UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION VIII EPA-908 /9-85-OOI
INVESTIGATION INTO THE HEALTH OF
FORESTS IN THE VICINITY OF
GOTHIC, COLORADO
JANUARY 1985
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DISCLAIMER
This report has been reviewed by the U. S. Environmental
Protection Agency, Reqion VIII, Division of Air and Toxic Substances,
Denver, Colorado and is approved for publication. Mention of trade names
or commerical products does not constitute endorsement or recommendation
for use.
DISTRIBUTION STATEMENT
This report is available to the public through the
National Technical Information Service, US Department
of Commerce, Springfield, Virginia 22161.
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EPA-908/9-85-001
January 1985
INVESTIGATION INTO THE HEALTH OF FORESTS
IN THE VICINITY OF
GOTHIC, COLORADO
A SCIENTIFIC REPORT
BY
Robert I. Bruck, Ph.D., Chairman,
Associate Professor of Forest Pathology
North Carolina State University
Raleiqh, North Carolina
Paul Miller, Ph.D., Forest Pathologist (Air Quality)
U.S.D.A. Forest Service
Pacific Southwest Forest & Ranqe Experiment Station
Riverside, California
John Laut, Forest Pathologist,
Colorado State Forest Service,
Fort Collins, Colorado
William Jacobi, Ph.D.
Assistant Professor of Forest Pathology
Colorado State University
Fort Collins, Colorado
David Johnson, Ph.D., Forest Pathologist
U.S.D.A. Forest Service, Region 2
Denver, Colorado
PROJECT OFFICER
LARRY SVOBODA
DIVISION OF AIR AND TOXIC MATERIALS
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION VIII
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PREFACE
Last summer, two scientists observed damage to trees near Gothic,
Colorado which appeared similar to air pollution damage to forests in
northeastern United States and central Europe. The scientists, one from New
England, the other from West Germany, announced their observation that evening
to attendees of an acid rain conference at Western State College in Gunnison,
Colorado. About 300 people were at the July 23-25 conference, including
several news reporters.
While the scientists had not said the tree damage was definitely caused
by acid rain, some conference attendees interpreted the remarks as a definite
'discovery' of acid rain damage in Colorado. The next day media reports
ranged from a major story headlined, "First Acid Rain Damaged Trees Found in
State", to comparisons of the Gothic situation to those in known areas of acid
rain damage outside the western states. Several days later, questions emerged
over the possible effect the reports of "Colorado's acid-rain-damaged forests"
would have on the state's important tourism industry. A seemingly casual
report of possible damage had escalated into considerable public concern about
a potential environmental and economic threat.
Because of a general lack of knowledge about atmospheric deposition and
its effect on western forest ecosystems, public agencies could not support or
refute the allegations quickly and decisively. Based on the high level of
public concern, several state and federal agencies formed a team of scientists
to assess the health of forests in the Gothic area. The team was composed of
experts familiar with the ecosystems in the Rocky Mountain region and
patholoqists expert in identifying and assessing air pollution damage to
forests.
Dr. Robert I. Bruck of North Carolina State University was named to head
the team because of his expertise in air pollution forest damage in eastern
United States and central Europe.
The team's sole purpose was to assess and document the health of forests
in the Gothic area and to identify probable causes of reported forest
decline. This report presents their methods and findings.
THE MAJOR CONCLUSION IS THAT THERE IS NOW NO EVIDENCE TO INDICATE THAT
AIR POLLUTION IS CONTRIBUTING TO NATURAL FOREST PROCESSES IN THE GOTHIC AREA.
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Still, this experience contains some important lessons. First, where
public and media interest is intense, scientists should use extra care in
offering conclusions to extremely complex questions. Second, we need
comprehensive baseline research and monitoring to assess the link between
atmospheric deposition and forest health in the western United States.
If either of these principles is neglected, the scientific community,
public decision makers and the public at large may be misled when making
important policy decisions about changes to ecosystems. We intend to pursue
the recommendations for cooperative interagency research on western
atmospheric deposition as described in this report.
John
RegiohtrT" Administrator
Environmental Protection Agency
Region VIII
Denver, Colorado
Robert A. Arnott, Ph.D.
Assistant Director
Colorado Department of Health
Denver, Colorado
James Torrence
Regional Forester
U. S. Forest Service
Region II
Lakewood, Colorado
James "Hubbarc
State Forester
Colorado State Forest Service
Ft. Collins, Colorado
David H. Getches
Executive Director
Colorado Department of Natural Resources
Denver, Colorado
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ACKNOWLEDGEMENTS
This report, describing investigations into the health of forests around
Gothic, Colorado was made possible only by the dedicated efforts and hard work
of numerous individuals. The spirit of cooperation demonstrated among and
between all members of the investigative team, invited observers and
representatives of the U.S. Environmental Protection Agency, (EPA), Region
VIII was outstanding. Special thanks are extended to Larry Svoboda of EPA for
his highly objective approach in dealing with this sensitive issue and for his
assistance in the preparation of this report. The scientific team never found
itself "predisposed" to forming premature conclusions about the investigation
and was given free reign to explore all areas of concern and ready access to
required data. The investigative team also thanks our official observers: Jim
Lehr (EPA), Dr. Ray Herrmann (National Park Service), Ronald Cattany (Colorado
Department of Natural Resources), and Beth Baird (Colorado Department of
Health), for adding the necessary scientific expertise to our field
excursions, providing needed data bases, and excellent and objective reviews
of this document. In addition, we thank Dr. Ellis B. Cowling of North
Carolina State University, Dr. Eric Preston of EPA (Corvallis, Oregon), Dr.
James Gibson of Colorado State University (and Director of the National Acid
Deposition Program) and Dr. Carse Pustmueller of the Colorado Department of
Natural Resources for their prompt and constructive review of this document.
Finally, we are grateful to Dr. Chris Bernabo, Executive Director of the
National Acid Precipitation Assessment Program, for his support and
encouragement throughout this project.
The forest decline investigation team believes that it had a most valuable
experience in assessing the alleged anthropogenic damage to the forests in the
vicinity of Gothic Colorado. We hope the substance and recommendations
presented in this report serve both the scientific and policy making
communities in directing future strategies for the protection of our
environment.
For the Colorado Forest Decline
Investigation Team,
Robert I. Bruck, Ph.D.
Chairman
January, 1985
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TABLE OF CONTENTS
Preface
Acknowledgements
Table of Contents
Executive Summary 1
I. Introduction 7
II. Description of Study Area 9
Ecology of Subalpine Forests in Colorado 9
Damaging Agents in Spruce-fir Forests 12
III. Scientific Methods 15
IV. Results and Discussion 25
Visual Observation 25
Analysis of Increment Cores, Soils and Ozone Levels 28
Increment Cores 28
Soil Analysis 30
Ozone Monitoring 33
SEM Examination 34
Review of Available NADP Data 39
V. Conclusions 49
VI. Recommendations 52
Appendix A 56
Appendix R 67
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Executive Summary
This report summarizes the activities of a task force assembled by the
United States Environmental Protection Agency (Region VIII) in cooperation
with the Colorado Department of Natural Resources, Colorado Department of
Health, the Colorado State Forest Service, and the U.S. Forest Service in
response to the alleged decline of forests in the Crested Butte/Gothic area
of Colorado. Following two preliminary field trips conducted in August and
September 1984, a team visited the Gothic site during September 19-21, 1984
to make on-site observations, collect and analyze soil samples, perform
increment core sampling and analysis, and assess the potential for both
biotic and abiotic causal agents in the alleged tree damage. Team members
include:
Robert I. Bruck, Ph.D., John Laut, Forest Pathologist
Chairman, Associate Professor Colorado State Forest Service
of Forest Pathology Fort Collins, Colorado
North Carolina State University
Raleigh, North Carolina
William Jacobi, Ph.D. David Johnson, Ph.D.
Assistant Professor of Forest Pathologist
Forest Pathology U.S.D.A. Forest Service, Region 2
Colorado State University Denver, Colorado
Fort Collins, Colorado
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Paul Miller, Ph.D,
Forest Pathologist (Air Quality)
U.S.D.A. Forest Service
Pacific Southwest Forest & Range
Experiment Station
Riverside, California
Included as observers were:
Jim Lehr Ray Herrmann, Ph.D.
U.S. Environmental Protection Agency, U.S. Department of the Interior
Region VIII National Park Service
Denver, Colorado Fort Collins, Colorado
Ronald Cattany, Assistant Director Beth Baird
Colorado Department of Colorado Department of Health
Natural Resources Denver, Colorado
Denver, Colorado
A preliminary reconnaisance of the Gothic area was made by a team of
forest pathologists and entomologists from the Colorado State Forest Service
and U.S. Forest Service in August 1984. In September, eight test plots were
established by Dr. Jacobi. Soil samples were taken at these test plots, and
analyzed for heavy metal content. More than one hundred increment cores of
Engelmann spruce and subalpine fir were collected and annual increments
measured. Both symptomatic and asymptomatic trees were examined for the
presence of biotic and abiotic etiological agents that could be causal in the
decline symptomology. Spruce and fir needle samples were also collected and
analyzed under a scanning electron microscope.
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It is essential to state the fact that "trees are always dying in our
forests." Spruce and fir trees in the Rocky Mountain forests are affected by
manv abiotic and biotic agents that may stress, injure and often lead to tree
death. This is, in fact, a "natural" and expected phenomenon in a normal
"healthy" forest.
The needle chlorosis (yellowing) leading to necrosis (cell death) of
spruce or fir trees is often attributable to common and potentially deadly
forest pathogens and insects. At all sites visited, this team specifically
identified fungal pathogens and/or insects that can, and often will, cause
their hosts to yellow, decline and exhibit suppressed annual increment growth,
leading to tree death.
Although the appearance of many spruce and fir trees in and around Gothic
is similar to trees observed at the European and eastern U. S. sites, the
symptoms on trees observed in Colorado appear NOT to parallel those in the
affected forest decline Waldsterben areas. A detailed description of the
Waldsterben type of symptoms and decline is provided in Appendix A and B of
this report. In Dr. Rruck's observations, there is little or no correlation
between the normal forest disease syndrome found near Gothic and the
inexplicable damages observed in the Waldsterben areas (central Europe and
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eastern U.S.) where air pollution is suspected as a major factor in forest
decline. In addition to these visual observations, various data were
collected and analyzed which confirm and scientifically support the
observations and conclusions of this investigation. In summary, these
additional data and analyses revealed the following:
(1) Microscopic analysis of spruce and fir increment cores revealed
NO severe synchronous qrowth suppression (as is often observed in
boreal montane ecosystems in the eastern U.S. and West Germany).
Approximately twenty percent of the cores examined exhibited a
marked INCREASE in qrowth over the past twenty years.
(2) Analysis of surface soils from the eiqht test plots indicated
no abnormal loading of heavy metals. Loading of lead, copper and
nickel was usually four to ten times less than documented eastern
U.S. sites and virtually two orders of magnitude below levels
currently being observed in central Europe.
(3) Scanning electron microscope observations of needle tissues
collected from spruce and fir trees at the eight Gothic test sites
indicated NO surface cuticular or cell damage (highly indicative of
a lack of oxidant damage).
(4) Ambient concentrations of ozone (03) were monitored in the
area for a four week period. This monitoring revealed very low
levels of ozone. From these limited data, there is little evidence
to indicate that the observed ozone levels would cause environmental
effects in forests or other vegetation. Dr. Miller observed several
'ozone sensitive species' in the understory which showed no evidence
of oxidant damage.
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(5) NADP (National Acid Deposition Proqram) data included herein do
not indicate that an aqueous, acidified precipitation problem
presently exists in the area where annualized rainfall pH isopleths
normally exceed a value of 4.9 in measured pH. A review of quality
controlled, yet unpublished hiqh elevation data*, reveals
precipitation pH values consistent with those observed at the
established low elevation NADP sites as presented in this paper.
The members of the team therefore unanimously conclude that:
A. Symptoms and siqns of "declininq" Enqelmann spruce and subalpine fir
in the Gothic area do not correspond with those symptoms and siqns
reported and observed in central Europe and at hiqh elevations of
the eastern U.S. There are a limited number of symptoms which a
diseased tree can exhibit. Althouqh the yellowinq and browninq of
individual spruce and fir may appear similar to Waldsterben damaqe,
thorough and careful observation of the specific symptoms and siqns
can clearly differentiate between the two syndromes.Forest
conditions were observed to be consistent up to timber!ine, unlike
abnormally declininq forests which tend to express increased decline
symptoms with risinq elevation.
B. Precipitation pH and ozone incidence and severity data (included
herein) do not indicate levels of sufficient maqnitude to cause
veqetation damaqe. Several ozone sensitive species were identified
within the understory of the observed forests and were found to have
no ozone related damaqe.
C. ALL specific symptoms observed at the Gothic sites of alleqed
"declininq" spruce and fir can, in qood confidence, be attributed to
well known and clearly defined natural disease/insect complexes
found in "normal healthy forest?75^ There is no evidence to believe
that atmospheric deposition is contributinq to or exacerbating this
natural process.
* NADP data from the recently established Buffalo Pass site near the Mt.
Zirkel Wilderness Area in northwest Colorado. Obtained throuqh personal
communication with Dr. James Gibson, NADP.
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Increment core analysis indicates there has been no abnormal tree
growth suppression in the Gothic area. In addition, observations of
foliage on tree limbs in Gothic forests showed an average of six to
eight years of needle growth on branches rather than the one to
three years of needle retention found in Waldsterben damaged forests.
The members of the team strongly recommend, however, that
responsible well supported monitoring of atmospheric deposition and
forest conditions be implemented in the Rocky Mountain states to
create an early warning system for potential unexplained forest
damage that may occur in the future. These recommendations are
presented in detail within the text of this report.
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I. INTRODUCTION
The purpose of this report is to present the findinqs of an investigation
of suspected anthropogenic forest decline near Gothic, Colorado. Map 1 shows
the general location of the Gothic study area within the state of Colorado.
The investigation was initiated by the U. S. Environmental Protection Agency
(Region 8), the Colorado Department of Health, Colorado Department of Natural
Resources and the U.S. Forest Service. The objective of the investigation was
to provide a scientific evaluation of the validity and possible extent of
alleged anthropogenic forest decline near Gothic, Colorado. The investigation
was planned as an effort to provide initial information on the reported tree
damage at the earliest possible date. Therefore, this study should not be
construed as a comprehensive or definitive evaluation of potential air
pollution related forest damage in Colorado. The focus of this effort is
limited to the subalpine forests in the immediate vicinity of Gothic.
Additionally, the information included in this report is limited to the most
important and relevant data and analyses available given the resource and time
constraints of the study.
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c»
COLORADO
FT. COLLINS
GEORGETOWN
LOVELANO PASS
DILLION
. GRAND
• JUNCTION
LEADVILLE
BUENA VISTA
GOTHIC
COLORADO
SPRINGS
CRESTED
BUTTE
GUNNISON
COT TON WOOD PASS
PONCHA
SPRS
» t
MAP I
TOUR ROUTE
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II. DESCRIPTION OF STUDY AREA
Ecology of Subalplne Forests In Colorado
The forest veqetation in the vicinity of Crested Butte and Gothic is
predominantly Enqelmann spruce (Picea enqelmanni_) and subalpine fir (Abies
lasiocarpa) . This forest type occupies the highest forest environment over
much of the Rocky Mountains of the United States and Canada. In Colorado
these species are predominant in elevations over 8,000 feet, on north-facing
slopes, and above 10,000 feet on all other aspects. Spruce and fir forests
occupy one-third of the commerical forest land.
The climate of the spruce-fir zone is characterized by extremes that
limit tree qrowth and reproduction. It is relatively cool and humid, with
lonq, cold winters and short, cool summers. Mean annual temperature is below
35°F, and frost can occur any month of the year. Precipitation, largely as
winter snow, is usually greater than twenty five inches annually.
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Spruce-fir forests are considered the climax forests where they occur in
the central Rocky Mountains. Climax forests are not easily displaced by other
vegetation; however, complete removal of a stand by fire, logqinq or mining
activity results in such drastic environmental change that spruce and fir are
usually replaced by lodgepole pine, aspen, or shrub and grass communities.
The type of vegetation initially occupying disturbed sites usually determines
the length of time reguired to return to climax spruce-fir forests.
The composition of spruce-fir forests varies considerably with
elevation. At high elevations, spruce may form nearly pure stands, while at
mid-elevations spruce usually predominates in the overstory and fir in the
understory. At lower elevations, where sites are drier, the ratio of spruce
to fir may be low and lodgepole pine may replace spruce in the overstory.
Aspen is also a common associate at mid to lower elevations.
* Alexander, R.R. 1974 Silviculture of Subalpine Forests in the Central and
Southern Rocky Mountains: The Status of Our Knowledge. U.S.D.A. Forest Service
Paper RM121, 88 pp.
10
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In the Crested Butte-Gothic area, spruce-fir forests occur from
streamsides at elevations of 8,500 to 12,500 feet, where they occur as patches
of dwarfed trees known as Krummholz. At hiqher elevations, trees are often
dwarfed as a result of extreme environmental conditions such as cold and
stronq winds, forminq a dense mat with branches pointinq leeward to the
prevailinq wind. At lower elevations, the forest is characterized by
unevenness of aqe and size of trees and is often interspersed with aspen and
meadow!and. Numerous standinq dead trees and downed trees are common.
The spruce-fir community type in this area forms a continuous belt from
10,500 to 11,500 feet and appears more similar to those of southwestern
Colorado and mountainous areas of the Great Basin than to those of other areas
in the Colorado Rockies.
11
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Damaging Agents In Spruce-fir Forests
The spruce-fir forest is affected by numerous abiotic and biotic aqents
that cause stress, injury and frequent mortality of trees. The most common
diseases and insects are listed in Tables 1 and 2. Many of the symptoms
expressed by trees injured or damaged by abiotic agents, including extremes of
weather and exposure to toxic materials, may mimic those caused by diseases
and insects. Specialized knowledge and local experience are often needed to
separate symptoms of airborne pollutant damage from those caused by natural
stresses such as nutrient deficiency, weather extremes, diseases and insects.
Water availability, hail, temperature extremes, light, and road cuts are
frequent causes of vegetation injury or mortality. Declining radial and
height growth of spruce and fir can result from root-infecting fungi such as
Armillaria mellea and Inonotus circinatus. Other symptoms associated with
root diseases include yellowing foliage and abundance of "stress" cones.
Various needle infecting fungi (Lirula spp.) and insects (spider mites and
aphids) may also cause yellowing of foliage and premature shedding of
needles. Dieback of tree tops can be caused by numerous agents, including
adverse weather, bark-feeding rodents and birds, canker fungi, and insects
(Ips and Scolytus species).
12
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Enqlemann
spruce
Table 1. List of Diseases Commonly Found in Spruce-fir Forests.
Diseases
Common name
red rinq rot
white pocket rot
spruce broom rust
cankers
brown felt blight
winter injury
needlecast
circinatus root rot
Armillaria
disease
root
Scientific name
Phe 11 inijs_(_Fomes) pini
Phe TTfnu s n fq'roTfmi t at u s
Chrysbmyxa arctostophyTf
Va'lsa kunTef
tierpotrichia juniperi
warm, Sry, winter winds
Lirula macrospora
Tnbntu's circinatus
(= PoTypqrus^ tomentosus)
ArmilTarfa me flea
Size
Distribution Class^
entire range of host 3, 4
entire range of host 3, 4
entire range of host 3, 4
central Colorado 2, 3, 4
entire range of host 1, 2, 3
Colorado 3, 4
Colorado 5
entire range of host 3, 4
entire range of host 2, 3, 4
Principal
Damage^
c
c
a, b, c
b, d, e
b, e
e
e
c
Subalpine red ring rot
fir red heart rot
butt rot
fir broom rust
Armillaria root
disease
annosus root disease
cankers
brown felt blight
winter injury
sunscald
needlecast
foliage disease
Phellinus (Fomes) pini
Haematostereum f= Stersum)
sangufnoTentum
Peniophora pufeana
Melampsorella
caryopliynac e arum
Armillaria mellea
Fomes annosus
Sc1erdderris abieticola
yalsa"aFietis
Herpotrfcbia .junipeH
wa~r m f "dry, vTTrft er wind s
increased light
Lirula abietis-concoloris
Virgella robusta
entire range of host 3, 4
entire range of host 3, 4
Colorado 3, 4,
entire range of host 2, 3, 4
entire range of host 2, 3, 4
Southern Colorado 2, 3, 4
Colorado 1, 2
Colorado 1, 2
entire range of host 1, 2
Colorado 2, 3, 4
entire range of host 2, 3
Colorado 5
Colorado 5
c
c
a, b, d
c, d
d
b, d, e
b, d, e
b, e
b, e
b, d
e
e
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Table 2. List of Insects Commonly Found in Spruce-Fir Forest
Common name
Scientific name
ENGLEMANN Cooley spruce qall aphid
SPRUCE spruce beetle
Adelqes cooleyi (Gill.)
Dendroctonus rufipennis
(Kirby.)
Enqlemann spruce enqraver Ips enqelmanni (Sw.)
pine enqraver
spruce enqraver
Ips pini (Say)
Ips spp.
Distribution
entire ranqe of host
Colorado, Wyominq
Colorado, Wyominq
entire ranqe of host
Colorado, Wyoming
SUBALPINE western spruce budworm
FIR
western balsam bark
beetle
fir enqraver
Choristonsura occidental is Colorado, Wyominq
Freeman.
Dryocoetes confusus Sw. entire range of host
Scolytus ventral is LeC. entire range of host
Size Principal.
Class' Damage'
2, 3,
3,
2,
3,
3,
2, 3,
3,
3,
4
4
4
4
4
4
4
4
b, e
d
b, d
b, d
b, d
e
d
d
1 Size Class Primarily Affected:
1 = seedlings (1.0" dbh);
4 = sawtimber (8.0" + dbh);
2 = saplings (2.0 - 4.0" dbh); 3 = poletimber (5.0 - 8.9" dbh);
5 = all size classes
Principal Damage:
a = qrowth reduction; b = deformity; c = cull; d = mortality; e = defoliation
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Abnormal masses of foliage and twiqs, commonly referred to as witches'
brooms, are caused by needle-infecting funqi (Chrysomyxa arctostaphyli on
spruce and Melampsorella caryophyllaceareum on fir). These brooms may
appear similar to those reported in European literature as caused by air
pollutants.
Rapid decline and death of spruce and fir, within one to two years, can
often be attributed to several species of bark beetles, including spruce
beetle (Dendroctonus rufipennis), western balsam bark beetle-in fir
(Dryocoetes confusus), and fir engraver (Sco1ytus ventralis).
15
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III. SCIENTIFIC METHODS
General Approach
There are a number of key symptoms and signs which serve as important
indicators in identifying air pollution related tree damage. Given the
constraints of both time and funds, this investigation established five key
sets of data from which air pollution related forest damage could be
identified. These included:
(1) VISUAL OBSERVATION- Both symptomatic and asymptomatic trees
were carefully examined" for the presence of biotic and abiotic
etiological agents that could cause decline symptomology in trees
and other vegetation.
(2) INCREMENT CORES- Plots were established with both dominant
and co-dominant tree species. Within the eight plots over 100
radial increment cores were taken and analyzed. Cores are used to
provide evidence of significant deviations in growth patterns.
(3) SOIL SAMPLES- Soil samples were taken at each of the eight
plots using standard ecological methods. Samples were analyzed
for calcium, magnesium, sodium, potassium, phosphorous, aluminum,
iron, manganese, titanium, copper, zinc, nickel, molybdenum,
cadmium, chromium, strontium, barium, lead, pH, and a number of
other important soil parameters.
(4) SCANNING ELECTRON MICROSCOPY (SEM)- Tree samples (needles)
were taken and observed using SEM. This method of analysis is
important in identifying air pollution related effects on the wax
and cuticle surface of needles.
(5) AMBIENT OZONE CONCENTRATIONS- A monitoring station was
installed near the reported areas of tree damage in an effort to
guantify levels of ozone which could be damaqing to trees and
other vegetation. In addition, species sensitive to elevated
ozone levels were identified and examined for existing oxidant
damage.
16
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These data were collected from each of the eight plots at the Gothic
site. Other areas examined involved visual observation only. Collectively,
these preliminary data would provide a sufficient information base on which
anthropogenic effects could be identified. These preliminary data could then
be used to direct additional research efforts as needed.
Investigations-Data Gathering
On August 6, 1984, a preliminary reconnaissance of the Gothic area was
conducted by a team of forest insect and disease specialists from the U.S.
Forest Service and the Colorado State Forest Service. Based on visual
observation and subseguent laboratory analysis, including culturing of decay
fungi, this group found that declining and dying Engelmann spruce and
subalpine fir were affected by a root disease-insect complex that is common
throughout the spruce-fir ecosystems in Colorado and other mountainous areas
of western North America. Other insects and disease-causing organisms were
also identified. This preliminary information was submitted to the U.S.
Environmental Protection Agency (Region VIII) on August 10, 1984 and served as
background for the more detailed investigation.
17
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Following the decision to conduct further investigations with scientists
having special air pollution and "acid rain" expertise, Dr. William Jacobi, a
graduate student and an EPA representative visited the site and took increment
cores from 100 trees in eight separate stands for radial growth analysis and
surface soil samples from each of those stands for chemical analysis. Table 3
provides a brief description of each of the eight study plots. The first four
plots were established on the basis of previously reported forest decline.
Plots 5 through 8 were selected to represent the natural ecosystem with
relatively little apparent human-caused disruption. The last four plots were
established in pairs with one plot (5 and 7) showing stressed trees and the
other (6 and 8) showing few symptoms of stress. Maps 2 and 3 show the general
location of the study plots near Gothic.
In addition, the Colorado Department of Health installed an ozone monitor
with an outdoor sensor at the Rocky Mountain Biological Laboratory at Gothic.
Ozone levels were monitored from August 12, 1984 to September 21, 1984.
During September 19-21, 1984, an additional comprehensive field trip to
the Gothic site was conducted by: John Laut, William Jacobi, Dave Johnson,
Robert Bruck, and Paul Miller.
18
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TABLE 3.
GENERAL PLOT INFORMATION
PLOT
1
?
3
4
5
6
7
8
LOCATION
Near Swallow's 32
Nest Cabin
Near Ore House 32
At top of Mil
north of Gothic
East of Barr Cabin
West of Avery Peak
Campqround
West Avery Peak 10
Campqround
East of Avery Peak
Campqround
East of Avery Peak
SLOPE
(*)
NNE
N
.2
27
25
NE
35
35
ASPECT
9,470
9,470
9,560
W
NE
9,640
SW
SW
ELEVATION
(feet)
9,600
9,640
9,800
9,800
ES
2
5
3
7
7
9
6
8
TREES SAMPLED1
SAP
3
0
2
8
8
6
9
7
AVERAGE
DBH
(inches)
13.2
13.3
15.2
10 9
13.4
16.6
17.3
18.5
ES = Enqlemann spruce
SAF = Subalpine fir
Terrain was undulatinq
19
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COLORADO
•
MAP 2
GOTH 1C COLORADO
PLOTS 1-4, AND PLOTS 7-8
QUADRANGLE LOCATION
20
-------
East
3
o
J-'13
•3\7
COLORADO
MAP 3
GOTHIC, COLORADO
PLOTS 5 AND 6
QUADRANGLE LOCATION
21
-------
Observers were Jim Lehr, EPA Reqion VIII, Denver; Ray Herrmann, United
States Department of the Interior, National Park Service; Ronald Cattany,
Colorado Department of Natural Resources; and Beth Baird, Colorado Department
of Health.
The team also visited additional high elevation spruce and fir stands
between Gothic and Denver at Cottonwood Pass and Love!and Pass. The purpose
was to observe symptoms and signs of disease on spruce-fir forests possibly
attributable to air pollution. The general locations of these sites are shown
in Maps 4 and 5.
22
-------
Browns^'
fPas. -
1
° ^
COTTONWOOD
:^ PASS SITE
\TOREST I
V.16I8 \
*"•>»» : \
7- '
*.^
V
/
/ *"/
ffar-»n«t«n °'n
LaJa
OUAD8WCLE LOCAT10H
MAP 4
COTTONWOOD PASS
23
-------
Loveland Pass -
BM 11990/7
-^ .O /,
LOVELAND PASS SITE
COLORADO
MAPS
LOVELAND PASS
QUADRANGLE LOCATION
24
-------
IV. RESULTS AND DISCUSSION
Visual Observation
Plate 1 (paqe 25) and Table 4 (paqe 26) describe the type of symptoms,
siqns and causal agents observed during the investigation. These agents,
alone, can in good confidence, explain the forest decline observed in the
Gothic area and other high elevation spruce-fir forests observed during the
field investigation.
Plate 1 illustrates some of the observations made by the team at sites
where alleged anthropogenic forest decline was occurring. It is often
difficult to diagnose insect and disease problems in situ (on site), even for
an experienced pathologist. However, this was not the case at Gothic. Trees
exhibiting yellowing, browning and general decline symptomotology were
examined and all had signs (actual fungal pathogens) of disease. Fungal
sporophores and mycelial fans of Inonotus circinatus and Armillaria mellea,
respectively, were observed on virtually all "sick" trees. In addition to
these root disease problems, Fomes pini was often fruiting on symptomatic
trees. From these initial visual observations the team had strong evidence
that spruce and fir exhibiting decline symptoms were, in fact, always
associated with root disease centers. No further pathogen identification
(aseptic culturing) was deemed necessary as positive identification was easily
made on site.
25
-------
VV *
-, ~^ -
, *
!' • I
-------
TABLE 4
LEGEND TO PLATE 1
(1) View of study areas near Gothic Peak.
(2) View of study areas near Avery Peak.
(3) Root rot focus near Plot 2. Typical yellowing and browning of foliaqe
due to A. mellea and I. circinatus infections.
(4) "Declining tree" symotoms on lodgepole pine near Cottonwood Pass, due to
heavy dwarf mistletoe infestation.
(5) Fungal conk of F. pini on spruce in plot 3 near Gothic. The "red ring
rot" disease leads to slow decline and death of its host.
(6) Mycelial (fungal) fans of A. mellea on buttress roots of spruce in plot 2
root rot center (see Picture 3) near Gothic. This disease leads to
yellowing, browning and eventual death of the tree.
(7) Fungal fruiting bodies of I. circinatus root rot in plot 1 near Gothic.
Signs and symptoms of I. circinatus and* A. mellea are common on
"declining" trees throughout the area.
27
-------
Analysis of Increment Cores, Soils and Ozone Levels at Gothic, Colorado
Increment Cores
Fiqure 1 illustrates the average annual growth increment of Enqelmann
spruce and subalpine fir at the eight plots representing age distribution of
70-389 years. 11 trees were dominant or co-dominant growing at an elevation
of from 9,469 feet to 10,028 feet above mean sea level.
There is little or no growth increment suppression in trees that were
asymptomatic or trees showing slight to moderate root rot or insect damage.
Severely insect or disease damaged trees exhibited only recent (3-5 years)
ring suppression commonly seen in the final stages of a terminal root rot or
insect infestation. Twenty percent of the cores exhibited growth stimulation
over the past 20 years. From this information there appears to be no
similarity or correlation between the central European and eastern U.S. growth
increment phenomenon (see Appendix 1) and the Gothic spruce-fir population.
28
-------
FIG I
5 2
iu
Ul
flc
a-SPRUCE
o-FlR
GOTHIC, COLORADO
A/ERA6E ANNUAL INCREMENT
ALL TREES DOMINANT/ CO-DOMINANT
ENOLEMANN SPRUCE N-62
5UBALPINE FIR N'79
I I
1950
I960
1970
YEAR
I960 (983
29
-------
Soil Analysis
Eiqht soil pits were excavated in and around the Gothic site. Surface
soil (0-5cm) samples were collected and sent to the Colorado State University
Soil Testing Lab. The results of the analyses are presented in Tables 5 and
6. The incidence of all heavy metals possibly attributed to atmospheric
deposition, with the exception of zinc (ZN), are in many cases an order of
magnitude or more below levels documented in the eastern U.S. and central
European Waldsterben areas. Levels of ZN, although elevated, are lower than
impacted areas in Europe and the eastern U.S. but are not in excess of levels
considered dangerous to tree growth. High elevation concentrations of lead
and cadmium considered prime suspects in forest decline are, in fact,
considerably lower in the Rocky Mountain boreal ecosystem soils sampled than
in those reported low elevation hardwood forest soils in the eastern U.S.
There is no evidence to indicate that anthropogenic atmospheric deposition of
heavy metals to the soils in and around Gothic could either trigger or sustain
a forest decline syndrome.
30
-------
Table 5. RESULTS OF SOIL ANALYSIS
PLOT NO. pH
1 6.3
2 6.7
3 6.8
4A 5.7
5 5.9
6 6.1
7 6.5
8 5.9
Mo
1 3
2 3
3 3
4A 5
5 3
6 3
7 3
Cond. Lime
Li,3 ILtrL^, (£SJLrJL
0.2 Low
0.2 Low
0.3 Low
0.2 Low
0.2 Low
0.2 Low
0.2 Low
0.2 Low
Tnfal fHF
Cd Cr
1 18
1 34
1 18
1 42
1 27
1 28
1 27
Wt. loss
on iqn.
K, O.M.
53.6
45.9
69.4
36.8
56.3
55.4
62.1
75.4
SY
121
112
130
125
95
88
78
ppm
N03-N
48
12
24
12
20
16
24
32
Ba ""
519
423
383
604
332
392
391
ppm ppm ppm ppm
P K Zn Fe
53.6 562 56.2 163.2
41.0 572 55.4 178.6
69.6 1,012 114.8 100.8
37.4 378 79.0 318.0
53.2 412 31.2 246.0
56.8 404 36.0 228.0
66.0 516 46.4 86.8
76.0 488 80.8 92.8
Pb
52
32
20
77
27
28
18
ppm ppm Texture
Mn . Cu JestJL
85.8 4.5 Org.
50.6 3.6 Org.
80.0 3.9 Org.
77.0 3.8 Org.
79.0 3.5 Org.
103.8 3.1 Org.
68.8 4.3 Org.
128.0 5.4 Org.
.—i
ro
-------
TABLE 6.
RESULTS OF SOIL ANALYSIS
Total (HF digest)
Plot ? £ £ £ nig /kg ££mg/kg £mg/kg mg/kgmg/kg
No. Ca Mg Na K P AT Fe Mn Ti Cu Zn Ni
1 1.76 0.55 0.69 1.12 972 3.09 1.48 760 0.36 19 128 12
2 1.49 0.63 0.60 1.52 983 4.09 1.89 480 0.46 22 166 22
3 1.99 0.37 0.27 0.84 940 2.16 1.09 550 0.27 17 273 12
4A 0.99 0.62 0.76 1.73 890 5.19 3.26 780 0.50 27 397 33
5 1.36 0.51 0.33 1.02 914 3.04 1.51 710 0.40 18 109 14
1.50 0.47 0.30 1.00 989 2.95 1.42 670 0.39 18 115 14
1.65 0.48 0.37 1.02 986 2.79 1.31 490 0.39 20 97 1_5
2.07 0.27 0.16 0.57 977 1.53 0.72 590 0.22 18 125 10
32
-------
Ozone Mom'tor ing
Through the services of the Colorado Department of Health, an ozone
monitor was placed at the Rocky Mountain Biological Laboratory within a
kilometer of the alleged forest decline site. Although ozone (0.,)
monitoring was limited to a four week period (insufficient data to draw
definite conclusions), the highest hourly reading during the measurement
period was .047 parts per million (ppm)( August 23, 1100 hours and September
20, 1500 hours). Tables 7 through 10 present the 0^ data collected on an
hourly basis during the monitoring period. Most readings were consistently
lower than ambient background levels for wide areas of the eastern U.S.
Observations of spruce and fir trees and natural herbaceous vegetation
revealed no indication of ozone damage, as determined by Dr. Paul Miller.
Although much more data would be necessary to draw "concrete" conclusions, the
team believes it is unlikely that ozone or other oxidants are either acutely
or chronically affecting spruce-fir ecosystems in the Gothic area.
The limited amount of continuous ozone monitoring data for the Gothic
area suggests that concentrations are typical of natural background levels in
the western United States. Measured ozone levels at Gothic ranged from .004 to
33
-------
.036 ppm on an hourly average basis. Sensitive conifers in California are
injured after exposure to 24 hour average ozone concentrations of 0.06 to 0.08
Dpm. Under intense California ir pollution conditions, to achieve 24 hour
averages of this magnitude, it is necessary to have daily peak values reaching
at least 0.10 to 0.175 ppm.
Particular attention was paid by Dr. Miller to herbaceous species in the
forest understory and in open grassy areas in an attempt to identify ozone
symptoms on plants that would be expected to be more sensitive than conifers.
One genus, Osmorhiza, was observed commonly in the spruce-fir understory. In
California this genus is considered to be ozone sensitive but no evidence of
leaf injury was identified in the Gothic area.
Scanning Electron Microscope (SEM) Examination of Spruce and Fir Foliage.
Twenty spruce and fir needle samples were collected on September 20 from
the othic area. The samples were returned to the North Carolina State
University SEM Laboratory, fixed, coated and observed via SEM for cuticular or
cellular damage attributable to oxidant injury. All samples proved to be
negative for signs of ozone damage.
34
-------
FABLE 7 HOURLY OZONE DATA FOR GOTHIC, COLORADO
(PPM)
DAY 00 01 02 03 04 05 06 07 08 09 10 11
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
0.008
0.008
0.031
0.016
0.018
0.010
0.020
0.014
0.015
0.010
0.012
0.008
0.008
0.013
0.012
0.009
0.010
0.008
0.030
0.018
0.018
0.009
0.016
0.012
0.015
0.013
0.009
0.008
0.008
0.009
0.014
0.008
0.009
0.008
0.024
0.021
0.014
0.009
0.015
0.010
0.012
0.008
0.012
0.009
0.009
0.009
0.023
0.010
0.007
0.008
0.019
0.025
0.013
0.010
0.015
0.010
0.011
0.009
0.008
0.010
0.010
0.008
0.037
0.008
0.007
0.007
0.016
0.019
0.013
0.012
0.021
0.009
0.012
0.012
0.008
0.012
0.009
0.009
0.029
0.010
0.007
0.008
0.016
0.019
0.010
0.007
0.022
0.009
0.014
0.007
0.010
0.010
0.008
0.009
0.019
0.012
0.005
0.005
0.019
0.021
0.013
0.00
0.019
0.009
0.012
0.005
0.013
0.010
0.004
0.019
0.015
0.010
0.009
0.019
0.029
0.015
0.008
0.020
0.015
0.014
0.010
0.018
0.013
0.012
0.024
0.035
0.032
0.032
0.033
0.040
0.041
0.033
0.027
0.019
0.040
0.035
0.030
0.028
0.027
0.025 0.034
0.025 0.039
0.039
0.035
0.033
0.033
0.039
0.040
0.031
0.030
0.027
0.037
0.039
0.033
0.030
0.032
0.037
0.042
0.044
0.035
0.033
0.034
0.036
0.038
0.031
0.033
0.024
0.037
0.040
0.035
0.033
0.032
0.038
0.034
0.043
0.045
MEAN .0132 .0126 .0126 .013 .0128 .0116 .0117 .0167 .025 .033 .0351 .0353
MAX 0.031 0.030 0.024 0.037 0.029 0.022 0.021 0.035 0.025 0.041 0.044 0.045
-------
TABLE 3 HOURLY OZONE DATA FOR GOTHIC, COLORADO
(PPM)
DAY 12 13 14 15 16 17 18 19 20 21 22 23 NO. MEAN MAX
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
0.035
0.033
0.034
0.033
0.034
0.031
0.032
0.029
0.040
0.040
0.035
0.035
0.032
0.039
0.034
0.040
0.044
0.035
0.038
0.029
0.038
0.029
0.033
0.034
0.042
0.041
0.035
0.039
0.033
0.038
0.034
0.043
0.044
0.035
0.028
0.039
0.029
0.034
0.035
0.045
0.041
0.034
0.035
0.033
0.039
0.034
0.043
0.045
0.035
0.034
0.035
0.034
0.032
0.035
0.044
0.041
0.033
0.034
0.030
0.037
0.028
0.043
0.047
0.030
0.032
0.033
0.031
0.033
0.032
0.036
0.042
0.040
0.029
0.030
0.024
0.033
0.020
0.044
0.044
0.023
0.017
0.031
0.025
0.023
0.028
0.038
0.044
0.035
0.020
0.019
0.015
0.032
0.023
0.039
0.038
0.017
0.014
0.033
0.021
0.023
0.020
0.020
0.036
0.020
0.010
0.015
0.009
0.024
0.019
0.025
0.029
0.017
0.010
0.034
0.016
0.018
0.015
0.020
0.021
0.019
0.010
0.013
0.014
0.019
0.025
0.020
0.019
0.014
0.012
0.034
0.015
0.018
0.013
0.028
0.016
0.019
0.014
0.020
0.019
0.012
0.014
0.017
0.020
0.010
0.010
0.038
0.018
0.019
0.013
0.020
0.014
0.020
0.012
0.020
0.013
0.008
0.009
0.014
0.017
0.010
0.009
0.034
0.018
0.018
0.014
0.024
0.012
0.016
0.010
0.014
0.012
0.009
0.009
0.015
0.013
0.009
0.009
0.033
0.014
0.018
0.012
0.017
0.014
0.015
0.010
0.012
0.015
0.008
0.012
0.010
0.012
8
23
13
0
4
0
15
23
23
23
23
23
23
23
23
21
22
23
24
23
.0162
.0181
.0176
.0335
.0339
.0259
.0241
.0208
.0206
.0274
.0238
.0197
.0196
.0176
.021
.0198
.0239
.0294
0.030
0.035
0.038
0.034
0.040
0.041
0.034
0.034
0.036
0.045
0.041
0.035
0.039
0.033
0.039
0.037
0.044
0.047
MEAN .0352 .0365 .0366 .0361 .0333 .028 .0209 .0181 .0176 .0159 .0148 .0137 .0224
MAX 0.044 0.044 0.045 0.047 0.044 0.044 0.036 0.034 0.034 0.038 0.034 0.033 0.047
-------
DAY
00
01
02
TABLE 9 HOURLY OZONE DATA FOR GOTHIC, COLORADO
(PPM)
03
04
05
06
07
08
09
10
11
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
0.009
0.010
0.005
0.005
0.005
0.012
0.013
0.013
0.010
0.020
0.007
0.010
0.007
0.008
0.007
0.009
0.005
0.005
0.005
0.008
0.012
0.015
0.010
0.016
0.007
0.012
0.006
0.006
0.007
0.009
0.005
0.005
0.005
0.010
0.010
0.013
0.009
0.020
0.006
0.030
0.006
0.008
0.007
0.010
0.007
0.007
0.007
0.007
0.013
0.009
0.013
0.009
0.008
0.025
0.005
0.004
0.008
0.010
0.007
0.005
0.004
0.007
0.009
0.009
0.008
0.007
0.004
0.015
0.003
0.002
0.009
0.009
0.005
0.004
0.005
0.008
0.010
0.008
0.007
0.008
0.005
0.014
0.002
0.005
0.017
0.010
0.008
0.007
0.007
0.008
0.009
0.008
0.008
0.008
0.005
0.015
0.003
0.009
0.033
0.020
0.018
0.017
0.015
0.013
0.019
0.013
0.013
0.014
0.012
0.025
0.012
0.009
0.022
0.033
0.033
0.028
0.029
0.033
0.032
0.023
0.026
0.034
0.034
0.032
0.034
0.034
0.029
0.033
0.035
0.034
0.028
0.030
0.034
0.044
0.037
0.033
0.035
0.035
0.033
0.034
0.039
0.037
0.032
0.034
0.035
0.047
0.035
0.035 0.037
0.038
0.019 0.026
MEAN .0094 .0087 .01
MAX 0.028 0.018 0.030
.0092 .0064 .0068 .008 .0155 .022 .03 .0334 .0359
0.025 0.015 0.014 0.015 0.025 0.022 0.035 0.044 0.047
-------
TABLE 10 HOURLY OZONE DATA FOR GOTHIC, COLORADO
(PPM)
DAY 12 13 14 15 16 17 18 19 20 21 22 23 NO. MEAN MAX
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
0.030
0.034
0.035
0.035
0.033
0.033
0.039
0.039
0.034
0.036
0.034
0.045
0.035
0.034
0.030
0.036
0.030
0.032
0.028
0.032
0.038
0.039
0.040
0.035
0.039
0.044
0.036
0.035
0.040
0.038
0.029
0.032
0.030
0.030
0.040
0.038
0.040
0.036
0.039
0.042
0.035
0.035
0.037
0.035
0.023
0.029
0.030
0.025
0.039
0.039
0.035
0.037
0.037
0.043
0.034
0.040
0.033
0.033
0.025
0.027
0.027
0.019
0.038
0.035
0.038
0.036
0.030
0.043
0.032
0.040
0.024
0.030
0.032
0.030
0.024
0.022
0.025
0.019
0.032
0.025
0.030
0.029
0.026
0.038
0.031
0.025
0.024
0.028
0.020
0.010
0.023
0.028
0.010
0.039
0.018
0.033
0.028
0.029
0.034
0.029
0.017
0.017
0.025
0.021
0.009
0.020
0.018
0.010
0.039
0.017
0.033
0.027
0.022
0.028
0.030
0.006
0.030
0.024
0.013
0.007
0.017
0.009
0.009
0.035
0.029
0.020
0.026
0.019
0.030
0.031
0.006
0.029
0.022
0.014
0.007
0.012
0.009
0.019
0.028
0.030
0.019
0.020
0.017
0.028
0.026
0.005
0.022
0.013
0.011
0.005
0.009
0.008
0.015
0.020
0.028
0.015
0.017
0.011
0.018
0.016
0.004
0.008
0.011
0.005
0.009
0.005
0.013
0.015
0.019
0.015
0.024
0.009
0.013
0.102
0.009
0
0
0
0
0
0
0
0
0
0
0
0
12
23
23
21
23
23
24
23
23
23
23
23
23
16
0
0
0
0
8
16
.0268 0.040
.0203 0.038
.0173 0.035
.0172 0.035
.0171 0.033
.0166 0.034
.0251 0.040
.0239 0.039
.0227 0.040
.0224 0.037
.0223 0.039
.0253 0.047
.0259 0.037
.0211 0.040
.012 0.025
.0152 0.030
MEAN .0354 .0352 .036 .0342 .0318 .0274 .024 .0223 .0202 .0185 .0135 .0119 .0210
MAX 0.045 0.044 0.042 0.043 0.043 0.038 0.039 0.039 0.035 0.030 0.028 0.024 0.047
-------
Review of Available NADP Precipitation Data
There is a limited amount of wet deposition monitoring data available for
the central Rocky Mountain area and Colorado. Many of the established
National Acid Deposition Program monitoring sites in Colorado are located at
lower elevations or are remotely located from the Gothic site. Therefore,
none of the existing monitoring sites are truly representative of the Gothic
area and caution must be exercised in making inference from the NADP sites to
the unique Gothic situation.
However, an examination of existing NADP data (which have been subject
to careful guality control) shows that precipitation pH, hydrogen ion
deposition, sulfate deposition and nitrate deposition in Colorado for 1980 and
1981 are well below the values believed to cause aquatic or terrestrial damage
and well below those values found in the eastern United States. Relative
values of atmospheric deposition parameters in central Europe, eastern U.S.
and Colorado are compared in Table 11. The information in Table 11 is
presented to document the relative differences in certain anthropogenically
produced air pollutants found in central Europe, high elevations of the
eastern U.S. and rural mid-altitude Colorado. Perhaps the most significant
and striking difference (with respect to this document) is the observed
difference in rain pH.
39
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TARLE 11.
TABLE OF ATMOSPHERIC DEPOSITION PARAMETERS*
CENTRAL EUROPE
Rain pH
Sulfate Deposition
Nitrate Deposition
Surface Soil Lead
Ozone
3.6 - 4.5
50 kq/ha/yr
50 kq/ha/yr
300 - 600 ppm
.06 - .19 ppm
EASTERN U. S. (Hiqh Elev.)
3.8 - 4.6
Approx. 50 kq/ha/yr
40 kq/ha/yr
150 - 300 ppm
.06 - .20 ppm
COLORADO (Rural)
4.9 - 6.0
20 kq/ha/yr
20 kq/ha/yr
50 ppm
.03 ppm
* Averaqe values of atmospheric deposition products attributed to anthropoqenic
emissions.
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A review of the relevant literature indicates that significant
perturbation due to acidified precipitation in terrestrial ecosystems has only
been observed below pH 4.0, both in simulator and field studies. Quality
assured and controlled data in Colorado have never been observed to reach
these pH extremes, while events below pH 4.0 are common in the eastern U.S.
and frequent in central Europe. Nitrate and sulfate deposition are much lower
in the intermountain region with total deposition rarely exceeding 10
kilograms/hectare/year (kg/ha/yr), eastern U.S. and central European values,
particularly in documented areas of forest decline, often exceed 50 kg/ha/yr
deposition of these toxic and nutritive compounds.
Finally, maximum ozone levels as assessed from rural Colorado data usually
do not exceed values that are considered 'ambient' for many affected areas of
the eastern U.S. and central Europe. Since the effect of ozone on plants is
usually considered an acute reaction (short time duration of very high levels
of oxidant), the preliminary analysis of rural Colorado data does not
indicate ozone levels of sufficient magnitude to induce herbaceous or tree
plant damage.
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Some important Colorado data are presented in Tables 12-14 which show
average annual ion concentrations for 1980 and 1981 and deposition for 1981
at each of the state's monitoring stations. In Table 12 data are presented
not only for hydrogen ion, sulfate and nitrate concentrations but also for
calcium, magnesium and ammonium which represent alkaline materials reponsible
for reducing potential acidity. Included in this Table are two sites which
demonstrate the extreme values found in the United States: Olympic National
Park in Washington and Parson, West Virginia. The values for Olympic National
Park (not corrected for marine salts) are relatively similar to those found in
the southern hemisphere in areas where values are considered to be at or near
natural background levels. Table 13 presents similar data for 1981, and Table
14 presents deposition values for hydrogen ion, sulfate and nitrate. Table 15
depicts data collected from the Rocky Mountain National Park NADP site. This,
the highest elevation and quality controlled site presently operating in the
state of Colorado, indicates a total volume weighted annual average
precipitation pH of approximately 5.0.
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Table 1?. Average annual concentration, 1980
Site
Alamosa, CO
Sand Springs, CO
Rocky Mountain
National Park, CO
Manitou, CO
Pawnee, CO
Olympic
National Park, WA
Parson, WV
Table 13. Average annual
Site
Alamosa, CO
Sand Springs, CO
Rocky Mountain
National Park, CO
Manitou, CO
Pawnee, CO
Olympic
National Park, WA
Parson, WV
0H
ueq/1
5.6
4.8
5.0
4.9
5.5
5.4
4.2
S04
- precipitation
27.0
22.0
25.0
45.0
31.0
7.0
74.0
NO 3
weighted
15.0
14.0
22.0
33.0
28.0
1.5
33.0
NH4
20.0
8.4
20.0
21.0
38.0
1.0
13.0
Ca & Mg
18.5
16.0
17.0
33.0
22.0
5.0
17.0
concentration, 1981.
pH
ueg/T
5.2
5.0
5.0
4.8
5.1
5.4
4.2
S04
- precipitation
38.0
33.0
33.0
34.0
45.0
8.0
74.0
NO 3
weighted
17.0
16.0
23.0
24.0
28.0
1.5
30.0
NH4
23.0
10.0
19.0
13.0
39.0
1.0
16.0
Ca & Mg
28.0
31.0
26.0
24.0
29.0
10.0
18.0
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Table 14. Annual deposition, 1981.
Site
Alamosa, CO
Sand Springs, CO
Rocky Mountain
National Park, CO
Manitou, CO
Pawnee, CO
Olympic
National Park, VIA
Parson, WY
H+
0.01
0.04
0.03
0.07
0.03
0.10
0.90
S04
T
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Table 15. Volume weighted annual average precipitation values for Rocky
Mountain National Park headquarters NADP site. Values are in ueq/1.
YEAR Total
Precip
(cm) Ca++ Mg++ K+ Na+ NH4 N03 Cl" SO^ pH
1980 13. 771 13.90 2.87 1.14 2.43 20.47 22.10 5.04 25.29 4.99
1981 31.70 19.41 6.76 1.18 5.09 18.73 23.33 4.38 32.69 5.01
1982 28.30 10.47 2.96 1.23 2.44 7.76 14.97 2.54 18.95 4.97
1 1980 reflects only 6 months of data, as the site began operation in June
of that year.
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One of the major factors in determining the potential for acidification in
aquatic and terrestrial systems is the rate of deposition. A 1983 survey of
data in Scandinavia and the United States suqqests that acidification of lakes
and streams in sensitive areas occurs when the oH of precipitation drops below
4.7. This is comparable to a sulfate deposition between 20-30 kq/ha.
Rainfall pH in Rocky Mountain National Park on the averaqe is not below
5.0 . It should be kept, in mind that the threshold value of 4.7 was
determined in areas of the world that receive considerably more rain volume
than in the Rocky Mountain region of Colorado. The deposition of nitrates and
sulfates is less that twenty percent of that in the eastern United States.
Deposition can therfore be considered to be currently below that which is
considered significant in terms of lake or stream acidification. Nitrate
levels in Rocky Mountain National Park are higher than expected which may be
cause for concern regarding potential effects upon vegetation.
* Personal communication, Dr. Jill Baron, National Park Service, Ft. Collins,
Colorado.
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Several conclusions can be reached when reviewing the Colorado NADP data:
1. Precioitation pH ranqes from approximately 4.8 to 5.6.
2. Calcium and ammonium concentrations represent significant levels for
alkalizing materials which are responsible for lower acidities than
would be expected from the concentrations of sulfate and nitrate (if
these are considered to originate as sulfuric and nitric acid).
3. Concentrations of sulfate in Colorado are four to five times greater
than those levels found in Olympic National Park and approximately
one half to one third less than those observed in Parsons, West
Virginia.
4. While there are small variations, sulfate concentrations are
reasonably consistent across the state indicating limited influence
of local sources.
5. Concentrations of nitrate are ten to twenty times more than those
found in Olympic National Park. NADP stations located on Colorado's
eastern slope indicate similar concentrations of nitrate as those
observed in West Virginia.
6. Nitrate concentrations are approximately fifty percent of sulfate
levels on the western slope but seventy percent of those on the
eastern slope most likely due to mobile sources in urban areas.
7. Because of lower concentrations and low precipitation at Colorado
sites (20 to 40 cm/yr), sulfate deposition values are less than
twenty percent of those in West Virginia and nitrate deposition
values are less than twenty five percent.
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As stated earlier, one of the major factors in determining potential for
acidification of aquatic and terrestrial ecosystems is the level of
deposition. It has been stated that acidic deposition represented by rainfall
pH of 4.6 or greater (sulfate deposition less than 20-30 kq/hectare) is not
believed to be significant in terms of acidification even in sensitive areas.
In Colorado, data suggest that rainfall pH on the average is not below 4.8.
The pH value of 4.7 was determined in areas of the world where rainfall
amounts are considerably higher than in the Rocky Mountain region in
Colorado. Sulfate deposition averages 5-7 kg/hectare and the deposition of
nitrates and sulfates is less than twenty percent of that in the eastern U.S.
Therefore, from these limited data it appears that wet deposition velocities
in Colorado are currently below the levels which are believed to cause damage
to forests and other vegetation.
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V. CONCLUSIONS
Trees are always dyinq in our forests. The Rocky Mountain spruce-fir
forests are affected by many abiotic and biotic aqents that may stress, injure
and often lead to tree death. This is, in fact, a "natural" and expected
phenomenon in a normal "healthy" forest. These types of effects are
illustrated in Plate 1 with the correspondinq description in Table 11.
The chlorosis (yellowing) leading to necrosis (cell death) of spruce or
fir trees is often attributable to common and potentially deadly forest
pathogens and insects. At all sites visited, the investigative team
specifically identified fungal pathogens that can, and often will, in and of
themselves, cause their hosts to yellow, decline and exhibit suppressed annual
increment growth, leading to tree death. The forest decline observed can be
considered a natural phenomenon typical of Rocky Mountain spruce-fir forests.
Conversely, the team found no evidence to suggest that anthropogenic factors
are contributing to forest decline in the Gothic area at the present time.
Although the superficial appearance of many spruce and fir trees in and
around Gothic is similar to that observed in other species of coniferous trees
found in central Europe and the eastern U.S., the symptoms and signs observed
at all Gothic sites appear NOT to parallel those in the affected Waldsterben
49
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areas of central Europe, which are described in detail in the text of this
report, Appendix A and B. In Dr. Bruck's observations, there is little or no
correlation between the Gothic normal forest disease syndrome and the
inexplicable damaqes observed in the forest decline in Waldsterben areas, of
central Europe and the eastern U.S.
NADP data included herein (Figure 7-10) do not indicate an acid rain
problem presently existing in Colorado where annualized rainfalls usually
exceed pH 4.9 to over 5.0.
Microscopic analysis of spruce and fir increment cores revealed no severe
synchronous growth suppression (as is often observed in boreal montane
ecosystems in the eastern U.S. and Germany). Approximately twenty percent of
the cores examined exhibited a marked increase in growth over the past twenty
years.
Analysis of surface soils from the eight test plots indicated no abnormal
loading of heavy metals. Loadings of lead, copper and nickel are usually 4-10
times less than comparable eastern U.S. sites and virtually 2 orders of
magnitude below levels currently being observed in central Europe.
Scanning electron microscope observations of needle tissues collected
from spruce and fir trees at the 8 Gothic test sites indicated no surface
cuticular or cell damage (highly indicative of a lack of oxidant damage.)
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The members of the forest investigation team therefore unanimously
conclude that:
A. Symptoms and signs of "declining" Engelmann soruce and subalpine fir
in the Gothic, Colorado area DO NOT closely resemble those reported
and observed from central Europe and high elevations of the eastern
U.S. There are only so many ways that a "tree can die" and although
the yellowing and browning of individual spruce and fir may appear
similar to Waldsterben damage—thorough and careful observations of
the specific symptoms and signs can clearly differentiate between
the two syndromes.
B. Precipitation pH and ozone incidence and severity data (included
herein) do NOT indicate levels of sufficient magnitude to cause
vegetation damage.
C. Virtually all specific symptoms observed at the Gothic test sites of
allegedly "declining" spruce and fir can, in good confidence, be
attributed to well known and clearly defined natural pathogen/insect
complexes found in a "normal healthy forest."
D. The members of the team strongly recommend, however, that
responsible well supported monitoring of atmospheric deposition and
forest conditions be implemented in the Rocky Mountain states to
create an early warning system for potential unexplained forest
damage in the future.
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VI. RECOMMENDATIONS
Based on this investigation, the team strongly recommends the
establishment of a comprehensive atmospheric deposition research and
monitoring program in the western United States. While it does not appear
necessary to suooort additional research at the Gothic site, research and
monitoring should be supported at representative sites within Colorado and
other western states.
This investigation was initiated by a cursory observation of stressed
trees near Gothic, Colorado displaying visual symptoms of damage similar in
appearance to those observed in the forests of central Europe and the eastern
United States. The need for the investigation emerged from the fact that no
public agency had reliable information to demonstrate that the reports of
'acid rain1 damage were incorrect. The lack of specific information on
atmospheric deposition in the West and the effect this deposition has or may
have on forests hindered an immediate and informed response by public
agencies. If more were known about the western situation, the public alarm
over 'acid rain' damage near Gothic could have been substantiated, prevented
or promptly defused.
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This investigation was designed to qather as much reliable information as
possible at a specific qeoqraphic site for a limited and specific period of
time. A more extensive research proqram should and must be developed and
supported to understand current and projected levels of atmospheric deposition
and to identify the real or potential impact of atmospheric deposition on
western terrestrial and aquatic ecosystems. Unlike many areas of the world,
the opportunity to prevent serious environmental problems is very hiqh in many
parts of the western United States. However, to adequately protect these
resources, it is necessary to understand the existing situation in the diverse
western ecosystems some of which appear to be highly susceptible to the
acidification process. It appears that slight increases in atmospheric
deposition could result in serious damage to western ecosystems. It is
important to initiate baseline monitoring and research in atmospheric, aquatic
and terrestrial systems to protect the environment of the western United
States.
It is critical at this point in time to begin by asking the right
questions. The forest decline phenomenon is frighteningly complex. Steps
should be initiated in the western U.S. to assess the value of central
European and eastern U.S. short and long term research and survey strategies
and their applicability to the western situation.
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Specifically, the team believes that a western research program should be
initiated to include:
1. A program to establish the baseline ambient air guality and atmospheric
deposition levels at various representative locations in the western
United States. This could be accomplished by adding new NADP monitoring
sites (particularly at high elevations) to the present network and by
establishing a series of comprehensive atmospheric monitoring stations at
key locations in the Rocky Mountain region. At the Gothic site, it would
be advisable to monitor air quality for a longer period of time and to
establish the seasonal peak values of ozone in the area.
2. The watershed studies currently being conducted by EPA (Region VIII),
NPS, USGS, USFS et. al. should be continued to establish baseline
information from which trends can be detected and to estimate the
acidification potential of high elevation lakes.
3. A program should be initiated to survey, monitor and conduct research
on terrestrial ecosystems in the West. An effort should be initiated to
utilize research and survey strategies already employed in central Europe
and the eastern United States, and to test their applicability to the
western situation. Species sensitive to atmospheric deposition should be
identified and monitored for vegetation damage. Long term monitoring
plots should be established in representative ecosystems to identify, at
the earliest possible date, the presence of damage to trees and other
vegetation from air pollution related causes.
4. Linkage between current and future research and survey programs (i.e.
U.S. EPA, National Park Service, U.S. Forest Service, Colorado Department
of Natural Resources and the Colorado Department of Health) should be
encouraged in order to enhance the efficiency and timeliness of new
initiatives.
5. Finally, it must be emphasized that this report should not serve as an
"end" but rather as the beginning of an effort to establish meaningful
programs to address potential damage of valuable western resources by
atmospheric deposition. A unique opportunity is at hand to gather
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critical baseline data to establish the current status of air pollution
and forest health in managed and natural terrestrial ecosystems.
Scientists and policy makers in the western states can avoid the "crisis"
atmosphere associated with central European and Eastern U.S. forest
decline by becoming more knowledgable of the conditions of non-air
pollution damaged forests. If and when pollution induced damage occurs,
it may be dealt with in a scholarly and responsible manner. In addition,
the spruce-fir ecosystems of the Rocky Mountain region serves as an
important "experimental" control for NAPAP (National Acid Precipitation
Assessment Program) initiatives in assessing the impact of anthropogenic
pollution on our environment. We strongly encourage inter-agency
cooperation to meet the above recommendations.
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APPENDIX A
FOREST DECLINE IN CENTRAL EUROPE AND THE EASTERN UNITED STATES.
"Waldsterben" or forest decline is a rapidly developing pattern of
changes in the appearance and behavior of forests in many parts of Germany and
other Central and eastern European nations. The symptoms of decline are not
identical in rate or sequence of development in various species of trees.
Nevertheless, they include the following features, some of which have never or
only very rarely been reported before in the literature of forestry and plant
pathology.
Changes in the forests have developed very rapidly and unevenly but
roughly simultaneously since 1979. Symptoms of decline have been observed in
many different species and types of forests, principally silver fir (Abies
alba Mill.), Norway spruce (Pjcea abies Karst.), European beech (Fagus
sylvatica L.), and Scotch pine (Pinus sylvestris L.), but also including red
maple, white oak, larch, white birch, alder, and white ash. The symptoms
include a general thinning, change in color and altered morphology of the
leaves and total tree canopy, particularly in spruce, fir, beech and pine.
Loss of foliage is common in both spruce and fir. A loss or sparse
development of foliage and abnormal development of branches are common in
European beech. The formation of smaller than normal leaves, especially in
beech and spruce, and misshapen (lobed) leaves, especially in beech, have been
noted.
Active casting (shedding) of green leaves during the growing season
especially in beech, fir, spruce, larch, alder and oak and of green shoots
whith intact leaves and needles, most notably in spruce and pine and
occasionally in oak have also been observed by German scientists. A decrease
in diameter growth, particularly in fir and spruce during the past 20 years,
has been noted. In spruce and fir the width of annual rings in affected trees
have been found to be greater higher on the stem and much reduced or absent
toward the base of the stem. This kind of abnormal distrubution of annual
increment has rarely been reported before.
Abnormally heavy cone and seed crops have been observed three years in a
row in spruce, pine and beech. This has not been reported in silver fir.
Unusually large numbers of adventitious shoots are formed on affected spruce;
epicormic branches are common on affected European beech trees. The complete
lack or great suppression of fine feeder roots and ectomycorrhizal roots, a
symbiotic association of fine roots and beneficial fungi, has been observed.
This poor development of fine roots is especially common in affected beech,
but is also less common and not as intense in spruce and fir.
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Wood, most notably of branches, has become unusually brittle in affected
beech trees. Marked deficiency of magnesium has been confirmed in the foliage
of affected spruce trees. Death of most or all of herbaceous vegetation
immediately beneath the canopy of some affected trees has been observed in two
locations in Bavaria. The formation of crystals of calcium sulfate in the
stomata on needles of affected spruce have been observed by electron
microscopy. This wide array of symptoms has developed very rapidly (since
1979) and is so widespread in occurrence that many private, industrial and
government foresters in West Germany are concerned that the forests as they
have known them may not survive.
In seeking to understand the possible causes of forest decline in central
Europe it is important to note that trees growing on fertile or infertile
soils, in both basic and acidic soils, are affected by "Waldsterben". In
forest stands regardless of aspect or orientation in southern Germany, and
particularly in Bavaria but more commonly on northwest-facing slopes in
northwestern German, north Rhine Westfalia and on west-facing slopes on
elevations above 100 meters in the Black Forest area of Baden Wurtenberg have
been most severely affected.
Although the most severe symptoms have been reported at high elevations,
800-1400 meters and above, essentially similar symptoms have also been
observed in forests at moderate and low elevation sites. The first survey
conducted in 1980 to delimit the geographic extent of forest decline in German
forests are showing some stage of forest decline.
Several hypotheses have been proposed alone and in combination on the
cause of forest decline including gaseous pollutants, magnesium deficiency
induced by atmospheric deposition, general stress resulting from a combination
of pollutants and drought, acidification of forest soils causing aluminum
toxicity to the roots, and other biotic and abiotic stress factors.
FOREST DECLINE IN THE EASTERN UNITED STATES
Over the past 20 years red spruce (Picea rubens Sarg.) located in the
high elevation forests of New York, Vermont and New Hampshire have exhibited
marked dieback and decline symptoms. Certain northern Appalachian red spruce
stands are presently exhibiting in excess of 80% dieback incidence and 60%
incidence of mortality. The decline is characteristic of a stress related
disease, and the etiology is not typical of a single biotic pathogen. In
November 1983, a preliminary survey of Mt. Mitchell, NC was conducted from the
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summit (6,684 feet MSL) to below 5,200 feet MSL to characterize and
photodocument the presence of any decline or dieback of red spruce in the
southeastern United States. Mount Mitchell is the highest peak in eastern
North America and its main peak and three high altitude ridges support vast
populations of red spruce and Fraser fir which comprise one of the largest
subalpine ecosystems east of the Mississippi River. All trees sampled at or
above 6,350' elevation regardless of vigor exhibited marked growth reduction
beginning in the early 1960's. On numerous samples the 21 annual growth
increments from 1962-1983 were equivalent in total diameter to the four annual
increments from 1958-1961. Precipitation data from 1930-1983 show that at no
time during these 53 years was there a drought at the summit of Mt. Mitchell.
Therefore growth suppression cannot be attributed to lack of moisture. In May
1984 a survey was begun to quantify and characterize the extent and rate of
high altitude spruce-fir forest decline in the southern Appalachian
Mountains. Our preliminary analysis indicates that the forest decline
syndrome is observed in varying degrees throughout the southern Appalachian
Mountains. West-facing slopes appear to have greater decline and dieback
incidence along with greater annual ring increment suppression, which is
observed on an average of 82% of all sampled red spruce dominant and
co-dominant trees. Preliminary soil analysis suggests higher loading of lead
on west-facing slopes. A series of permanent plots has been established on
eight high elevation peaks which will be periodically revisited to quantify
the temporal and spatial dynamics of the forest decline.
RESULTS OF SOUTHERN U.S. INVESTIGATIONS
During the 1984 field season, permanent plots were established on six of
eight mountain areas visited. The northernmost area studied was Mt. Rogers in
Virginia. Moving southward, plots were established on Grandfather Mountain,
Roan Mountain, Mt. Mitchell, Gangsman's dome (GSMNP), and Mount Le Conte
(GSMNP). The southernmost site visited was the Joyce Kilmer Wilderness area,
however, permanent plots were established at this site due to a lack of
suitable stands of red spruce and Fraser fir. This was also true of the Plott
Balsams which are located east of the Great Smokey Mountain National Park.
The frequency of decline for all low altitude sites between 5200 ft and
5,600 ft is summarized in Figure 1, while the frequency of decline for all
high elevation sites between 5,600 ft and 6,684 ft is summarized in Figure 2.
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A decline class rating of 1 signifies relatively healthy trees with a
defoliation index of between 0 and 10%. As can be noted in Figure 1, the
average number of trees throughout the southern Appalachians showing a decline
class rating of 1 is approximately 79%. It should be noted, however, that the
west-facing slope of the respective mountainsides have a significantly greater
amount of deline symptomatology with only 62% of the trees in decline
class 1. Figure 2 illustrates the frequency of decline for all high elevation
sites sampled. The average percent of the high elevation trees showing
decline class 1, i.e., healthy trees, is generally less, with an average of
68% in this category. Only 54% of trees on west-facing slopes fell into
decline class 1, thus indicating that approximately one-half of all high
altitude trees exhibited some decline symptomatology.
Increment cores were removed from only dominant and co-dominant red
spruce and Fraser fir trees. Figures 3-9 outline the results of this
increment core analysis on Mt. Rogers, Roan Mountain, Grandfather Mountain and
both high and low elevation sites on Mt. Mitchell. For the purpose of this
report, the results from additional increment cores taken outside of
established plots were included in Figures 3-9. On these mountains there was
an abrupt and synchronous suppression of annual growth of both Fraser fir and
red spruce beginning between 1958-1965.
However, we consistently found that red spruce was in a much more serious
state of growth suppression than was Fraser fir in all sites. Perhaps the
most abrupt increment suppression observed was on Mt. Rogers in Virginia.
Although the amount of visible decline here was the least of the sampled, with
approximately a five-fold decrease in radial increment since 1960 as compared
to the annual increments from 1950 to 1960. The overall frequency of red
spruce increment suppression averaged approximately 82%. The lowest incidence
of approximately 43% was found in the low elevation red spruce trees on Mt.
Mitchell. It should be noted that the definition of severe increment
suppression in this particular study is at least a 2 1/2 fold decline in the
average annual increments of 1960-1970 as compared to 1950-1960. Virtually
all red spruce trees showed a slowing of growth during this period; however,
many natural factors such as the natural aging process can account for a
relatively slower growth rate.
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Figures 8 and 9 illustrate a comparison between hiqh and low elevation
sites and red spruce growing at east and west aspects on Mt. Mitchell. It is
interesting to note that not only are westward-facing trees in a more severe
state of decline as illustrated in Figures 1 and 2, but there also appears to
be a greater amount of relative increment suppression in westward-facing trees
as compared to eastward-facing trees. Although this correlates nicely with
soils data showing higher amounts of loading of lead on the westward-facing
slooe of the mountain (Table 1), it is premature to conclude that in fact
decline symptomatology and growth increment suppression are necessarily cause
and effect related to the west-facing aspect of the mountain and hence the
incoming atmospheric deposition. Many other natural phenomena such as wind
damage and more severe temperatures may also account for the greater decline
and increment suppression on the west fact of the mountain.
DISCUSSION OF SOUTHEASTERN U. S. STUDIES
Presented in this report is a preliminary analysis of some data collected
by a survey during the past field season. Work is continuing in the field and
the laboratory to further characterize our permanent plots. Therefore, it is
inappropriate at this time to attempt further evaluation of the data in
Figures 1-9, and in Table 1.
CONCLUSIONS OF SOUTHEASTERN U.S. STUDIES
1. Boreal montane forest tree decline of red spruce and Eraser fir in the
southern Appalachian Mountains appears to be a visible and guantifiable
phenomenon.
2. Incidence of decline symptomatology is present throughout the southern
high altitude mountains and may be more pronounced on west-facing slopes.
3. Severe synchronous annual growth increment suppression in red spruce and
to a lesser degree in Fraser fir has been documented for four sites in
the southern Appalachian Mountains. Preliminary analysis indicates that
more severe suppression may occur on west-facing slopes, which correlates
with both the incidence of tree decline and the presence of atmospheric
deposition products.
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OBSERVATIONS AND EXPERIMENTS WITH MYCORRHIZAE IN SOUTHEASTERN U. S.
Roots of spruce, pines and other needle-bearing trees usually show a
symbiotic association with beneficial fungi. These fungus-root structures are
called mycorrhizae fmyco = funqus, rhiza = root). We observed a statistically
significant correlation (P = 0.05) between the percent of spruce short roots
that are mycorrhizal and the elevation at which the tree was growing. Trees
growing above 6,350 feet averaged about 35% mycorrhizal incidence and spruce
at or below 5,200 feet averaged about 72% mycorrhizal incidence.
When percent mycorrhizal roots were plotted against the degree of decline
of the host tree, a highly significant correlation coefficient (P = 0.01) was
found. Trees exhibiting 80% or more defoliation (spruce at high altitudes)
averaged about 30% mycorrhizal roots, whereas trees with few decline symptoms
averaged about 75% mycorrhizal roots.
High altitude red spruce roots exhibited a far greater degree of
disintegration (fine root necrosis) than did the creamy white, fungus mantle
covered, tree roots found at lower elevations.
Acid rain simulation mycorrhizae experiments in greenhouses at North
Carolina State University have demonstrated that incidence and vigor of
loblolly pine were severely retarded at pH 4.0 compared to pH 2.4, 3.2 or
5.6. We believe this is the first significant biological effect to be
documented at the pH of ambient rainfall for the state of North Carolina.
Mycorrhizal roots of red spruce at low and high elevations on Mt.
Mitchell were very similar in appearance and state of necrosis to the pine
roots in these rain simulation experiments and were similar in morphology and
state of necrosis as compared to the pH 4.0 rain simulation experiments.
OBSERVATIONS ON ROOT-INHABITING FUNGI
Root isolations made from declining (high elevation) and non-declining
(low elevation) red spruce roots revealed that at least two species of the
fungal root pathogen Pythium were frequently isolated only from the roots of
delining trees. Roots of vigorous trees at low elevation often failed to
yield any pathogenic fungi.
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OBSERVATIONS OF FOREST REPRODUCTION
At altitudes above 6,350 feet little successful fir, spruce, or shrub
reproduction was observed. The ground was barren of any living woody
vegetation. Slopes on the mountain below this altitude showed normal
reproduction—they were heavily colonized with seedlings and saplings of all
age classes. By contract, a vegetation survey in 1958 showed that all Mt.
Mitchell slopes from the summit down had lush and abundant ground covers.
OBSERVATIONS OF TOXIC METAL ACCUMULATION
Lead concentrations in excess of 2 grams per square meter were commonly
observed in forest litter at elevations above 6,000 feet. Lower elevations
(5,000-5,500 feet) showed considerably less lead loading. It was also found
that western-facing slopes (predominant wind direction) had higher lead
content than east, south and north-facing slopes. The high altitude soil and
litter lead contents are greater than those found in similar samples in the
mountains of the northeastern United States. Unusually large amounts of Cu,
Ni, Zn, and Mn were also detected on Mt. Mitchell, all in amounts greater than
those observed from northeastern mountain litter samples, and in amounts that
far exceed those for low elevation forests in North Carolina. The possibility
that lead and copper toxicity to plants may exist on Mt. Mitchell must be
investigated.
SUMMARY REMARKS—SOUTHEASTERN U.S.
These observations, which suggest that major climatic perturbation
(drought, abnormal high or low temperatures) is not of significance in the
southern Appalachian mountains, strengthen the hypothesis that atmospheric
deposition may contribute or be causal in the etiology of red spruce decline.
Some of the possible mechanisms that need to be investigated include:
1. Hydrogen ion deposition inducing aluminum leaching, resulting in root
toxicity and tree decline,
2. Calcium depletion from the soil matrix causing deficiency.
62
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3. Nitrogen deposition (averaging about 40 pounds per acre per year causing
nitrogen toxicity, (i.e., death of ectomycorrhizae), uptake of excess N
resulting in abnormally succulent crowns and shoots, thus decreasing the
resistance of red spruce to frost, wind desiccation, and fungal or insect
parasites.
4. Effects of the abnormally high concentrations of heavy metals in organic
matter and soils on the vigor of roots and hence the vitality of red
spruce.
63
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t.O
1.1
1.0
MT MITCHELL N.C.
LOW ELEVATION SIOO-SiOCT
AVEMAOE ANNUAL INCREMENT
FREQUENCY or
SMUCE SU»?ftESSION-41«
MX TWEES DOMINANT AND CO-OOMINANT
M« 40 wo SPMUCE/2S FMASEM
MED SF-HUCE- *
FKASEH Fl«- •
2.5
2.0
u
c
u
1.0
0.8
MT MITCHELL N C
HIQH ELEVATION ««oo-«««4
AVERAQE ANNUAL INCREMENT
AU. TREE* DOMINANT AND CO-DOMINANT
N> •• MED mtUCE/M FHACEH FlU
1MO
1MO
1»70
ItM
1t«0
YEAH
Figure 1: Annual increment of red
spruce and fraser fir at lower eleva-
tions at Mt. Mitchell, NC (Bruck, 1984b)
TEAM
Figure 2. Annual increment of red
spruce and fraser fir at high eleva-
tions at Mt. Mitchell, NC (Bruck, 1984b)
1.71
t.t
t.O
1.0
MT. MfTCMIU. N.C.
LOW ELEVATION CAST •• WEST
AVEMAOC ANNUAL MCMEMENT
• 100-MOO'
AU. MEO MNUCITNCE*
OOMMAMT AND CO-OOMINANT
MB M IA9T/M WIST
IMT-*
MT. MTTCHtU. M.C.
H1OM ELCVATWW EAST •• WEST
AVENAOC ANNUAL MCMEMCNT
AU mo »r«ocE TMEES
OOMMANT AMD CO-OOMMANT
MB 34 EAST/M WEST
1STO
YEAH
1SSO
1MO
T»M**
Figure 3: Legend is the same as in
Figure 1 except for the aspect (Bruck,
1OSAKA
Figure 4: Legend is the same as
in Figure 2 except for the aspect
(Bruchk, 1984b)
-------
i.o
1.0
o.t
MT BOQEBS VA
AVERAGE ANNUAL INCREMENT
ALL TREES DOMINANT ANO CO-DOMINANT
51 RED SPRUCE/62 FMASER FIR
2 S
2.0
z
w
£ i.>
o
<
z
z
<
t.O
AVERAGE ANNUAL INC"CWCNT
ALL TREES DOMINANT ANO CO-DOMINANT
MCO
Of
aup»«ES«iOM-r*«
ItM
«MO
1«70
YCAN
1040
1«TO
YEA*
Figure 5: Red spruce and fraser fir
decline at Mt. Rogers, VA (Bruck, 1984b)
Figure 6: Red spruce and fraser fir
decline at Grandfather Mt., NC (Bruck,
1984b).
ro
I
I l.t
1.O
NOAM MT. M.C.
AMMUAt. MCNCMEMT
AU. TWEEt OOMMAMt ANO CO-OO*«HIAMT
M. 40 MEO MHUCC/S* niAMd mi
nwow«»CY of mo
-WO
1«*0
1MO
1«TO
YCAII
Figure 7: Red spruce and fraser fir decline at Roan Mt., NC
(Bruck, 1984b).
-------
eo
80
a.
W 60
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APPENDIX B*
TARLE 1. Comparison of Symptoms of Forest and Tree Dec1i n e in Central
Europe and Eastern North "America
Symptoms
Growth-decreasing symptoms:
1. Yellowing of foliaqe from
the lower to the upper
and from the inner to the
outer portion of branches
— oldest tissues
affected first.
2. Dying back from the top
of trees -- youngest
tissues affected first.
3. Increased transparency of
crowns due to gradual
loss of leaves but with
leaves retained to the
very top of the trees.
alder.
4. Losses of fine-root
biomass and mycorrhizae
(beneficial symbiosis
between tree roots and
soil fungi).
5. Synchronized decrease in
diameter growth
other visible symptoms
6. Synchronized decrease in
diameter growth with
other visible symptoms
leading to death.
Central Europe
Observed mainly in
white fir and Norway
spruce at high
elevation.
Common in oak and
ash, less common in
birch and beech.
diebacks.
Observed in Norway
spruce, white fir,
Scots pine, larch,
beech, birch, oak,
maple, ash, and
Common in white fir,
Norway spruce and
beech. Not studied
in other species.
Not reported in
Europe.
Studied mainly in
Norway spruce, white
fir and beech. Not
Eastern North America
Observed recently in
red spruce in New York
and Vermont.
Conspicuous in red
spruce, maple, and oak
decline; ash and birch
Observed only in the
littleleaf disease of
shortleaf pine and in
the beech-bark disease
Observed mainly in red
spruce decline, birch
dieback, and little
leaf disease.
Observed in pitch pine
and shortleaf pine.
Observed in red spruce
and Fraser fir mainly
at high elevation.
67
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7. Progressive decrease in
diameter growth with
other visible symptoms
leading to death.
8. Death of herbaceous
vegetation beneath some
affected trees.
Abnormal-growth symptoms:
9. Active casting off
(abscission) of leaves
and shoots while still
green.
10.Change in relative length
of long shoots and short
shoots.
11 .Concentration of leaves
at tips of branches in
tufts or clumps.
12.Change in size and shape
of leaves.
Not reported in
Europe.
13.Excessive production of
seeds and cones
Observed in high
elevation spruce and
beech forests.
Common in spruce,
fir, and beech, ash
larch, and Scots
pine.
Common in beech and
larch.
Common in beech and
ash.
Common in beech,
occasionally in
spruce, fir, birch,
and oak.
Common in spruce,
fir, beech, and
birch; often
observed several
years in a row.
Observed in ash and
birch, diebacks, some
maple and oak declines,
sweetgum blight,
littleleaf disease,
pole blight.
Not observed in North
America
Reported only once in
North America.
Reported only in the
mycoplasma-induced
"yellows" of ash.
Reported only in the
declines of broad-
leaved trees.
Common in white pine,
littleleaf disease of
shortleaf pine, and
some maple and oak
declines.
Observed in many
stressed trees but
mainly one year at a
time
68
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General Observations
Many different species
suddently showinq substan-
tially similar symptoms
Commerical forests
showinq extensive
decline.
Soil relationships
Elevation relationship.
Yes,
Yes,
Trees affected on
nutrient-rich and
acid soils and basic
Needle-bearinq trees
affected at all
elevations.
No.
No, except for red
spruce in certain parts
of eastern North
America.
Trees affected more on
nutrient poor and acid
soils.
Needle-bearinq trees
affected mainly at
hiqh elevation.
Symptom 3 has not been reported before 1979 affecting more than one species of
tree.
Symptom 8, 10, 13, and 14 have not been reported before 1980 affectinq any
tree species.
Symptom 9 has been reported only once in North America and not before 1979 in
central Europe.
69
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing!
1. REPORT NO.
EPA-90879-85-001
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
Investigation Into The Health Of Forests In the
Vicinity of Gothic, Colorado
5. REPORT DATE
Tarniarv, 1Q«S
6. PERFORMING ORGANIZATION CODE
7. AUTHORis)wiiiia,,, Jacobi, Ph.D., Colorado State Universit
Robert I. Bruck, Ph.D., North Carolina State Unvieriity
Paul Miller, Ph.D. U. S. Forest Service
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
U. S. Environmental Protection Agency
Region VIII
1860 Lincoln
Denver, Colorado 80295
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
U. S. Environmental Protection Agency
Region VIII
1860 Lincoln
Denver, Colorado 80295
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
EPA-908
15. SUPPLEMENTARY NOTES
16. ABSTRACT
This document presents the methods and findings of a scientific team of forest
experts assembled to investigate reports of air pollution damaged forests near Gothic
Colorado. Tree damage similar in appearance to the acid rain damaged forests in the
Eastern U. S. and central Europe was observed by two visiting scientists in 1984.
The report presents the findings of the team which concluded that no evidence now
exists that air pollution in contributing to the natural forest decline in the area.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Atmospheric Deposition
Forest Decline
Air Pollution
Tree Damage
Western Atmospheric Deposition
18. DISTRIBUTION STATEMENT
19. SECURITY CLASS (This Re pan I
21. NO. OF PAGES
20. SECURITY CLASS (This page/
22. PRICE
EPA Fo»m 2220-1
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