1-7)   Soil Cover Less than 25 cm
     Because of the scouring action of tides, waves and flood events,  thin soil
 cover may be only a very temporary containment treatment for this land type.
 Thus its use in marsh systems may be limited.
     The effects o£"this treatment are in two areas—the area covered and the
 source of the cover material.  Naturally the magnitude of effects,  and hence
 the restrictions to recovery are a direct function of the area treated.
     In the covered area, the habitat of epibenthic, burrowing and semi-
 terrestrial animals would be destroyed.  Also young stands of marsh grasses
 would be buried and would not be expected to survive.  Larger grasses, bushes
 and trees would not be buried; however machinery used to dump the cover soil
 may be very destructive.
     Recovery would be more rapid than if the covering process was preceded
 by vegetation removal,  as root or stem sprouting may not be prevented with the
 shallow cover.  Vegetation recovery would be fairly rapid with this treatment
 due to the shallowness of the cover which would not bury larger plants and
 which would probably soon erode.

     (1-8)   Soil Cover 25 to 100 am
     If the uncontaminated soil fill is up to 100 cm in depth, then the marsh
has simply been filled in and it no longer can be referred to as a coastal marsh.
The addition of 100 cm of soil may cause the land level to excbed the tidal
ranges and, consequently, the saltwater intrusion which is characteristic of a
coastal marsh will cease to occur.  The marsh may:  (1) cease to have a hydric
soil and begin to behave as a predominantly non-hydric type;  (2) change from a
vegetation cover of hydrophytes to predominantly mesophytes or xerophytes;
(3) change from land that is flooded at some time of the year to land that is
infrequently or never flooded during years of normal precipitation.

    Treatments  considered next  are  those  which  remove  contaminated  soil
layers.   Mechanical  and  chemical  stabilization  after  soil  removal is  also
discussed.
                                      7-20

-------
    (2-1)   Remove Plow Layer1                             ,.
    The plow layer is defined here as the soil layer from the surface to a
depth of about 10 centimeters.  Removal would be accomplished by hand shovel-
ling or larger digging machinery.  The unstable marsh soils would necessitate
working from platforms, barges or other support structures.
    The ecological effects of soil removal in the marsh would be similar to
those discussed for surface alteration (scraping and grading) and vegetation
removal.  Some inference can also be drawn from the earlier discussion of
dredging effects  (Section III).  Major influences include
        — acceleration of surface runoff
        — alteration of drainage patterns
        — loss of habitat for wildlife
        — increased erosion
        — loss of organic matter and nutrients in surface
          soil layers.
Recovery would be similar to that for scraping and grading but would be
slower because more of the soil-organic layer is removed and elevations are
somewhat altered thus changing the tidal flooding depth.

    (2-2)   Remove Shallow Root Zone
    In a coastal marsh, the root zone is relatively shallow and theiefore,
the effect of soil removal to the depth of a plow layer and/or to the shallow
root zone can be treated the same.  See treatment 2-1.

    (2-3)   Remove by Scraping and Grading,
            Meohanioally Stabilize
    The effects of scraping and grading are discussed in treatment 1-4.
This treatment, combined with "mechanical stabilization" includes removal of
contaminated soils (less than 5 ^m in this case) and compaction of subsurface
soils or surfacing with impervious materials to seal the subsurface against in-
filtration.  As previously noted  (treatment 1-1) infiltration control in a marsh
area which is at' least periodically flooded has little meaning.  Hence this
combined treatment method is inappropriate since mechanical stabilization is
inappropriate.
                                      7-21

-------
    (2-4)   Remove Plow Layer., Meohaniaally Stabilize
    This combined treatment is inappropriate for the marshland type; see treat-
ment 2-3 and 2-1 for further discussion.

    (2-5)   Remove Shallow Root Zone, Mechanically Stabilize
    This combined treatment is inappropriate for the marshland type; see treat-
ments 2-3 and 2-2 for further discussion.

    (2-6)   Remove by Scraping and Grading,
            Chemically Stabilize
    The effects of this combined treatment are essentially those discussed in
treatments 2-3 and 1-1.  The chemical stabilization method employed would
have to be instituted for erosion control rather than infiltration control for
the reasons previously given.  The erosion control provided would be expected
to be transient but might be sufficient to somewhat mitigate runoff impacts
resulting in a more rapid recovery than scraping and grading alone.

    (2-7)   Remove Plow Layer, Chemically Stabilize
    This combined treatment would result in effects similar to those discussed
for plow layer removal alone (treatment 2-1).  However, as discussed above,
erosional problems would be mitigated temporarily and recovery would be some-
what more rapid than that without stabilization.

    (2-8)   Remove Shallow Root Zone, Chemiaally Stabilize
    The effects of this treatment are discussed in treatments 2-2 and 2-7.
    Barriers to exclude people and to exclude both large and small animals are
discussed in the following treatments.

    (3-1)   Barriers to Exclude People
    It is assumed that exclusion would be accompanied through the use of
barbed wire fencing or some sort of mesh material such as chain link or Cy-
clone fencing, hardware cloth, or poultry wire.
    If a natural state is deemed beneficial, then nothing but benefit can
derive from the exclusion of humans.  Benefits due to increased "naturalism"
will accrue in direct proportion to  the  intensity of previous human use or
intrusion.  Numbers of species and their diversity will certainly  increase as
shy species return to  the marsh; this may be especially true  in  the case  of

                                   7-22

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migratory game fowl if hunting is terminated.  Vegetative cover, arid hence
primary and secondary productivity, will increase if these parameters had been
below maximum levels due to human trampling.  However, note that secondary
productivity is not likely to increase greatly due to the lack of macrophyte-
consuming herbivores which frequent salt marshes.  Finally, erodibility would
likely remain unchanged or perhaps even decrease; indeed, a negative erodibility
may exist for marshes since they are areas of deposition.

     Humans often find cause for interfering in coastal marshes, especially
 when they live near such areas.   Natural marshes are .doomed to self-destruc-
 tion due to sedimentation and consequent evolution (succession) into an.up-
 land habitat.   Part of this evolution is often the buildup of a bar at the  "
 tidal inlet(s),  hence,  the tidal flushing of the marsh is greatly reduced or
 eliminated.  As  this happens, conditions may become anaerobic as water temper^
 ature and salinity rises and, therefore, marsh flora and fauna die and decay.
 Such conditions  create a great nuisance near points of human activity, and
 they provide a haven for insects such as gnats and mosquitoes, further ag'gra-
 vating the condition of local human populations.  For exactly these reasons,
 and also to maintain a maximum level of productivity, marsh channels are often
 dredged regularly, especially at the tidal inlet(s).4  Such dredging also en-
 hances the flood control value of marshlands by providing open channels for
 runoff during precipitation events.  Thus, exclusion of human activity may not
 be taken to include channel dredging, especially if there is significant human
 activity in the vicinity of the contaminated area.  It should be noted that, if
 periodic dredging is performed,  the dredged materials must be checked for con-
 taminant level and, if found to contain unacceptable levels of contamination,
 must be dealt with accordingly.

     (3-2)   Barriers  to Exelude  Large Animals
     Not applicable to this land type.

     (3-3)   Barriers to Exclude Large and Small Animals
     It is assumed that exclusion would be accomplished through the use of
fine-meshed materials, such as screen with mesh diameter less than 1.0 cm, or  "
through the use of solid materials,  for example,  brick and cinder block.
                                     7-23

-------
     Animals such as mice, voles, raccoons, rabbits, possums, skunks,  weasels,
                                                 4
 and coyotes could be excluded by this treatment.   Mammals rarely live within
 a coastal marsh; generally they reside in nearby upland habitat and use the
 marsh only for forage, consuming seeds, some plants, insects, and other small
 aniirals.  Further, such mammals are noted to be "represented by relatively
 small populations."  Hence, exclusion of these creatures would have very little
 effect on the marsh ecosystem; a slight drop in species diversity and in the
 total number of species occurring in the marsh would be the only noteworthy
 effects.
     However, if a large area, e.g. 1 to 10 km2, were fenced off, the result-
 ing pressure on surrounding lands for forage and prey could cause significant
 harm to these lands.  This also could cause effects on nearby human popula-
 tions ranging from a minor nuisance to a significant economic hardship, for
 example, if the search for food led the displaced animals into human dwellings
 or into agricultural lands, of if predators were forced to prey upon domestic
 animals.

     Birds are the most important small animals in a coastal marshland from the
perspective of contaminant mobility.  Birds forage on seeds, benthic invertebrates,
open channel vertebrates, and insects; some of these prey species may concentrate
a contaminant through direct ingestion (e.g., worms and filter feeders), or
through their own food source which has already ingested a contaminant and per-
haps concentrated it to some degree.  Hence the birds may ingest significant
quantities of a contaminant and may then pass it through their digestive system
and deposit it offsite in feces or concentrate the contaminant in their own tis-
sues and then die or be preyed upon offsite.  The former seems more probable.
The same set of circumstances may also apply to fish and insects, in which cases
the latter event is more likely.

   Therefore it may be pointless to prohibit only horizontal crossings at the
 land surface; some sort of barrier to movements above and below the surface
 may also be desirable.  The effects of such barriers would be considerable,
 compounding greatly as the size of the area of exclusion increases.
                                      7-24

-------
    First, although net secondary productivity may change very little over a
long period of time, large short-term fluctuations may be expected as predator
species and prey species adjust to sudden partitioning from each other.  It
is especially the prey species which may explode in population with a sudden
halt to predation.  "Boom and bust" cycles of prey populations could be ex-
pected as the affected species increase their numbers, outstrip the available
food supply, and die back in catastrophic instances, whereupon the cycle is
renewed.  Ifcan be seen that, within this cycle, vast effects on the food
sources of the former prey species can be expected.
    Additional effects can be anticipated from the elimination of certain
species which spawn in the marshland.  These effects may range from the triv-
ial to the extreme depending on the size of the area fenced from the intru-
sion, the availability of alternative breeding sites, and the importance of
the species whose spawning grounds have been contaminated.
    Additional pressure on surrounding lands from avian predators and for-
agers displaced from the contaminated areas can be highly significant if sur-
rounding marshland is burdened beyond its capacity to produce food for the
                                                                   o
displaced birds.  This could, occur, for example, if half of a 20 km  marsh
were fenced and screened*  Thus, wildly fluctuating populations of predator,
prey, and forage species may occur offsite in areas unaffected by contamina-
tion.
    Finally, diversion of migratory waterfowl from contaminated marshlands
can not only have serious effects on surrounding areas, but may also irrevoc-
ably reduce the populations of sensitive species already pressured by general
habitat reduction, diversion from nesting or wintering sites by human activi-
ties other than habitat reduction, and hunting.  Such effects would be en-
tirely site-specific and cannot be addressed further for the general case.

    (4-1)   Asphalt Hard Surface Stabilization
    This treatment is outside the scope of work.

     (4-2)   Conarete Hard Surface Stabilization
    This treatment is outside the scope of work.

     (5-0)   Application of Sewage Sludge
    This treatment is outside the scope of work.

                                    7-25

-------
     (6-1)  High Presure Washing  (<3 om)
    This treatment is outside the scope of work.
     (6-2)   Flooding to SO am
    This treatment is outside the scope of work.
     (7-0)   Soil .Amendments Added
    ftiis treatment is outside the scope of work.

7.5   RECOVERY AFTER CLEANUP
    Recovery of coastal marsh ecosystems following clean-up operations is de-
pendent upon several factors beyond the characteristics of the clean-up oper-
ation itself.  Included in these factors are
        — the size of the area affected by the clean-up operation
        — location of the disturbed area relative to open water (areas
          adjacent to open water are subject to wave and tidal effects
          as well as fresh water runoff)
        — weather conditions following cleanup  (heavy rains would
          increase runoff erosion problems)
The sequence of events leading to "complete" recovery in a coastal marsh sys-
tem is not a multistep successional scheme such as is the case with develop-
ment of the classic climax forest.  Recovery in the marsh system would be
                                        •
essentially directly from disturbed state  (e.g. denuded) to the original
vegetation type (e.g., Spartina).  Graphs portraying a very general recovery
sequence are provided in Figures 7-3 through 7-5 (see Appendix B).
    The rate of recovery is largely determined by the erosional processes.
which characterize the marsh system and which may be intensified by cleanup.
The growth rate of vegetation is probably secondary to the physical processes
determining soil stability and substrate composition.  With the normal high
productivity rates characteristic of the marsh land type, once erosion is con-
trolled and revegetation initiated, recovery would be expected to proceed quite
rapidly.

7.6   QUANTITATIVE ASSESSMENT OF CLEAN-UP  IMPACTS
    Clean-up procedures in coastal marshes are scaled in Table 7-5 with re-
gard to impact on this ecosystem.  The scaling provides a relative view of
the length of time (in growing seasons) required for complete recovery to the
                                     7-26

-------
          SOIL STABILIZATION (Chemical)
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Figure 7-3.   Recovery of coastal  inter-tidal  marsh following  chemical

              soil stabilization and application of shallow  soil  cover,
                                  7-27

-------
           VEGETATION REMOVAL
                                                   SOiL REMOVAL
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Figure 7-4.   Recovery of coastal inter-tidal marsh following vegetation
             removal and shallow layer soil  removal.
                               7-28

-------
                    ACCESS BARRIERS
        D O
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Figure 7-5.   Response of coastal  inter-tidal
              marsh to the erection of fencing,
                        7-29

-------
 "natural" state after clean-up operations are terminated.   It should be
 stressed that these rankings are highly subjective in nature.  The specula-
 tive nature of these results is also emphasized by the location and meteor-
 ological factors which will influence recovery.
     The confidence with which this scaling is provided is somewhat inversely
 related to the size of the area affected.  This results from the uncertainties
 related to recovery processes and the potential for external influences on
 the marsh ecosystem subsequent to clean-up operations.  Hence the scaling
 here is much more relative than absolute  (more numerical than quantitative).
     The rationale for developing Table 7-5 is provided in Section 7.4.   General
conclusions drawn from Section 7.4 and Table 7.5 are presented in the following
section.
     Examination of Table 7-5 indicates that for the 0.01 km  area, the treat-
 ments may be grouped into three basic categories with regard to level of ef-
 fect and length of time to recovery.
     The lowest impact group includes construction of barriers  (3-1, 3-2),
 chemical stabilization alone (1-1), clear cutting  (1-2) and soil covering
 (1-7, 1-8).  Tne common characteristic of this group of treatments is gen-
 erally a lack of disturbance of the root and "native soil" structure. Or-
 ganic muds and root systems may mitigate erosion, which is an  important fac-
 tor in recovery of the coastal marsh.  Naturally, some disruption will occur
 from the means and equipment involved in the clean-up operations.  Hence, bar-
 rier construction  (3-1, 3-2) will have the least impact and soil covering
 (1-7, 1-8) the most within this relatively low impact group of treatments.
     Deep soil coverings  (1-8) may elevate the marsh to a level where the
 natural flooding cycles ar'e eliminated.  Recovery  in such areas would not
 lead to a marsh habitat, but creation of a new terrestrial habitat type with-
 in the coastal marsh.
     The group of treatments which have an intermediate level of effect in-
 cludes surface alteration  (scraping and  grading) alone  (1-4) or accompanied by
 chemical stabilization  (2-6);  stump and  root removal  (1-3);  and removal of
 the plow layer followed by  chemical stabilization  (2-7).  These clean-up
 treatments are characterized by a more severe  disruption of  the native soil
                                     7-30

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-------
structure than would be experienced with the lowest impact group.   Thus the
potential for erosion is more substantial and recovery would be delayed as
a result.
    In addition to increasing erosion, removal of roots and disruption or re-
moval of surface soils would remove the plant and soil materials which would
most enhance rapid habitat recovery.  Root sprouting, which would occur after
clearcutting (1-2) would be eliminated and revegetation would occur via root
systems in adjacent areas and seeds dispersed by wind and flooding of the area.
Revegetation by seeds would be hindered to some extent by surface disruption
and soil removal.
    The most deleterious set of clean-up treatments  include removal of the
plow layer  (2-1) and removal of the shallow root zone  (2-2).  The processes
of increased erosion and delayed revegetation, which are discussed above, are
enlarged by these treatments.
    As previously stated, the level of effect associated with any of the
treatments for the marsh land type  is area dependent.  That is, the effects
generally increase with size of the area affected.   This dependence can be
clearly  seen from the  importance of erosion  in determining recovery and the
importance of neighboring areas for revegetation.  With the smaller sized
clean-up areas, the surrounding area  would  act as  a  buffer for  both tidal
and  freshwater flooding events.  In addition, seeding  and root  sprouting  from
adjacent areas would be more  effective with smaller  cleared zones.  Larger
clean-up sites would benefit  less  from these erosion buffer and revegetation
processes,  and hence  slower natural recovery would be expected.
     Treatments which do not involve disturbing  the spill  area (i.e. natural
rehabilitation  (0-1)  and  barrier  construction (3-1,  3-2)  would not have area
dependent  impacts.   However,  some  increased stress in adjoining areas may re-
 sult with increasing  size of barrier  enclosures.
     As discussed in the preceding sections several of the alternative clean-
 up treatments may effectively destroy the marsh land type.   In these instances,
 recovery would not be to the original habitat form.  Such treatments include
 2-2, removal of the shallow root zone (less than 40 cm), and 1-8, deep soil
 covering (up to 100 cm).  The flooding cycle may be disrupted  to the extent that
 the former treatment results in an open water area  and the latter in a more
                                      7-32

-------
 dryland environment.   Because of these consequences,  these treatment types  may
 not be reasonable with regard to recovery  considerations.   The  effects of
 other treatments  are  probably not irreversible  although  subsequent  erosional
 damage may result in  an extended recovery  period,  particularly  for  larger
 treatment  areas.

 7.7   CONCLUSIONS
      Of the clean-up  treatments  considered, several were concluded  to be inap-
 propriate  for  the coastal marshland type.  Shallow and deep plowing is not  ap-
 propriate  for  containment of  spill materials.   Mobility  would be enhanced rather
 than retarded  by  this action.  Also, mechanical stabilization is inappropriate
 as  a mechanism for sealing the marsh soils against infiltration.  This is because
 infiltration control  has no clear meaning  for a frequently flooded  environment
 such as a  marsh.   For similar reasons,  some chemical  stabilizers are inappropri-
 ate treatments in coastal marshes.  However, for binding, soil materials together
 to  mitigate erosion,  chemical  treatments may be useful as  a temporary measure,
 particularly for  rather small  disturbed areas.

     Soil removal methods were  concluded to be the most deleterious  to marsh
 recovery.   Effects  of such treatment increases  with the  depth of removal.
 Deep  soil  coverings may have  similar effects.   In  fact,  appreciable eleva-
 tion alterations in either direction may effectively destroy the marsh hab-
 itat; recovery may be to more  terrestrial or to open-water  communities.  Chem-
 ical stabilization may mitigate erosion and thus aid recovery for all soil  re-
moval techniques from scraping and grading to removal of the shallow root
 zone.  Vegetation removal was  felt to be less destructive than soil removal
 treatments since the substrate materials which  supported "climax" vegetation
may remain largely undisturbed.  Clear cutting  is certainly less detrimental
than removal of all vegetation and roots.
    Barriers were felt to have little overall effect on the coastal marsh
although certain stresses in neighboring areas may result.
                                   7-33

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 7.8   COASTAL INTER-TIDAL MARSH REFERENCES


 1.   Bayly,  I.  A.  E.  and  W.  D.  Williams.   Inland  Waters  and Their  Ecology.
     Longman,  Australia,  1973,  316 pp.

 2.   Bourn,  W.  S.  and C.  Cottam.   Some  Biological Effects  of  Ditching Tide-
     water Marshes,  Res.  Rep.  19,  U.S.  Fish  and Wildlife Service,  1950,  30 pp.

 3.   Brown,  C.  L.  and R.  Clark.   Observations of  Dredging  and Dissolved  Oxygen
     in a Tidal Waterway, Water Resour.  Res.  4(6):1381-1384,  1968.

 4.   California Department of  Fish and  Game.   The Natural  Resources  of Capinteria
     Marsh and Recommendations for Use  and Development,  Coastal  Wetlands Series
     No. 13, 1976.

 5.   Chapman,  D. W.  Effects of Logging  Upon  Fish  Resources of the  West Coast,
     J. Forest., 60:533-537, 1962.

 6.   Frankenberg,  D.  and  C.  W.  Westerfield.   Oxygen Demand and Oxygen Depletion
     Capacity of Sediments from Wassaw  Sound, Georgia,  Bull.  Georgia Acad.- Sci.,
     1969.

 7.   Moore,  D.  and L. Trent.  Setting,  Growth and Mortality of Crassostrea
     virginica in a Natural Marsh and a Marsh Altered by Housing Development,
     Proc. Nat'l.  Shellfish Assoc. 61:51-58, 1941.

 8.   Smith,  W.  G.  Spartina "Die-back" in Louisiana Marshlands, Coastal Studies
     Bull. Special Sea Grant Issue, 5:89-96, 1970.

 9.   U.S. Dept. of Interior.  Interim Classification of Wetlands and Aquatic
     Habitats of the United States, U.S. Fish and Wildlife Service,  1976, 109 pp.

10.   U.S. Dept. of Interior.  A Study of the Disposal of Effluent  from a Large
     Desalinization Plant, Office of Saline  Water R§D Prog. Rep. No. 316, 1968.

11.   U.S. Environmental Protection Agency.  Impacts of Construction Activities
     in Wetlands of the United States,  Rep.  No.  EPA-600/3-76-045,  1976,  392  pp.

12.   Whittaker, R. H.  Communities and Ecosystems.  The Macmillan Company,
     London, 1970.
                                     7-34

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              PART  II
        MANAGED ECOSYSTEMS

CHAPTER 8,  AGRICULTURAL LAND AREAS
CHAPTER 9,  URBAN/SUBURBAN LAND AREAS

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                                  CHAPTER 8
                                 AGRICULTURE
8.1  OVERVIEW
     Lands used for the production of renewable resources and products con-
sumed as food, fiber, timber, and feeds for livestock are by definition agri-
cultural lands.  Crops raised for livestock feeds are discussed as forage,
permanent pasture, rangeland and the native pastures of woodlots.  Plant spe-
cies discussed range from local area natives to patented specialty cultivar
crops.
     In the broad sense, agricultural land could include tundra crops of li-
chens consumed by reindeer herds and the alpine meadows grazed by rodent her-
bivores.  A narrower view is held in this chapter.  Agricultural lands are
considered to be those managed to produce crops at commercially significant
rates for food, feeds, and fibers.
     In this chapter the impacts by cleanup are taken as short-term disturb-
ances because the vegetative component can be replaced precisely—for a price.
Mature deciduous trees as large as 20 to 23 cm in diameter and 8 meters tall
can be dug up, moved, and replanted in normal landscaping.   Sodding or reseed-
ing is likewise economically determined as are most decisions about rehabili-
tation of agricultural lands after cleanup of some contaminant.  As a routine
practice in the deciduous forest, a farm can be cleared of standing crops,
whether small grains or timbered woodlot, surface-mined for coal, the spoils
graded to the original contour, limed, fertilized, reseeded, and be back in
full production in 2 years.  Equipment used in surface mining is different
from earthmoving equipment for local road building, light building construc-
tion and farming.  In general, surface-mining earthmoving equipment is orders
of magnitude larger than usual construction equipment.
     Agricultural land is estimated to be from 526 million hectares to 930
million hectares in the United States  but a variety of figures are used for
agriculture depending on the author's interest.  The percentages of use are

                                     8-1

-------
approximately 25 percent for grazing in livestock production and 20 percent
for crop production.
     This chapter concentrates on farming in three of the natural ecosystems.
These are the hot desert of the southwestern United States,  where irrigation
supplies almost all agricultural water supply, the adjoining midcontinental
grasslands, and the formerly hardwood forest areas.  These are located as
defined in Figure 8-1.  Because it lies in the intermediate position between
the other two sources of agricultural land, and because almost the entire
grassland has been appropriated for agriculture, the prairie is described in
some detail with its crops.  The irrigated desert is confined to gently slop-
ing or flat terrain and the actual commercial use is a small portion of the
desert terrain.  Deciduous hardwoods occupy rolling to steeply sloping terrain
but agriculture is practiced on the flatter slopes which, as in desert, are
only a fraction of the total area.
     Agriculturally important, the midcontinental grasslands in Figure 8-1
reach from the 30th parallel in the south to the north beyond the Canadian
border.  Bordered on the west by the Rocky Mountains, they rise along the
105th meridian from the central Mexican border into Wyoming, turning north-
westly across 8 degrees of longitude before meeting the Canadian border.  The
eastern grasslands boundary lies along the 96th meridian with a major incur-
sion, generally northeast on a concave arc, from the Red River into south cen-
tral Ohio.  The east grassland boundary keeps west of the Mississippi River
to the Missouri River, crosses both in a few miles and arches north of the
Ohio River into central Ohio, north across Ohio, and turns generally west to
recross the Mississippi and parallel it to the northwest, crossing into Canada
on the 96th meridian.
     Topography of the agricultural prairie ranges from the western short
grass high terraces and alluvial fans across the plains to the steep hills and
lakes on the eastern fringes of Illinois and west Ohio.  The wide, level to
gently rolling plains with tree-clad streambanks in the prairie midsection
were the first to fall totally to the plow as croplands.  Hard red winter
wheats grow in -the southern prairie and grade into hard spring wheats in upper
Nebraska north to the Canadian border.    Annual precipitation in the winter
wheat belt ranges from 350 mm in eastern Colorado, Wyoming, and Montana to

                                      8-2

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8-3

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900 mm in eastern Kansas and Oklahoma, with warmer summers and longer growing
seasons than the spring wheat belt.  Precipitation" in the spring wheat belt
ranges from 300 mm in northern Montana to 600 mm in western Minnesota and
eastern Dakotas.  Generally, the separation of the winter and spring red
wheats is the isotherm of 18°C for the three summer months of growth into
ripeness.
     Precipitation regimes for prairie are shown in Chapter 2, Part I, and
these are basic figures around which agricultural needs are managed.  In the
west side near the Little Powder River in northeast Wyoming, annual rainfall
is 400 mm with an evaporation potential for 1500 mm in an area where wheat
and oat agriculture displaced mixed prairie grassland and artemesia species,
but the primary use became cattle-grazing because of the combination of lim-
ited rainfall and deficiencies in soil phosphorus and nitrogen.
     The physical characteristics of prairie soils reflect the environmental
regimes of the grasslands as shown in Table 8-1.  On the Missouri side, the
soils are deep and the rainfall is sufficient for tall grass.  The Colorado
side of the prairies have permanently dry subsoil and short grass.  Between
these boundaries lies the minimum line of annual runoff shown in Figure 8-1
as the 2-cm precipitation isogram.  The small grains straddle this precipita-
tion feature and their presence results in the designation of "breadbasket."

Table 8-1.  Relationship between annual precipitation, species composition,
            and moisture consumption, Rocky Mountains to Missouri transect
            of prairie (adapted from Jenny

Indigenous
Plant
Community
Grama grass
Buffalo grass
Wire grass
Bluestem grass
Bunqh grass
Bluestem grass
Sod grass
Depth to
permanently
dry zone
(cm)
30-36
60-80
85-115
absent
Approximate
annual
pptn
(cm)
<45
45-55
55-70
70-100
Plant
height
(cm)
10-35
45
75
110
Region of
observations
Eastern Colorado
Western Kansas
Central Kansas
Eastern Kansas and
Western Missouri
                                     8-4

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8.2  NATURAL PERTURBATIONS               .          .
     The significant agricultural event in physical and economic terms is the
                                  18
loss of soil by erosion processes.    These losses are generated by two dif-
ferent agencies, wind and water runoff.  West of the 2-cm isogram (Figure 8-1)
erosion is driven by wind.  East of the 2-cm isogram water runoff is the
principal erosive force.
     Publications dealing with erosion are numbered in the thousands.  One
agency field office has collected 2,500 reports, bulletins, and books on wind
erosion alone.   This author estimates runoff erosion publications number
more than twice as many as cited for wind erosion.  A simplification is called
for.
     The national wind erosion area is defined in Figure 8-2, while water
erosion sites are shown in Figure 8-3.
     Wind erosion data and its erosive forces are used in general predictions
of soil loss as shown in handbooks.   However, these must be used with cau-
tion.  Attempts to estimate wind erosion by land types across the spectrum of
suggested cleanup techniques faces a basic inadequacy in the primary data.
The data on wind speed and direction are generally collected at airport loca-
tions and a few electricity-generating plants.  These locations are represen-
tative of flat terrain rather than rolling, or hilly or mountainous regions.
The erosive power of wind may be seriously underestimated by using published
                                                               2     '
data to predict wind erosion damage for sites as small as 10 km  and smaller
and a few kilometers distant, since the extreme wind speed is pertinent.
Horizontal extrapolation of wind speed for offsite predictions faces direc-
tional shear, turbulent discontinuities, and orographic deflection of unknown
magnitudes.
     Wind-energy distribution maps are being undertaken at this time and may
alleviate a degree of the risk in making horizontal extrapolations from the
site of measurement to the cleanup site.  These maps will be useful in flat
terrain under overcast conditions.  They are not available for generic use
unless the cleanup treatments are restricted to the vicinity of airports.
     Probably the best return in deciding what sites should be chosen as can-
didates for cleanup would come from installing remote wind recording equipment
                                     8-5

-------
               Wind erosion
          Soil moisture-Wind velocity factor
              Very low   [1110-10%
              Low

              Intermediate ["JJ 26-60%

              High      ££381-150%

              Very high   QH > 150%
Figure 8-2.
Surface soil  moisture-wind velocity  soil loss
factor as a  percent of soil  loss at  Garden City,
Kansas (marked by X)  (adapted  from Agricultural
Research Service^).
                               8-6

-------
          Figure 8-3.  Rainfall erosivity index, based on maximum
                       30-minute intensity, from an average of
                       annual maximums (from Wischmeierl?).
and precipitation recorders at the sites.   From onsite data general regres-
sions would be possible with the weather station network data.   Without onsite
data the predictions are worthless since they can be highly misrepresentative
of the site.
     Rainfall intensity is the factor detaching soil fragments  and allowing
runoff to carry them away.  The data summarized in Figure 8-3 represent a
portion of the work done by Wischmeier and his colleagues."  .One of their sum-
maries  has been widely used in erosion predictions.  Two reviews of erosion
dislocation mechanisms and of detachment by wind  and water   lay the basis
for the widely used "Universal Rainfall-Erosion Equation."  This is based on
the kinetic energy of the rainfall and the maximum 30-minute intensity of
the storm.  It must be used by trained staff for particular sites.
     Plant growth, precipitation and climate are interrelated variables that
determine the erosive force exerted upon soil from which sediments are derived.

                                     8-7

-------
A general  integration  for  all  these  factors  is  shown  in Figure 8-4.  That
precipitation regime transects the natural ecosystems upon which the agri-
culture discussed  in this  chapter draws.  These are the natural forces that
test the wisdom  in selection of cleanup treatment, when the choice is field-
tested at  a  site.



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Figure 8-4.  Idealized effective precipitation, vegetation, and sediment .yield
             on west to east transect (adapted from Bennett and Donahue8).

8.3  MAN-MADE PERTURBATIONS
     All agriculture is a man-made perturbation that functions as a production
system because of the energy added to change it from a natural ecosystem.  In
                                     8-8

-------
the context of this chapter the alleviation of natural perturbations on
cleanup areas is addressed.                                 •
     The ideal preventative of wind and water erosion is a layer of wetted,
attached mulch.  For semi-arid lands the procedures were derived after the
enormous dust storms of the late 1930s.  The amount of mulch needed varies
with soil texture and species of crop.   A summary of application rates for
deciduous forest agriculture is given in Table 8-2.  As shown there seedling
plants hold soil losses to those comparable to tonnage quantities of straw
and stover (fodder) residues.  Plant residues and seedling grasses are almost
universally used for wind and water erosion control.

          Table 8-2.  Effectiveness of ground cover on soil erosion
                      loss at construction sites in deciduous forest
                      zones.
          Ground cover
Soil loss relative
 to bare surfaces
     (percent)
          Established seedlings
            Permanent grasses
            Ryegrass (perennial)
            Ryegrass (annual)
            Small  grain
            Millet and sudangrass
            Field  bromegrass
          Grass sod
          Hay (5 tons per ha)
          Small grain straw (5 tons per ha)
          Corn residues (10 tons per ha)
          Wood chips (10 tons per ha)
          Asphalt  emulsion (310 gal per ha)
         1
         5
        10
         5
         5
         3
         1
         2
         2
         2
         6
         2
          (Adapted from Notes et al.11)
     Large amounts of surface runoff are generated by acreages of cropped
soils.   Need for runoff control is intensified where the soil is bared and
                                    8-9

-------
multiple treatments are rated for runoff control in Table 8-3.   These are
the kinds of combined treatments that are evaluated in Section 8,.6,  Quanti-
tative Assessments.

           Table 8-3.  Control systems and relative effectiveness.
     System
             Components
Percent effectiveness
       1.
       2.
       3.

       4.
Seed, fertilizer, straw mulch plus
erosion structures, normal
Same as (1) except chemical (12
months protection) replaces straw
Same as (1) except chemical straw
tack replaces asphalt
Seed, fertilizer, straw mulch with
diversion berms plus sediment basins
Seed, fertilizer, straw mulch; down-
stream sediment basin using flocculants
Same as (3) without straw mulch
Chemical (12 months protection) sedi-
ment basin using flocculants
Same as (4) with seed, fertilizer
         91

         90

         91

         90

         96.

         94
         94

         96
     (Adapted from Hotes et al.11)
8.3.1  Runoff and Fertilization
     Runoff does more than produce sedimentation.  It can strip away organic
matter and mulches.  The plant nutrients lost in this way are some of those
recommended for reseeded areas in Table 8-3.  These nutrient losses were
studied quantitatively on field plots in 1917 and included nitrogen, phos-
phorus, calcium, and sulfur.   A recent review on phosphorus   losses from
                                                                     14
vegetables fertilized with manure placed losses at 70 kg/ha per year.
This is much more than many farm programs call for in fertilization regimes.
                                                                      4
Seasonal variations are pronounced with three identified loss periods.    Most
of the nitrogen and phosphorus loss occurred when the plants were newly estab-
lished and correspond to plowing and soil cover treatments evaluated in Section
3.6.
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     The 24 cleanup treatments are potential treatments for a variety of
soils and crops grown in the desert, grassland, or forest.  Representative
groupings of species for different purposes are shown in Table 8-4 with the
environment in which they are being produced.  A number of the contaminant
removal techniques include soil removal to a. specified depth and these depths
can be compared to the optimum root zone shown in Table 8-5 that each species
will permeate in deep soils.

8.3.2  Soil Compaction
     .The average density of weathered rock fragments in soil is approximately
2.5 times the density of water.  Taking the density of air as close to zero,
compared to rock, and a mixture of 50 percent air and 50 percent rock, the
average density of the mixture would be expected to be about 1.25 times that
of water.  For most soils with rock minerals as their principal ingredient,
the density is near 1.3.  In these soils there is a little more rock than
air if the density is judged from this discussion.
     Our hypothetical soil with 50 percent air would be a mass of small rock
fragments, with holes among the solid particles for the air.  The rock frag-
ments would not float because they are about 2.5 times heavier than water.
After a rain part of the air space is filled with water; in fact,the escape
of air can be seen where water is held on soil as in basin irrigation.  In
most soils the water wets the weathered rock particles and lubricates them
with the result that they slide across one another much easier wet than when
dry.
     The objective in compacting soils is to squeeze the particles close to-
gether so the volume occupied by the soil is smaller,  and the density is more
like rock than air.  When the density is near 1.5 to 1.7 plant roots do not
penetrate and plant growth is halted.   The water sprayed onto soil during
compaction is intended to lubricate the particles so they move across one
another under pressure from equipment.  A list of equipment and the depths
to which it compacts the root zone is given in Table 4-2 of Chapter 4.  These
are the depths to which the soil must be broken apart  for crop production if
the soils are intended for agriculture.
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Table 8-4.  Commercial crop species in managed ecosystems.

Ecosystem Forage/pasture Row crops/field crops
Desert alfalfa/ladino clover sugar beets/dry farmed
dry beans/dry fanned
vegetables/dry farmed
Grasslands sweet clover/ fescues corn /winter wheat
alfalfa/wheatgrasses soybeans /spring wheat
home grass sorghum /barley
sugar beets/rye
Deciduous clovers/1 espedosa corn
forests timothy/bluegrass soybeans
tobacco
vegetabl
Table 8-5. Rooting depths of agricultural
soils.*
/spring wheat
/oats
es
crops in fertile,
Orchards
citrus
apricot
peach
household
plants
apple
pear
peach
deep, well drained

Use/species
Forage
alfalfa
sweetclover
clover
timothy
Pasture
ladino clover
fescue
wheat grass
brome grass
1 espedosa
blue grass
Row Crops
cotton
sugar beets
dry beans
corn
*Examples are irrigated
Rooting depth
observed
(meters)
3-4
3
1-2
1
0.5
1-2
3-4
1-2
1
0.5
1.5-3
1-2
1.6-1.8
2
Use/ species
Field Crops
wheat
barl ey
rye
oats
flax
Orchards
citrus
peach
apricot
apple
pear
Row Crops
sorghum
soybeans
tobacco
vegetables
Rooting depth
observed
(meters)
2-3
2-3
2-3
2
2
2-3
2
5
8-10
2
2-3
1.5-2
1-1.5
1-4
desert and tall-grass prairie.
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8.3.3  Compaction and Runoff
     Any description of hydrologic effects originating from clearing large
tracts of cultivated land and then resurfacing with an impervious layer de-
pends on having generic predictors available.  The net hydrologic effects
from resurfacing do have an area-dependent generic factor.  Intuitively, the
surface-storage of runoff is related to precipitation intensity and to local
topographic features.  Resurfacing a flat, downwardly concave area creates
runoff storage capacity that may enhance groundwater supplies locally, but
resurfacing the rolling topography that formerly supported deciduous forest
has variable outcomes that are directly dependent on the area involved.
     Flood water runoff on the northeastern belt of the former deciduous
forests of Ohio was most highly correlated with watershed area.  However,
there were two distinctly different area-dependent watershed classes, so
different that square kilometers of area drained was used as the criterion
for dividing the classes.  The zone separating the two flood classes was
           o
50 to 75 km .  Runoff volume correlated best with drainage area size, rain-
fall intensity, and soil infiltration rate.  These three variables were sig-
nificantly different from random correlates (probability of random correla-
tion being less than 1 percent for all three variables taken together or
individually).
     The effects of compacting soil on local runoff from micro-areas are
well known.  Examples are streets that require storm drains and diversion
structures, parking lots, building sites, and construction areas in general.
Bar-Kochba and Simon  rated infiltration rate into surface soil as the most
important non-climatic variable in their eastern Ohio study.  Reduction of
surface water infiltration rates has the obvious effect of increasing runoff
and reducing groundwater recharge rates.  This effect is less damaging upon
     2
10-km  areas in humid precipitation regions than in semi-arid zones where
agriculture depends on pumped water for crop production.  Thus, the effect
of a compacted area in restricting groundwater recharge increases as the hypo-
thetical compacted area is moved westerly along a decreasing precipitation
gradient.
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8.3.4  Infiltration and Crops
     In an intensively studied area, eastern Ohio, the average water infil-
tration rate for grassed areas was more than twice the intake rate of adja-
cent row-cropped fields.   A soil-series-dependent influence on intake rate
was measurable but the relative infiltration rates were consistent among the
                                                      2
several soil series within the approximately 40,000-km  study area.  The
higher infiltration rate suggests why runoff is reduced and groundwater re-
charge increased by grass cover in deciduous forest agriculture.  Grass is
the preferred cover for drainage waterways because the stems reduce runoff
flow velocity and the abundant fibrous roots keep soil aggregates in place
against detachment.

8.4  EFFECTS OF CLEANUP PROCEDURES ON AGRICULTURE
     Qualitative descriptions of the effects that each of the different
cleanup treatments have on agricultural land are presented in this section.
The recovery of longer-lived agricultural crops to their precleanup produc-
tivity is briefly described in Section 8.5.  Quantitative assessment of the
impacts of cleanup treatments on agricultural systems is given in Section 8.6
in terms of the estimated times required for return to commercial productivity.
     The cleanup procedures described in this section have essentially three
different kinds of functions:  (1) treatments temporarily holding the con-
taminant in place, (2) treatments physically removing contaminants which
depend upon stabilization after the cleanup to prevent wind or rainfall ero-
sion until rehabilitation occurs, and (3) restriction of access into the
area by humans and animals.
     The projections made in this section are predicated on the information
which was available at the time the literature survey was completed.  Serious
revisions of these recommendations or rejections  of the projected  consequences
of the cleanup  in agricultural lands as more information is obtained appear
unlikely.  However, a number of publications will soon be available which are
indirectly related to cleanup techniques  in agricultural areas.   Surface min-
ing  in the Western states has resulted  in a great many techniques  being per-
formed for rehabilitation and reclamation of semi-arid and  arid lands.  These
techniques are  experimental  at present  and are being  evaluated for their

                                     8-14

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effectiveness at the different sites involved in surface mining.  In a few
years these experimental methods will have been published in journals which
carry reports of experimental research, and subsequently they will be in-
corporated into books and reports that will be of use to individuals con-
cerned with agricultural land cleanup after a contaminating event.  An ;exam-
ple of the kind of material to be anticipated from surface mining rehabili-
tation is the statement in the recently released operating handbook published
by Coal Age.  This handbook stated in its Foreword:
          This Coal Age operating handbook of underground mining
          is the first of a series of books planned to cover key
          areas of present day coal mining operations.  Future books
          in this series will cover strip mining and reclamation,*
          coal preparation, management, and maintenance"]
     As noted in Section 8.1 the agricultural areas described as impacted
represent the irrigated southwestern desert, the short grass irrigated and
dryland agriculture on the west side of the American prairies and grasslands,
and from the midcontinent east to the northeastern middle-west of the United
States formerly covered by hardwoods and river bottom deciduous forests.
The desert area represents a transect across the American Southwest, extend-
ing east from the Imperial Valley of California to those irrigated parts of
New Mexico and southwest Texas.
     The impact of the cleanup treatments on domestic animals is not covered
here.  It is presumed that rehabilitation of contaminated areas for produc-
tion of agricultural crops is a prerequisite to any animal husbandry enter-
prises.  The general crops for which cleanup impacts are described generally
fall within three groups of cultivars:  (1)  dryland and irrigated forage
crops, (2) commonly produced row crops and small grains, and (3) tree crops
ranging from the citrus orchards of the irrigated desert to the stone fruit
and pome orchards in originally deciduous forest areas.

     CO-1)  Natural Rehabilitation
     Unlike natural ecosystems, agricultural ecosystems have no capacity to
replace the destroyed commercial crop by the same species after cleanup.
Since agricultural crops are grown at an energy cost, when this energy is
*Emphasis added.
                                    8-15

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no longer supplied to the system the crops will no longer grow in commer-
cially productive quantities.  Waiting for natural rehabilitation to replace
an agricultural crop is an unacceptable procedure.  The time course of re-
turn from agricultural to natural ecosystems (Old Field Studies) has been
defined in Chapters 1, 2, and 3 under the heading Man Made Perturbations.
Further details for recovery sequences are in each of those chapters in
sections headed Recovery after Cleanup.  Those descriptions should be re-
viewed before forecasting the vegetational changes that will occur on aban-
doned farmland.  Ecologic journals are replete with flora succession studies
conducted on Old Field farmlands; they do not return to cultivars.

     (1-1)  Chem-leal S-tdb-Jt-izat-ion
     Containing the contaminant to diminish its redistribution has an imme-
diate and obvious benefit in both hazard reduction and in minimizing the size
of the area of ecological impact by later cleanup methods.  The function of
chemical stabilization in an agricultural system is to prevent redistribution
of the deposited contaminant.  More than seventy stabilizers are reviewed in
Appendix A; those suitable for use in agricultural fields have been desig-
nated in Table A-l.  With the exception of water-soluble emulsions, applica-
tion of a preferred chemical stabilizer requires a number of preparatory
steps before the field can be treated.  The area to be treated must be cleared
of vegetation or clearcut, stumped, and grubbed for tree crops, the slash and
vegetative refuse removed, and the fields smoothed and either graded or shal-
low plowed.  Most of the "preferred" stabilizers require direct mixing with
friable soils before they become effective in preventing resuspension of soil
and contaminant particles.  Because of this requirement for similar pretreat-
ment, the after effects from most of the chemical stabilizers will be very
similar on the farmlands treated.
     Chemical stabilizers which deflocculate soil particles, such as sodium.
chloride, sodium hydroxide, sodium carbonate, and Ca.lgon, are unsuitable for
use in western agricultural fields.  Although this class of alkaline and high-
sodium dispersants would stabilize surface soil, they can only be used in
areas which have high  levels of precipitation or access to free water in basin
irrigation.  The requirement for large amounts of water is to assist plants
in withstanding the effects of the saline soil that would be produced by these
                                    8-16

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stabilizers.  Leaching of the soil for a long period of time before green
manure crops would compound the damage these stabilizers produce by removing
free salts, resulting in the deflocculated smrface soil becoming impervious
to water infiltration.  Sodium adsorbed on clay disperses mineral particles
and prevents water infiltration.  Lack of soil moisture prevents subsequent
plant growth.  Growth of plants prior to extensive water leaching has been
found the simplest way to remove the effects of sodium deflocculants and
reconstruct soil tilth.  Surface incorporation of high quantities of organic
matter into the soil is mandatory at the time recovery is instituted.  Crop
residues from plants produced for organic matter (green manure), or addition
of mulch which is worked into the surface soil are standard procedures.
     Thirty-six "preferred" stabilizers for agricultural  use are listed in
Appendix A; 29 of these require reseeding or replanting of the crops to which
they are applied.  The remaining seven would not destroy the crop to which
the stabilizer was applied.  Appendix A has an additional list of 22 "accept-
able" stabilizers that are acceptable as alternates for use when the pre-
ferred stabilizer cannot be used.
     Only 9 of the 58 stabilizers can be applied directly on growing crops
without totally endangering their commercial value.  Two of the nine plant-
safe stabilizers require special handling for cropland application; three
of the nine that are safe for plants are  water emulsions of asphalt or
resin, and four are colloidal suspensions of protein.

     (2-2)  Clearcutting Vegetation
     Clearcutting orchards has the same effect as clearing coniferous and
deciduous forests insofar as crop production is concerned.  It is very
improbable that the operators of commercial orchards would depend on stump
sprouting, for those species in which it occurs, as a method of creating
a replacement orchard.  It is more likely that the trees would be removed
in toto (treatment 1-3).  Clearcutting of irrigated and nonirrigated for-
age is the normal harvesting procedures and would have no significant im-
pact in cleanup considerations.
     Row crops would be eliminated by Clearcutting if undertaken before the
normal harvest time.  Clearcutting is the method of harvest for a number of

                                    8-17

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row crops.  Examples are machine-harvested tomatoes, combine harvesting of
all the small grains, the harvesting of the various species of maize and
sorghums, and the mechanical picking of cotton crops.
     The physical structure of agricultural soils would be unaffected by
this treatment.  Organic matter content would be undisturbed and the fer-
tility levels unchanged.  There would be no change in the suitability of
seed beds for subsequent crop production.

     (1-3)-  Stumping and Grubbing
     With the exception of orchards, this treatment is inappropriate for
agricultural crops.  The effects of stump chippers and root rakes on east-
ern orchards would be similar to the effects described for deciduous forests
(Section 3.4).  This technique would, of course, eliminate any productive
capacity of an orchard by eliminating the producing plants.
     The physical effects on the soils in the eastern United States would
be due primarily to mixing the fertile surface layers with the relatively
infertile subsoil layers which the new tree roots would normally penetrate.
For desert orchard soils, there would be a small increase in fertility of
the lower segments of the profile and little decrease in fertility of the
upper parts of the profile,  Irrigated desert citrus would be eliminated
as a crop, but the effects upon the soil structure would be relatively mild
for most undeveloped irrigated desert soils.  The principal post-cleanup
effects would be the reduction in the fertility of the profile utilized in
the new mixed soil surface.  This would need correction before reestablish-
ing orchards in the eastern United States.  A secondary impact on eastern
orchards would be displacement of wildlife from hedgerows and fencelines
surrounding the orchards.  The measure of any economic impact would be the
potential for a reduction in production of those crops dependent upon dis-
placed animals for pollination.

     (1-4)  Scraping and Grading
     The consequences of surface scraping and grading upon any agricultural
crop is seasonally dependent.  Performing this operation when fields have
been harvested and are normally clear of crops would result in removal of
                                     8-18

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 substantial  portions  of the limited  organic  matter  in the  desert,   it  would••--'•;-
 have essentially no effect  in the grassland  areas but clearcutting  would make
 it  be an extreme perturbation in  eastern  orchard areas and on  any of the grow-
 ing eastern  row crops.   Surface soil  would be  laid  bare to wind  and water  ero-
 sion.   If the  soil were moist at  the  time of scraping and  grading Cpresumably
 by  heavy equipment such as  road graders,  land  scrapers,  and bulldozers), sig-
 nificant compaction would be  likely  to result  (the  effects of  soil  compaction
 are described  in cleanup treatments  2-3,  2-4,  and 2-5).
      The physical-chemical  properties of  most  agricultural soils would not
 be  greatly changed by scraping and grading (excluding compaction effects).
 The principal  effects would be increased  susceptibility to wind or  water ero-
 sion at  the  loosened  surface.  However, there  would be little  opportunity for
 excess  sedimentation  since  the basic  runoff  water diversion structures would
 be  unchanged.

      (1-5)  Shallow Plowing
     Shallow plowing  would  eliminate  an unharvested cultivated crop and, if
 the  crop were near maturity, would create a  trashy surface.  In the noncrop-
 ping season  its  impact would be minimal or insignificant since plowing is a
 normal operation of agriculture.   Plowing with disc equipment would have lit-
 tle  impact on standing orchards in either irrigated or rainfed agriculture.
 The most likely  effect would be soil compaction in the wheel tracks, and fur-
 row bottoms resulting from the use of plowshare equipment,  if the soil were
 significantly moist at the time operations were carried out.
     The effects overturning the plow layer has on the seed sources, vegeta-
 tion, and soil erosion processes of semi-arid rangeland sods-are overcome in
one or two seasons of regrowth.  Shallow plowing of less than 10 cm has little
 impact on survival of grasses but  afterward the roughened  surface is unsuit-
able for stabilizing by mechanical compaction because the  surface is trashy.
Clays and deflocculants would fall among the sod chunks and be lost  to subse-
quent stabilization techniques.
     Runoff is reduced by the increase of surface storage  in the roughened
area but groundwater recharge in the western shortgrass prairie would be un-
changed because the subsoils are permanently dry.  Surface erosion by wind

                                     8-19

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and water would be unchanged as grass cover is the cure recommended for both
erosion mechanisms.
     Damage to woody plants is of short duration.   Seed stocks would remain
and stump and root sprouts would soon revegetate the plowed rangeland.   Ani-
mal grazing on the new growth may be a problem in establishing regrowth.

     (1-6)  Deep Plowing
     Plowing to a depth of 40 cm would entirely disrupt any of the agricul-
tural crops during their growing season.  If the land were fallow, it would
eradicate standing orchards, pastures, and rangelands.  The fallow season im-
pact in areas with row crops and small grains would be relatively small and
approximately analogous to the consequences of shallow plowing (treatment 1-5).
Its effect in pastures and rangelands would be a reduction in productivity
of one or more growing seasons.  On shallow profiles in the short grass prai-
ries it is likely to produce a mixing of the A- and B-horizons, reducing plant
growth in subsequent seasons unless fertilization, and possibly reseeding in
the drier areas (less than 35 cm mean annual precipitation), is carried out.

     (1-7)  Soil Cover Less than 25 cm
     The significance of the impact on agricultural crops is a direct function
of the quality of the soil used for the cover.  A soil high in clay would sig-
nificantly impair aeration in orchard crops and production decline would begin
in a few months.  Attempts to add soil to areas with row crops would be im-
practical in terms of attempting to save the crop from the equipment.  The
minimum impact would occur in those areas which are grassed—either rangelands
or irrigated grasses.  Sweetclover forages would probably survive but the sur-
vival of  irrigated forages, such as alfalfa and ladino clover, is uncertain.
The basic soil fertility  in the root  zone would be unchanged by this depth of
cover.  The principal effects on seed bed  suitability  for cropping would be
fertility changes  from the soil added.  The soil used  for covering would prob-
ably not  be equal  in tilth and fertility to the soil  it covers up.

      (1-8)  Soil Cover 25 to 100 am
      It  is improbable that commercial agricultural  crops would survive the
addition  of a  soil cover  of this depth.
                                      8-20

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     (.2-1)  Remove Plow Layer
     This layer is about the minimum depth that can be removed as a controlled
cut by ordinary heavy earthmoving equipment.  Soil removal would create a
radical disturbance in agricultural land, almost regardless of the crops that
were involved.  It would totally destroy rangeland grasses, forage crops,
irrigated forage crops, small grains, and standing tree crops normally found
in orchards.  It would represent an especially severe disturbance east of the
2-cm -runoff isogram (Figure 8-1).   In the short grass prairie this treatment
accomplishes complete removal of the A- and a substantial part of the B-horizon
with the corresponding loss of the normal organic accumulation upon which the
fertility of the land is based.  Removal of the organically rich A-horizon in
this area would leave the soil with a severe nitrogen deficit.
     It is unlikely that any of the standing orchard species would survive
removal of the surface 6 inches of soil in the long term, outside of irrigated
areas.   Minimum effect would be anticipated in those deep-lying desert soils
that are normally irrigated for crop production.  These generally coarse-
textured soils allow a more rapid deep penetration of plant nutrients from
surface and shallow subsoil applications into the soil profile than occurs
with nonirrigated agriculture.  However, removal of this layer in irrigated
agriculture would destroy row crops produced there.

     (2-2)  Remove Shallow Root Zone
     On the shallower soils, removal of up to 40 cm of soil profile would
eliminate the fertilized root zone where the major dry-farmed crops are grown
(i.e.,  the infertile and highly calcareous regions of the short grass prairie  •
and in some of the caliche areas underlying irrigated deserts).  The resulting
truncated soil profile would more nearly resemble an unpaved roadway after
deep cuts to maintain a uniform grade in hilly terrain. • Shallow root zone
removal in the tall grass prairies would have relatively little effect since
the profile would still contain significant depth and amounts of organic mat-
ter below the soil cut away.  In crop lands formerly occupied by deciduous
forests, this treatment would destroy the agricultural potential of many of
the farmed areas,  eradicating the entire organic matter content of those soil
profiles as well as any residual artificial fertility elements applied to pro-
mote production of crops.  The phosphate-rich plow layer would be removed and
the surface remaining would be more suitable for nonagricultural purposes.
                                     8-21

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     Prevention of erosion is the immediate problem in soil management when
the root zone has been stripped to a depth of 40 cm.  West of the 2-cm runoff
isogram surfaces not naturally compacted or cemented are vulnerable to wind
erosion.  East of the 2-cm isogram, post-cleanup surface erosion by runoff
water would be a severe problem throughout the stripped areas.  Uniformly
removing 40 cm of soil surface would impair runoff diversion structures nor-
mally incorporated into farmlands.  Removal of the shallow root zone west of
the 2-cm runoff isogram would leave a smooth erodible surface in the place
of the roughened trashy surface normally utilized to prevent wind erosion;
that is, planting ridges, grass waterways, lister ridges, shallow terraces,
and the basic contour structures would be removed.  The basic contour struc-
ture could be maintained if care were taken during the soil stripping to take
the soil along field contours previously constructed for dry farming and
irrigation.
     The most severe impact in the excavated agricultural areas would be soil
erosion.  Other serious impacts relate to crop production, i.e., loss of the
soil organic matter, and hence loss of soil fertility.

     (2-3)   Remove Scraping and Grading, Mechanically Stabilize
     This treatment would have little impact on the internal structures nor-
roal to control of overland water flovf in agriculture.  The dikes, berms,
drainage ditches, grassed waterways, and overfall structures normally present
would be devegetated but not basically eradicated.  Scraping and grading on
grasslands in pasture- and rangelands would remove the surface organic matter
layer, subsequently reducing nitrogen availability in the grasslands.  The
principal consequence would be reduction of sedimentation onto lands adjoin-
ing the cleaned up area.  Scraping and grading, removing the loosened mate-
                                                            2
rial, and stabilizing the surface in areas as large as 10 km  would signifi-
cantly reduce sediment loss that would otherwise occur from scraping and
grading large areas.
     The effects of this treatment and removal of deeper layers of soil to
40 cm were previously described in cleanup treatments 2-1 and 2-2.
     The basic physical effects of this cleanup treatment on desert, grass-
land, and crops grown on the formerly deciduous forest lands have been de-
scribed in Chapters 1.4, 2.4, and 3.4  (under cleanup treatment 2-3) to which
                                    8-22

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 the reader is referred for added detail.  The effects and probabilities of
 wind erosion and runoff erosion by surface flow are discussed there and are
 not repeated here.  The descriptions in Chapter 2 (Prairies) are especially
 pertinent to cleanup in areas producing grasses under dryland conditions and
 for both native and reseeded vegetation on rangelands.
      The number of mechanical stabilization procedures that can be used in
 agricultural areas to be returned to croplands is limited.  The slopes in
 cropped areas are not usually steep enough to require that meshes, nettings,
 or plastic films be laid in the areas involved.   Furthermore, the areas; to
 be protected in farmed fields may be so large that substantial problems would
 arise from attempts to use plastic films as covers.   In a relatively short
 time the plastic would rip and tear and lose its effectiveness in containing
 contamination.   The otherwise usable mechanical  stabilizations would subse-
 quently require removal of an additional layer of soil because they are
 variations of the compaction process.
      The success of compaction methodology is directly dependent  on the
 amount  of clay in the soil which is compacted.   It is unsuccessful in the
 coarse-textured,  sandy soils frequently found in the  irrigated desert where
 reduction of pore space will be sufficient to destroy agricultural crops.
 Removal of shallow soil and mechanical  stabilization  by compaction in an
 orchard would kill  the trees in a  short time  due to the combined  effects  of
 poor aeration and severe moisture  deficits brought about  by  preventing pre-
 cipitation infiltrating into the soil profile of the  orchard.   If there is
 enough  clay in  the  surface soil  for compaction to  be  effective, compaction
 would be relatively permanent in agricultural terms.   Return of the area  to
 agricultural  productivity  would  require rippers,  subsoil  chisels,  repeated
 plowing,  and  other  action  to break  apart the  compacted layer and  free the
^oil aggregates  from the effects of prior  compression.  The  offsite surface
 flow of runoff would have  a major  impact on adjacent  areas.   For  areas  as
 large as 10 km  ,  uncontrolled runoff could be a  significant  factor  down-
 stream.   It is also  probable  that there  would be a drastic reduction  of the
                                  2
 groundwater in an area  where  10  km  was  mechanically  compacted  for  stabili-
 zation  purposes.   It  is unlikely that deflocculants such as  sodium  chloride
 would be  tolerated  for  lands  that were to  be  returned  to agricultural pro-
 duction,  so mechanical  stabilization or  short-term chemicals  are needed.
                                    8-23

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     (2-4)  Remove Plow Layer-} Mechanically Stabilize   '                  .
     The physical effects on the suitability of the cleaned-up area for agri-
cultural crops under this cleanup treatment are essentially the same as those
described under cleanup treatment 2-1.  The effects of mechanical stabiliza-
tion would be very similar to those described in treatment 2-3.  The princi-
pal differences relate to changes in organic matter and soil fertility induced
by compaction. .Where there is a relatively high water table and a high or-
ganic matter content below the compacted area (e.g., from a large root mass),
the fields would be subject to anaerobic decomposition of the organic matter
and the nitrogen would be reduced to ammonia forms with the potential for its
slow volatilization out of the soil profile.  Effectively, the nitrogen con-
tent of the cropland would be reduced compared to that which existed prior
to the cleanup, as in treatment 2-3.  Crop production could not be resumed
until the compacted area had been broken apart by mechanical means.

     (2-5)  Remove Shallow Root Zone, Mechanieal~iy Stabilize
     The effects of this treatment, insofar as agricultural use of-the land
is concerned, are very similar to those for plow layer and shallow root zone
removal.  Soil fertility would be reduced more than with removal of the plow
layer.  The deeper truncation of the soil profile would render revegetation
of the rangcland or native pastures unlikely without renovation in the semi-
arid short grass prairie region.  The desert soils on alluvial fans and
deeper profiles would be least affected by this treatment.  The deeper cut-
ting is likely to have significant effects on surface runoff control struc-
tures in the sub-humid and humid agricultural regions.  These control and
diversion structures would have to be reinstituted before surface stabiliza-
tion was undertaken if severe erosion effects are to be avoided.  The same
soil preparation methodology as described for treatments 2-3 and 2-4 would
have to be undertaken to neutralize soil compaction disadvantages prior to
reestablishing agricultural production.

     (2-6)  Remove Scraping and Grading,, Chemically Stabilize
     The physical effects upon agricultural production from this .treatment
are about the same as the combined  effects of cleanup treatments 1-4 and  2-3.
The effects of chemical stabilization would, not be as. long-lasting as the

                                    8-24

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 mechanical  stabilizing  treatments,  and  in  a number  of  cases  immediate reveg-
 etation with some  variety of the grasses is required where runoff may cause
 surface erosion.   Infiltration  into the soil profile is  controlled by the
 soil profile physical and chemical  characteristics  rather than by the chemi-
 cal stabilizer  applied;  hence,  it is unaffected by  this  treatment.
     The most suitable  chemical  stabilizers to use  in  an agricultural area
 are those which break down without  leaving toxic residues that would impair
 food values  or  plant growth  at  a later  time.  Some  of  the chemical stabili-
 zers described  in  treatment  1-1  would be the stabilizers of  choice in this
 treatment also.

     (2-7)  Remove Plow Layer, ChemJoally  Stabilize
     This is  a  composite  technique  described separately  under treatments 1-4
 and 2-6.  The overall consequence is one of reduced soil fertility with seed
 bed conditions  less suitable  for reintroduction of agricultural crops than
 those conditions resulting from  treatment  2-6.

     (2-8)  Remove Shallow Root  Zone, Chemically Stabilize
     Slicing  away the surface profile to a depth of approximately 40 cm would
 require  the greatest application  of chemical stabilizers.  Loss of the or-
 ganic debris  leaves the grassland soils susceptible to wind erosion,  and re-
 quires immediate reseeding with  grasses to stabilize the soil against runoff
 in sub-humid  to humid regions.   Removal of the loosened  soil minimizes sedi-
mentation problems downstream in the runoff area but increases flooding po-
tential  from  runoff out of areas as large as 1 to 10 km2.

     (3-1)  Barriers to Exclude People
     The most effective fencing for the exclusion of people would be  a chain
 link fence 6 to 10 feet high posing a physical restraint to trespassers.

     (3-2)  Barriers to Exclude Large Animals
     Design of fences to restrain cattle is a well developed technology.  Re-
 straining of  large game animals, such as elk and moose,  is not likely to be
a problem in most agriculturally developed areas.   Preservation of mechani-
cally and chemically stabilized surfaces would require  that large animal

                                    8-25

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traffic be restricted.  The hooves of domestic cattle and sheep would rapidly
break down either of the stabilized surfaces, especially since the animals
are prone to travel single file which concentrates the cutting action of the
hooves in a small path.

     (3-3)  Barriers to Exalude Large and Small Animals
     Attempts to eliminate small burrowing animals, such as ground squirrels
and gophers, would probably not be successful in large areas.  Containment
of these animals within the area would be more successful than elimination.
Consequently, fencing should be directed towards retention of animals pre-
sumed to have become contaminated in the area rather than to keep small mam-
mals out of the area.  Horizontally oriented small-mesh fencing in ditches
around the cleaned-up area and backfilling to provide a mesh ledge will pre-
vent the escape of both large and small burrowing animals.  Because these
animals have a relatively limited home range there is not much danger of
them transporting large quantities of contaminants significant distances.
Fencing of successive containment areas may be the most practical method to
deal with burrowing animals.  It is assumed that-larger animals can be suc-
cessfully excluded from contaminated areas until the appropriate cleanup
treatment has been selected for the area.

     (4-1)  Asphalt Hard-Surface Stdb-Llizat-ion
     Consideration of the use of this treatment  in an agricultural area
should be based on the understanding that it will be a very temporary cover.
Since the surface in most: agricultural areas will inevitably be disrupted
by stray cattle at some time soon after the material is  laid down, it cannot
be considered to be a permanent way of securing  a contaminant.  In areas
where surface soil experiences freezing and  thawing, such as the  grassland
and deciduous forest  areas, frost heaving is  likely  to be highly  destructive
to an asphalted or road-oil treated area in  a relatively few seasons.
     Application of hot road oil  or asphalt  to an  existing crop in agricul-
tural production would be  disastrous.   In most circumstances the  standing
agricultural  crop  would be removed, with the possible  exception of tree
crops.  An  agricultural crop must be  considered a  total  loss if the  appli-
cation  of asphalt  or  hot  road  oil is  necessary to  hold the contaminant  in
                                     8-26

-------
place until  subsequent cleanup treatments are undertaken.  Few agricultural
crops can resprout and puncture heavy asphalt surfacing.  The more damaging
effects would include compression tracks introduced by the heavy equipment
needed for transporting asphalt or hot road oil across the areas to be
treated.  Reclamation of the sites will be an extremely expensive process
since the oil-soaked or asphalt layers must be removed before agricultural
production can be resumed.

     (4-2)  Concrete Hard-Surfaoe Stabilization
     This is the most severe cleanup treatment proposed for use in agricul-
tural areas.  The expense of removing the concrete at a later date almost
entirely eliminates use of this cover from consideration.  It is inappropri-
                                           "2
ate for use in areas as large as 1 to 10 km .  The transportation costs of
recovering and disposing of the large amount of concrete that would be re-
quired for even 0.01 km  is almost certain to eliminate it from serious con-
sideration in areas where agriculture is to be resumed.

    . (5-0)  Application of Sewage Sludge
     The properties of urban sludge are significantly different from farm
manures and crop residues.  The use of sludge requires highly specialized
information in agricultural management practices.  Outright recommendations
for the application of sludge are unsafe.  Urban sludge is still suspected
of containing viable viruses and must not be allowed to come into direct
contact with the edible portions of plants.
     Sludge contains high quantities of industrial wastes at times.   Such
wastes contain heavy metals which are poisonous to man:  lead, cadmium,
chromium,  copper, and nickel.  Other elements hazardous to man (unless proper
soil management practices are used)  are aluminum in various compounds, ar-
senic,  selenium, antimony, and mercury.   Wastes from industrial electroplat-
ing processes are extremely high in these particular metals.

     Sludge supplies moderate amounts of nitrogen to cropland and increases
the organic matter content of soils.   Sludge application is not safe for
crops grown on acid soils of the former deciduous forest areas for either
human consumption*or as animal, feeds.  However,  the low solubility of the

                                    8-27

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heavy metal elements in neutral and alkaline soils minimizes these hazards.
Sludges contain from 1 to 6 percent nitrogen on a dry-weight basis.   Moder-
ate amounts of sludge would supply nitrogen to croplands and significantly
increase the organic matter content of the soil.  Five to 40 tons of dry
matter per hectare will supply nitrogen and organic matter in the alkaline
grassland and desert soils.  A decay series worked out for breakdown of the
organically contained nitrogen indicates that approximately 25 percent of
the nitrogen will be available to plants in the first four years the sludge
is in the field.  Approximately 30 to 60 percent of the nitrogen in the
sludge is in an inorganic form and would be readily available to plants in
the first year after the sludge application.  This soluble nitrogen poses
a potential hazard to groundwater supplies.  For this reason, large excesses
of sludge should not be applied in renewing the organic content of soils
following soil removal, scraping and grading of desert soils, or the addi-
tion of soil covers at a depth of 25 to 100 cm over croplands.

     (6-1)  High Pressure Washing (<3 mm)
     This cleanup treatment is outside the scope of work for this report.

     (6-2)  Flooding to SO am
     One-time flooding for redistribution of the contaminant into the soil
profile is outside the scope of work for this report.

     (7-0)  Soil Amendments Added
     Experiments in which a variety of materials have been added to soils
for the purpose of preventing plant uptake of hazardous material have been
unsuccessful.  Contaminants that are adsorbed onto the exchange surfaces
of soil minerals become available to plants either by contact exchange be-
tween the mineral surface and the root or by normal  solution processes.
Once a contaminant  is no longer retained on the surface  soil but has,  in
fact, penetrated the root  zone of agricultural  crops, the  suggested reclama-
tion procedure  is one of management that will produce  luxuriant vegetative
growth that  is  discarded.  This is accomplished by normal  management  prac-
tice,  soil  liming where needed in  the  deciduous area,  and  large  additions
of nitrogen,  potassium and phosphate  to  promote luxuriant  plant  growth where

                                    8-28

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 water supplies are adequate.  In the prairie and desert areas the limiting
 factor in land reclamation is the water supply.  Attempts to immobilize
 heavy metals to avoid plant uptake in the deciduous area have been unsuc-
 cessful.   Breakdown of the sludge releases nitrates, sulfates, and other
 acid forms which will readily consume the added lime and result in highly
 acid soils from which plants readily extract the injurious metals cpntained
 in the sludge.

 8.5  RECOVERY FOLLOWING CLEANUP
 8.5.1  Irreversible Changes
      The  complement of cleanup techniques discussed in this report has  no
 irreversible changes.   The limits to recovery of croplands are economic;  the
 question  is  whether to rehabilitate  the spill area,  soils, and crops.  The
 limits to the use  of the most  damaging  cleanup practices,  asphalt (treatment
 4-1)  and  concrete  (treatment 4-2), are  the cost and  effort required to  in-
 stall the asphalt/concrete cover  and remove it later.   The soils  under  these
 two hard  surfaces  are  damaged  more by compaction than  by seepage  of chemi-
 cals.   Compaction  can  be rectified mechanically,  as  highway reconstruction
 and relocation have shown.

 8.5.2  Rates  of  Recovery
      In this  chapter all the cropping systems  that are  discussed  have been
 created by energy  input  by man.  The rates  of  recovery  from  cleanup are
 directly  proportional  to the energy  input  expended for  rehabilitation in
 agricultural  systems.  None of the agricultural  systems described will re-
 habilitate themselves  to commercially viable  levels once cleanup has been
 performed.  Agricultural systems do not follow  the concept of species suc-
 cession through intermediate stages to climax as described in Appendix B
 for natural ecosystems.  They follow the growth, pattern of one individual
plant.
     Few of the environmental insults that may have extremely large impacts
 in natural systems would have significant impacts in nonorchard agricultural
systems.  Agricultural systems normally have structures appropriate for con-
trol of erosion by wind or water runoff.  The suggested cleanup treatments
need not destroy structures.
                                    8-29

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     Rangeland and pasture grasses would need reseeding and modest nitrogen
fertilization to recover their productivity.  Precipitation controls the
rate of recovery to be expected.  Unusually intense rainfall would float
the seed away and drought would kill the seedlings after germination.  In
normal weather, productivity on rainfed land is regained in 2 to 3 growing
seasons.
     Row crops, small grains, and field crops would need the same management
they are given each season for normal productivity.  The same recovery scheme
is appropriate to nontree irrigated crops.  Land leveling for irrigation is
more severe than any of the recommended cleanup techniques; only mechanical
stabilization and asphalt/concrete resurfacing are more disturbing than re-
sloping a field for irrigation.
     Orchards would require replanting after any but cleanup treatments 1-1,
5-0, and 7-0.  First fruit bearing would begin in 5 to 6 years and full pro-
duction by 10 to 12 years, including citrus.
     The general case for recovery of row crops, small grains, irrigated,
and rainfed pastures follows the  sequence imposed by natural disasters  such
as drought, fire, or flooding.  Tree orchards  likewise have as their recov-
ery model the growth and management steps that would follow renovation  of
an old, declining orchard.

8.6  QUANTITATIVE ASSESSMENT OF CLEANUP  IMPACTS
     The impact assessment assumes  in cleanup  treatments that the contaminant
is on  the  surface  soil  initially, and that  clearcutting  is carried out  before
any of the other temporary containment  and  removal  measures  (1-3  through 2-2,
2-3 through  2-8, and 4-1  and 4-2) are performed.   Tree crops are  assumed to
be  entirely  removed prior to  soil manipulation,  including  root  removal  (treat-
ment  1-3) .
      All erosion  control  devices  for  runoff are  expected to remain functional
 in the eastern hardwood croplands.
      The  impacts  in this chapter  require the intervention of man in almost
 all cases  after a cleanup treatment has been performed.   The multitude of
 corrective actions possible with four kinds of crops (forages and pasture,
 row crops,  small  grains,  and citrus,  stonefruit  and pome orchards), 24 cleanup
                                     8-30

-------
techniques, and three ecosystems (desert, grassland, and deciduous forest)
requires that the impact analysis be general and easily reproduced.  To that
end the impact indexing system is shown here for reference.
     Response Required to Resume Production
       No measurable impact, no correction needed
       Loss ends with crop directly exposed to contaminant
       Restored by normal agricultural practice for that crop
       One renovating technique required for crop next year**
       Two renovating techniques required for crop next year**
       Three or more renovating techniques required for crop
       next year**
       Renovation restores crop production in second growing
       season**
       Greater than 5 seasons for commercial crop
       Greater than 10 seasons for commercial crop
 Index
Number*
  0
  1
  2
  3
  4
  6
  7
  8
     The soil profile and climatic variables for pasture and grassed range
are discussed in Chapter 2.6.  Removing 40 cm of soil on the Rocky Mountain
side of the shortgrass prairie cuts into the alkaline B-horizons.  In that
region natural precipitation is too low for maize and orchards.  On the Iowa
side of the grasslands revegetation will recover almost spontaneously in
rainfed pastures.
     Cleanup techniques that are similar in impact intensity to normal farm-
ing are mowing (1-2) forage and pastures; shallow plowing (1-5) and scraping
and grading (1-4, 2-1) are similar to land leveling and are readily erased
by the usual seed bed preparation in row crops; and small grains.  Trees are
entirely traumatized by clearcutting (1-2); thus stumping and grubbing and
subsequent operations have no additional effect on the tree crop.  Trees in
orchards in the broad sense are totally destroyed by cleanup.  They survive
 *A11 treatments requiring unusual treatments for regaining productivity are
  equivalent to conditionally retrogressive (Index Number = N+2).
**Renovating techniques are early reseeding, early transplants, annual fer-
  tilizer additions, mulching, unusual irrigation, reterracing, recontouring,
  and other substantial, unusual treatments such as early summer defoliation
  of orchards.
                                    8-31

-------
contamination retention processes and soil amendment but not any of the
standard decontamination procedures where soil is moved about.
     No significant physical impact on the land occurs when barriers (3-0)
are used, but the economic impact caused to the owner by lack of resource
availability may be severe.  This is true in all the systems reviewed and
for normal fertilization (7-0).  Recommended chemical stabilizers (1-1) have
a similar impact across the species and soils and cause the loss of the
standing contaminated crop from the sprays and machinery used in the fields.
Clearcutting (1-1) forage and pastures is ordinary mowing and likewise costs
one cutting of one crop.  On row crops the entire crop seasons' product is
lost from clearcutting (1-1) unless it occurs at harvest time.  Sludge ap-
plications (5-0) are risky and surface applications are limited to fields
that grow animal feeds or to citrus orchards if injected into the subsoil.
     Rendering the surface impervious to precipitation entry has two effects,
deficits in subsurface stored water and downstream channel flooding, whether
it is accomplished by soil compaction (treatments 2-3, 2-4, and 2-5) or by
paving (treatments 4-1 and 4-2).  Groundwater in the treated zone is cut off
from local recharge and channel flow becomes proportional to the incidence,
intensity, and duration of precipitation once the surface threshold for wet-
ting is reached.   Erosion control structures would need to be maintained on
all far^s to handle the increased runoff from soil stabilizers.
     Loosening the surface soil by plowing (1-5, 1-6) and using soil covers
(1-7, 1-8) can lead to enormous runoff erosion losses but are otherwise non-
traumatic to forage, pastures, and small grains.  Land leveling fills is
similar to treatment 1-4, and erosion control terracing and contouring fields
are analogous to treatment 1-8.
     Hardsurfacing treatments (4-1 and 4-2) are likely to be acceptable on
a few acres if they are removed later or the land is condemned.  The concrete
or asphalt residues are not especially harmful to plants where they have been
mixed with the soil.  Removal of slabs might be expensive but hard surfacing
has features of, retention that other treatments lack.
     No treatments were judged entirely prohibited on a reclamation basis,
except some chemical stabilizers.
                                    8-32

-------
     Successful soil compaction increases runoff from rainfall to high per-
centages.  The proportion may increase to three-quarters of the local pre-
                                                                          2
cipitation, and downstream flooding is assured in areas as large as 1.0-km .
The degree of success in compaction sets the magnitude of impact afterward
for degrees of hazard.  An effective resurfacing depends on low organic
matter content in the soil and high clay.  These are soil characteristics
of the deciduous forest agricultural areas.  Cleanup treatments 2-3, 2-4,
and 2-5 have been given consistently high recovery time indices in ail non-
tree crops in deciduous areas, and lesser impact recovery time indices in
prairie.  Mechanical compaction is impaired in prairie fields by the high
organic matter residue in the profile, even if 40 cm of topsoil is removed
as in treatment 2-5.
     Lands in crops will have basic erosion control structures in place be-
fore cleanup where wind or water erosion is predictable; however, as the
area compacted increases in size, effects on underlying groundwater tables
and adjoining water sheds become more severe.  Community flood control
structures needed for 1.0- and 10-km  fields would exist in deciduous agri-
cultural zones.
     Desert crop system impact indices are shown in Table 8-6.  Removing
soil and chemically or mechanically stabilizing the fields has relatively
low impact because the coarsely textured soils pack together poorly and
plant nutrients are dispersed vertically throughout the profile.  Surface
soil removal has less impact on fertility than in other land types, and a
lower impact recovery time index rating.  Soil renovation practices needed
for recovery are ordinary irrigation management practices in irrigated
agriculture.  Soil chisels and heavy fertilization are common.
     Grasslands in small grains and irrigated row crops have deep lying
nitrogen reserves in the soil profile and are less impacted than the shal-
lower profile on the forested land types.  The relative impact index for
grasslands under cleanup is given in Table 8-7.  Soil cover in grasslands
may add weed seeds and be infertile, which has more impact than in forested
lands which are of lower fertility initially.
     Removing the upper profile has severe impact on later crops in the
deciduous forest land type by removing fertility in organic matter and nu-
trients.  The deeper cuts have greater impact as shown in Table 8-8.  Runoff

                                   8-33

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erosion is more of a problem because the deep cuts on pastures remove pro-
gressively more grass roots, that have bound soil together.  Row crops gen-
erally are on flatter slopes in well managed farms where erosion is less
severe than on scalped pastures.

8.7  CONCLUSIONS
     The preferred cleanup treatments are those which isolate the food chain
from man.  For small areas this may include fencing (treatment 3-1) or apply-
ing hard surfaces (treatments 4-1 and 4-2) to a small area with the expecta-
tion that they will be retrieved at a later date.  Shallow or deep plowing
to 40 cm is acceptable with the exception of eastern orchards which might
suffer moderate root pruning from deep plowing.  Seven of the chemical sta-
bilizers recommended for agricultural use would be appropriate in short-term
response to a contaminating event.
     Cleanup techniques which axe inappropriate in an agricultural area ex-
pected to be returned to crop production are those which involve dispersing
soil by the addition of sodium compounds in large quantities, particularly in
either desert or semi-arid grassland areas.  Removal of the shallow root zone
soil to 40 cm depth should not be considered for areas larger;than 1 or 2 hec-
tares because the problem of disposing of the contaminated soil is a greater
problem than other ways of decontaminating.  Although fenced areas to exclude
cattle have been recommended in the natural ecosystems as a preferred treat-
ment, they are not recommended here because of their position near the top
of the food chain leading to man.  Jt is almost inevitable that domestic
cattle would breach fencing in grassland or deciduous forest areas if the
land is left fenced for more than a few months.
                                   8-37

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8.8  AGRICULTURAL REFERENCES

 1.  Agricultural Research Service.  Predicting Rainfall-Erosion Losses from
     Cropland East of the Rocky Mountains:  Guide for Selection of Practices
     for Soil and Water Conservation.  Agriculture Handbook No. 282, U.S.
     Dept. of Agriculture, 45 pp.

 2.  Agricultural Research Service.  A Universal Equation for Measuring Wind
     Erosion—An Aid to Conservation Farming in the Great Plains.  U.S. Dept.
     of Agriculture, Special Report ARS-22-69, 1961, 20 pp.

 3.  Agricultural Research Service.  Wind Erosion Forces in the United States
     and Their Use in Predicting Soil Loss.  Agriculture Handbook No. 346,
     U.S. Department of Agriculture, 42 pp.

 4.  Alberts, E.E., G.E. Schuman, and R.E. Burwell.  Seasonal Runoff Losses
     of Nitrogen and Phosphorus from Missouri Valley Loess Watersheds.
     J. Environ. Qual., Vol. 7, No. 2, 1978, pp. 203-208.

 5.           .  Don't drift . . . avoid Wind Erosion.  Agribook Magazine,
     Vol. 3, No. 1, 1977, p. 10.

 6.  Bar-Kochba, Y., and A.L. Simon.  Factors Affecting Floods from Watersheds
     in Humid Regions of Northeastern Ohio.  Water Resources Bulletin, Vol. 8,
     No. 6, 1972, pp. 1235-1245.

 7.  Barrows, H.L., and V.J. Kilmer.  Plant Nutrient Losses from Soils by Water
     Erosion.  Advances in Agronomy, 15:  303-316, 1963.

 8.  Bennett, F.W., and R.L. Donahue.  Processes, Procedures and Methods to
     Control Pollution Resulting from Silvicultural Activities.  Misc. Publi-
     cation, U.W. Environmental Protection Agency, Office of Air and Water
     Programs, Washington, D.C. 1973.

 9.  Chepil, W.S., and N.P. Woodruff.  The Physics of Wind Erosion  and Its
     Control.  Advances in Agronomy, 15:  211-302, 1963.

 10.  Godfrey, R.S., ed.   Building  Construction Cost Data, 34th Annual  Edition.
     Robert Snow Means Co., Inc.,  Duxbury, Mass., 1975,  330 pp.

 11.  Hotes, F., L.K.H. Ateshian, and B.  Sheikh.  Comparative Costs  of  Erosion
     and  Sediment Control, Construction  Activities.  EPA-430/9-73-016, U.S.
     Environmental Protection Agency, Washington, D.C.,  1973,  205 pp.

 12.  Jenny, H.  Factors of Soil Formation.  McGraw-Hill,  New York, 1941.

 13.  Nuttonson, M.Y.  Wheat-Climate  Relationships and  the  Use  of Phenology in
     Ascertaining the Thermal  and  Photo-Thermal  Requirements of  Wheat.   Ameri-
     can  Institute of Crop  Ecology,  Washington,  D.C.,  1955,  388  pp.

 14.  Ryden, J.C., J.K.  Syers,  and  R.F. Harris.   Phosphorous  in Runoff and
     Streams.   Advances  in  Agronomy,  25: 1-45,  1973.

                                      8-38

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15.



16.



17.



18.
      D        ™
     , Fart  it  1924.
                    >  Z°n>  Natural  Vegetation.  Atlas of American Agricul-
'H'  WiSCh*eier-
                                            Erosion.  Advances  in Agronomy,
Wischmeier  W.H.  A Rainfall Erosion Index for a Universal Soil-Loss Equa
tion.  Soil Sci. Soc. Amer. Proc. 23: 246-249, 1959.

Wischmeier, W.H.  Use and Misuse of the Universal Soil Loss Equation
Soil Erosion, Prediction and Control.  Soil Conservation Society of
America, Ankeny, Iowa, 1977, pp. 371-378.
                                     8-39

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                                 CHAPTER 9
                           URBAN/SUBURBAN AREAS
9.1  OVERVIEW
     Urban/suburban areas differ from the agricultural and undeveloped areas
addressed in other chapters of this report in a number of ways that affect the
reclamation decisions and their impacts.

     The characteristics of urban/suburban areas that may influence the cleanup
strategies and procedures are diverse.  At one extreme, urban/suburban areas
include downtown areas of major cities which are completely covered by build-
ings and pavements, with residential and transient populations numbering hun-
dreds of thousands of people per square mile at any one time.  In contrast,
urban/suburban areas also include single-family homes on spacious lots with
only a small fraction of the land area covered by buildings and paved walkways
and roadways, and with populations of, at most, a few thousand persons per
square mile.  Between these extremes are various other types of land use
classes, such as commercial and industrial sections.  In addition, within an
area of certain overall characteristics, such as a residential area of single-
family homes, great diversity can exist.  Such places can have significant park
and recreational areas, scattered shopping centers and other commercial areas,
and undeveloped areas.*

     In addition to the diversity of population density and land use and the
degree of structural buildup, a particular area will have other characteristics
that influence the cleanup options.  Some of these factors are:  the surface
and subsurface hydrology of the area, the existing sewer and storm-drain sys-
tem, availability of equipment and manpower, the source of water supply (in-
cluding areas outside the affected area whose water supply might become
*Undeveloped areas within urban/suburban areas are not addressed in this chap-
 ter.  For these areas, the land type which best describes the undeveloped
 area should be determined and the appropriate chapter in this report referred
-to while recognizing that the greater likelihood of human exposure in the
 vicinity of urban/suburban areas may require special considerations as to the
 cleanup techniques.
                                      9-1

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contaminated unless care is taken), season of the year (e.g.,  whether the
ground is frozen or covered with snow), and short-term meteorology (e.g.,
humidity, winds, likelihood of rain).

     From this discussion it must be recognized that for any particular inci-
dent that releases contaminating materials in an urban/suburban area, the
courses of action and the effectiveness and consequences of such actions are
highly dependent on the specific situation.  However, it is useful to attempt
to describe a "typical" urban/suburban area.  One important characteristic is
the fraction of land area that is covered by (1) impervious surfaces such as
roofs, paved walkways and road areas,  and  (2) permeable surfaces consisting
of lawns, plants and trees, and bare earth.  Each of these types of areas
requires different cleanup techniques having different environmental impacts.

     The Census Bureau defines an "urbanized area" as a central city (or con-
tiguous cities) with a total population in excess of 50,000 plus the surround-
ing "closely held" populated areas, i.e., what is generally thought of as an
urban area and its suburbs (exclusive of large parks, golf courses, cemeteries,
etc.).  Based on 1970 Census data,  there were 248 such urbanized areas in the
United States with a total land area of 35,081 square miles and a total  popu-
lation of 118,446,566 people, or 58 percent of the total U.S. population.
Thus, according to the U.S. Bureau  of the  Census , the average population
density in urbanized areas is 3,376 people per square mile.

     National statistics regarding  the fraction of ground surface covered by
streets, buildings and permeable surfaces  in urban/suburban areas could  not
be found, so residential areas in  Santa Barbara, California,  were randomly
selected and surveyed to develop these statistics.  The population density of
the "place" of Santa Barbara  is 3,333 people per square mile6, which is  in
excellent agreement with the  average population density of urbanized areas,
so it is assumed that statistics for Santa Barbara are reasonably representa-
tive of  typical urban/suburban areas of the Nation.

     Within single-family  housing  tracts  of Santa Barbara, the approximate
coverage of the ground  surface area is 20  percent by buildings;  15 percent
by streets; 8 percent by driveways, sidewalks,  walkways, patios,  etc.;  and
the remaining  57 percent by  lawn and soil  areas.  Thus  within housing  tracts,
                                       9-2

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the  impervious surfaces comprise approximately 43 percent of the surface
area.  Such single-family housing tracts that are fully developed have popu-
lation densities of approximately 10,000 persons per square mile.

     The above statistics are applicable for small areas within fully devel-
oped single-family housing tracts.  Within a larger area, the permanent popu-
lation density is less because of commercial areas, open spaces, etc., and
therefore -the proportion of the area which is covered by impervious surfaces
may differ.  A recent study was concerned with the recharge of groundwaters
in suburban areas of Santa Barbara.   Within the area of interest of that
study, which can be described as primarily residential single-family suburban
housing tract areas (upper-middle to middle income housing), the population
density is approximately 3,500 to 4,500 persons per square mile (i.e., roughly
in agreement with the typical population density of an urbanized area).  The
ground surface consists of approximately 37 percent impervious surfaces (build-
ings, streets, etc.), 24 percent lawn and yard areas, 9 percent agricultural
areas, and 30 percent open space and native vegetation areas.  Thus it can be
seen that a surprisingly large percentage of a suburban area (39 percent for
the case of Santa Barbara) consists of areas having "rural" or "natural" char-
acteristics.  However; the percent of surface which is impervious is not much
less than the value of 43 percent within housing tracts.

     It is estimated that approximately one-half of the rainfall from small
storms in Santa Barbara that falls on impervious surfaces finds its way to
storm sewer systems with the remaining one-half soaking into the ground.4
Therefore,  if the cleanup option is to flush the contaminant from building
roofs,  streets,  and walkways with water, approximately one-half of the con-
taminated water can be expected to soak into the ground unless measures are
taken to prevent this occurrence.

     Other data for the upper Santa Ana Valley in California indicate that the
fraction of land area which is covered by impervious surfaces varies linearly
from approximately 20 percent for an area that is 40 percent urban developed
to approximately 70 percent for an area that is 100 percent urban developed.4
For the Santa Barbara area,  which is approximately 60 percent urban developed,
the ground surface should be approximately 38 percent covered by impervious
surfaces.   This  is in excellent agreement with the actual value of 37 percent.
                                     9-3

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     In summary, the characteristics of small areas of 0.01 km  in size withir,
an urbanized area may vary considerably.  If one randomly selects a small area
within an urbanized areas, the probability is approximately 40 percent that
the area will have "rural" or "natural" characteristics rather than urban
characteristics.  As the area, of contamination is increased to the maximum of
10 km2 used in this study, the characteristics of the area approach the aver-
age characteristics of 60 percent urban developed with 37 percent of the land
covered by impervious surfaces and a population density of approximately 3,400
people per square mile.

9.2  NATURAL PERTURBATIONS
     Natural perturbations that produce some of the environmental effects that
could occur from cleanup treatments in urban/suburban areas include most of
the natural disasters, i.e., floods, fires, earthquakes, and severe storms.
In most cases, these natural perturbations will have significant effects on
man-made structures; whereas the reclamation treatments will have little ad-
verse effects.  In contrast, some of the reclamation techniques will typically
have more adverse effects on the "natural" ecology of urban/suburban areas than
do natural disasters.  For example, removing 40 cm of soil will destroy essen-
tially all vegetation, whereas no natural disaster is likely to produce this
degree of total destruction.

9.3  MAN-MADE PERTURBATIONS
     A number of activities of man can cause destruction to the man-made envi-
ronment and the natural environment of urban/suburban areas.  Such activities
include war, urban development or redevelopment, and spills of hazardous ma-
terials.

     The normal construction activities associated with urban development or
redevelopment usually employ most of the cleanup techniques that are discussed
in Section 9.4.  Typically, earthmoving and destruction of vegetation are re-
quired to prepare land for development.  By design, the land is not allowed
to return to its natural condition; instead, lawns are established and desir-
able trees and  smaller plants are planted.  Within a few months to a couple
of years the desired vegetation, except large trees, is established.
                                      9-4

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      Spills  of materials  that  are  hazardous  or  ecologically damaging  require
 cleanup techniques  identical or  similar to the  treatments  for  cleanup of  radio-
 active material.  Again,  in the  urban/suburban  situation there is usually no
 significant  lasting effect  (except for  social and  economic impacts) because
 the  artificial man-made environment that is  disturbed by the treatment can
 usually be reestablished  relatively quickly.  An exception to  this  statement
 would OCCIT  if the  contamination could  not be cleaned up to the necessary de-
 gree,  forcing  restriction or abandonment of  an  urban/suburban  area  or removal
 of structures.  However,  even  in this case the  impact is primarily  social and
 economic, with little additional effect on the  natural  environment.

 9.4   EFFECTS OF CLEANUP PROCEDURES  ON
      URBAN/SUBURBAN AREAS
      The urban/suburban environment  is  largely  a man-made  environment,  in
 contrast to the natural environments of undeveloped areas.   Some cleanup  op-
 tions  that might^cause significant  environmental impact in  undeveloped  areas
 (e.g., vegetation clearing, removal of  soil  layers, and applying soil  cover)
 are common activities in  urban/suburban areas.

      Because of the greater hazard to humans from contamination of urban/
 suburban areas, a greater cleanup effort  is not only justified but required.
 To clean up the area to the maximum possible extent, a series of cleanup  tech-
 niques would probably be used rather than a single technique.  The effective-
 ness of the cleanup is primarily limited only by the monetary cost of carrying
 out the tasks.  For example, contaminated roofs could be stripped of shingles
 and reshingled if necessary.  Contaminated pavements could  even be removed.
 In an urban/suburban area, virtually the entire surface area could be stripped
 and removed without significant  impact on the "natural" ecology—but with a
high monetary and social cost.

     Treatments that can be used in urban/suburban areas to remove contami-
nants or to reduce the hazard from such contaminants can be grouped into
those that lend themselves to application for lawn, plant,  and soil areas in
yards and parks (treatments 1-1 through 7-0 in the following list),  and those
 that lend themselves to application for hard, relatively impervious, artifi-
cial surfaces, such as building roofs, walkways, and paved areas (treatments
8-1 through 8-7 in the following list).
                                     9-5

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         Treatments for Lawn, Plant and Soil Areas*

         0-1  Natural Rehabilitation-
         1-1
         1-2
         1-3
         1-4
         1-5
         1-6
         1-7
         1-8

         2-1
         2-2
         2-3
         2-4
         2-5
         2-6
         2-7
         2-8

         3-1
         3-2
         3-3

         4-1
         4-2

         5-0

         6-1
         6-2

         7-0
Chemical Stabilization
Clear Cutting Vegetation
Stumping and Grubbing
Scraping and Grading
Shallow Plowing
Deep Plowing
Soil Cover Less than 25 cm
Soil Cover 25 to 100 cm
       Plow Layer
       Shallow Tloot Zone
       Scraping and Grading, Mechanically Stabilize
       Plow Layer, Mechanically Stabilize
       Shallow Root Zone, Mechanically Stabilize
       Scraping and Grading, Chemically Stabilize
       Plow Layer, Chemically Stabilize
       Shallow Root Zone, Chemically Stabilize
Remove
Remove
Remove
Remove
Remove
Remove
Remove
Remove
Barriers to Exclude People
Exclude Large Animals
Exclude Large and Small Animals
Asphalt Hard Surface Stabilization
Concrete Hard Surface Stabilization
Application of Sewage Sludge
High Pressure Washing (<3 mm)
Flooding to 30 cm
Soil Amendments Added
          Treatments for Hard,  Impervious,  Artificial  Surfaces
          8-1  Washing with High-Pressure Water (Firehosing)
          8-2  Vacuuming
          8-3  Sweeping
          8-4  Mechanized Street Flushing
          8-5  Surface Removal  Techniques
          8-6  Other Removal Methods
          8-7  Containment

    ' In general, treatments 1-1 through 1-8 are not treatments for the removal

of a contaminant (although 1-2 is a removal treatment if contamination of
vegetation is significant).  Instead, these treatments are those that might be
*This list of treatments applies to all land types, and is included for a com-
 plete discussion.  Some of these treatments are not appropriate for urban/
 suburban areas.
                                     9-6

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 applied  as  a  temporary measure  to  hold  the  contaminant  in  place  to  prevent  its
 redistribution.   In  the  case  of treatments  1-5  through  1-8,  the  immediate haz-
 ard  is reduced because the  contaminant  is shielded  by soil cover.

     Treatments  1-1  through 7-0 apply to land types in  general.  • Most  of these
 treatments  also  apply for the lawn, plant,  and  soil areas  (yards) of urban/sub-
 urban areas.  However, in the urban/suburban situation  some  of the  treatments
 may  be more appropriate  than  others and the environmental  impacts may  be sig-
 nificantly  different than would be the  case for an  undeveloped or, agricultural
 area.

     Because of  the greater potential hazard from a contaminating incident  in
 a populated area, several of  the treatments might be used  on urban/suburban
 yards so as to reduce the hazard to the maximum practical  extent.   For example,
 a stabilizer might be applied to lawns  to hold  the  contaminant in place while
 the  sod is  removed and any  residual contamination hazard might be further re-
 duced by turning over the soil  before resodding.

     Depending on circumstances it may  be desirable or  it  may be -undesirable
 to coat the ground with a sealant, such as  liquid asphalt, so that  contami-
nated water from washing of roofs and walkways  will run off into the storm
drain system rather than soak into the  soil.

     Flushing with water or blowing with compressed air may remove the con-
taminant from the foliage of plants if  the resuspension in air or the washing
into the soil of the contaminant is acceptable.   Otherwise, the contaminant
can be fixed onto the leaves of the plant by a  stabilizer  and then the plant
can be pruned, defoliated, or removed.

     Some of the treatments which are used for  cleanup of hard artificial
surfaces, such as sweeping and firehosing,  cam  also be used with some limited
effectivess on frozen ground.

     Each of the potential treatments is discussed below in the order listed.
The discussion is based primarily on Owen et al.  and to a lesser extent on
Bennett and Owen  and Cobb and Van Hemert.
                                     9-7

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9.4.1   Lawn,  Plant and Soil  Area Treatments
     (0-1)   Natural Rehabilitation
     Because of the proximity of humans, it is assumed that doing nothing to
clean up urban/suburban areas is not a viable option; rather, any contamina-
tion will have to be reduced to some acceptably low level.   Therefore, natural
restoration does not apply for urban/suburban areas.

     (1-1)  Chemical Stabilization
     The purpose of the chemical stabilizers is to hold the contaminant in
place, to prevent redistribution until the contaminant can be removed.  The
properties of the general classes of chemical stabilizers are given in Appen-
dix A, Soil Stabilizers.  Chemical stabilizers vary as to their effectiveness
and longevity in holding the contaminant in place and in their effects on
vegetation.  Some of the stabilizers cannot be used without necessitating
subsequent removal of the vegetation>

     In  lawn areas the sod will undoubtedly be removed and the lawn area re-
established with seed or resodding,  in which case the use of chemical stabi-
lizers has no significant adverse environmental effect.

      (1-2)   Clear Cutting Vegetation
     For lawns  and ground covers, this  treatment consists of mowing or perhaps
renovating down to the soil.  There  is  no  significant adverse effect  from mow-
ing or renovating, since the root zone  is  not damaged and the grass or ground
cover grows back relatively  quickly.

      In  general,  clear cutting  of bushes and  trees  is to clear the ground  sur-
face  for plowing or  soil removal.   Many bushes,  and some  trees,  will  reestablish
from  the r-oot  systems of  the clear-cut  vegetation,  although  not  as quickly as
grass.   The  time to  reestablish varies  from  a year  for  small  shrubs to many
decades  for  large trees.

      (1-3)   Stumping and Grubbing
      This  treatment  contributes little  additional  impact  to  that which occurs
when the trees and bushes  are  cut down.  If  trees  are cut  down,  new  trees  would
probably be planted so  removal of stumps is  desirable.   Shrubs would  have  to be
replanted rather than allowed to propagate from existing root systems.

                                  9-8

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      (1-4)   Scraping and Grading
      The removal  of up to 5  cm of soil  by scraping  and  grading  is  equivalent
 to removing the sod layer for lawns.  Removal  of this layer  will not have any
 effect  on trees and larger shrubs unless  they  must  be removed to provide room
 for equipment.  Smaller plants may be damaged,  but  they would likely be re-
 moved in any case to ease the task of scraping and  grading.

      (1-5)   Shallow Plowing
      The disturbance of the  upper 10 cm of soil by  shallow plowing will have
 more significant  effects than treatment 1-4.   If plowing is  done close to
 small plants they may be killed by root disturbance; but most trees will not
 be killed or seriously damaged by plowing to this depth.

      (1-6)   Deep  Plowing
      Deep plowing (10  to 40  cm)  will have more  serious  effects on  trees.  Most
 trees in  yards and parks have shallow root systems  because of improper water-
 ing;  plowing  to a depth  of 40 cm will damage these  root  systems.   However, be-
 cause of  interference by larger  roots it  may not  be possible to plow close to
 the  tree, so many trees  that  might otherwise be killed by close plowing will
 survive.

      (1-7)  Soil  Cover less than  25 am

      (1-8)  Soil  Cover 25 cm  to  100 am
      If not only  a temporary  treatment, and if not  removed within  a relatively
 short time period, soil  cover  in  an urban/suburban  area will change grade lev-
 els  and affect water drainage around buildings.  As a short-term measure,  add-
 ing  soil cover will not  affect trees and  larger bushes.   Smaller bushes may be
 covered and killed and lawns will die in  a short time period.

      Except for palms, trees cannot tolerate the permanent addition of soil
unless measures are taken to ensure adequate air circulation about the trunk
down  to the original grade level.  If soil is placed around the trunk,  rot
will  set in and the tree will eventually die.  The  addition of 25 cm of soil
will have no effect on trees if it is kept from the trunk.  A 100-cm layer
requires a larger space around the trunk to ensure  adequate air circulation,
and can be expected to affect the root system of the trees by oxygen depletion.
                                     9-9

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     There may be practical limitations on using soil cover.   To cover the
ground to a depth of 100 cm in one square kilometer of the typical urban
area, whose surface is comprised of 63 percent soil and vegetation, requires
824,000 cubic yards (630,000 cubic meters) of fill soil.

     Treatments 2-1 through 2-8 are designed to remove a contaminant from
yards so that it can be transported to a safe place.  These treatments are
straightforward—by whatever means are practical, sod and layers of soil are
removed until the residual contamination is at an "acceptable" level.  In the
urban/suburban situation, uncontaminated topsoil will usually have to be
brought in as fill to restore yards to the original grade level.  Stabilizers
might be used to prevent erosion, but stabilization techniques which have
adverse effects on the revegetation of the area, such as compacting, would
not be required.  Stabilization is required only for a relatively short time
period while lawns become established.

     The depth to which soil can be removed from around a tree without injur-
ing or killing the tree depends on the proximity of the root system to the
ground surface.  This, in turn, primarily depends on the type of tree, its
location, and the watering it has received.  Some of the most desirable trees,
such as maples and some oaks and conifers, have relatively shallow root sys-
tems.  Also, because of frequent and shallow watering, trees in yards often
develop root systems relatively close to the ground surface; such trees ar&
more susceptible to damage from soil removal than are trees which rely on
rainfall.

     For lawns, using sod cutters and rolling up the sod for hauling away is
effective.  Past experiments indicate that this procedure will remove 98 per-
cent to 99 percent of a contaminant.  Removing sod by garden tractors or by
hand shoveling appears to be less effective in removing contaminant than us-
ing a sod cutter, although the data are limited.

     Where access is not restricted, larger machinery such as bulldozers, back-
hoes, road graders, etc., may be used to scrape off the top layers of soil.
Typically, for large working areas, removal of 5 to 10 cm of soil will  sig-
nificantly reduce contamination, although results are quite variable.  For
smaller working areas, such as typical urban/suburban yards, the effectiveness
of heavy machinery is limited and it must be supplemented by hand  labor.
                                     9-10

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      The magnitude  of  the  disposal  problem  associated  with  removing  contami-
nated soil,  and  the task of  hauling in uncontaminated  soil  for  fill, must be
appreciated.   Removing the plow  layer of  soil  (10  cm)  from  the  "typical"
urban/suburban area requires  the disposal of 82,400  cubic yards (63,000 cubic
meters) of contaminated earth per square  kilometer,  compacted to  the original
density.  Disturbed earth  takes  up  more volume than  undisturbed earth, prob-
ably  by a factor of 20 to  40  percent, so  removing  the  plow  layer  of  soil from
a 10-km2 typical urban/suburban  area requires disposing of  approximately one
million cubic  yards of contaminated earth and hauling  in the same volume of
uncontaminated earth for fill.   Removing  soil in the shallow root zone quad-
ruples these requirements.

      (2-1)  Remove  Plow Layer
      In the urban/suburban situation there  is little impact from  removing the
top 1.0 cm of soil from  yards.  Lawns can be reseeded or resodded, and plants
and small bushes can be replaced.   Only very shallow-rooted trees will be
seriously damaged or killed by the  removal of soil to  this depth.

      (2-2)  Remove Shallow Root  Zone
     Whether or not a tree is killed from removal of 40 cm of soil depends
on the particular tree and its situation; however, in  general,  the removal
of this amount of soil will probably kill most trees that do not have signif-
icant taproots.  The use of heavy equipment will cause more damage than care-
ful use of hand tools.
     , . : » " ' , , ".  •
      (2-3)  Remove Seraping and  Grading,  Mechanically Stabilize
     Removal of the top 5 cm of  soil will have no significant effect on trees
and large bushes.  This is equivalent to removing the  sod layer from lawns.
The lawns can be reseeded or resodded,  and smaller plants that have been
removed can be replaced.  Compacting of the soil for erosion control would
not be required;  other means of  stabilization that are practical would have
no significant adverse effects.
     (2-4)  Remove Plow Layer, Mechanically Stabilize
     The impact is the same as for treatment 2-1, provided compacting or hard-
surface stabilization techniques are not used.

                                    9-11

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     (2-5)  Remove Shallow Root Zone, Mechanically. Stabilise
     The impact is the same as for treatment 2-2, provided compacting or
hard-surface stabilization techniques are not used.

     (2-6)  Remove Scraping and Grading, Chemically Stabilize
     The impact is the same as for treatment 2-3.

     (2-7)  Remove Plow LayeT3 Chemically Stabilize
     The impact is' the same as for treatment 2-1.

     (2-8)  Remove Shallow Root Zone, Chemically Stabilize
     The impact is the same as for treatment 2-2.

     (3-1)  Barriers to Exclude People
     This technique is probably practical only as a short-term measure while
the contaminant is removed.  Barricading people from urban/suburban areas to
which they normally have access for  longer than a few days or weeks would
cause considerable social disruption and adverse economic impact.

     (3-2)  Exclude Large Animals
     Any barrier to exclude large animals would also exclude people, which is
unacceptable in an urban/suburban area  except for a brief time period.  Because
of the relative scarcity of large animals in urban/suburban areas, there would
be no significant impact on them.

     (3-3)  Exclude Large and Small Animals
     Except for very small areas, exclusion of small animals would be difficult.
Household pets would have to be relocated with their owners or impounded.  Wild
animals, primarily birds and rodents, might multiply.  They also might become
vectors for spreading a contaminant  to  other areas.

     (4-1)  Asphalt Hard-Swfaoe Stabilization
     Probably in most cases asphalt  hard-surface stabilization would be com-
bined with some degree of plant and  soil removal,  thus entailing additional
logistic and economic problems both  for initial  treatment and subsequent
                                      9-12

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removal.  An asphalt surface would kill any unremoved vegetation.  Unre-
moved  trees would die  from  lack of water  and  oxygen  to  the roots.

     Ii^JLLJ?grcorete Hard-Surfaae Stabilization^
     The same comments apply as for  treatment 4-1, except that concrete would
provide a more permanent surface or,  if removed, be  slightly more difficult
to break up and transport.

     (5-0)  Appliaation of Sewage Sludge
     Outside the scope of work.

     (6-1)  High-Pressure Washing
     Outside the scope of work.

     (6-2)  Flooding to 30 am
     Outside the scope of work.

     (7-0)  Soil Amendments Added
     Outside the scope of work.

9.4.2  Impervious, Artificial Surface Treatments
     The treatments that may apply to remove a contaminant from the hard, im-
pervious artificial surfaces that cover much of the urban/suburban land areas
are:   washing with high-pressure water (treatment 8-1), vacuuming (treatment
8-2)," sweeping (treatment 8-3), mechanized street flushing (treatment 8-4),
surface removal techniques (treatment 8-5), and other removal techniques
(treatment 8-6).

     As would be expected,  smoother surfaces retain less residual contaminant
than  rougher surfaces,  larger particulates are more effectively removed than
smaller particulates,  and the fraction of contaminant removed is greater for
initially greater loading densities.   Data on the effectiveness of the cleanup
techniques are primarily based on results of simulations using sand.   The par-
ticulate sizes were often on the order of 100 microns or more and the surface
loading densities on the order of 100 grams/ft2.  For smaller particulates and
less  dense surface loading,  effectiveness should be considerably less.

                                  9-13

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     (8-1)  Washing with High-Pressure Water f>3 mm)
     Large, impervious areas such as roofs and streets can be cleaned by high-
pressure streams of water.  The high-pressure water dislodges and dilutes most
of the contaminating particles and carries them away in the runoff.   In this
case, the contaminant is simply being moved to a different location.  Deter-
gents, manual or motorized scrubbing, and special hose nozzles may be employed.
In general, firehosing has been envisioned as an emergency technique to be used
in catastrophic situations to clean up a relatively large populated area where
concern with the runoff of contaminated water is secondary to reduction of the
immediate hazard.

     Examination of results from numerous experiments summarized by Owen et al.
indicates that, in general, firehosing will remove 90 percent or more of con-
taminating particulates from areas paved with asphalt, concrete, and asphaltic
concrete.  Often less than 1 percent of the residue remained after a single
pass.  Repeated passes with the water stream removed more contaminant, but
with decreasing effectiveness.  Contaminants in  slurrys appear to be removed
as effectively as are particulates.  Although roofs are not as effectively
firehosed as are street areas, tar-and-gravel and composition shingle roofs
can be 90 percent or more decontaminated.  Limited data on wood  shingles  indi-
cate 80 to 90 percent decontamination effectiveness.

     Firehosing roofs and paved areas requires  10 to  20 liters of water per
square meter of area per pass.  To  treat a typical suburban area in .this  man-
ner would  require 1 to  2 million gallons  (3.7 to 7.4  million  liters) of water
per square kilometer per pass, exclusive of water needed  to wash down vertical
      *l                                            O
surfaces.  Even the smallest-sized  area of 0.01  km  would result in  500 to
1,000 50-gallon drums of wastewater.  Thus,  except for very  small areas,  it may
not be practical to collect  and  store contaminated wastewater from  cleanup  .

     Hosing down impermeable  surfaces simply moves the bulk of the  contaminant.
to a different location and/or reduces it to more acceptable  concentrations.
Runoff from structures  moves  the contaminant  to the ground level onto other
impermeable surfaces, or  onto soil  and plants.   Flushing  walkways and  streets
moves the  contaminant onto  soil  surfaces  or  into storm drain systems.   If
                                      9-14

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 measures are not taken to collect the runoff, shrubs, lawns, and bare earth
 areas will receive contaminated water as will storm drain discharge points.

      Uncontaminated, permeable surfaces can be sealed with substances such as
 liquid asphalt to prevent contaminated runoff water from soaking"into the
 ground.  However, it is unlikely that all splashes can be contained; in fact,
 it may be desirable in some instances to let contaminated runoff water soak
 into permeable ground surfaces as a means of contaminant collection.  Radio-
 active contaminants are often quite insoluble and can be effectively filtered by
 soils, and the portions that are soluble are quickly adsorbed onto surface
 soil particles.   For example,  as discussed in The Behavior of Radioactive
 Fallout in Soils and Plants^  approximately 99 percent of fallout is insoluble
 (in distilled water)  and a solution oi soluble portions poured through the
 soil in one set  of experiments was 80 to 85 percent adsorbed by the first few
 centimeters of soil.   Plutonium,  a radionuclide of great concern,  is very in-
 soluble in water and  might best be trapped by soil filtration and subsequent
 removal of a layer of soil.

      (8-2)   Vaouuming
      Removal  of  contaminating  particulates from hard  surfaces by  vacuuming  has
 not  been  examined  in  as much detail  as other  techniques,  such as  firehosing.
 The  reason  for this relative neglect may be because of  the  slow working rate
 compared  to  firehosing.  A street  can be firehosed at a  rate  of 300  to 500
 square  feet per minute compared to a few tens of square  feet  per minute for
 vacuuming.  Nevertheless,  examination of the data from Owen et al.5  indicates
 that vacuuming can be effective in removing particulate  contamination from
 hard surfaces.  In general, based on  a limited number of experiments, vacuum-
 ing can remove in excess of 90 percent,  and sometimes in excess of 99 percent,
 of the particulate contamination from composition shingles and concrete with
 a single "pass."  In the single experiment where repeated vacuumings were
 employed to decontaminate concrete, the  second vacuuming removed 90 percent
 of the residue from the first vacuuming and the third and fourth vacuumings
 removed about one-half of the remaining residue.  Thus, it appears that care-
 ful vacuuming can remove in excess of 99 percent of particulate contamination
from pavement and roofs.  In an experiment for decontaminating frozen bare
ground, vacuuming removed about 60 percent of the contaminant after 4 passes
 (40 percent was removed on the first pass).
                                     9-15

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     Details on the design of the vacuuming experiments are not.available,
but it is presumed that the particulates were "fresh," i.e., the particulates
were not allowed sufficient time to "weather" and become more firmly attached
to the contaminated surfaces.

     Vacuuming has a significant advantage over firehosing and other types of
methods that simply move the contaminant to another location because vacuum-
ing picks up the contaminant and contains it for safe disposal.  Care must be
taken that absolute filters are used, in addition to the coarse filters in
the typical vacuum cleaner, so that very small particulates will be trapped
rather than resuspended in the air by the cleaner's exhaust.  Otherwise, no
adverse environmental effects appear to be associated with vacuuming contam-
inants from hard surfaces.

      (8-3)  Sweeping
     Mechanized street sweepers can remove significant amounts of contaminants
from dry paved surfaces.  In experiments few passes of these sweepers typically
removed more than 99 percent of the contaminant.  Mechanical street sweepers
have a realtively high rate of cleaning, e.g., a few thousand  square feet per
minute per pass.  Again, in a large-scale emergency where  the  primary concern
is to reduce the gross hazard as quickly as possible,  street sweeping may be a
viable technique.  However, in cases where it  is less  critical,  street  sweepers
probably would be a less acceptable alternative due to resuspension of  paticu-
late  materials.  Dust can be kept down  to  some extent  by  sprinkling.  In any
event, mechanized street sweepers can only be  used on  large paved  areas where
access is available.  (Street sweepers can  also be used, with  limited effective-
ness, on open  areas of  frozen ground.)  Hand brooms have  some  limited effective-
ness  for sweeping roofs.

      Environmental  impact  from  sweeping is  limited  to particulate  resuspension.

      (8-4)   Mechanized Street Flushing
      As  is  the case with mechanized street sweepers,  street flushers have  the
 advantage  of a high rate of areal coverage,  e.g.,  a few thousand square feet
 per minute per pass.   A single  pass typically removes 90 to 99 .percent  of the
 contaminant and a second pass  typically results in more than 99 percent removal
 of the original amount of contaminant.   Thus mechanized street flushers appear
                                      9-16

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 to be as  effective as  firehosing  and  faster.   However,  their use  is  limited
 to streets  or other large paved areas.

      Using  mechanized  street  flushers-poses  the  potential  problem of flushing
 contaminants  into the  storm sewer system and thence  into the sewage  treatment
 plant or  some other discharge point.   If this is not desired,  the runoff must
 be captured.   Otherwise,  there are no significant adverse  ecological effects.

      (8-5)  Surface Removal Teohni-ques
      Firehosing,  flushing with water,  sweeping,  and  vacuuming  do  not usually
 have  any  significant effect on the building  or paving surfaces which are being
 decontaminated.   Another  class of cleanup techniques for hard  surfaces consists
 of removal  of some  of  the surface to  which the contamination adheres.  Surface
 removal techniques  would  likely be applied only  for  residual contamination
 which cannot  be removed by the nondestructive techniques.  These  techniques
 include removal of  contaminated surfaces by chemicals,  scraping or wirebrush-
 ing,  sandblasting,  or  other abrasive  techniques.  Sandblasting, while very
 effective in  removing  contaminants from hard  surfaces,  poses the  hazard of
 suspending  contaminants in air unless preventive measures are  taken.

      Using  surface  removal techniques on artificial  surfaces poses no signif-
 icant  ecological problems.  Paint  stripping requires  the use of caustic chem-
 icals, but  the sludge will have to be collected  in any  case.   Sandblasting is
not a viable  technique unless measures are taken to  contain the particulate
dust which would otherwise be  resuspended in  the air.

      (8-6)  Other Removal Methods
     Other methods for removing contaminants from hard  surfaces,  primarily
small areas,  include wiping with tac-cloths or similar material,  applying
strippable films,  and perhaps even ultrasonic cleaning.   Strippable films and
wiping are probably only effective on very smooth surfaces such as furniture
tops or automobiles, but may have some application.  Ultrasonic cleaning poses
the possible hazard of resuspending small particulates.

      (8-7)  Containment
     Containment techniques may be used (1)  to temporarily immobilize contam-
inants onto hard surfaces while cleanup measures are being formulated, (2)  as
                                     9-17

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a long-terra measure to seal off a contaminant from being a hazard,  or (3)  as
a final step to seal off any residual radiation after cleanup measures have
been completed.  Containment techniques using an impervious sealant are 100
percent effective for reducing the hazard from alpha emitters since the ex-
ternal hazard from these radionuclides is negligible.  However, the sealant
must be maintained for as long as the underlying surface might be a hazard,
to avoid a hazard when the sealant weathers or otherwise deteriorates.  Paint,
tar, oils, and liquid asphalts are the commonly known containment materials,
based on 1950s and 1960s technology that was primarily concerned with nuclear
weapon fallout.  Many of the soil stabilizers shown in Table A-l (Appendix A)
could also be used to temporarily contain contaminants.

     If the containment is temporary, solvents or other techniques are needed
to remove the sealant to permit cleanup of the surface.  (The sealant itself
may be employed as a means of removing the contamination by "locking onto"
the contaminant so that it is removed with the sealant.)

     Applying techniques for containing contaminants in place on impervious
surfaces and then perhaps removing the containing material may be costly in
monetary terms and disruptive to human activities, but otherwise there is no
significant effect on the environment.

9.5  RECOVERY AFTER CLEANUP
     Most of the cleanup techniques for urban/suburban areas will not cause
significant long-term ecological damage.  Within a matter of months to a year
or two following the destruction of vegetation, lawns and small plants could
be reestablished.  The only  long-term impact would be the lack of large trees
and shrubs, if they had to be removed.

     Many of the treatments  involving earthmoving, destruction of vegetation,
or soil stabilization are commonly used  in urban/suburban areas when preparing
land for development.

9.6  QUANTITATIVE ASSESSMENT OF CLEANUP  IMPACTS
     Table  9-1 is an  estimate of the relative  impact on  the  ecology of an
urban/suburban area as a result of applying  the cleanup  treatments described

                                      9-18

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in Section 9.4.  The impacts are rated on a scale of 0 (no impact)  to 100
(greatest impact) for the various treatments and the size of the area disturbed.

     In the urban/suburban case impact is assumed to be directly proportional
to the area affected, because there are relatively few wild animals, except
those considered pests, to be displaced and the vegetation will be replaced
rather than permitted to reestablish naturally.  Therefore, the impact on a
10-km2 area is assumed to be 1,000 times greater than the impact on the 0.01-
km2 area.  This is" in contrast to undeveloped land types where impact is not
assumed to be directly proportional to the size of the area.

     Treatments 4-1 and 4-2, stabilization with a hard surface, are judged to
be the most severe with a rating of 100.*  Not only will these treatments re-
sult in killing all vegetation and obviating most social and economic uses,
but the surface remains in place for a significant time period, in contrast
to the other treatments where the area can be restored to near its original
condition within a few years.

     Treatment 1-3, stumping and grubbing, and treatments 2-2, 2-5, and 2-8,
removing the shallow root zone, are rated next in severity with a rating of
75.  These treatments will result in the death of essentially all vegetation.
Treatment 1-2, clear cut vegetation, is rated  less damaging at 70 because some
of the vegetation can propagate from existing  root systems.

     Treatments  1-7 and  1-8, soil cover; treatment  1-6,  deep plowing;  and
treatments 2-1,  2-4, and 2-7, removing the  plow  layer,  are  judged roughly
equivalent with  a rating of 50.  Most trees will  not  be seriously damaged  or
killed by these  treatments,  but  all other vegetation  will  be destroyed.  Treat-
ments  1-4, 2-3,  and  2-6, scraping and grading, and  treatment  1-5, shallow  plow-
ing,  are rated approximately equal  with  a  rating of 25.   Damage is  to a lesser
degree than  with removal of the plow  layer.

      Treatments  3-1, 3-2, and  3-3,  barriers to exclude people  and animals,
are  assigned impact  ratings of  10.  Presumably the  barriers are for a short
time period.   Application of sewage sludge  may pose some problems  in social
unacceptability.
 *A11 ratings are for a 10 square km area.

                                      9-20

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      Treatment 1-1,  chemical  stabilization,  and treatments  8-1  through 8-7,
 treatment for artificial  surfaces,  are judged to have negligible environmental
 impact provided they are  done correctly so that the  contaminant is  either con-
 tained or controlled in a desirable manner.

 9.7   CONCLUSIONS
      Although it may be very  expensive and socially  disruptive  to clean up
 contamination from a large urban/suburban  area,  significant adverse effects
 on the natural ecology are short term.   Many of the  treatments  are  used during
 normal construction  activities that occur  in urban/suburban areas.   Within a
 matter of months to  a year or two following  cleanup,  lawns  and  small plants
 will  be reestablished (except in the case  of hard-surface stabilization).
 The only  change  will  be the lack of large  trees  and  shrubs  if they  have been
 removed.   The  consequences of not effectively cleaning up the contaminant
 (e.g.,  human health)  may  be more significant than concern for the environ-
 mental  impact  of cleanup  treatments.  Thus,  environmental impacts must  be
 secondary to selecting the most effective  treatment  or treatments.   The resid-
 ual contamination must be reduced to some  acceptably low level;  if  this neces-
 sitates the complete  destruction of  all vegetation,  that impact must be ac-
 cepted.   In this context  there are no treatments that are'unacceptable, ex-
 cept natural rehabilitation.   Circumstances  will dictate the most desirable
 treatments for a particular situation.

 9.8  URBAN/SUBURBAN LAND AREAS REFERENCES
 1.   Bennett, C.B., and W.L.  Owen.   Planning Radiological Reclamation of Test
     Facilities at Kwajalein Contaminated by Plutonium, Volume II—Radiologi-
     cal Reclamation  Procedures.   U.S. Naval Radiological Defense Laboratory,
     San Francisco, CA 94135,  Report USNRDL-TR-67-68  (AD 820010), 29 May 1967.
      (Official Use Only)
 2.   Cobb, LTC F.C.,   and LTC  R.L.  Van Hemert.  USAF,  Source Book on Plutonium
     and its Decontamination.   Field Command, Defense Nuclear Agency, Technol-
     ogy and Analysis Directorate,  Kirtland Air Force Base NM 87115, 24 Sep-
     tember 1973.
 3.   National Academy of Sciences,  National Research Council.  The Behavior of
     Radioactive Fallout in Soils and Plants.  Washington,  D.C., Publication
     1092, 1963.
4.   Office of Environmental  Quality (in cooperation with Geotechnical Consul-
     tants, Inc.).   Impact of Urbanization on Recharge Potential of  the Goleta
     Groundwater Basin.   Prepared for the County of Santa Barbara, Santa Barbara,
     California, March 1976 (revised July 1976).

                                     9-21

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Owen, W.L., F.K. Kawahara, and L.L. Wiltshire.  Radiological Recalamation
Performance Summary, Volume 1-Performance Test Data Compilation.  U.S.
Naval Radiological Defense Laboratory, San Francisco, CA 94135, Report
USNRDL-TR-967, OCD Work Unit No. 3114A, 13 October 1965.
U.S. Bureau of the Census.  County and City Data Book-1972 (A Statistical
Abstract Supplement).  U.S. Government Printing Office, Washington, D.C.,
1973.
                                  9-22

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      PART III



      WILDLIFE







CHAPTER 10, WILDLIFE

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                              CHAPTER  10
                              WILDLIFE
 10.1  OVERVIEW

     A  large amount of information must be integrated to describe which
 impacts to wildlife will occur in particular situations.  For example,
 the time span over which impacts occur, the type of disturbance, land
 area, land types, vegetation component,  wildlife component, and wild-
 life ecology all must be considered.  In addition, feedback and inter-
 actions among these factors must be considered.  So that this informa-
 tion can be more easily dealt with, several simplifications will be
 made.  These include a standardization of the above variables.  This is
 followed by a general discussion of characteristics which relate to im-
 pacts on each wildlife group of birds and mammals.  This discussion is
 made first for immediate impacts, and then repeated for long-term effects.

     The term "ecological impact" implies two basic actions.  First,
 there is some disturbance to an area.  Second, there is a reaction
 (impact) which results from the disturbance.   Of interest are those im-
 pacts caused by human disturbance which result in a change in population
numbers and/or species content of an area.  Since impacts can be subtle
 or gross, only those impacts which are quantitatively measurable in the
 field are considered.

     The impact on an area usually has short-term and long-term com-
ponents.  The short-term component can be measured immediately following
 the disturbance.   The long-term component must be examined for duration
as well as magnitude.   Some criterion is needed to decide how much change
 is required to "recover" the disturbed areat (i.e., the quality of the
 recovery), and how long the recovery will take.  However, the product of
 the recovery can vary.  If the land and vegetation return to a different
 condition, a new wildlife community may become established which is very
                                 10-1

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different from the original one.  Naturally, the rate of recovery will
vary among land types and climates.

     This raises the question of the location of the end point of the im-
pact.  Since "impact" is defined as a change, the end point is where
changes become too small to measure quantitatively.  However, natural en-
vironmental processes are dynamic; that is, they fluctuate constantly.
When this fluctuation is slow the ecosystem is considered stable, or in
equilibrium.  Likewise, wildlife communities are only relatively stable.
Thus it is both unreasonable and impossible to restore a community to its
exact original condition.  The practical solution is to restore the origi-
nal natural conditions in land and vegetation as nearly as possible, and
simulate recolonization of wildlife.  A new, but somewhat different, wild-
life community will become established in a dynamic equilibrium with the
new and somewhat different habitat.

     A broad range of human disturbances can result from the treatment of
hazardous material spills.  The least significant disturbance is probably
surface scraping of a thin layer of ground.  The impact of this to wild-
life might be unmeasurable.  Probably the greatest impact would result
from defoliation of plant life,  followed by covering the soil surface
with cement or some other mechanical stabilizer.  If done on the maximum
area size, this treatment would cause immediate local extinction or emi-
gration of the majority, if not all, of the wildlife in the area.  It
might also cause abnormally high population densities in areas contiguous
to the treated area due to emigration.

     In order to evaluate the impact of treatment disturbance in the dif-
ferent land types, a reference standard for "disturbance" is needed.
This standard will be taken as the most drastic disturbance as described
above.  In this case the immediate impact is that which follows the
treatment.  The recovery phase is defined as following the erosion or
removal of the ground covering.  For simplicity this is assumed to be
removed at one point in time.  Less drastic treatments can be evaluated
across the land types by using the same rationale applied on a lesser
scale.
                                10-2

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     The impact to the local wildlife of a land treatment is heavily
dependent on the land area that is disturbed.   The areas of concern
range from 0.01 km  to 10 km2.  These areas can be envisioned as
squares:  the smaller is 100 meters on a side and the larger is approxi-
mately 3.16 km on a side.  Since a point-to-point discussion of this
entire size range is impractical, these end points plus a midpoint area
of 1 km2 (1 km or 1000 meters on a side) will be discussed.  An addition-
al area 100 km2 is also included because it approaches an upper "end
point", at which a measurable impact can be expected for almost all wild-
life species.  These should typify the desired range of areas.

     A wide variation in habitats exists for each land type under con-
sideration.  Again, some simplification is needed in order to organize
the wide range of impacts.  This can be done by using a procedure which
has proved successful in plant ecology; i.e., describing a typical
habitat type within each land type.  The following is an adaptation of
Whittaker's system   for this purpose:

  •  Deserts include a wide range of communities.  It is appropriate to
     note that two types of desert occur in the United States:  (1) warm-
     temperate deserts, represented by the widespread creosote bush com-
     munities and the floristically rich uplands of the Chihuahuan and
     Sonoran deserts, and (2) cool-temperate desert scrub, including the
     sagebrush semidesert of the Great Ba.sin.  The floras of both these
     desert types share a scrubby habitat.  Also, in both a lack of
     moisture is critical to the maintenance of the various habitats.
     Thus deserts can be typified as those areas of extremely low
     annual rainfall.

  •  Prairie (or grassland) includes the great prairies, plains, and
     desert grasslands of the United States.  Despite reduction of
     vegetation structure to a single major horizontal stratum, plant
     species diversity in grasslands can be high compared with most
     forests.  These are areas of relatively low rainfall  (but more
     than  deserts)  and experience  a broad  range  in mild  temperatures.
                                10-3

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•  Deciduous forests grow in modera,tely humid, continental, tem-
   perate zone climates, with summer rainfall and severe winters.
   Broad-leaved deciduous trees (oak, beech, maple, ash, basswood,
   etc.) are dominant in forests with trees 30 to 40 meters tall.
   Animal life of temperate deciduous forests is abundant but
   varies according to the season; diversity of plant and animal
   species is moderately low to moderately high.  Deciduous for-
   ests are extensively developed in the eastern United States.

C  Coniferous (evergreen) forests occur in varied temperate zone.
   circumstances.  Extensive needle-leaved evergreen forests occur
   in continental climates of the western United States, and in
   places where soil characteristics, or fire frequency, or both,
   favor pines over broad-leaved trees in the milder climate of
   the eastern United States.  Coniferous forests are dominated
   by pine, fir, spruce, etc.  A special type of coniferous for-
   est is the subarctic-subalpine needle-leaved forest of the
   cold edge of the climatic range of forests.  These areas exist
   in the northern part of North America and exist to the south
   at higher elevations in mountain areas.

a  Mountain areas can be categorized as vertical extensions of
   other land types, as well as those areas which are exclusively
   non-forested aeolian or alpine regions.  Aeolian mountain areas
   are almost never the sole habitat of animals using them.  There-
   fore, wildlife responses detailed in the discussions of the
   other land types are applicable.  When mountain areas are ex-
   tensive, they may be very similar to tundra, and that land
   type should be referred to.  The reader  is referred  to these
   specific sections for treatment of the wildlife of mountain
   habitats.

•  Turidras are the treeless arctic plains.  The vegetation forms
   are varied and there are often complex patterns of dominance  by
   dwarf-shrubs, sedges and gresses, and mosses and  lichens.   In.
   many tundras the deep layers of the  soil are permanently  frozen,
   and only the surface soil is thawed  and  becomes biologically

                             10-4

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   active during the summer.  In many of these communities, re-
   peated freezing and thawing of the soil separates rocks from
   finer soil materials and arranges the rocks in parallel strips,
   or in networks with polygonal cells; striking internal pattern-
   ing of the plant communities in relation to soil differences
   results.  Vegetation cover decreases toward the sparse lichen
   communities, rock fields and ice of high elevations.

•  Coastal inter-tidal marshland can be salt-water or estuarine.
   These areas, especially salt-water marshes, are extremely rich
   energy sources.   Like prairies,  they are limited in vertical
   structure.  The plants of salt-water marshes are herb and forb-
   like.   Marshes are not usually extensive,  but are rather patchy in
   occurrence, or form a narrow band along a lake or coast.

•  Agriculture is unique, being the substitution of a usually monotypic
   community for one or more natural plant communities.  Agriculture
   is practiced in nearly all climates,  although many hot and cold
   areas are not yet occupied fully.   Agriculture can be characterized
   as managed fields with generally low vegetation (under 12 feet)
   dominated by 1 or 2 cultivated plant species.  The most common
   secondary species are those generally considered "weeds," i.e.,
   introduced herbs.  Agriculture is extremely widespread .in the
   United States except where climate and/or terrain are exceed-
   ingly harsh.

•  Suburban land types are best described as  those areas which make
   up areas of human habitation.   Like agriculture,  these areas are
   extremely widespread.   The numerous roads  and human activity
   associated with this land type severely restrict  the type of
   wildlife which can exist.   The human dwellings are usually asso-
   ciated with exotic introduced  plants  and/or weedy species.   As
   with agriculture,  this land type is an imposition of a new com-
   munity upon a previous and older natural community.   This favors
   a low number of species,  but with high densities.
                              10-5

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     Some species have extremely low population numbers and must be
examined individually to assess potential cleanup impact.   Identification
of these sensitive species can be obtained from Federal and State lists
                                     5 22
of threatened and endangered species. '    State lists are to be pre-
ferred since they often include recent information on steps which have
been taken to protect the species.   State agencies also usually have
recent literature and staff knowledge which may bear on the problem.

     If a habitat which supports such, a species is disturbed, several
things may be done to speed up the recovery phase for the animal.  This
may be necessary for disturbances to rare species.  For example, the
Trumpeter Swan was close to extinction (about 65 birds) in 1935.   Areas
where these birds breed were designated as off-limits to hunters.  Also,
additional food was made available at these sites in winter.  Finally,
the birds were introduced to other potential breeding sites.  Due to
these steps, the population had recovered (to about 915 in the U.S.)
by 1976.   Other direct steps can be taken to accelerate faunal recovery,
that is, increasing the rate of vegetative recovery.

     Faunal recovery is strictly related to the recovery of the vegeta-
tion.  The fauna cannot normally respond before the vegetation has
done so.  There are three components of the vegetation which are particu-
larly important to animals.  The first is the plant species which colo-
nize a disturbed area.  These are of especial importance to the herbivores.
The other two components are vegetative height and density, i.e., the
vegetational structure (see Emlen  for an exception).  All three of the
above components will change over time in the successional processes of
the vegetation.  Faunal recovery must, to some degree, be an upward pro-
cess in terras of the food chain.  Carnivores cannot colonize an area
until their prey is available.  Since abundances may  increase  slowly by
reproduction, or quickly by invasion, it is difficult to predict a  re-
covery  for animals at the top of the food chain.  However,  these effects
can be mitigated for those predators which can utilize a wide  variety  of
prey, so that food can be caught during several stages of the  vegetation
succession.
                                 10-6

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      Once vegetational succession has produced a new climax community,
 the more similar the new vegetation is to the original, the more similar
 the new fauna  should be to the original fauna.  This does not require a
 vegetation be  established that is identical to the original.  All that
 should be required is an approximation of the original vegetation which
 provi-es the same resource value in terms of food and structure.  The
 critical questions to wildlife restoration are the "quality" and duration
 of vegetation  recovery.
                                                               25
     Plant succession has been well studied by plant ecologists   but
the faunal community succession process which occurs in nature has not
been studied as much.   As plant succession occurs,  multiple feedbacks
are possibly among and within plants and animals (not to mention soil
content changes, ground-level temperature regime cahnges,  etc.).  The
network can be extremely complicated.   However,  faunal changes can be
closely examined with respect to plant succession,  and different animal
species will show greater or lesser facility for recovery.

      In most cases some species which were not among the original fauna
of the area will move in during part of the vegetative recovery.  These
species will probably move out of the disturbed area as the habitat
changes toward one more similar to the original one.  This causes a
decrease in species diversity as the climax of the faunal succession is
 reached.  The  pattern of plant species diversity in succession  emerges
as a  rise from the start of recovery to a pre-climax peak, and  then a
 leveling off at a slightly lower level as the dynamic equilibrium of
                  Q
the climax ensues.
     The few studies that have been done on faunal succession draw
evidence from  the fossil record and emphasize evolutionary (very long
term) time.  Of concern here is ecological, not geological, time, i.e.,
a relatively short period of time during which succession may occur,
                     19
but evolution  cannot.    Thus this discussion emphasizes the responses
which are expected from individual species, rather than faunal  succession.
                                 10-7

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10.2  EFFECTS ON BIRDS
     Much information must be integrated in an examination of impacts on
birds.  Unfortunately, much of this information dealj with particular
species, making generalizations difficult.  However, in order to understand
impacts on birds some generalization is necessary, as a discussion of each
species individually is impractical.  Therefore, impacts are described
for groupings of birds which share some general life history and/or feed-
ing characteristics, or are closely related.  These groupings are examined
for short-term effects (immediate impacts) and long-term effects (recovery
phase), then each land type is examined for specific short- and long-term
effects.
     Measurement of a change in the numbers, or population, of a bird
species is not an easy or unambiguous process.  First the term "popula-
tion" must be defined in some way which is not necessarily land-area de-
pendent.  Once this is done a census method must be picked from those
which have been shown to be accurate. '    But even after a standard for
measurement is chosen, and the data taken, it is still necessary to put
the measured impact into context.  What is really desired is the effect
on the  local species.  This effect can only be ascertained by having a
local wildlife expert analyze the data for the disturbed area and gener-
alize the measured impact into an impact value based on local abundances.

10.2.1  Short-Term Effects
     In general, a disturbance to an area will be much more serious to
permanent residents than to migrators.  This is especially true where the
disturbed area is along a migration route.  If .adequate alternative routes
of migration are available there may be no quantitative impact.  Where
only one route is possible, if food is not taken from the area by the
migrants the impact may be very slight.  However, once alternative routes
of travel are used, it may prove very difficult to reintroduce the dis-
turbed  area as a part of the migration route.  This will depend on how
many of the migrators are lost, whether the alternative route is really
as adequate as the original, and whether the route is learned or innately
known.  The slow rate of reintroduction of residents and migrants who
                                   10-8

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feed on an area should be slightly greater for the more mobile migrant
populations.
     The seasonality of a disturbance is of extreme importance to birds.
In general, disturbances in the spring will have a much greater initial
impact than those in other seasons for two principal reasons.  The first
is that the breeding season occurs in the spring for most American bird
        24
species.    The second reason is that the spring is also a very critical
time of growth for plants.  Naturally, a disturbance in another season
can affect spring conditions; however, most bird species can react to ad-
verse habitat conditions before breeding occurs.  For example, they may
nest elsewhere, or at least nest in lower densities.
     Among most birds, a disturbance to the breeding grounds is generally
more serious than an equal disturbance to the wintering range.  Many
birds hold territories during the breeding season, but form flocks during
the winter.  Flocks can lose members to other flocks when food is scarce,
or can remain cohesive at a small cost to each of the members.  This is
not true of the destruction of breeding territories.  The area lost here
will almost always result in a lower number of breeders.  Thus an immediate
impact is more likely to be of greater magnitude when breeding habitats
are destroyed.
     Some birds feed away from the nesting area or hold feeding terri-
tories around the nesting area.  The nesting can be done in tightly
packed colonies or, when food is taken at some distance away from the
area of the nest, in looser aggregations.  Those species which hold
feeding-nesting territories are much more spaced out.  Obviously, dis-
turbance of a colonial breeding area will affect more birds than the
same area disturbance to a feeding-nesting territory.
     A strong correlation between body size and feeding-nesting terri-
tory size has been shown for many bird species.    Thus a disturbance
of a given-sized area will usually affect more members of small species
                                                 2                         ~
than larger ones.  The loss of an area of 0.01 km  can cause the loss
of six song sparrows' feeding-nesting territories.  However, the same
area is only 0.25 percent of a red-tailed hawk's feeding-nesting terri-
             2
tory.  A 1 Ion  area is roughly a quarter of the size of a red-tailed hawk's
                                    10-9

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territory, and is a reasonably large area in terms of most smaller birds.
                                                                         2
In any case, there can be little doubt that the loss of an area of 100 km
from the breeding range of almost any species will have a measurable impact.

10.2.2  Long-Term Effects
     Birds respond very quickly to habitat changes due to their high mo-
bility.  When the proper conditions prevail, bird dispersal is facilitated.
However, different life histories will cause some differences.  Size dif-
ferences will also be critical, as larger birds can expand their terri-
tories more easily than smaller birds.  The following differences also
hold for some broad groups of birds.
    • In general, migrators being more mobile than permanent residents,
will colonize areas more quickly.  However, where migration routes and
summer/winter grounds do not border on a suitable area, colonization can
be much slower.  Permanent residents have an advantage in being able to
establish themselves at a time when migrators are not present.  Some
species, such as the Trumpeter Swan, can migrate or not, depending upon
food resources, and will recover accordingly.
     The area used for breeding grounds by migrators may spread at a
somewhat more rapid rate than that of permanent residents.  However, the
choice of wintering grounds is  likely to be even more flexible.  The par-
ticular migratory species which uses an area will probably depend on the
successional  stage of  the vegetation.  Some species of migrators may
colonize new  breeding  habitats more quickly than others.  These effects
may not have  corresponding effects on the wintering range except  for a
change in the number of  young present.  However,  since the breeding ter-
ritories must be reestablished  each year, complicated variable changes  in
the species pattern on the breeding grounds may occur.  The damping of
these  changes may extend beyond the vegetative recovery phase.
     Feeding  flocks are  apt to  be  rapid  colonizers  since  their foraging
method entails  high mobility  and allows  them to  exploit  a thinly  spread
          f\
resource.    Birds with feeding  territories  usually colonize from  a
"leading  edge"  of the  population.   This  movement  is necessarily slower.
The  recruitment into  flocks may be somewhat slower,  by reproduction,  so
                                   10-10

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that even though a flock may use an area, the vegetation is not exploited
to as great an extent as by the slower colonizing territorial species.
     Competition among species may be important to recolonization.   The
first bird species to colonize an area can move in unopposed.  However,
the species which replace it in faunal succession may have to compete
with the established species in the area.  The net effect is one of pro-
longing the faunal successional process.   Just how long the succession
takes will therefore be somewhat dependent on the intensity and duration
of the total amount of interspecies competition that occurs.
     The following "trophic/niche" groups of birds contain families whose
species share trophic level and lifestyle characteristics.  Naturally,
some families have members in more than one group.  These families  are
divided into the respective groups in the following discussion.  Examples
of typical families are:
     1.  Large carnivorous birds:  American vultures, buteo hawks
         (Accipiter family), and large owls..
     2.  Medium-sized carnivorous birds:   medium-sized falcons, kites
     3.
(Accipiter family), and medium-sized owls.
Small carnivorous birds:  kestrels (Falcon family), shrikes,
and small owls.                    ;
Large primarily herbivorous birds:  grouse, pheasants, and
turkeys.
Medium-sized primarily herbivorous birds:  mockingbirds,
thrashers, thrushes, blackbirds, and quail (Pheasant family).
Small primarily herbivorous birds:  hummingbirds, titmice,
and sparrows (i.e., almost all of the Fringillid family).
Medium-sized insectivorous birds:  woodpeckers, tyrant fly-
catchers, and swallows.
     8.
     9.
Small insectivorous birds:
All sized truly omnivorous birds:
gulls.
wrens, vireos, and wood warblers.
       ducks, jays, crows, and
    10.  All sized aquatic feeder birds: plovers, sandpipers, and
         phalaropes.
     Some land types take longer to restore than others.   This can be
considered the sensitivity of the land type to disturbance.   The reasons
for sensitivity can be the magnitude of the disturbance,  the amount of
vegetative structure, and climatic conditions present, the length of the
                                  10-11

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growing season, the soil types present, and other, factors.   These many
factors are integrated in the analysis of recovery of vegetation and land
types over time.  Here, differences in the responses of the bird faunas
to the immediate disturbance and the subsequent recovery of the different
land types are described.
     Table 10-1 gives examples of bird species from each trophic/niche
group in each land type which yield a measurable impact if the maximum
disturbance has been made on the specified (or larger) land areas.  The
table uses ;area size differences among groups of birds to show how the
groups are affected.  This should not be equated with the qualitative
"importance" of a species.  For example, more robins would be lost than
red-tailed hawks for a disturbance to a habitat for both.  But the hawks
may be more "important" than the robins in terms of numbers in existence
or aesthetics.
     The table assumes that at least ten breeding territories must be
lost to a species before impact can be measured.  No literature is
available upon which to base an estimate of the number of breeding pairs
which must be removed from a habitat to yield a measurable impact,
The figure of ten was chosen because it represents a number at which
large and/or uncommon species will begin to show a measurable impact.
The figure of ten is thus a minimum.  The real figure should be higher
for many species.  However, lower figures should seldom occur.  A
further assumption is made that measurement is solely on a local scale.
Bird breeding territory area is used because the breeding grounds are
of the greatest immediate importance to the multiplication (reproduction)
of most populations.  Bird breeding territories may vary with food
resources in some cases.  However, breeding area should generally be
less variable than any other type of defended area used by individual
birds.

     10.2.2.1  Deserts—
     The imp'act of a disturbance in deserts will be greatest for  small
herbivores, medium  sized  insectivores,  and all carnivorous birds.  An
added impact on carnivores is the  loss  of a great diversity of reptilian
                                   10-12

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Table  10-1.
Examples of bird  species  impacted  by  maximum  disturbance
to  specified types  arid  sizes  of land  areas.
MAJOR GROUPS
1. LAND TYPE
DESERT
Large Carnivores
Medium Carnivores
Small Carnivores
Small Herbivores
Medium Insectivores
PRAIRIE
Large Carnivores
Medium Carnivores
Small Carnivores
Large Herbivores
Omnivores
DECIDUOUS FOREST
Large Herbivores
Medium Herbivores
Smal 1 Herbi vores
Medium Insectivores
Small Insectivores
CONIFEROUS FOREST
Small Herbivores
Medium Insectivores
Small Insectivores
TUNDtfA
large Herbivores
Aquatic Feeders
COASTAL INTER-TIDAL
Medium Herbivores
Small Herbivores
Medium Insectivores
Small Insectivores
Omni tore:
Aquatic Feeders
2. LAND USES
AGRICULTURE
Large Carnivores
Medium Carnivores
Small Carnivores
Medium Herbivores
Small Herbivores
SUBURBAN
Medium Herbivores
Small Herbivores
Medium Insectivores
Omnivores
SIZE fir LAND AREA
0.01 km2












Franklin's gull




Least flycatcher
White-eyed vireo









Song sparrow
Bank swal low







Robi n
House sparrow

Cardinal6
Song sparrow
Cliff swallow

1 km2




Loggerhead shrike
Black-throated s,parrow
Ash-throated flycatcher




Greater prairie chicken
Common crow

Ruffled grouse
Baltimore oriole
Black-capped chickadee
Acorn woodpecker
Tennessee warbler

Pine siskin
Western flycatcher
Olive warbler

Willow ptarmigan
Whimbrel

Yellow-headed blackbird
Marsh wrens
Tree swallow
Yellow- throat
Pintail
Willet



Loggerhead shrike
Mockingbird
Chipping sparrow

Mockingbird
House finch
Black phoebe
Blue jay
10 km2




Elf owl





Sparrow hawk
























Barn owl
Burrowing owl
Sparrow hawk







100 km2


Red-tailed hawk-
Prairie falcon




Golden eagle
Prairie falcon


Common raven































   Territory sizes takjn from Welty  and Schoener  or estimated from sizes of similar species.

   Species nomenclature follows Peterson,1 where scientific name;, are also qiven.

   Member of the sparrow family.
                                        10-13

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prey.  Large- and medium-sized herbivores occasionally occur in desert,
usually on its fringes, as is true of most small insectivores and omni-
vores which live in or near deserts.  The desert itself is not the sole
habitat of these species, and impacts are thus lessened.
     Resident desert bird faunas should contain a high proportion of
specialist species which have low population densities.  These birds
will be extremely slow to respond to most recovery situations.  The
generalist species which do occur in desert can usually be expected to
expand their numbers beyond the normal level upon colonizing a disturbed
area.  In this particular habitat the presence of generalists in abundance
will probably further retard reeolonization of specialists to a measurable
degree.  Management may be extremely useful in this unusual case.

     10.2.2.2  Prairies--
     Prairies are remarkable for having a distinct lack of vegetative
height.  Large herbivores and omnivores are the groups most impacted by
a disturbance here.  These are  closely followed by carnivores of all
sizes.  Carnivores feed not only on bird prey on prairies, but also on
the  high populations of mammals which are common herbivores.  Medium-
sized  and small herbivores, while not as diverse on prairies  as  in other
land types, may still  be very abundant.  Once again,  as smaller herbi-
vore*  are examined; the  impact  of a disturbance is usually magnified.
Medium-sized insectivores often feed over prairie, but seldom nest there.
Thus the impact to this  group should be reduced.  Even less  impact should
be seen in aquatic feeders, who use prairie areas as  stopping-feeding
sites  during migration.
     Prairies  contain  an imbalance  of generalist  species, mainly due  to
the  high  carnivore and omnivore diversity.  Thus  the  recoveries  of prairie
bird faunas  are  largely secondary effects,  since  both the above  groups
depend to some extent  on animal prey.   Carnivore  recovery may lag far
behind the vegetative  recovery.  The omnivores,  on  the other hand,  are
 generalists  and  will  recover more quickly.  Much more omnivore feeding
 than breeding occurs  in prairie areas,  also facilitating  the return of
 this group.   The remaining breeding species are herbivores which are
                                   10-14

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generally mobile species for their size.  They will recover relatively
quickly.

      10.2.2.3  Deciduous Forests--
      Deciduous forests have good diversity and abundance of herbivores
and insectivores of all sizes.  These groups will bear the major impact
of a  disturbance in most cases.  Here also large and medium sized
carnivores will occur mainly where there are breaks in the forest, and
be impacted in proportion to the disturbed area of the forest breaks.
Small carnivores and omnivores, while lacking in diversity in these
forests, may be locally abundant.  These last two groups should be wide-
spread where they occur, thus lessening potential .impacts upon them.
      Deciduous forests are generally richer in bird fauna than coniferous
forests and relatively higher proportions of specialist species occur.
Thus, the faunal recovery will take longer in deciduous forests.   However,
these forests also have the advantage of being extensive, so colonists
are available.  These bird faunas may be extremely sensitive to dis-
turbance, since the specialists may have a more "patchy" distribution
as well as lower population densities.  Because of their size and lesser
mobility, the smaller herbivores and insectivores may be very slow in
recolonization.

      10.2.2.4  Coniferous Forests—
     The disturbance of coniferous forests should impact small herbivores
and insectivores of all sizes to the greatest degree.   A great abundance
and diversity of these groups occur here.  In breaks in the forest,  large
and medium-sized carnivores occur and will be impacted where the breaks
are disturbed.  Coniferous forest supports relatively less small  carni-
vores, large and medium-sized herbivores, and omnivore diversity.   Where
these groups occur, however, they may do so in abundance, and thus be
impacted.  Again,  these last groups (except the small  carnivores)  are
more  likely to occur in breaks in the forest.
      Coniferous forests tend to contain a relatively limited fauna
compared with the other land types.  However, the number of specialists
                                   10-15

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and generalists is usually evenly balanced.  Naturally, the generalists
will respond to vegetative recovery more quickly.  However, since coni-
ferous forests are generally extensive, surrounding forest areas are
almost always present to provide colonists.  As vegetative recovery nears
completion, more and more specialists will move in to supplement the
labile generalists.

     10.2.2,5  Aeolian Mountain Peaks—
     A disturbance to a mountain-alpine habitat will affect only those
few birds which have adapted to this barren land type.  An example of
one of the few species of birds which are specialized for this type of
habitat are the Ptarmigans (in the Grouse family).  During winter,
alpine birds move to lower elevations, and live in other land types.
Herbivores of all sizes will receive the greatest impact from an environ-
mental disturbance, because of the disruption in their food supply.
Large and medium sized carnivores may use alpine areas for hunting and
breeding, but carnivores will be impacted to a lesser degree due to
their ability to move into other types of habitat below treeline.  The
other trophic/niche bird groups should rarely occur in alpine areas and
thus receive no impact from a disturbance to it.
     Due to specialization of herbivorous alpine birds and the patchy
and disconnected nature of the alpine habitat, recovery from a disturbance
will be an arduous process.  Mountains are to a  large extent "islands"
                               25
separated by a "sea" of forest;   therefore, recolonization of alpine
areas may only be possible from within the original population.  Many
alpine birds winter in nearby forests, thus, the more isolated a mountain
is, the longer it will take for colonists from other mountains to arrive.
Since large and medium carnivores of alpine areas are generalists they
will recover more quickly.  However, they will only be able to recolonize
alpine areas as their prey also recolonizes.

     10.2.2.6  Tundra Areas—
     The tundra is commonly only the summer range of  species which  breed
there.  However, a group  of large herbivores  (ptarmigans)  are resident
on tundra, and thus are subject to  the greatest  impact of  any disturbance.
                                    10-16

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 Impact on  the principal'summer breeding migrants, the aquatic feeders, is
 also very  serious.  Many of  these birds nest  in  aggregation, so impacts
 are either drastic  or  considerably dampened,  depending on the location
 of the disturbance.  A few omnivores  (gull  species)  share this charac-
 teristic and nest on or near tundra.  Two large  carnivores  (the snowy
 owl and gyrfalcon)  feed on tundra and breed nearby.  These  last two birds
 have large ranges which help to mitigate any  impact  upon them.
     Tundra bird faunas are  largely migratory, so that bird recovery can
 be relatively rapid.   However, since the bulk of breeding for the aquatic
 feeders occurs here, the recovery of breeding populations must generally
 follow the recovery of food  resources.  The yearly freezing of the. ground
 does not encourage  invertebrates, so that more vegetation must be eaten.
 The only resident birds, the large herbivorous ptarmigans, are also
 closely tied to vegetative recovery.  Where tundra occurs it is usually
 extensive, so that the  bird  fauna can recolonize an  area easily.

     10.2.2.7  Coastal  Inter-Tidal Marshlands—
                                               OC
     Marshlands are usually  rich energy sources   and therefore all non-
 carnivorous groups except large herbivores are usually represented.
The small  insectivores  and aquatic feeders are especially noticeable,
 the former even more so in fresh-water marshlands.  Since those species
which live in marshes are pften restricted to it, they will be impacted
 severely by a disturbance.    Large- and medium-sized carnivores which
frequent marshes usually include other areas  in their hunting range,
or can easily do so.  They are therefore less impacted.   Many aquatic
feeders and omnivores use marshland as stopping and/or feeding places
during migration, and can be subjected to a lesser impact by changing
their migration routes.
     Marshland bird species are generally very sensitive in terms of
faunal recovery.   A very high relative proportion of specialists occurs
here.   Their recovery is complicated by the patches in which this habitat
occurs.   If the disturbance occurs over an entire patch of marshland,
recovery will be much slower than that expected for a disturbed area
within a patch.   Thus,  disturbed area size effects are especially
                                   10-17

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important.  Size effects will be greatly magnified for smaller birds,  but
may have relatively little significance for the more mobile large- and
medium-sized carnivores.

10.2.3  Land Uses
     10.2.3.1  Agricultural Areas--
     Agricultural areas contain either breeding or feeding areas for
some members of all the trophic/niche groups except small insectivores.
However, the groups which are most impacted by disturbance of agriculture
are the medium and small herbivores and the carnivores of all sizes which
prey upon them.  Large herbivores, medium insectivores, and omnivores are
more likely to feed on agricultural areas than to breed on them, and will
usually be less heavily impacted.  Aquatic feeders are the least likely
group to be impacted since they occur only under special conditions
(excess water or ponds available).  However, the impact on this group
increases if they can breed where an area is disturbed, again a special
case.
     Agricultural land mainly supports generalist type bird species (i.e.,
those with a broad niche).  This  land type has not existed long enough for
specialists (birds with a narrow  niche) to evolve necessary adaptations
for habitat specialization.  The  few specialists found here were pre-
adapted to some special feature of the agricultural habitat, and moved
in from other habitats.  The result is an extremely resilient bird
fauna.  This fauna will follow vegetative recovery very closely.  Since
the species which occur in agricultural areas have dense populations,
dispersal from surrounding populations should send almost constant waves
of colonizers into the disturbed  area.
     A second alternative for agricultural land  is to allow it  to revert
to a state more similar to its preagricultural condition.  In this case
the agricultural condition can be considered an  additional disturbance
from which the avifauna must recover.  In order  to evaluate this particular
type of recovery, the  sections dealing with the  preagricultural land
type should be consulted.  Differences from these  land type recoveries
should not vary greatly due  to the agricultural  use of the land.  The
                                   10-13

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avifauna will change from an agricultural one to one commensurate with
the particular land type's plant succession.

     10.2.3.2  Suburban Areas--
     Suburban birds are generally birds which were preadapted to live
with humans.  This implies a versatile lifestyle and a broad niche.
The groups which would be impacted  (about equally) by a disturbance are
medium and small herbivores, medium-sized insectivores, and omnivores.
Groups which occur on the fringes of suburban areas are large carnivores,
large herbivores, small insectivores, and aquatic feeders.  These will
be lightly impacted by a suburban disturbance, if at all.
     Suburban bird faunas will also respond quickly in recovery of a
disturbed^area.  Evidence for this is abundant in almost any spreading
city.  A heavy proportion of generalists exists in most suburban habi-
     9                                                      12
tats.   In addition, rather dense populations usually occur.    These
areas are usually extensive or at least connected by corridors such as
freeways, construction sites, and/or rural human populations.  Thus
colonization can be extreme during the recovery of the land type.  In
addition, the recovery of many species need not be tied to vegetation
recovery since human dwellings provide structural diversity, and may
provide food.
     As in the agricultural land use, the alternative of allowing the
suburban area to succeed to something more like the presuburban land
type exists.. However,-this process is complicated by the presence of
semipermanent structures (e.g., buildings) which increase bird habitat
heterogeneity.  Without these structures a recovery similar to that
described in the appropriate land type is possible.  However, if suburban
land is simply deserted, species which depend on suburban structures for
nesting and/or roosting (or cover from predators) will be favored.
These will generally not be the species commonly found in the presuburban
land type, and recovery will be retarded.
                                  10-19

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     7.  Small omnivorous mammals:  opossums, raccoons, ringtails,
         and armadillos,
     8.  Insectivorous mammals:  shrews and moles.
     9.  Flying mammals:  two bat families.

     10.3.1.1  Large Carnivores--
     The primary immediate impact of a land disturbance to the large
carnivores should be negligible for the range of area sizes under
consideration.  An area of 100 km  is equivalent to only about one to
                              23
six mountain lion home ranges.    Due to the wide ranging of these cats,
even a much larger disturbance would be very hard to measure in terms of
a change in population numbers.  However, a secondary impact to this
animal is the loss of its prey.  Again this effect is probably unmeasur-
able, since the deer they feed on are also large animals which are
widely distributed.
     A slightly different situation exists for the other large carnivore
group, the wolves.  Measurement of populations is extremely difficult,
even for the exceedingly common coyote.  But in addition to measurement
problems, the grey (timber) wolf also forms packs.  A disturbance to the
      2
100 km  area size could eliminate (from the area) a minimum size pack of
two, but this area is only about one-tenth the home range of a pack of
eight,   so that primary impacts are impossible to assess.  Some attempt
can be made to measure the change in pack size as an indication of impact,
but this is an extremely variable characteristic.  Again, secondary im-
pacts are possible, but they are unlikely to be measurable.  In all large
mammalian species emigration is the most likely cause of a drop in popu-
lation numbers after a disturbance.

     1073.1.2  Medium-Sized Carnivores—
     Impacts on medium-sized carnivores are also difficult to measure,
Once again, the maximum disturbance to the maximum area size specified
      2
(10 km ) for consideration should not produce a measurable impact in
most cases.  The major prey of these carnivores, small herbivorous birds
and mammals, will be impacted at some area size, so that it may be
possible to get some measure of secondary impacts.  The medium-sized
                                   10-21

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carnivores are not as mobile as the large carnivores,  so that it may
be possible to estimate an impact in some cases for a disturbed area
size of 100 km2.

     10.3.1.3  Small Carnivores--
     Many of the small carnivorous mammals are nocturnal, and thus
ignored by the majority of humans.  However, it is in this group that
impacts in the larger area sizes can be measured.   Weasels will have
measurable impacts where pre-cleanup prey densities are either high,
or are moderate but extensive in area.  The other small carnivores
have larger home ranges in general and will be much harder to examine.
Secondary (prey) effects need not be examined for the groups which have
measurable impacts, since these effects are included in the change in
population size.

     10.3.1.4  Large Herbivores—
     With the large herbivores size of the cleanup area again becomes
important.  This difficulty is compounded by the ability of most large
herbivores to change home ranges seasonally  (by migration).  Local
changes in population size can probably be measured for disturbances
of the 100 km  area size.  However, these changes will probably be
measurable only immediately, for the high mobility of the larger herbi-
vores will soon reduce the possibility of finding many of the animals
which reside in the area, since they may leave it or perish.  Animals
which successfully leave the area are not defined as being impacted.

     10.3.1.'5  Small Herbivores--
     Small herbivores are generally restricted to  living  their  entire
lives in  relatively small areas.  The once  popular idea  that some small
                                                         13 14
mammal herbivores  migrate has  been thoroughly disproved.   '   .  These
animals are the most  important United States mammals  in  terms  of  species
diversity and abundance.  Their populations are easily  sampled and  moni-
tored in  most cases.   In addition,  they  form an important link between
primary producers  (plants)  and the  carnivores  which depend on  them  for
 -  ,  11
food.
                                   10-22

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      Table  1Q-2  gives  examples  of  small  herbivorous mammal  species that
 occur in each land  type  which yield  a measurable  impact  if  the maximum
 disturbance has  been made  on the specified  (or  larger) land areas and
 types.   The table indicates  the kind of  rodents and lagomorphs  (the
 rabbit  order)  which occur  in the various land types and  the general
 disturbed area sizes which will produce  impacts.  The density of these
 animals is  relatively  easy to measure.
      Table  10-2  assumes  that at least 12 to  15  home ranges  must be lost
 in  an area  before a local  impact can be  measured.  As in the bird section,
 this  home range  (area) amount is a minimum for  measurable impact, except
 for large and/or uncommon  mammals.   A special case of vole  and lemming
 home  ranges  being very small is somewhat counteracted by their excep-
 tional  movement  abilities, so that a larger  area must be disturbed for
 these species  than  just  15 home ranges.   Home range size usually varies
 with  changes in  the density  of  food  resources.  Special  cases in specific
 locations are  to be expected to vary from the predictions of the table.
      It may be that small  herbivore  species  can be used  as  indicators
 to measure the effects of  various disturbances.   Small herbivore species
 can change at  the onset  of a disturbance.    As succession  ensues,  changes
 in  species composition and density can also occur.16  When  the original
 species distribution and density reoccur, an advanced stage of recovery
 has probably been entered.   A distinction must be made,   however, between
 those small rodent species considered "pests," or those deemed undesirable
 by man, and species which  are more beneficial to man's interests.   Pest
 species are generally exterminated periodically where they exist near
 humans and impacts on them,  although measurable, may not  be of real
 concern.

      10.3.1.6  Large Omnivores—
      Large omnivores (bears)  are another group for which  it is exceedingly
difficult to measure impacts.  Only three bear species occur within  the
designated land types in North America.   These will  not  be measurably
 impacted for disturbances to the land area sizes under consideration.
For example, even without the problems  of impact measurement, the  100 km2
                                   10-23

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Table 10-2.  Examples of -small  herbivorous mammals, impacted  by maximum
             disturbance to specified types and sizes of land areas.a
   MAJOR GROUPS
   LAND TYPE

      Desert
      Prairie
      Deciduous
      Forest
      Coniferous
      Forest
      Tundra
   LAND USE

      Agriculture
       Suburban
                                   SIZE OF LAND AREAb
  0.1 km£
Cactus mouse
Pocket gophers
Pocket mouse
Harvest mouse
Grass voles
Jumping mouse

Deer mouse
Deer mouse
Phenacomys
Redback voles
Lemmings
Tundra  redback  vole
 House mouse
 Pocket gophers
 Cotton ratsc

 Black ratc
 Norway rat
 House mouse
                                                     1  km
Antelope squirrels
Kangaroo rats
Wood rats
Jackrabbits

Ground squirrels
Prairie dogs
Jackrabbits
Tree squirrels
Flying squirrels
Chipmunks
Cottontail rabbits

Marmots
Tree squirrels
Flying squirrels
Chipmunks

Showshoe hare
 Ground squirrels
 Jackrabbitsc
    a  Home range sizes  taken  from  McNab,    Vaughn,    and  Burt and
      Grossenheider,4 or estimated from home  range  sizes  of  similar
      species.   Nomenclature  of the genera  and  species  follows  Burt
      and Grossenheider,4 where scientific  names  are also given.

    b  For land areas of 0.01  km2 or less no small mammal  herbivore
      should be impacted, above 1  km2 all  should  be impacted.

    c  Denotes pest species or genera.
                                  10-24

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 area size is only about half the size of the Grizzly bear home range.23
 However, the actual effects on these animals can be serious since they
 art. restricted to isolated patches of wilderness areas,4 and emigration
 may not always be possible.

      10.3.1.7  Small  Omnivores—
      The impacts from disturbance of the larger area sizes may be
 measurable for the small omnivores.   These animals  are generally nocturnal
 and occur in areas which are human-disturbed (mainly agricultural).   Im-
 pacts should be easier to measure for opossums,  and more difficult to
 measure for the wider ranging raccoons.17  These animals are widely dis-
 tributed where they occur,  so that immediate impacts are difficult to
 measure due to a reassortment of individuals during movement away from
 the disturbed  area.

      10,3.1.8   Insectivores—
      Insectivores  are small mammals with  extremely  limited mobility.
 Like small  rodents, they are  closely  tied to  their  area  of residence
 and can  be  expected to be measurably  impacted in disturbances to  all  but
 the  smallest land  area sizes.  In'addition, these animals depend on insect
 and  other small  animal prey,  so that  a disturbance  to the prey can cause
 as great an impact as a  direct disturbance to the insectivores themselves.

      10.3.1.9   Flying Mammals—
      The impact  from  a disturbance on the flying mammals  (bats) is
 roughly  comparable to that on insectivorous birds.  These nocturnal
 animals have excellent mobility, but are most sensitive to disturbances
 to breeding areas.  In addition, many bat species are colonial, so the
breeding areas are patchy in occurrence.   A disturbance of the smallest
designated area size could have a measurable impact on a breeding colony.
On the other hand, much  larger feeding areas would have to be disturbed
to yield a measurable impact.  Bat species occur in several types of land
areas.
                                   10-25

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10.3.2  Long-Term Effects
     The recovery phase of a mammal community is closely tied to the re-
covery of the vegetation.  The food value of the vegetation is an impor-
tant determinant in mammal recovery.  In addition, the amount of cover
provided by the vegetation is important to small mammals which are subject
to avian predators.  The vertical height of the vegetation is actually of
less general importance since relatively fewer mammals are canopy dwellers
than ground dwellers.  The main benefit provided by the vegetation height
is the amount of feed which exists at each level for herbivores and om-
nivores.  Another extremely important benefit for some prey species is
cover.6  Naturally, the habitat beneath the vegetation should vary with
vegetative height and density.  Therefore an important indirect benefit
is provided.

      10.3.2.1  Large Carnivores--
      Large carnivores will respond  to the recovery of their prey following
a disturbance.  The functional response of carnivores, an  increase  in  the
exploitation of prey, can be  practically  instantaneous.  However, the
numerical response, an  increase  in the number of  predators in an area,
is  necessarily slower.   This  response can occur both  through  immigration
or  large carnivores to  the recovering area   and  by reproduction, but
the latter process  is much slower  and may be masked by  immigration.
Since large  carnivores  are not measurably impacted by a  disturbance,
their recovery in an  area will be  a qualitative rather  than a quantita-
tive change.  Qualitative changes  can be  measured, but  only on a very
restricted  local  scale,  so that  the measurements  are  of questionable
significance in  assessing  impacts  to the  individuals  of highly mobile
species. The pertinent point is that  the quality of  the local area
changes when the animals leave.

      10.3.2,2  Medium-Sized Carnivores--
      The recovery of medium-sized carnivores should share the same
 characteristics as the recovery of large carnivores,  but on a more local
 scale.  Since medium-sized carnivores have less mobility, they will be
 slower  in responding to prey in the interior of a large disturbed area.
                                      10-26

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 However,  the numerical  response  will  still  be made mainly by  immigration.
 Again,  population changes  of these  animals  will  be limited by changes  in
 the populations  of their prey.   The medium-sized carnivores are also
 unlikely  to  be impacted measurably, so  that recovery will only be a
 qualitative  process.

      10.3.2.3 Small  Carnivores--
      Disturbances  to  the larger  land  area sizes  will have measurable
 impacts on the small  carnivores, and  therefore "recovery" can  be demon-
 strated quantitatively.  Since these  carnivores  are less mobile than the
 larger classes, much  of the numerical response must come from  reproduc-
 tion.  Small  carnivores  should follow fluctuations in prey density much
 more  closely  than  larger carnivores due to  their more limited mobility.

      10.3.2.4  Large  Herbivores--
      For  large herbivores, size effects are again of critical importance
 in  evaluating recovery  from a disturbance and their recovery will be
 qualitative rather than  a measurable change.  Since the large herbivores
 are highly mobile  (some are migratory),  the rate of movement  back into
 an area will depend on the reestablishment of edible vegetation.   The
number of large herbivores that a disturbed area can support  will  change
 gradually, and some disturbed areas may actually support higher densities
than originally existed.  This will occur where  the plant food is
actually denser and/or of better quality during  recovery than  in  the
 climax community.
complex.
      12
     10.3.2.5  Small Herbivores--
     The recovery phase of small herbivore populations can be extremely
        3,12
              Interspecies competition effects will be important in many
cases.~~  The recovery of small herbivore numbers should depend on both
immigration and reproduction.  Small mammals are noted for their ability
to respond reproductively, but dispersal abilities can also play a
key role in their population dynamics.    The recovery of small herbi-
vores should be very closely tied to changes in the vegetation, and
several distinct successional communities may occur.
                                     10-27

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     The immediate disturbance to an area may well create ideal conditions
for invasion by small "pest" rodents.  These animals may aid plant suc-
cession by cycling nutrients in the community and thus provide a beneficial
function.    However, competition may occur among "natural" species attempt-
ing to immigrate and could have a very detrimental effect.  Careful manage-
ment of small mammals can provide means for facilitating community recovery.
Predators can be introduced to dampen outbreaks in small herbivore popu-
lations, if control measures are needed.  Small mammal populations can
provide an index for monitoring community recovery of both the flora and
              i.
fauna.
     10.3.2.6  Large Omnivores—
     Because of their great mobility and large home range sizes, the re-
covery of large omnivores (bears) after a disturbance to an area is, like
that of other large animals, a qualitative process.  The recovery of bears
is most likely to consist of them simply using the area to forage and/or
den in again.  The problem of range reduction is a serious one for North
American bear species.  Therefore real recovery may be very difficult if
the maximum area size disturbance causes the loss of one or both of a
breeding pair which live in an isolated patch of habitat.  This problem
will rarely occur, however, and can be overcome by introduction of one or
more outside individuals as appropriate.

     10.3.2.7  Small Omnivores--
     The small omnivorous mammals are for the most part opportunistic
species.  Both the opossum and raccoon are familiar species which have
managed to survive in areas of human disturbance due to their versatile
feeding abilities.  The armadillo has actually extended its range of
occurrence in the Southwestern United States during the last hundred
years.    Quantitative recovery of these species should occur closely
in pace with changes in both vegetation and prey species on the largest-
size area.  These Species are reasonably mobile and can probably spread
as well by immigration as by reproduction.
                                      10-28

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      10.3.2.8  Insectivores—
      Insectivore recovery will depend on the recovery of insectivorous
 prey,  which in turn will  probably depend largely on vegetative  recovery.
 Thus the return of insectivores to a disturbed area is a second-order
 effect and will'require a longer time lag than that which will  occur
 for the similarly impacted small rodents.   The recovery of moles  will be
 stimulated where macroinvertebrates are  added to the soil ,o  assist
 vegetative recovery.   Few insectivores breed more than twice  a  year, and
 many breed but once.   This will tend to  retard recovery,  as reproduction
 is  an  essential part  of colonization due to the animal's  limited  mobility.

      10.3.2.9  Flying Manrnals—
     The recovery of  bats after a  disturbance to an area  will vary with
 the nature of the disturbance.   Like many birds,  bats  require the re-
 establishment of vertical structure in the  vegetation.  However,  several
 bat species roost in  dead trees, so that  available  roosts may actually
 increase from a disturbance.   Bats  are commonly known  for their mobility.
 Several  species  migrate seasonally,  or nightly,  to  food sources.  For
 these  reasons,  bat  recovery can  occur rapidly after recovery of insect
 prey in  feeding  habitats,  and  densities may actually increase given the
 proper circumstances.  Changes  in bat populations will usually be due
 to  emigration  and immigration  rather  than reproduction,

 10.3.3   Land  Types
     Table  10-3 gives examples of mammal species other than small herbi-
vores  from  each trophic/niche group in each  land type which are measurably
 impacted if the maximum disturbance has been made to the  specified land
areas.  Large mammal groups are extremely mobile, and are therefore im-
pacted only by area sizes greater than 100 km2.  Many of  the species occur
in more than one  land type.  This phenomenon is more evident in this table
than it is for birds  (Table 10-1) and small herbivorous mammals (Table 10-2)
The greater body size and mobility of many of the mammal species may be the
reason for this.  Again, the number of home ranges lost is used in estimat-
ing the types of species lost when a given size area is disturbed.
                                     10-29

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Table  10-3.
Examples  of mammals  other  than small  herbivores  impacted  by
maximum  disturbances to  specified types  and sizes of land
areas.3
MAJOR GROUPS
1. LAND TYPE
DESERT
Large Carnivores
Medium Carnivores
Small Carnivores
targe Herbivores
Bats
PRAIRIE
Large Carnivores
Medium Carnivores
Small Carnivores
Large Herbivores
Small Oronivores
Insectivores
DECIDUOUS FOREST
Large Carnivores
Medium Carnivores
Small Carnivores
Large Herbivores
Large Omnivores
Small Omnivores
Inseetivores
Bats
CONIFEROUS FOREST
Large Carnivores
Medium Carnivores
Small Carnivores
Large Herbivores
Large Oranivores
Small Oranivores
Insectivores
Sats
TUNDRA
Large Carnivores
Medium Car-sivoren
Small Carnivores
Large Herbivores
Large Omnivores
2. LAND USES
AGRICULTURE
Medium Carnivores
Small Carnivores
Large Herbivores
Small Omnivores
Insectivores
Bats
SUBURBAN
Small Omnivores
Bats
SIZE OF LAND AREA
0.1 km2


. b
Yuma myotis


Vagrant shrew


Pacific mole b
Little brown myotis

Shortfall shrew .
Mexican freetail bat0



Eastern mole
Evening batD
h
Pallid bat0
! km2








Armadi llo


Least weasel


Least weasel






10 km2


Hoqnose skunk


Spotted skunk
Opossum


Long-tail weasel
Opossum


Short-tail "weasel
Opossum


Short-tail weasel

Spotted skunk
Opossum


Opossum

-100km2

Mountain lion
Kit fox
Mule deer

Coyote
Red fox
Pronghorn

Mountain lion
Lynx
Marten
Whitetail deer
Slack bear
Raccoon


Grey wolf
Lynx •
Marten
Mule deer
Grizzly bear
Raccoon


Grey wolf
Arctic fox
Barren ground caribou
Grizzly bear

Red fox
Mule deer
Raccoon


Raccoon

       3  Home ranqe si^es  taken from McNab,  Vaughn,23 and Burt and Grossenheider,  or estimated from home range sizes
          of similar species.  Nomenclature of the genera and species follows Burt and Grossenheider»H where scientific
          names are also given.
       0  Bats, although migratory, appear in the smallest area category because of their colonial or semicolonial
          nesting :haracteristics.
                                                 10-30

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     Impacts can be defined more precisely as smaller mammals are ex-
amined, due to their reduced mobility which smaller size usually causes.
Therefore, in the discussion of the mammal fauna, small mammals are
emphasized.  In addition, some land types, notably agricultural and
suburban, support more "pest" specimens than others.  A special con-
sideration regarding these land types is the desirability of restoring
these mammals.

     10.3.3.1  Deserts—
     The single most important and prevalent group of mammals in the
desert habitat is the small herbivores.  Although large, medium, and
small carnivores, large herbivores, and bats may occur in deserts, their
diversity does not approach that of the small herbivores.  When a desert
area is disturbed, some measure of the impact on small mammals is often
obtainable.  However, the impact must be '.nferred from a comparison of
the disturbed area with some nearby area.  The return of herbivores will
keep pace with the vegetation return, a distinctly slow process.  Deserts
are continuous, so that colonization by both dispersal and reproduction
can occur from the edges of the disturbed area.  Intermediate faunal com-
munities are not expected for succession in most desert disturbances.

     10.3.3.2  Prairies—
     The prairie habitat supports a diversity of large herbovores.  Car-
nivores of all sizes as well as small omnivores may occur here, but by far
the most abundant and diverse group in prairies is the small herbivores.
The importance of small herbivores in this habitat is greater than in any
other habitat except tundra, where their importance is roughly equal.
A disturbance to prairie will certainly have a measurable impact on some
small herbivores for all but the smallest area size.  Therefore some
measurement of the recovery may be possible.  The recovery of the small
herbivores may involve changes in the densities and distributions of the
species present, as the vegetation changes.  The community recovery in
this habitat can be relatively rapid.  The continuous nature of prairies
should aid in this process.
                                     10-31

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     10.3.3.3  Deciduous Forests--
     Deciduous forests follow a pattern of response similar to coni-
ferous forests, but with some important differences.  These forests can
be expected to be somewhat richer in their mammal fauna.  The seasonal
change in canopy cover allows a richer understory of forage for both
large and small herbivores.  Bats and insectivores occur here, but are
seldom a major component of the fauna.  Medium size carnivores and
small omnivores should occur more frequently in deciduous forests.  The
response of the mammal fauna to a disturbance may again involve the
movement of large mammals out of the area, and an increase in small
herbivores.  In comparison to forests, the importance of small mammals
will be greater than in nonintensive agriculture during the recovery;
but in the mature forest, small mammals will have a similar importance
to that in nonintensive agriculture.

     10.3.3.4  Coniferous Forests—
     In coniferous forests during the recovery cycle following a dis-
turbance the number of small mammals will probably increase rather than
decrease.  Large mammals (carnivores, herbivores, and omnivores) will
usually leave the area, at least until restoration is well under way,
and then return.  Thus in coniferous forest, impacts are very difficult
to measure but: recovery is easier to assess.  This habitat is ideal for
the use of small mammals as indicators of recovery.
     Bats and insectivores are relatively unimportant components of the
mammal fauna, though they do occur in coniferous forest.  If insectivores
are present they may feed on insects which attack the dominant trees,
and thus increase their importance.  The medium carnivores and small
omnivores are more likely to occur at the forest border, and thus will
recolonize from other habitats.   The continuity of coniferous forests
should help most species recolonize from undisturbed areas.

     10.3.3.5  Tundra Areas--
     In tundra, small herbivores are key species to the ecosystem
economy.    Small carnivores depend upon these herbivores for prey.
                                     10-32

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Large herbivores, large omnivores, and large and medium carnivores may
also occur seasonally in tundra.  A disturbance to tundra will certainly
impact the small mammals measurably in most years.  The well known cyclic
fluctuations in population size of the dominant herbivores may cause an
inability to measure immediate impact in some years.  However, the
recovery phase measurements of following years will show the impact
belatedly.  Tundra is extremely sensitive to disturbance and a long
period of time is required for the vegetation to recover.  Whether
the recovery of the tundra habitat and fauna is possible in ecological
time is questionable, and predictions about recovery cannot be made.

     10.3.3.6  Coastal Inter-Tidal Marshlands--
     The marshlands are not expected to support extensive mammal faunas.

10.3.4  Land Uses
     10.3.4.1  Agricultural Areas--
     Herbivorous species are generally detrimental to man's interests
where they occur in agricultural areas.  The most common pests are, of
course, the small herbivores.  However, as the intensity of agriculture
increases, the role of small herbivores decreaises.    The other trophic/
niche groups are less frequent in occurrence in agriculture, but small
omnivores and medium-sized and small carnivores are considered pests
where animal husbandry is involved.  Large omnivores and carnivores
should occur only rarely.  Farm buildings are usually excellent places
for bat "nursery" breeding places, so that their occurrence in agri-
culture areas may be relatively high.  Insectivores are a relatively
unimportant, though occurring, component of the mammal fauna here.
     The recovery of mammals, particularly small herbivores, on dis-
turbed agricultural land can be extremely rapid.  Most, if not all, of
the responding animals will be pest species.  Most recovery problems
will involve having too many animals, at least in density, rather than
too few.   Some beneficial effects may result from nutrient cycling
through small herbivores.  However, these benefits are minimal because
of the control that man can exert on the nutrient balance.
                                     10-33

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     Here again, another alternative exists of allowing succession to
something similar to the preagricultural land type.  This is best thought
of by considering agriculture as an additional disturbance to the treat-
ment under consideration.  The mammal recovery will be similar to the
recovery described for the specific preagriculture land type, except
where precluded by fencing.  Fences which restrict large mammal access  .
will not greatly retard recovery, but may have subtle effects.  For
example, if predators are excluded, prey species may be affected.  A
fence which excludes all ground-moving mammals will eliminate, the re-
covery for all mammals except bats, and in some cases squirrels.

     10.3.4.2  Suburban Areas—
     The suburban habitat, much like agriculture, is typified by pest
species.  No large mammals of any type and no carnivores of any size
occur regularly in this habitat.  Small omnivores, small herbivores,
and bats make up the rather depauperate mammal fauna of the suburban
habitat.  The small omnivores have principal habitat elsewhere, and
the easily measurable impact to small herbivores is probably not of
concern.  Feral domestic species, especially cats, may be impacted.
Again this is probably not of concern.  What may be very important,
however, is the increase in rodent pests, and the diseases they carry,
during the recovery.  Introduction of predators such as feral cats may
be the best technique for managing these outbreaks.  The importance of
mammals in suburban faunas is likely to be quite low, perhaps on a
par with intensive agriculture.
     If the suburban land use is abandoned, succession to a land type
similar to the presuburban one may occur.  However, the rate and quality
of this recovery will depend on whether man-made structures remain or
not.  As in agriculture, this land use itself may be considered a dis-
turbance.  Fencing out large mammals will simply cause the loss of these
animals as participants in the recovery.  However, fencing out all
ground-moving mammals may also fence surviving pest species in,,  These
pests may require control measures to avoid health hazards to humans
which might periodically occur in the fenced area.
                                     10-34

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10.4  CONCLUSIONS
     The impact of a disturbance to a species was carefully defined at
the beginning of the wildlife section, but many people may simply want
to know if the disturbance will have a significant impact on the wild-
life species.  This demands not only  a definition of impact, but also an
evaluation of impact significance.  If significance is defined as whether
or not a disturbance puts any species in danger of becoming extinct, for
the vast majority of wildlife species and the designated land areas the
answer is "no".
     The real concern must be for those species so small in numbers that
extinction is a danger to them.  These species fill the rare, threatened,
                             5 22
and endangered species lists. '    Many of these species are nearly
extinct due to man's encroachment upon their habitats.  Other species
may be on the way to extinction with or without man's help.  These two
classes of endangered species may be difficult to tell apart.  Whether
or not species which are becoming extinct should be preserved is a social
decision.  This decision, conscious or unconscious, will govern their
fate.
     Many sensitive species may not be recoverable after a disturbance
to their range.  Other sensitive species may require expenditure of a
great effort in order to assure their revival.  This must be decided
upon in each case where an endangered species is affected, presumably
on the basis of the social and political values which predominate at
the time of the disturbance.   Any effort directed to this end may also
have a fringe benefit of aiding in the recovery of the total floral and/or
faunal community.
     Table 10-4 rates the relative impacts on wildlife, immediately after
cleanup, of the maximum disturbance possible in the individual treatment
categories in each land type for the stated area sizes.  Impacts on
mammal and bird wildlife are scaled from 0 (no measurable impact) to 5
(elimination of most original species) for each combination of the three
axes of  land type, treatment, and area size with the exception of fencing,
which divides impacts on mammals and birds.
                                 10-35

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Table  10-4.
Relative impacts of land cleanup treatments on  wildlife
following maximum  possible  land disturbance.
MAJOR GROUPS
LAND TYPE
Desert
Prairie
Deciduous
Forest
Conl ferous
Forest
Mountains
(Alpine)
Tundra
Coastal
Inter-Tidal
LAND USES
Agriculture
Suburban
TREATMENT

Stabilization, asphalt
Vegetation removal
Soil removal, stabilization
Fencing (mammals only)
Fencing (birds only)
• Vegetation removal
'Soil removal, stabilization
Fencing (mammals only)
Fencing (birds only)
Stabilization, asphalt
Vegetation removal
Soil removal, stabilization
Fencing (mammals only)
Fencing (birds only)
Stabilization, asphalt
Vegetation removal
Soil removal, stabilization
Fencing (mammals only)
Fencing (birds only)
Vegetation removal
Soil removal, stabilization
Fencing (mammals only)
Fencing (birds)
Flooding
Vegetation removal
Soil removal, stabilization
Fencing (mammals only)
Fencing (birds' only)
Vegetation removal
Soil removal, stabilisation
Fencing (birds only)

Stabilization, asphalt
Vegetation removal
Soil removal, stabilization
Sludge application
Fencing (mammals only)
Fencing (birds only), soil additive
Stabilization, asphalt
Vegetation removal
Soil removal, stabilization
Fencing (mammals only)
Fencing (birds only)
TREATMENT*
NUMBER

4^0
1
2
3-2
3-2
1
2.
3-2
3-3
4-0
1
2
3-2
3-3
4-0
1
2
3-2
3-3
4-0
1
2
3-2
3-3
1
2
3-2
3-3
1
2
3-3

4-0
1
2
5-0
3-2
3-3
4-0
1
2
3-2
3-3
RELATIVE IMPACTS FOR DIP- b
FERENT AREA SIZES (in km2)
0.01 0.10 1.0 10 100

34555
1 2345
24555
01210
00001
1 2344
23455
01221
00011
24555
1 1233
23455
01210
00011
24555
1 1223
23455
0 12 10
00011
34555
34555
12321
00011
000 00
3 4 5 5 5
34555
12321
00011
34555
345 55
Oil 11

2 4 555
22345
1 1233
0 01 22
01211
00011
1 2345
01234
0 1122
001 00
0 0.0 00
        a Treatment number 1 implies treatments 1-2 through 1-8, in general.
         Treatment number 2 implies treatments 2-1 through 2-8, in general.

         Relative impact, based on reduction in biomass
                 0 - No measurable Impact on species, < 5 percent reduction
                 1 - 5 to 35 percent reduction
                 2 - 35 to 60 percent reduction
                 3 - 60 to 80 percent reduction
                 4 - 80 to 90 percent reduction
                 5 - Original species eliminated, > 90 percent reduction
                                             10-36

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     The assignment of the values of the table is a subjective process     •
which necessarily assumes that all wildlife responds homogeneously to the
disturbance.  Although such an assumption is unrealistic, the table still
provides insights toward the truth, i.e., reasonable estimates of hpw a
wildlife community responds to a disturbance.  The table can also be viewed
as a ranking of treatments within each land type and area size.
     Table 10-5 estimates the relative time for recovery of wildlife from
the maximum disturbance possible and the individual treatment categories
of each land type for the stated area sizes.  The relative time to recovery
is scaled from 0 (about one year) to 5 (2 or 3 centuries).  The one-year
period is required as a baseline to measure whether a community has changed
to a greater degree than would be expected under "natural" conditions.
The 5 rating puts recovery sufficiently far into the future that it is not
reasonable to consider that recovery can take place, since evolution'may
change the community before it reaches equilibrium.
     One major assumption has been made in the derivation of relative im-
pacts:  that is, the colonization rate must remain constant for all species
in the succession^! process.  While this is not true in most individual
cases, it may be true on the average.  That is, the species in the coloni-
zation process may have varying movement rates.  But if the rates do not
vary widely, then violating the assumption may not be very serious.  The
mathematical reasoning implies a linear relationship between area size and
recovery time.  The constant colonization rate assumption is actually
another form of this assumption.              .
     Wildlife'is dependent on vegetative recovery; in fact, it is not
reasonable to try to uncouple these two types of recovery.  Therefore,
Table 10-5 includes biases which are a direct result of considering the
total environment in which the wildlife lives.  These biases are necessary
in order to improve the accuracy of impact assessment, and the computa-
tion of recovery times.
                                     10-37

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Table 10-5.
Relative  time  for recovery of wildlife following
maximum disturbance  to land and cleanup  treatment.
MAJOR GROUPS
LAND TYPE
Desert
Prairie
Deciduous
Forest
Coniferous
Forest
Mountains
(Alpine)
Tundra
Coastal
Inter-Tidal
LAND USES
Agriculture
Suburban
TREATMENT
Stabilization, asphalt
Vegetation removal
Soil removal, stabilization
Fencing (manna Is only)
Fencing (birds only)
Vegetation removal
Soil removal, stabilization
Fencing (mammals only)
Fencing (birds only)
Stabilization, asphalt
Vegetation removal
Soil removal, stabilization
Fencing (mammals only)
Fencing (birds only}
Stabilization, asphalt
Vegetation removal
Soil removal, stabilization
Fencing (mammals only)
Fencing (birds only)
Vegetation removal
Soil removal, stabilization
Fencing (mammals only)
Fencing (birds only)
Flooding
Vegetation removal
Soil removal, stabilization
Fencing (mammals only)
Fencing (birds only)
Vegetation removal
Soil removal, stabilization
Fencing (birds only)
Stabilization, asphalt
Vegetation removal
Soil removal, stabilization
Sludge application
Fencing (mammals only)
Fencing (birds only), soil additive
Stabilization, asphalt
Vegetation removal
Soil removal, stabilization
Fencing (mammals only)
Fencing (birds only)
TREATMENT3
NUMBER
4-0
1
2
3-2
3-3
1
2
3-2
3-3
4-0
1
2
3-2 '
3-3
4-0
1
2
3-2
3-3
4-0
1
2
3-2
3-3
1
2
3-2
3-3
1
2
3-3
4-0
1
2
5-0
3-2
3-3
4-0
1
2
3-2
3-3
RELATIVE TIME FOR RECOVERY FORb
DIFFERENT AREA SIZES (in km2)
0.01 0.10 1.0 10 100
55555
22344
34555
21100
00000
11222
12344
2 11 00
0 00 00
45555
22333
23455
21100
00000
45555
22333
23 4 5 5
2 1 1 00
00000
34555
33455
21100
00000
00000
34555
33455
21100
00000
1 2,3 44
11222
00000
45555
11111
11111
11111
11000
00000
34555
12233
11122
1 1000
00000
    a Treatment number 1  implies treatments 1-2  through 1-8, in general.

      Treatment number 2  implies treatments 2-1  through 2-8, in general,


    b T - - 1 year
      1 - 1 to 3 years
      2 - 3 to 5 years
      3 - 5 to 50 years
      4 - 50 to 100 years
      5 -  -100 years
                                      10-38

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 10.5  WILDLIFE REFERENCES
 1.  Adams, D. L. ,  and G. W.  Barrett, 1976.  "Stress Effects on Bird Species
         Diversity Within Mature Forest Ecosystems."  American Midland
         Naturalist, 96(1), p. 179.

 2.  Belrose, F.  C., 1976.  Ducks, Geese, and Swans of North America.
         Harrisburg, Penn.: Stackpole Books.

 3.  Bunnell, S.  D., and D. R. Johnson, 1974.  "Physical Factors Affecting
         Pika Density and Dispersal."  Journal of Mammology, 55(4),
         pp. 866-69.

 4.  Burt, W. H., and R. P. Grossenheider, 1964.   A Field Guide to Mammals.
         Boston,  Mass.: Houghton Mifflin Co., 284 pp.

 5.  California Department of Fish and Game, 1976.  At the Crossroads.

 6.  Cook, Sherburne F., Jr., 1959.   "The Effects of Fire on a Population
         of Small Rodents."  Ecology 40(1), pp.  102-108.

 7.  Delacour, J.,  1954.  The Waterfowl of the World.   London: Country
         Life Ltd.

 8.  Emlen, J. M.,  1973.  Ecology:  An Evolutionary Approach.   Reading,
         Mass.: Addison-Wesley Pub.  Co.

 9.  Emlen, J. T.,  1974.  "An Urban  Bird Community in  Tucson,  Arizona:
         Derivation, Structure, Regulation."  Condor 72(2), pp. 184-97.

10,  Frauzreb, K. E., 1976.  "Comparison of Variable Strip Transect  and
         Spot Map Methods for Censusing Avian Populations in a Mixed
         Coniferous Forest."   Condor 78(2) , pp.  260-62.

11.  Golley, F. B., K.  Petrusewicz,  and L. Ruszkowki,  editors, 1975.
         Small Mammals:  Their Productivity and Population Dynamics.
         Cambridge, Mass.: Cambridge University Press.

12.  Joule, J., and G.  N. Cameron, 1975.  "Species Removal Studies I.
         Dispersal  Strategies of Sympatric Sigmodon hispidus and
         Reithrodontomus fulvescens  Populations."  Journal of Mammology,
         56(2), pp. 378-96.

13.  Krebs, C. J.,  1964.  "The Lemming Cycle at Baker  Lake, Northwest
         Territories, during  1959-62."  Arctic Inst. N.  Amer.  Tech.  Paper
         No. 15,  104 pp.

14.  Krebs, C. J.,  1966.  "Demographic Changes in Fluctuating Populations
         of Microtus californicus."   Ecological  Monographs, 36(3), pp.
         239-73.
                                   10-39

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15.   Krebs, C.  J., 1972.   Ecology.   New York:   Harper  §  Row,  Inc.

16.   Lawrence,  George C., 1966.   "Ecology of Vertebrate  Animals  in Relation
         to Chaparral Fire in the Sierra Nevada Foothills."   Ecology,
         47(2), pp. 278-91.

17.   McNab, B.  K., 1963.   "Bioenergetics and the Determination of Home
         Range Sizes."  American Naturalist, 97(3),  pp.  133-40.

18.   Peterson,  R. T., 1964.  A Field Guide to Western Birds.   Boston,
         Mass.: Houghton Mifflin Co.

19.   Pianka, E. R., 1974.  Evolutionary Ecology.  New York:  Harper-Row,
         Inc.

20.   Schoener,  T. W., 1968.  "Sizes of Feeding Territories Among Birds."
         Ecology, 49, pp. 123-41.

21.   Twigg, G.  I., 1975.  "Marking Mammals."  Mammal Review,  5(3), pp.
         191-16.

22.   U.S. Department of the Interior, Fish and Wildlife Service, 1976.
         Endangered and Threatened Wildlife and Plants.   Federal Register,
         Wed. 27 Oct. 1976, pt. IV.

23.   Vaughn, T. A., 1972.  Mammology.  Philadelphia, Penn.: W,B. Saunders
         Co.

24.   Welty, J.  C., 1962.  The Life of Birds.  Philadelphia, Penn.: W.B.
         Saunders Co.

25.   Whittaker, R. H., 1970.  Communities and Ecosystems.  New York:
         MacMillan.
                                   10-40

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              PART IV
            APPENDICES
APPENDIX A,  STABILIZERS
APPENDIX B,  IMPACT ASSESSMENT
APPENDIX C.  LAND TYPES
APPENDIX D,  CLEANUP TREATMENTS
APPENDIX E,  GLOSSARY

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                                    APPENDIX A
                                   STABILIZERS
    A.I   INTRODUCTION
        This appendix contains a brief description of the major categories of
   soil stabilizers, the subgroupings of stabilizers, and the values assigned to
   the stabilizer subgroupings, land types, and land-use classes given in Table
   A-l.  The use of Table A-l is also explained.

   A.2  TYPES OF STABILIZERS
        For purposes of this report, "soil stabilizers" are defined and categorized
   to determine their practical application to soil stabilization with the land
   types defined Herein.  Stabilizers are generally classified into three major
   categories according to Ingles and Metcalf:1  chemical,  mechanical,  and physi-
   cal.   A fourth category,  chemical with mechanical characteristics,  is also
   considered here.
        Individual  stabilizers are shown  at the top of Table A-l.   The  major
   category of each is  shown by a symbol  underneath in one  of the first two
   horizontal rows;  these rows additionally denote  whether  the stabilizer is
   organic or inorganic.   The  stabilizers listed in Table A-l  are listed in
   Table A-2 with  information  on  manufacturers provided  for those that  have
   patented name.

   A.2.1   Chemical
        These  stabilizers  are  liquid  or  solid  additives to  soil that  effectively
   alter the physical  properties  of the  soil being  treated.

•  A.2.2 Mechanical
       These  stabilizers mechanically provide  sufficient  stability to bare soils
  to retard and/or prevent  soil erosion caused primarily  by wind and water,
                                        A-l

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 I,
 I lit
IJ
   j
   k

   I

         CM
         I

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 without modifying the physical properties of that soil.  The process con-
 sists primarily of compacting soils to a density that rejects water.  It also
 includes hard surface materials, manufactured soil retention materials,  and
 chemical aids to compaction.                                                  •
      Materials used for mechanical stabilization of soils include,  but are not
 limited to,  hard surface paving such as concrete and bituminous surfaces.  .Other
 manufactured materials are meshes, polyvinyl films,  and erosion control-nettings.
 Materials such ,as burlap bags with concrete, sandbags,  rip-rap, and. cribbing
 are also means of mechanical, stabilization.                              •
      Other forms of this type of stabilizer  include  the use of. grouts,  sand,
 and other filler compounds that  can be used  to  physically fill voids in  the
 soil by absorbing water and swelling to seal off the surface area from water
 infiltration.
      Equipment used for mechanical soil  stabilization is divided into  two  types:
 (1)  compaction equipment such as pneumatic-tired rollers,  tandem rollers,  sheeps-
 foot rollers, vibratory rollers,  vibratory packers;  and  (2)  application  equip-
 ment such as concrete  pavers,  asphalt  pavers, rock spreaders,  distributors, and
 sprayers.
      A  third subcategory of equipment  also should be  considered for mechanical
 stabilization of  contaminated  areas.   This includes  equipment  such as bull-
 dozers, turn-a-pulls,  and  scrapers which are used to  construct  diversion channels,
 ditches,  berms, and retention  basins around  the  affected area.  (These structures
 would be  temporary to  collect, divert, or retard surface drainage from adjacent
 areas or  to prevent water  from leaving affected  areas and causing downstream
 contamination.)

 A.2.3   Physical
     These stabilizers stabilize soils by modifying their physical properties
with heat, electricity, and cold.

 A.2.4   Chemical with Mechanical  Characteristics
     This term applies to stabilizers that are chemically produced or chemical
compounds that bind surface soils for short  periods of time.  Primarily,  they
                                     A-3

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are compounds used by the agricultural industry to promote germination and
then break down once germination has begun.  They are not true "mechanical"
stabilizers because of their lack of relative permanency, and because there
are brief periods between application and stabilization during which chemical
reaction with soil occurs.

A.3  STABILIZER GROUPINGS
     The four categories of stabilizers can be further categorized into group-
ings.  These groupings define the physical characteristics and treatment types
to promote "prescription-type" treatment of affected areas within the land
types defined in the report.  These groupings are shown at the left of Table
A-l, separated by broken  lines.  To determine the rating of a grouping cate-
gory for a particular stabilizer, use the number  immediately above the broken
line for the grouping category.  The key to these number ratings is at the
bottom of Table A-l.
     The following definitions are provided for the  groupings of soil sta-
bilizers:
     Organic and  Inorganic  — the category given  to  stabilizers that  generally
     define the physical  composition  of the specific material.
     Hazard  Levels  — primarily  the degree of  safety with  which a  stabilizer
     can be  handled by  personnel during the application  periods.   It  also
     includes  the "environmental safety" of the material  after application.
     Application  —  the method  or procedure of applying  the  prescribed
     stabilizer  to a defined  area as  it relates  to  available normal  applica-
     tion  equipment and methods.
     Durability  — the  ability of a chemical  or mechanical stabilizer to
     maintain a  specified treatment for  a  prescribed time period.   This
      includes the ability of a specified  stabilizer to withstand  the effects
      of the seasonal environmental  changes.
      Vegetation Recovery Period —  the ability of a chemical or mechanical
      stabilizer to disintegrate in the normal revegetation process where
      localized natural seed sources are present  (does not include conventional
      reseeding methods).
                                       A-4

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A.4  RATINGS OF STABILIZER GROUPINGS
     The ratings of the stabilizer groupings noted on Table A-l are defined
as follows:
     1,  Safe — a material or technique that is generally harmless to the
     applicator, environment, and .equipment.
     2,  Handling Precautions Required — requires compliance with manufac-
     turers instructions for physical applications during handling, mixing,
     applying, and temperature extremes.
     5,  Adverse Environmental Effects — materials where there is no oppor-
     tunity for the area to recover from the use of a stabilizer without
     major rehabilitation operations.  It does not include consideration as
     a toxic substance to man.
     4,  Highly Hazardous — materials or techniques where the "cure" is
     more dangerous than the "disease."  However, these can be situations
     where highly specialized personnel can be called upon to perform this
     type of stabilization.

A. 4.1  Application
     1,   Manual  (normal) —  hand-operated.equipment that can be used effec-
     tively and is frequently available to the home gardner.
     2,   Mapual  (difficult)  — stabilizers that must be applied to a small
     area,  are caustic to operators and equipment, have difficulty staying
     in solution,  require difficult or specialized mixing techniques, or
     require special carrier substances for proper application.
     5,   Equipment (normal)  — can be applied to large affected areas using
     standard agricultural or construction equipment; restricted to areas
     where there is space for the equipment to be used effectively.
     4,   Equipment (specialized)  — requires specially, manufactured equipment
     for proper application  or standard equipment greatly modified to accom-
     modate the stabilizer to be  used.
                                     A-5

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A.4.2  Durability
     1,   Permanent — will remain in place without radical physical change as
     a result of normal climatic conditions.   This includes the use of chemical
     stabilizers that permanently change surface soil characteristics.  Any
     alteration of an area where this stabilizer is used would require major
     construction.
     2,   Intermediate — broad terminology meaning that natural recovery will
     eventually take place.  This also applies to stabilizers that persist
     for at least 5 years when considered for surface applications.  These
     same stabilizers can persist for periods of more than 5 years when in-
     corporated into a compacted soil.
     3,   Short Term (1 year or less) — stabilizers that effectively control
     soil movement resulting from normal rainfall.  It also includes stabilizers
     generally accepted in the agricultural industry as erosion retardents
     during germination periods of most crops.

A.4.3  Vegetation Recovery
     1,   Immediate (natural) — stabilizers which have little resistance to
     climatic conditions, and which permit natural invader plants to germinate
     and grow on disturbed areas.
     2,   Requires Seeding  (normal response) — effectively hold surface soils
     intact for a period of at least 6 months, providing the applied membrane
     is not disturbed.  Revegetation requires normal seedbed preparation and
     planting of  selected varieties.  Residues of these stabilizers, after
     they are incorporated, are biodegradable and have no effect upon the new
     seedlings.
     3,  Complete New Seedbed Required  —  stabilizers that were used must be
     completely removed or buried at  sufficient  depth with new "cold  soil"  so
     that an affected area can provide  suitable  growing conditions  for vegeta-
     tive reestablishment.
     4,  No Recovery  — change the  physical makeup of the  surface  soil  suf-
      ficiently so that the plant  zone cannot  subsequently support  any type  of
     vegetation,  and  the  stabilizer is  not effectively  altered by  normal  freeze
      and thaw conditions.
                                       A-6

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 A.5  LAND TYPES AND LAND USE CLASSES
      The  seven  land types  and two  land use  classes  discussed  in this report
 are shown at  the right  of  Table  A-l,  separated  by solid  lines.  To determine
 the rating of each  stabilizer on each land  type or  land-use class, use the
 letter  above  the solid  line  for  the  particular  land type or class.  The key
 to  these  letters (ratings) is located at  the  bottom of Table  A-l.  Each of
 these ratings is defined as  follows.
      a,   Preferred  — materials  that  are  short-term effective, generally
      environmentally safe  naturally  and sociologically,  and subject to the
      general  moisture and  climatic conditions of a  land  type.
      b,   Acceptable as  an  Alternate  — basically the same characteristics as
      those classified "preferred," however, because of the effectiveness of
      the  material or application procedures they should  not be considered
      exclusively for stabilization of affected  areas.
      c,   Not  Acceptable  (last  resort  measure) — materials that should not be
      used because of the resultant damage, primarily to  the natural environ-
      ment.  When there  are situations where the  natural  environment cannot be
      protected  from irreversible effects of "accidental  spillage," these
      materials  may  be used.   This assignment is  also made to materials when
      applied  to various  land  types because of the variability within the land
      types  themselves.   For example,  "prairies"  can  be divided into many
      types  of "prairie"  and a  particular stabilizer  can  be effective for
      one  of these "prairie" types without serious environmental damage.  In
      other  "prairies," however,  this  same stabilizer would produce irreversible
      effects  and must not be used.   Based upon this  type of comparison with
      each of  the land types, the Mnot acceptable" assignment is made where
      there  is an irretrievable commitment of the natural resources present.
      d,   Not  Applicable  — materials  that cannot be  applied because of soil
      conditions, temperature  extremes, or moisture  conditions.

A.6  APPENDIX A REFERENCE
1.
Ingles, O.G., and J.B. Metcalf.  Soil Stabilization Principles and Practice.
J. Wiley § Sons, New York—Toronto, 1973.  374 pp.
                                      A-7

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