FEDERAL WATER POLLUTION CONTROL ADMINISTRATION
WORTHIEST RE&ION^LASIOV WATER LABORATORY
02o
EFFECTS OF FOREST
WATER QUALITY IN INTERIOR ALASKA
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EFFECTS OF LARGE SCALE FOREST FIRES ON WATER
QUALITY IN INTERIOR ALASKA
by
Frederick B. Lotspeich,
Ernst W. Mueller,
and Paul J. Frey
UNITED STATES DEPARTMENT OF THE INTERIOR
FEDERAL WATER POLLUTION CONTROL ADMINISTRATION
ALASKA WATER LABORATORY
College* Alaska 99701
February 1970
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CONTENTS
PAGE
INTRODUCTION 9
Forest Fires in Alaska 9
Objectives 13
SUMMARY AND CONCLUSIONS 15
RECOMMENDATIONS 17
DESIGN OF PROJECT 19
RESULTS AND DISCUSSION 35
Soil Analytical Data 35
Properties 35
Soil Saturation Extracts 47
Water Chemistry 55
Stream Biology 68
General Discussion 86
ACKNOWLEDGEMENTS 91
LITERATURE CITED 93
APPENDIX 95
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TABLES
TABLE PAGE
1 Soil Analytical Data from Cement and Big Timber
Creek Profiles 38
2 Soil Analytical Data from West Fork Profiles 39
3 Soil Analytical Data from Taylor Highway Profiles AO
4 Soil Analytical Data from Logging Cabin Creek Profiles . . 41
5 Chemistry of Saturation Extracts from Soils of Cement
and Big Timber Creek Profiles 48
6 Chemistry of Saturation Extracts from Soils of
West Fork Profiles 49
7 Chemistry of Saturation Extracts from Soils of
Taylor Highway Profiles 50
8 Chemistry of Saturation Extracts from Soils of
Logging Cabin Creek Profiles 51
9 Miscellaneous Chemical Analyses of Stream Waters 59
10 Nutrient Chemistry of Stream Waters 66
11 A Qualitative Comparison of Organisms Collected From
Three Stations on the Dennison Fork, Chicken, Alaska ... 75
12 Number and Percentage of Organisms Per Square Meter
of Bottom from Three Stations on Dennison Fork in
1967 and 1968 76
13 A Qualitative Comparison of Organisms Collected from
Two Stations on the West Fork, Chicken, Alaska 78
14 Number and Percentage of Organisms Per Square Meter
of Bottom from Two Stations on West Fork in 1967
and 1968 79
15 A Qualitative Comparison of Organisms Collected from
Big Timber Creek and Cement Creek, Chicken, Alaska .... 81
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6
TABLES Continued
TABLE PAGE
16 Number and Percentage of Organisms Per Square Meter
of Bottom from Two Stations on Cement and Big
Timber Creek . . 82
17 A Qualitative Comparison of Organisms Collected
from the West Fork and the Mosquito Fork 84
18 Number and Percentage of Organisms Per Square Meter
of Bottom from Mosquito Fork and West Fork 85
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FIGURES
FIGURE PAGE
1 Map of the fire area, showing how the fire spread. ... 11
2 Map of the area showing stream sampling and soil
sampling points (marked by a circle and number) 20
3 Dennison River at D-100 21
4 West Fork at W-200 22
5 Cement Creek at C-200 23
6 Big Timber Creel< at T-200 24
7 Soil Profile near C-200 25
8 Sampling soil near T-100 26
9 Soil sampling site on unburned Logging Cabin Creek
watershed 27
10 Soil sampling site on burned Logging Cabin Creek
watershed 29
11 Aquatic Biologist sampling the benthic community .... 30
12 Shrub community on low land slopes a year after the
fire (September 1967) 31
13 Erosion of a bulldozed fire line in a small valley
one year after the fire (September 1967) 32
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INTRODUCTION
Forest Fires in Alaska
Large and frequent fires are not new to the Taiga of Alaska,
nor is Alaska unique among northern regions in this respect.
In his study of the ecological effects of fires in Alaska, Lutz
(1956) also cites many examples of extensive fires in Canada, Siberia,
and Scandinavia. The pcesent mosaic of vegetational patterns in
Alaska is caused by previous fires, both in the historic and pre-
historic past. Aborigines were careless with their fires and Lutz
believes that many prehistoric fires were caused by them, although
a significant number of fires were caused by lightning. When mining
activity became a part of early Alaskan history, the number and
size of fires increased because of carelessness and increased activity
associated with mining. No attempt was made to control these early
fires because of unavailable manpower and also because it was felt
that control was unnecessary.
Interior Alaska was very dry in the summer of 1966 and thunder-
storms were frequent. The fire on which this report is based was
caused by lightning on July 23, 1966, and burned into September,
covering a total of over 1/4 million acres. The day the fire started,
the potential for fire was great and the Bureau of Land Management
had planes patrolling to report fires. This fire, later designated
as Y34, was first reported at 3:00 p.m. during a thunderstorm in
the Dennison River watershed about 20 miles south of Chicken, Alaska.
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10
Within two hours, 15 smoke jumpers were dispatched from Fairbanks.
Nine of these jumped a nearby fire and the remaining six jumped
Y34, which by then covered about 100 acres (Figure 1). Unable
to contain the fire, the six jumpers did clear two heliports. By
the next day the fire was about one mile long by 1/2 mile wide.
The control plan was to keep the fire in the Cement Creek watershed,
but adverse winds and very^dry conditions allowed the fire to burn
out of control and it spread south across the ridge toward Big
Timber Creek, resulting in an estimated 40,000 acres being burned
by August 1 (see map for sequence of events). The fire crossed
Dennison Fork on July 29; no control was possible from August 1-
9.
The fire, which crossed the Taylor Highway on August 5, had
burned over 150,000 acres by August 9. Rainy weather halted spread
of the fire from August 9 to the 17th and some equipment and personnel
were transferred to other urgent fires. On August 17, when strong
south winds caused the fire to break out, new crews were brought
in. By August 19 the fire had spread to the line shown in Figure
1. Winds on August 19 caused breakouts along Walker Fork and south
of Chicken. By August 23 the fire was generally under control,
although there were several small breakouts that were subsequently
brought under control. Cloudy, moist conditions during August
25-26 allowed direct attack along most of the fire line, with only
a small part of the northern line being critical. General light
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12
rains on September 1 prevented spread of the fire. Heavier rains
by September 5ywith snow at higher elevations, kept the fire under
control; demanning started during this time and was completed by
September 13.
At one time a total of 600 men were fighting the fire, which
eventually burned an area of 250,000 acres during a period of 44
days. In all, more than 400 miles of fire-trails were built. This
fire was an example of one that defies strenuous efforts at control
because of adverse winds and extremely dry fuel during a very hot
summer. Conditions for fire were predicted, a patrol was in the
vicinity and reported the fire soon after it started, smoke jumpers
were on the scene a few hours later, but it still became a major
fire.
About two months after termination of the fire, representatives
of the Bureau of Land Management (BLM) contacted scientists from
the Alaska Water Laboratory (AWL) for assistance in evaluating some
effects of this large fire. After exploring several means of assistance,
it was agreed that AWL would conduct a research study in cooperation
with BLM. AWL would conduct field and laboratory studies and
prepare a report on the findings. BLM was to furnish general
logistical support and helicopter transportation to sampling sites
because the fire area was inaccessible to surface means. In addition,
BLM would provide information on the fire history, control methods
used, and such technical assistance as they had available. It
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13
was agreed that AWL would make five sampling trips to the fire
area at specified times, the first trip, just before breakup,
to be in May 1967.
Objectives
Objectives of the study were: (1) to develop sufficient
understanding of the effects of forest fires on water quality
of Alaskan streams so that it may be possible to make rational
decisions for allocating manpower and funds for controlling specific
fires, and (2) to develop an understanding of needs for rehabilitation
(revegetation, erosion prevention, etc.) to control immediate and
future polluting effects of the fire on the aquatic environment.
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SUMMARY AND CONCLUSIONS
1. In general, burning was not severe enough to destroy the
entire organic layer.
2. The depth of thawing was not affected by the fire.
3. Burning of the organic layer causes a decrease in the cation
exchange capacity of the soil.
4. Only the organic layer is useful in diagnosing the changes
in soil chemistry.
5. The only evidence of increased erosion was in the fire trails.
6. Potassium is increased in the burned organic layer.
7. Burning may release significant quantities of soluble material
which, because of the permafrost, remains in the organic horizon.
8. There is an increase in the chemical oxygen demand concen-
tration in streams in the burned area.
9. Potassium concentrations are higher in streams draining burned
areas than in streams draining unburned areas.
10. There was no change of statistical significance to the benthic
fauna of the streams that can be attributed to the effects of
the fire.
11. Fire control methods may cause more serious, long-lasting
damage to the aquatic ecosystem within the burned area than the
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16
fire itself. In developing a fire control plan, sufficient forethought
should be given to the possible consequences of control measures to
prevent extensive damage to the taiga ecosystem.
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RECOMMENDATIONS
The following recommendations are based solely on data and
observations collected during the course of the study (conclusions
and recommendations of the Bureau of Land Management are included
in the appendix) and reflect recommendations and conclusions of both
agencies.
1. If a fire cannot be controlled early by smoke jumpers, fire
fighters with hand tools, or aerial application of retardants, serious
consideration of soil types, topography, and permafrost should be
made before constructing fire lines with bulldozers or other heavy
machines.
2. Artificial revegetation should not be attempted where burning
was not severe enough to remove the entire organic horizons or where
revegetation would expose mineral soils and cause melting of permafrost.
Natural processes will revegetate a burn more rapidly than artificial
means if burning is not severe or a nearby seed source is available.
3. A long-range, more in-depth investigation should be under-
taken to study the after-effects of fires in the taiga of Alaska.
Results of the present study indicate that soil analyses can be limited
to saturation extracts and that the benthic community requires immediate
study after a fire followed by continuous surveillance. Comparison
of severely to moderately burned areas to assess the effects of fires
on water quality should receive high priority.
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DESIGN OF PROJECT
The over-all project required analyses of soils, water, and aqua-
tic organisms on unburned and burned areas. Thus, it would be possible
to determine changes in soil chemistry caused by burning and associate
these with changes in water chemistry which in turn could cause changes
in stream biota. Five stream sampling trips were scheduled: breakup
in 1967 (May), after breakup (late May or early June), low water just
before freezing (September), breakup in 1968 (May), and after breakup
(June 1968). Soil samples were to be collected only in 1967.
After extensive map reconnaissance and consultation among AWL
scientists and BLM specialists, nine sampling stations were estab-
lished. These stations are shown in Figure 2 and are as follows:
Dennison River downstream from the fire (D-100) (Figure 3), just up-
stream from its confluence with the West Fork (D-200), and upstream from
the fire area (D-300), and the West Fork upstream from the fire area
(W-200) (Figure 4), and a short distance upstream from the Dennison
River (W-100). Two small east-west streams were selected east of the
Dennison River to represent streams with similar watersheds. Cement
Creek represented a burned watershed and Big Timber Creek represented an
unburned watershed. Two stations were established on each stream: (C-100)
at the mouth of Cement Creek and C-200 (Figure 5) several miles upstream;
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Figure 2
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Figure 3. The Dennison River at Station D-100, showing ice
blocks just after the ice had broken out. Much of the
bottom was still covered with anchor ice (May 1, 1967).
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Figure 4. West Fork at Station W-2G0 showing extensive
open water with some surface ice remaining. Anchor ice was
extensive (May 1, 1967). Surface ice at W-200 remained
several days later than for W-100 or stations on the
Dennison River.
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Figure 5. Cement Creek at Station C-200, showing water flow-
ing over surface ice (May 1, 1967). These small creeks
appear to freeze solid during winter and melt-water at
break-up flows over the ice, giving the appearance of
flood stage because the channel is still filled with
winter ice.
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Figure 6. Big Timber Creek at Station T-200, showing the
stream bank full over the ice (May 1, 1967). This creed did
not break up as early as Cement Creek in the burned area;
this was noted in May 1968. Timber Creek also has condsider-
able groundwater that forms aufeis, which was not true for
Cement Creek.
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Figure 7. Soil profile near Station C-200. Ruler is 15 cm
(6 inches) long. Here the organic layer was nearly destroyed,
but 4-6 cm remained, as can be seen. Bottom of the ruler is
resting on frozen soil (May 3).
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Figure 8. Sampling soil near Station T-100. Here the moss
and organic layer was about 20 cm thick, with the mineral soil
frozen (May 3).
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Figure 9. Soil sampling site on unburned Logging Cabin Creek
watershed, showing the forest and understory vegetation as it
appeared before the fire (June 20, 1967).
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28
T-100 on Big Timber Creek just upstream from where the fire line
crossed the creek, and T-200 (Figure 6) several miles upstream.
None of the watershed of Big Timber Creek above the sampling sites
had been burned.
Biological samples were collected at each water sampling station.
Quantitative benthic samples were collected with a Surber sampler and
qualitative samples with a long-handled dip net. All samples were
preserved in formaldehyde in the field and sorted and identified at
the Alaska Water Laboratory.
The actual number of samples that were collected was less than
planned. During the first sampling trip in 1967, water samples were
collected at all stations, but because of bottom ice, no biological
samples were obtained. Soil samples were collected at sites shown in
Figure 2 on a burned area about 1/2 mile north of Cement Creek (1)
(Figure 7), on Big Timber Creek (Figure 8) about 1/4 mile north of
Station T-100 (2), on the West Fork watershed, burned and unburned
(3 and 4), and along the Taylor Highway, burned and unburned (7 and
8). At this time, the soil was frozen to the bottom of the moss layer
except for site 1, which was black, on a southern exposure, and thawed
to a depth of about four inches.
No water samples and only two biological samples were collected
during the sampling trip scheduled in June 1967, because all heli-
copters under contract to BLM were engaged in firefighting activities
and none were available for our use. However, soil samples were
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Figure 10. Soil sampling site on burned Logging Cabin Creek watershed,
showing the complete kill of spruce trees. Much of the organic layer
remained to protect the soil and many shrubs were alive. Soil was
thawed to a depth of about 30 cm (June 20, 1967).
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Figure 11. Aquatic biologist sampling the benthic community on West
Fork River (June 20, 1967). This was not a designated sampling site,
but an alternate one selected when helicopter transportation was not
avai Table.
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Figure 12. Shrub community on low land slopes a year after the fire
(September 1967). Here the fire burned over the entire area, but
burning was not severe enough to kill the shrubs.
Library
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200 S. ! Street
Ccrv_.. ... c -in 97330
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Figure 13. Erosion of a bulldozed fire line in a small valley one
year after the fire (September 1967). This ditch was caused primarily
by melting ice; when the organic layer was removed, enough water was
released by melting to carry away the soil. This ditch ranges in
depth from 5-15 feet.
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33
collected from the site on Taylor Highway and from another site on
the highway about six miles to the south, where samples from burned
and unburned areas were collected (5 and 6). Figures 10 and 12 show
how the vegetation appeared before and after burning and is represen-
tative of the entire burned-over area except for that small portion
above timberline. The soil was thawed to a depth of about 16 inches
at all sites. There was no significant difference in the depth of
thawing between burned and unburned profiles.
In September 1967, complete sets of all samples were collected.
Depth of thawing was 26 inches under undisturbed forest and 28 inches
on the burned site at Cement Creek. Soil temperature at the one-foot
depth was 1°C for all measured profiles. The entire measured profile
was saturated with water, as indicated by slumping of the walls of
the soil pit during sampling. This sampling trip completed the
schedule of soil samples.
In May 1968, another scheduled sampling trip was made to the
fire area and a complete set of water samples collected. Breakup
was in progress and both Cement Creek and Big Timber Creek had water
flowing over the ice. Water in Cement Creek was brown colored, where-
as that in Big Timber Creek was nearly clear.
The last sampling trip was completed in June 1968. During
this trip, biological and water samples were collected from all
stations on Dennison River and West Fork; however, because of
heavy rains which caused Cement Creek and Big Timber Creek to be
in flood stage, only water samples were obtained on these streams.
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RESULTS AND DISCUSSION
Soil Analytical Data
Properties
Soils were first sampled before they had thawed in the spring
of 1967, following the very dry summer of 1966. Nutrients released
by burning should have remained on or near the soil surface and
movement of water from snow melt and rain should have carried these
nutrients deeper into the profiles. The samples collected in
June should reflect this initial movement and the samples collected
in September ought to reflect maximum downward movement of released
nutrients.
Permafrost is a complicating element in this region. In
temperate regions, water moves freely downward until it reaches
groundwater (if precipitation is sufficient); however, in the
arctic, a frozen layer prevents this movement, causing a perched
water table. Such a phenomenon probably explains the saturated
condition of the soil when sampled in June and September.
Surface samples were collected from the lowermost organic
layer; contact with the organic and inorganic horizons was distinct
and, for gravelly profiles, was marked by a horizontal alignment
of pebbles. Mineral soil samples were taken at measured depths
Instead of at horizon delineations because no clear horizonation
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3b
was present. Samples were collected from 0-5, 5-10, and 10-
20 or 10-30-cm depths except when the soil was frozen.
Samples were brought to the laboratory in plastic bags,
dried, crushed, passed through a 2mm sieve, and stored in glass con-
tainers. Chemical analyses were made on the soil, saturated water
extracts, and NH40AC extracts. Chemical analyses of the soil included
pH, total carbon, nitrogen, phosphorous, exchangeable cations (calcium,
magnesium, sodium and potassium), and total acidity. Cation exchange
capacity was determined by summation because these soils were all
acid and this method is suggested for such soils (1965). Chemical
data from saturation extracts included total carbon, calcium, magnesium,
potassium, and conductivity; procedures for all these anayses were
from Methods of Soil Analysis(1965).
Data collected by previous workers, mostly in coterminous U. S.,
suggest that forest fires cause some changes in soil properties,
the magnitude of which depends on the severity of the fire. For
example, even slight burning of desert shrub was found by Klemmedson
et al_ (1962) to increase soluble salts and available nitrogen. Wright
(1966) showed that high temperatures result in loss of total nitrogen
from forest soils. Likewise, with severe burning, potassium, phos-
phorous and pH tend to increase and cation exchange capacity tends
to decrease, probably because of the destruction of organic matter
with its high exchange capacity (Klemmedson, rt aK 1962, Tarrant,
1956). Scotter (1963), working in northern Saskatchewan, concluded
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37
that soil physical properties were not significantly changed unless
burning is intense enough to destroy the forest floor. Intense
burning may cause changes in physical properties that result
in less stable aggregation and decreased percolation (Dyrness
and Youngberg, 1957; Tarrant, 1956). Changes in percolation
rate and reduced aggregation may pose an increased erosion hazard
(Sweeney and Biswell, 1961). Most of the cited work was done
in temperate climates; soils in permafrost areas of Alaska may
not react similarly because water stays perched in the active
zone above the frozen subsoils.
This discussion will first describe chemical properties
of soil and compare those of burned with unburned areas. At
no sampling site was it observed that the entire organic layer
had been consumed; even on Cement Creek, where the fire started
and was most severe, the lowermost 5-0 cm of duff remained to
give some protection from surface erosion and raindrop Impact.
A site on the north slope of Big Timber Creek was chosen to
compare soil properties with those of the profile on Cement
Creek; these two sites were separated by about five kilometers.
The sites on West Fork were about 50 meters apart, those on
Taylor Highway about 100 meters, and those on Logging Cabin
Creek about one kilometer apart. Textures of comparative profiles
were similar. Figure 2 shows the sampling sites and Tables
1-4 present the analytical data.
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TABLE 1. SOIL ANALYTICAL DATA FROM CEMENT AND BIG TIMBER CREEK PROFILES
Depth
Ex.
Cations
(meq/100q)
TA
CEC
Sample
Inches
Texture
PH
C%
N%
C/N
Mq/q
CA
Mq
Na
K
(meq/lOOq)
1
2-0
Fib.
4.35
23.10
0.92
23.1
0.041
7.4
5.1
0.23
1.20
37.3
51.2
2
0-2
Si.
4.57
1.98
0.11
18.5
0.001
13.8
3.8
0.10
0.31
5.9
23.9
3
2-4
Si.
4.67
1.30
0.08
16.3
0.001
6.4
3.3
0.12
0.23
2.5
12.5
4
4-6
Si.
4.82
1.74
0.08
21.7
0.001
12.6
3.5
0.17
0.20
14.2
30.7
5
2-0
Fib.
5.52
30.47
1.40
21.8
0.011
35.3
10.1
0.42
0.32
38.0
84.1
6
0-2
Si.
5.07
3.74
0.26
14.2
0.002
6.9
3.5
0.19
0.18
7.8
18.6
32
4-0
Fib.
5.12
24.28
0.96
25.4
0.011
22.1
9.8
0.30
1.01
45.8
79.0
33
0-2
Si.
5.17
3.79
0.23
16.5
0.00
7.2
3.5
0.14
0.23
13.2
24.2
34
2-4
Si.
5.15
3.85
0.23
16.8
0.00
6.8
3.0
0.18
0.18
19.4
29.6
35
4-8
Si.
5.12
3.34
0.21
15.9
0.00
6.5
3.5
0.16
0.20
21.1
26.6
28
3-0
Fib.
4.80
22.77
1.05
21.8
0.003
20.5
6.2
0.39
0.48
57.5
85.1
29
0-2
Si.
5.62
2.76
0.16
16.8
0.00
8.5
3.3
0.17
0.15
11.0
23.2
30
2-4
Si.
5.67
1.76
0.13
13.8
0.001
7.4
2.8
0.13
0.15
19.0
29.5
31
4-12
Si.
5.73
2.43
0.16
15.2
0.000
7.2
2.8
0.17
0.16
31.4
41.8
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TABLE 2. SOIL ANALYTICAL DATA FROM WEST FORK PROFILES
DepthPEx. Cations (meq/lOQq)TACEC
Samples Inches Texture pH C% N% C/N Mg/g Ca Mg Na K (meq/100/g)
7 2-0 Fib. 4.46 19.13 0.83 23.3 0.007 10.1 6.1 0.24 0.97 44.3 61.7
8
9
40
41
42
43
36
37
38
39
2-0
Fib.
4.73
15.85
0.80
19.8
0.00
8.6
6.5
0.29
0.39
43.6
59.3
0-4
Gr.Si.
4.67
9.14
0.48
16.2
0.00
7.2
5.3
0.32
0.27
26.1
39.2
3-0
Fib.
4.66
18.92
1.18
17.2
0.001
12.5
7.9
0.31
0.92
57.2
78.8
0-2
Gr.Si.
4.95
2.01
0.11
17.9
0.00
3.7
3.5
0.12
0.12
10.0
17.4
2-4
Gr.Si.
5.10
1.37
0.09
14.9
0.001
3.7
4.2
0.13
0.10
7.6
15.7
4-12
Gr.Si.
5.28
2.63
0.15
17.8
0.00
5.8
5.0
0.20
0.14
10.0
21 .1
3-0
Fib.
4.10
15.48
0.70
22.0
0.001
9.2
2.9
0.28
0.63
62.8
75.8
0-2
Gr.Si.
5.39
0.70
0.06
12.3
0.00
3.1
2.7
0.09
0.15
11 .8
17.9
2-4
Gr.Si.
5.50
0.53
0.04
12.0
0.001
3.8
3.1
0.10
0.16
-
7.2
4-12
Gr.Si.
5.65
0.50
0.05
9.6
0.001
4.6
3.3
0.08
0.14
0.8
8.9
Gr.Si. = Gravelly Silt
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TABLE 3
SOIL ANALYTICAL DATA FROM TAYLOR HIGHWAY PROFILES
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Depth
P
Ex. Cations {meq/100g)
(meq/lOOg)
Sample
Inches
Texture
pH
C%
C/N
Mg/g
Ca
Mg
Na
K
Ta
CEC
11-A
2-0
Fib.
4.97
10.88
0.50
21.8
0.004
15.7
10.7
0.28
0.19
17.3
44.2
11 -B
0-2
Si.Cl.
5.60
3.42
0.20
16.8
0.001
13.2
8.8
0.24
0.24
—
22.4
10
0-2
Si.Cl.
5.50
2.78
0.17
16.2
0.12
9.2
5.3
0.19
0.31
-
15.0
20
4-0
Fib.
4.83
14.91
0.88
17.0
0.00
13.4
6.1
0.24
0.42
44.4
54.5
21
0-2
Si.Cl.
5.93
1.33
0.10
13.4
0.06
7.6
6.3
0.18
0.22
23.6
37.9
22
2-4
Si.Cl.
6.10
1.34
0.10
13.1
0.00
8.6
5.5
0.18
0.23
9.7
25.2
23
4-8
Si.Cl.
6.48
1.14
0.09
13.3
0.001
8.0
6.8
0.18
0.26
-
15.2
24
2-0
Fib.
4.24
17.96
0.90
20.0
0.004
9.4
7.7
0.29
0.63
59.7
77.7
25
0-2
Si.Cl.
5.23
2.34
0.17
13.8
0.001
8.1
7.9
0.18
0.32
16.1
32.6
26
2-4
Si.Cl.
5.55
1.73
0.12
14.3
0.001
8.0
5.1
0.18
0.27
11.6
26.0
27
4-8
Si.Cl.
5.58
1.68
0.12
14.4
0.001
8.1
8.1
0.40
0.23
2.3
19.1
44
2-0
Fib.
4.40
22.18
0.82
27.0
0.030
12.8
10.0
0.30
0.87
50.5
74.5
45
0-2
Si.Cl.
6.61
1.81
0.12
15.0
0.00
2.9
6.8
0.39
0.43
2.5
13.0
46
2-4
Si.Cl.
6.88
0.85
0.07
12.0
0.001
7.7
5.1
0.17
0.40
-
13.4
47
4-12
Si.Cl.
6.87
0.77
0.06
12.6
0.001
8.1
6.0
0.27
0.45
0.4
15.2
48
2-0
Fib.
3.92
23.60
0.70
34.0
0.016
29.8
6.2
0.43
1 .15
54.8
92.4
49
0-2
Si.Cl.
5.12
3.34
0.16
21.4
0.001
9.3
9.9
0.33
0.48
10.8
30.8
50
2-4
Si.Cl.
6.28
1.85
0.13
14.0
0.001
10.2
9.9
0.36
0.43
4.4
25.3
51
4-12
Si.Cl.
6.20
2.14
0.13
16.1
0.00
10.0
9.9
0.33
0.41
5.4
26.0
Si.Cl. = Silty Clay
-------
TABLE 4. SOIL ANALYTICAL DATA FROM LOGGING CABIN CREEK PROFILES
Depth
Ex.
Cations (meq/lOOg)
TA
CEC
Sample
Inches
Texture
pH
C%
H%
C/N
Mq/q
Ca
Mg
Na
K
(meq/lOOq)
12
3-0
Fib.
4.50
13.31
0.68
19.5
0.002
7.3
6.1
0.26
0.47
40.7
54.6
13
0-2
Gr.
4.58
1.49
0.11
14.9
0.001
1.8
3.8
0.12
0.16
1.0
6.9
14
2-4
Gr.
4.43
1.04
0.08
13.7
0.00
1.8
2.7
0.11
0.14
-
4.7
15
4-8
Gr.
4.70
0.68
0.04
18.9
0.001
5.0
3.0
0.10
0.13
-
3.2
16
4-0
Fib.
3.85
20.16
0.67
30.9
0.001
1.9
3.9
0.29
1.06
49.7
56.9
17
0-2
Gr.
4.40
0.56
0.04
14.7
0.001
0.7
1.2
0.08
0.15
-
2.1
18
2-4
Gr.
4.86
0.22
0.02
10.5
0.000
1.3
1.6
0.07
0.10
-
3.1
19
4-8
Gr.
5.30
0.16
0.02
8.9
0.001
1.7
1.7
0.08
0.10
6.9
10.5
56
3-0
Fib.
4.44
26.65
1.03
25.9
0.012
9.7
9.0
0.21
1 .33
64.4
H3.6
57
0-2
Gr.
4.98
1.46
0.08
18.5
0.00
3.7
3.7
0.11
0.22
28.8
36.5
58
2-4
Gr.
5.17
0.73
0.04
20.3
0.00
3.3
2.5
0.12
0.14
27.3
33.3
59
4-12
Gr.
5.26
0.38
0.02
17.3
0.00
2.7
1.9
0.13
0.10
20.2
25.0
52
4-0
Fib.
4.13
28.13
1.10
25.4
0.002
8.6
3.7
0.18
0.41
57.2
70.1
53
0-2
Gr.
4.50
4.49
0.21
21.8
0.00
1.7
1.5
0.26
1 .07
22.5
27.1
54
2-4
Gr.
4.60
2.07
0.12
18.0
0.00
2.0
1.4
0.27
0.32
13.7
17.7
55
4-8
Gr.
4.64
0.68
0.05
13.3
0.00
1.7
1 .3
0.06
0.21
2.9
5.8
-------
42
Comparing data from the Cement Creek area with that from
Big Timber Creek (Table 1) discloses that pH of all samples
was very strongly acid and did not appear significantly changed
by burning. Carbon content data are inconclusive. Nitrogen
appeared to decrease somewhat with burning in the organic layer
and to increase with time at lower depths. Carbon to nitrogen
ratios (C/N) of all horizons were slightly higher on burned
soils. Phosphorous concentration was low and differences between
burned and unburned appear insignificant. None of the exchangeable
cations showed a consistent trend, with the exception of potassium
which appeared to increase somewhat with burning. Cation exchange
capacity of the organic layer decreased with burning, probably
because of the destruction of organic matter as postulated by
Klemmedson et al (1962). A significant portion of exchangeable
cations is contributed by total acidity, which is to be expected
for these acid soils.
Burning for the West Fork profiles was judged as light.
All horizons of these soils were strongly to very strongly acid
and burned and unburned profiles did not appear to be significantly
different (Table 2). Carbon concentration in burned profiles
was higher than in unburned profiles. This holds true for nitrogen
content also, but for both elements, the trends were not consistent.
This inconsistency was reflected in C/N, which varies widely,
although it appeared to be greater in burned soils. Phosphorous
-------
43
concentration was low in these soils and differences are insignificant.
Exchangeable cations behaved similarly to those noted for Cement
and Big Timber Creek soil samples with potassium somewhat higher
in the organic layer of burned soils. Cation exchange capacity
is not significantly different between these profiles; total
acidity contributed a majority of the exchange cations.
The profiles along Taylor Highway are considered to be
the most representative of all sites because these profiles
were extremely similar in texture, aspect and vegetation (Table
3). These soils are silty clay in texture and had the highest
pH of all soils sampled in this study; two horizons of the burned
soil sampled on September 14 were in the neutral range for soils.
The only significant differences in carbon, nitrogen and C/N
for these profiles appear in the organic horizons. In these
horizons the burned soil contained more carbon than did the
unburned soil before the soil had thawed. Later in the season,
carbon was higher in unburned soil. Nitrogen behaved similarly,
although the concentration in the burned soil was slightly higher
in September. Trends for C/N were similar to those for C, but
none of these trends establishes a definite pattern. Phosphorous
content was low and differences were insignificant.
The burned soil contained more calcium and magnesium early
in the summer; however, this weak trend appears to be reversed
later in the season with the deeper horizons gaining these elements.
-------
Sodium was low in all horizons and, aside from a small accumulation
in deeper horizons late in summer, trends do not appear to be
significant. Potassium behaved differently in these soils than
in those described earlier. At the other sites burned organic
layers contained more potassium than did unburned layers; here
the reverse was true. Again, there seems to be a slight accumulation
of potassium with time. Exchange capacity was high in the organic
layers and was chiefly caused by total acidity associated with
the organic matter. In the mineral horizons, the sum of bases
contributed more to the exchange capacity; some of the least
acid samples did not have any measurable total acidity. Cation
exchange capacity was higher in the unburned organic layers
except for the initial samples collected in May. The trends
in the deeper horizons were erratic and not considered to be
significant.
Soils on Logging Cabin Creek were not sampled in May; the
first samples were collected in June when they had thawed to
about 40 cm. Data for these soils are presented in Table 4.
Soils at this site were gravelly (20-25% gravel) and developed
on weathered schist that was disaggregated but retained its
mineral identity. Burning was moderately severe on this site,
although no mineral soil was exposed. Figures 3 and 4 are from
these sites and illustrate the condition of the forest before
and after the fire.
-------
45
These soils ranged from strongly to extremely acid in all
horizons with no significant differences between burned and
unburned soil. Carbon content of the organic layer was higher
in the unburned soil; otherwise, no definite trends appear.
Nitrogen content under both conditions was not significantly
different; the same held true for C/N except that C/N of the
unburned organic layer was higher in June than was that of the
burned soil. Phosphorous concentration was low and differences
were insignificant as before. Calcium concentration was lower
in these soils than in those discussed earlier and the burned
soil contained more calcium at both sampling dates. Magnesium
was similar to calcium both in concentration and behavior. The
gravelly nature of these soils and the high acidity are probably
contributing factors to this observed behavior. Sodium concen-
tration, although detected, was low and differences between
profiles were insignificant. Potassium content was erratic,
being higher in the organic layer of the unburned soil in June
that in September. Cation exchange capacity of these soils
was caused mainly by total acidity; when total acidity was
low, cation exchange capacity was low. No significant difference
between burned and unburned soils was apparent.
In summary, these data do'not show consistent trends on
the effects of burning. Severity of burning seems to cause
a decrease in cation exchange capacity of the organic layer and
-------
46
an increase in potassium because this element is released by
burning. Phosphorous was low in all samples and no trends were
apparent between burned and unburned soils. Calcium and magnesium
contents did not exhibit any significant trends with burning
although, on the gravelly soil at Logging Cabin Creek, both
of these elements showed an increase with burning in the organic
layer. Thus, texture seems to be a factor in whether burning
causes enrichment of a particular element.
These analytical data do not entirely confirm results from
other areas. Nitrogen and carbon are lost if burning is intense
enough to consume the entire organic horizon because that is
where most of them are present. Moreover, potassium seems to
be enriched by burning. The presence of permafrost does not
permit downward drainage of water within the profile, which
normally occurs in thawed soils. This phenomenon should influence
processes in the soil profile and cause elements to behave differently
than that expected in warmer climates. At none of these sites
was burning severe enough to entirely destroy the organic layer
which on unburned soils was about 20 cm thick. Another significant
observation is that the depth of thawing in September was nearly
the same for burned as for unburned soils, both profiles thawing
to about 70 cm. All profiles were very wet and cold (1.0°C
at 30 cm) and roots of spruce trees were confined to the organic
layer and the upper 6 cm of mineral soil.
-------
47
Soil Saturation Extracts
In addition to the data obtained from analyzing soil samples,
water extracts of these soils were analyzed for several constituents.
Constituents of such extracts should be similar to concentration
levels found in runoff from a saturated soil.
Extraction was done by Richard's funnel technique (Anonymous,
1955) and cations measured with an atomic absorption photometer.
All water extract samples were stabilized with a few drops of
mercurous chloride to prevent microbial activity. Total carbon
of the extracts was measured with a Beckman Carbonaceous Analyzer*
and conductivity with a Beckman bridge. These data are presented
in Tables 5-8.
Comparing data from Cement Creek with those from Big Timber
Creek (Table 5) shows that for the May samples, extracted total
carbon from the unburned soil was approximately 1/10 that of
the burned soil. However, by September, total carbon of the
burned profile was much lower than in May, with the two profiles
being about equal, except for the organic horizon. In the organic
horizon the unburned soil was about five times that of the burned
soil. Soluble calcium was much higher, up to 165 mg/1, in the
burned soil, especially in May, and the organic horizon contained
*Use of product and company names is for identification only and
does not constitute endorsement by the U. S. Department of the
Interior or the Federal Water Pollution Control Administration.
-------
TABLE 5
CHEMISTRY OF SATURATION EXTRACTS FROM SOILS
OF CEMENT AND BIG TIMBER CREEK PROFILES
Depth Total C Cations (mg/1) Cond.
Sample Inches mg/1 Ua Mg K" umhos/cm
-a
c
s_
rs
00
OJ
>> "a
A3 CD
s: c
s-
-O
C
=5
1
2
3
4
5
6
2-0
0-2
2-4
4-6
2-0
0-2
5250
640
410
470
450
66
165
21
111
112
62
12.8
4.5
3.8
3.2
6.5
7.3
6.5
5.0
3.4
4.2
4.8
455
90
118
135
205
210
XJ
PO
QJ
r—
C
s-
*
3
CM
CD
'—
S~
a>
JD
E
a>
-a
+->
0)
o.
c
cu
i-
CO
3
JO
c
ZD
32
4-0
83
116
10.1
11.2
300
33
0-2
47
28
5.3
2.4
145
34
2-4
50
20
3.2
1.8
130
35
4-8
42
20
2.5
1.8
118
28
29
30
31
3-0
2150
21
6.0
6.1
220
0-2
56
13
6.7
1.6
188
2-4
48
81
4.5
1.8
160
4-12
48
-
10.5
2.0
170
-------
TABLE 6
CHEMISTRY OF SATURATION EXTRACTS
FROM SOILS OF WEST FORK PROFILES
Depth Total C Cations (mg/1) Cond.
Sample Inches mg/1 Ca Mg K ^mhos/cm
7
2-0
630
50
5.3
15.7
245
8
2-0
38
10
1.7
1.7
59
9
0-4
30
38
2.5
3.9
80
40
3-0
2540
148
9.3
12.2
250
41
0-2
47
105
4.1
2.7
112
42
2-4
36
56
2.9
1.5
100
43
4-12
38
20
2.5
1.6
100
36
3-0
3750
84
5.3
8.9
170
37
0-2
55
35
4.5
3.1
130
38
2-4
36
128
4.3
2.9
122
39
4-12
29
43
3.8
4.1
120
-------
TABLE 7
CHEMISTRY OF SATURATION EXTRACTS
FROM SOILS OF TAYLOR HIGHWAY PROFILES
Depth total C Cations (mg/1) Cond.
Sample Inches mg/1 Ca Mg K ymhos/cm
>>
ro
O
CNJ
a>
rs
-o
CD
c
s-
rs
ca
"O
•P
Q.
a>
(/¦)
¦o
-------
TABLE 8
CHEMISTRY OF SATURATION EXTRACTS
FROM SOILS OF LOGGING CABIN CREEK PROFILES
Depth Total C Cations (mg/1) Cond.
Sample Inches mg/1 Ca Mg K ymhos/cm
o
CV1
CO
"D
a)
c
S-
3
CD
12
13
14
15
3-0
0-2
2-4
4-8
450
610
440
340
30
20
10
30
4.1
9.9
4.7
3.8
3.9
2.8
2.2
2.0
118
160
110
95
-Q
+->
a.
-o
52
4-0
3540
54
5.1
11.8
160
0)
CO
QJ
c
53
0-2
2300
20
3.0
5.3
120
Z3
54
2-4
705
62
3.0
4.5
96
_a
c
55
4-8
850
15
2.8
4.8
130
-------
52
116 mg/1 of this element in September. Magnesium in the surface
layer was 12.8 mg/1 in the burned soil; however, in the mineral
soil layers, it was approximately equal in all samples. Soluble
potassium was considerably increased with burning and generally
followed the trend set by calcium and magnesium. Specific
conductance verifies these trends.
Table 6 presents data from the West Fork site, portraying
trends similar to those just discussed. At this site burning
was light, although spruce trees were killed. Higher concentra-
tions of calcium, magnesium and potassium in these burned organic
horizons indicate that the burning released salts.
At the Taylor Highway site (Table 7), trends in the distri-
bution of soluble salts do not follow those for the preceding
sites. Total extracted carbon in the organic horizon was 780 mg/1
on burned soils in May, yet in June little difference existed.
In September, total extracted carbon rose to 5340 mg/1 in the
extracts from the unburned soil, although the organic layer
contained about half that of the organic layer of the burned
soil. Calcium content was 214 mg/1 in the organic layer of the
burned soil early in the season, and in general the burned
soils contained more of this element. Data for magnesium suggest
that it was released in the burned organic horizon early in the
season; however, later in the season these differences disappeared.
Data for potassium are incomplete and the trends inconsistent.
-------
53
Specific conductance verifies these inconsistencies. This soil
has a finer texture and a higher pH than all other soils sampled
in this study. These properties evidently must be considered
as factors when evaluating the effects of burning.
In June at Logging Cabin Creek, total carbon in the organic
horizon of the unburned soil was 2900 mg/1 (Table 8). By the
end of the summer both profiles were similar. Changes in calcium
are insignificant in these profiles, although this is a moderately
burned area. Magnesium concentrations are similar to calcium
except that in September the magnesium content of the organic
layer of the burned soil was 15 mg/1, which was higher than
all other surface horizons. In June potassium content was 15.1
mg/1 in the unburned organic layer; otherwise, these profiles
were similar. By September both profiles showed high potassium
in the organic layer, the unburned profile containing 11.8 mg/1,
compared to 21.3 mg/1 in the burned. Unlike the other three
sites, conductivity at this site did not tend to increase in
the organic layer of burned soil except in September. These
soils behaved strangely during the procedure of making a saturating
paste. They became very compact at saturation and any excess
water appeared on the surface; moreover, these samples yielded
a small volume of extract under vacuum. Such behavior probably
results from the particle size distribution of these soils,
which is an important factor In the compactability of soils.
-------
54
The large potassium concentrations probably originated in the
mica minerals so prominent in these profiles.
In summarizing these extract data, it appears that only
the organic layer can be useful in indicating changes in soil
chemistry caused by burning. This does not prohibit using other
horizons of a profile under severe burning when the organic
layer is destroyed; however, none of the sites sampled in this
study had been burned severely enough to expose mineral soil.
Almost without exception, extracts of the organic horizon yielded
higher concentrations of total carbon, calcium, magnesium and
potassium. Conductivity of these extracts was generally higher
than those from the mineral soil horizons. Moreover, the volume
of extract from the organic horizons was greater than those
from mineral horizons. This suggests that burning may release
significant quantities of soluble material which remains in
the organic horizon. Since percolation is impeded by permafrost,
excess water must be disposed of by surface or near surface
(within the organic horizon) runoff. These processes would
add soluble material to the streams and the soluble carbonaceous
material from burned or unburned soils would color the water.
-------
Water Chemistry
55
Samples were collected from the stations indicated in Figure
2 on May 5, 1967, September 19, 1967, May 3, 1968/and June 26,
1968. Samples were taken in plastic bottles or glass dissolved
oxygen bottles, then transported to a field laboratory, where
determinations of dissolved oxygen, pH and conductivity were
made. In all cases, these analyses were made within six hours
after collection. In situ temperature measurements were made
with a calibrated thermometer reading directly to 0.1°C. Samples
were then frozen prior to transportation and kept at a temperature
of -70°C. Alkalinity was measured on an unfrozen sample taken
to the laboratory at College.
After transporting to the Alaska Water Laboratory, samples
were transferred to a freezer for storage at -20°C. Immediately
prior to analysis, samples were thawed and, if analysis was
not complete on the same day, refrozen until it could be completed.
Trace element determinations were made on a Beckman Model
979 or a Perkin-Elmer Model 303 atomic absorption spectrophotometer.
In the case of calcium and magnesium, 1% lanthanum solution
was added to the sample to prevent interference by phosphate
and sulfate. In addition, calcium and magnesium were measured
using the acetylene-nitrous oxide flame.
-------
56
Iron, potassium, sodium, manganese and copper were determined
by using the air-acetylene flame. In the Beckman instrument,
the Beckman laminar flow burner was used; in the Perkin-Elmer
instrument, the Boling 3-slot burner head was the principal
burner, although for higher concentrations, especially for sodium,
the short path burner head was used. In determining calcium
and magnesium with the Perkin-Elmer instrument, the specially
developed nitrous oxide burner head was used. As source lamps,
the Westinghouse or Perkin-Elmer hollow cathode lamps were used
for calcium, magnesium, iron, copper and manganese. Osram spectral-
discharge lamps were used for sodium and potassium.
The azide modification of the Winkler technique was used
for dissolved oxygen. Samples were fixed in the field by the
addition of manganous sulfate, alkaline iodide azide, and sulfuric
acid reagents, and transported to the field lab for titration.
pH was measured in the field, using a Beckman Model N2 pH meter.
Values were corrected to 25°C. Conductivity was determined,
using an Industrial Instruments conductivity bridge and a cell
with a constant of 0.1. Conductivity is reported as corrected
to 25°C. Total hardness was determined by titration with ethylene
diamine tetraacetic acid. Alkalinity was determined by titration
with sulfuric acid to a pH of 4.60. In all cases total alkalinity
rather than phenolphthalein alkalinity was recorded, as the
pH of all samples was so low that phenolphthalein alkalinity was zero.
-------
Chloride, sulfate, chemical oxygen demand, ammonia and
nitrate were determined using Standard Methods, 12th Edition
(1965). Nitrate was determined using the modified brucine method
(Jenkins and Mesdker, 1964). Total and orthophosphates were
determined colorimetrically by the method developed by Riley
and Murphy (1962).
The effects of a major ecological disturbance on the general
chemistry of a watershed and its reflection in the streams themselves
might be observed in many ways. In unpopulated areas, the principal
source of organic materials in gravel bedded, fast running streams
is extraction from the soil organic layer by runoff water. An
increase in runoff caused by removal of vegetative cover may
result in an increased quantity of organic materials in the
streams. This could also result in increased turbidity and
color.
Waste products of the burning process may also be transported
to the stream, either through surface drainage or wind action.
These might include nutrient materials, particulate organic
and inorganic debris, and soluble organic compounds resulting
from the partial burning of plant materials.
Part of the study plan was to select two streams, one a
control whose watershed was completely outside the fire area,
and one with a similar watershed, but which was completely inside.
Big Timber Creek was chosen as the control stream and Cement Creek
-------
58
as the experimental stream. Although these streams were quite
similar in watershed type, both being westerly-flowing into
the Dennison Fork of the Forty Mile River, this selection later
proved to be poor. This is particularly evident when we observe
the conductivity of these streams during the early May sampling
periods in 1967 and 1968. During both of these times, the conduc-
tivity of Big Timber Creek was found to be much higher than that
of Cement Creek. This is reflected in other measurements such
as total hardness, trace elements, and alkalinity. As this
time period should show the least effect of pollutants from
the fire itself, these great differences would indicate that
the selection of these streams for future comparison was poor.
Table 9 contains data collected from all stations. Samples
taken in May show temperatures very close to 0.0°C, since there
was considerable ice cover at all stations. At a few stations
the water samples may have been surface water running over anchor
ice. The nonavailability of helicopter transportation caused
cancellation of a scheduled trip to the area in June 1967; hence,
chemical samples were not collected. However, on June 26, 1968>
temperatures in the rivers were approaching their maxima. It
is interesting to note that temperatures in the lower rivers,
such as the Dennison and the West Fork, were quite high, with
a maximum of 11.9°C, whereas the stream tributaries of these
rivers, Cement Creek and Big Timber Creek, were as low as 3.5°C.
-------
TABLE 9
MISCELLANEOUS CHEMICAL ANALYSES OF STREAM WATERS
5
19
3
26
5
19
3
26
5
19
3
26
STATION
May
Sept
May
June
May
Sept
May
June
May
Sept
May
June
1967
1967
1968
1968
1967
1967
1968
1968
1967
1967
1968
1968
DISSOLVED OXYGEN (Mg/1)
CC
100
12.1
11.34
12.2
10.6
7.10
6.75
7.0
6.48
0.2
3.0
0.0°
5.5
T3
D
300
8.4
11.23
7.6
9.7
6.93
6.90
6.7
6.85
0.4
4.3
0.0°
11.4
£
S_
T
100
12.1
11.2
12.3
11.2
6.40
6.90
7.6
6.69
0.5
-
0.0°
3.5
-O
T
200
12.0
10.7
12.0
11.0
6.60
6.75
7.3
6.50
0.4
4.5
0.0°
3.5
C
=>
W
200
7.2
10.6
12.3
9.3
7.00
6.80
6.7
6.88
0.5
4.8
0.0°
11.3
HARDNESS TOTAL
as CaC0->
CONDUCTIVITY
umho/cm.
CORR.
ALKALINITY As
CaCOj
to
25°C
-o
/II
CC
100
36.9
56.9
44.9
34.0
100
77
122
46
10.0
13.0
28.0
9.7
W
C
CC
200
41.8
41.1
39.2
22.0
112
84
114
51
10.0
14.8
23.0
9.8
3
D
200
41.0
26.5
27.5
26.8
110
58
76
57
16.0
18.6
23.6
19.4
W
100
41.3
26.5
32.6
52.8
104
66
94
54
16.6
14.8
15.0
17.6
D
100
42.6
30.8
61.2
20.0
122
60
147
54
17.0
18.8
52.6
21.3
0)
D
300
72.2
33.6
51.6
35.4
126
66
123
52
58.4
16.4
42.4
17.1
S.
T
100
148.6
25.7
147.9
21.6
275
66
342
39
75.8
15.6
86.4
11.7
-Q
T
200
97.3
26.1
102.0
17.4
190
55
235
32
62.2
14.0
78.0
9.4
Z3
W
200
75.8
28.8
44.9
28.0
178
90
119
51
42.2
13.8
12.0
15.7
-------
TABLE 9 (Continued)
5
19
3
26
5
19
3
26
5
19
3
26
May
Sept
May
June
May
Sept
May
June
May
Sept
May
June
STATION
1967
1967
1968
1968
1967
1967
1968
1968
1967
1967
1968
1968
CALCIUM,
Mg/1
MAGNESIUM
, Mg/1
IRON Mg/1
CC
100
9.0
6.9
12.1
5.7
5.1
0.2
3.4
2.6
0.22
0.43
.14
.10
CC
200
10.5
10.2
10.8
5.8
5.4
0.8
4.2
2.7
0.18
0.32
.14
.20
D
200
9.0
6.6
7.4
10.3
5.2
0.2
1.9
2.0
0.21
0.50
.10
.20
W
100
9.8
10.5
7.7
8.3
5.1
0.2
3.7
2.8
0.23
0.56
.10
.35
D
100
10.7
8.4
15.3
7.6
5.6
0.6
4.9
1.5
0.24
0.38
.06
.20
D
300
15.9
13.5
13.8
6.8
8.6
1.5
3.5
3.8
1.65
0.56
.10
.20
T
100
36.6
11.7
21.2
6.4
19.2
1.3
13.6
1.6
0.07
0.56
.06
.35
T
200
25.6
44.4
23.6
3.6
11.4
3.1
9.6
0.8
0.07
1.02
.06
.20
W
200
17.4
8.1
10.5
10.2
9.5
0.6
3.8
2.9
1.52
0.56
.18
.20
POTASSIUM,
Mg/1
SODIUM,
Mg/1
MANGANESE
(Mg/1)
CC
100
8.8
.93
4.6
0.7
2.9
2.7
4.4
4.4
0.18
.05
.02
.01
CC
200
8.5
.75
4.8
0.7
4.2
2.6
4.6
3.9
0.29
.04
.02
.01
D
200
8.2
.63
3.7
0.6
5.8
2.2
3.5
4.4
0.19
.05
.02
.03
U
100
7.6
.54
5.2
0.6
3.4
2.2
3.5
4.8
0.18
.06
.00
.03
0
100
8.7
.65
1.00
0.7
3.9
2.2
7.3
4.5
0.19
.03
.75
.05
D
300
2.0
.67
0.6
0.7
7.0
2.6
4.4
4.9
0.24
.05
.25
.05
T
100
3.6
.78
2.6
0.8
11.5
2.8
7.85
4.2
0.10
.06
.13
.02
T
200
2.7
.10
1.6
0.5
7.2
2.9
7.7
4.4
0.10
.15
.10
.03
M
200
2.0
.47
4.6
0.5
14.7
2.2
3.0
4.2
1.04
.05
.04
.03
-------
TABLE 9 (Continued)
5
19
3 26
5
19
3
26
5
19
3
26
STATION
May
Sept
May June
May
Sept
May
June
May
Sept
May
June
1967
1967
1968 1968
1967
1967
' 1968
1968
1967
1967
1968
1968
CHLORIDE (Mg/1)
COPPER (Mg/1)
SULFATE (Mg/1)
CC 100
4.6
2.0
2.7 2.4
.02
.05
.02
.01
19.0
16.2
16.8
79.8
CC 200
3.2
1.5
2.7 1.2
.02
.01
.01
.01
29.2
17.0
14.4
80.7
D 200
3.3
1.2
2.8 1.5
.02
.041
.02
.05
20.5
12.2
8.3
36.0
W 100
3.7
1.5
2.4 4.2
.009
.005
.02
.01
15.1
16.7
14.9
17.0
D 100
3.5
1.2
2.0 2.4
.024
.0025
.02
.023
20.3
14.2
10.4
36.0
D 300
1.4
1.3
1.8 2.0
.018
.0145
.02
.05
15.8
17.4
7.2
66.0
T 100
1.1
1.5
1.2 1.4
.02
.035
.01
.01
52.0
16.7
67.4
14.0
T 200
0.9
1.7
0.9 1.4
.009
.0533
.02
.023
24.6
27.5
32.7
23.0
W 200
5.0
1.4
2.4 2.0
.008
.0145
.01
.01
17.6
16.9
24.0
36.5
TURBIDITY
(Mg/1)
COD
CC 100
4.4
94.0
55.3
82.3
CC 200
2.6
87.4
42.9
84.8
-
D 200
6.0
92.9
43.0
75.9
-
W 100
3.7
102.6
66.4
87.0
-
D 100
8.3
94.4
48.0
51.6
_
D 300
3.7
67.0
64.5
35.4
-
T 100
3.7
44.1
65.8
43.6
-
T 200
10.6
40.6
74.5
25.6
-
W 200
4.4
42.5
65.5
75.5
-
-------
62
By September the temperatures had dropped; the highest temperature
found in September 1967 was at the lower reach of the West Fork,
where temperature was 5.2°C. Temperatures also seemed to be
quite similar throughout the system; by this time Cement Creek
and Big Timber Creek were be ween 3 and 5°C.
Samples collected immediately prior to the ice breakup
on the streams (that is, those collected in May) were primarily
composed of groundwater during low runoff conditions, as is
reflected in the conductivity measurements. However, in September
1967 and June 1968 the samples were composed of groundwater
mixed with surface water. This was especially noted on June
26, 1968, when samples were collected following a period of
heavy rainfall which significantly diluted the waters. September
1967 followed a summer of abnormally heavy rainfall throughout
interior Alaska. For this reason the usual fall low-flow conditions
did not prevail.
Organic materials introduced into the system from erosion
or surface transport of detritus from the fire area might be
expected to cause a lowering of dissolved oxygen in the waters.
However, the dissolved oxygen concentrations in Big Timber Creek,
completely outside the burned area, appear to be quite similar
to those found in Cement Creek, within the burned area. On
May 3, 1968,the lowest Dennison station indicated a lower dissolved
-------
63
oxygen concentration than the upper stations and also a great
deal lower than the West Fork. The reason for this depletion
is unclear.
Organic material transported from the burned site to the
river system as a result of increased erosion should be reflected
in an increase of the chemical oxygen demand of the water. This
does appear to happen, as shown by comparison of Big Timber
Creek with Cement Creek in May 1967 and 1968. Chemical oxygen
demand values of Big Timber Creek are less than half of those
found in Cement Creek. Observation of the West Fork and the
Dennison Fork show similar trends, the chemical oxygen demand
concentrations increasing as these streams enter the fire areas.
Little change or, as on May 3, 1968, an actual decrease was
noted in the chemical oxygen demand concentrations of the Dennison
Fork as it left the fire area.
The fact was mentioned in the soils section that the conductivity
of extracts of the burned layer was usually higher than that
of the unburned layer. In addition, certain metals, particularly
calcium, magnesium and potassium, were found to be higher in
these same extracts. We found this trend to be reflected in
the flowing waters, as a principal source of these constituents
should be the extraction by surface water and subsequent transport
to the streams.
-------
64
Conductivity of the streams, however, did riot appear to
be influenced by the fire. The highest conductivity measurements
found were on Big Timber Creek, completely outside the fire
area. In almost all cases, conductivities were lower in the
lower reaches of the streams—Big Timber Creek being the exception.
The apparent anomaly to this statement is the case of the lower
Dennison station, which is invariably higher than the station
inside the fire area; this may result from groundwater influences
in that area. This may also be an explanation for the low dissolved
oxygen mentioned above.
Trace element concentrations in the streams should be similarly
affected. These may be more easily seen than the conductivity
changes, as conductivity is a gross estimate of all ions. Specific
concentrations thus might be more indicative of true effects.
Potassium concentrations appear to show the most pronounced
increase in waters flowing through the burned area, Big Timber
Creek showing consistently lower potassium concentrations than
Cement Creek. The West Fork consistently had higher values
of potassium in the lower stations than in the upper station.
The Dennison Fork does not show such pronounced changes. This
is probably because it is a much larger stream, much of which
is outside the burned area, and the total effect would not be
as noticeable as in a smaller stream, such as Cement Creek,
whose watershed lies entirely within the fire area.
-------
65
Neither magnesium nor calcium shows effects similar to
that of potassium. The highest concentrations of these ions
were usually found in Big Timber Creek, which accounts in part
for its high conductivity. Trace metals, iron, manganese and
copper also do not show any particular trends that might be
attributed to the fire. Sodium, which frequently shows trends
similar to potassium, does not appear to do so here.
Of major importance to the biological community are the
nutrient cycles (Table 10). Nitrogen and phosphate content
of the water is of particular interest here, as they are primary
food sources for phytoplankton. Nutrient cycle changes noted
here that could be explained as resulting from the fire are
questionable. Total and orthophosphate are consistently higher
in Cement Creek than they are in Big Timber Creek. The West
Fork and the Dennison also show an increase in phosphate concen-
trations in areas within the fire area as compared with upstream
stations, but these changes are not uniform: e.g., Cement Creek
does not show consistent changes. In addition, increases in
nutrient concentrations downstream are typical of most streams.
Big Timber Creek shows an increase in phosphates downstream, ex-
cept for total phosphates sampled on May 5, 1967, and orthophos-
phate are not available for May 5, 1967, and June 26, 1968.
-------
TABLE 10. NUTRIENT CHEMISTRY ON STREAM WATERS
5
19
3
26
5
STATION
May
Sept
May
June
May
1967
1967
1968
1968
1967
NITRATE
IMg/l)
CC 100
.01
.12
.05
-
.78
CC 200
.01
.32
.06
-
.65
D 200
.01
.13
.03
-
.73
W 100
.01
.07
.03
-
.88
D 100
.01
.12
.08
.825
D 300
.02
.08
.07
-
.400
T 100
.00
.00
.04
-
.295
T 200
.00
.02
.04
-
.250
W 200
.01
.00
.18
-
.290
PHOSPHATE -
Total
CC 100
0.50
.14
1.60
.022
_
CC 200
0.44
.21
1.00
.000
-
D 200
0.63
.17
1.20
.067
-
W 100
1.03
.11
1.51
.220
-
0 100
0.91
.25
2.58
.06
D 300
0.04
.22
1.01
.03
-
T 100
0.04
.20
0.81
.00
-
T 200
0.50
.17
0.72
.00
-
W 200
0.01
.13
1.32
.17
-
19
3
26
5
19
3
26
Sept
May
June
May
Sept
May
June
1967
1968
1968
1967
1967
1968
1968
TRITE (Mg/1)
AMMONIA
as N
.01
.00
.00
2.+
1.1
1.7
1.0
.00
.00
.00
2.+
0.7
1.8
1.2
.01
.00
.00
2.+
0.9
1.8
1.4
.01
.00
.00
2.+
1.4
1.8
1.4
.01
.00
.01
2.+
1.23
1 .10
1.7
.01
.00
.00
1.42
1.31
0.78
1.3
.00
.00
.00
0.89
1.09
0.67
1.008
.02
.00
.00
0.88
1.31
0.59
0.903
.01
.00
.01
1.41
1.17
1.64
0.575
PHOSPHATES - Ortho
.03 1.30
.05 1.16
.04 0.81
.04 0.98
.03 0.00
.05 0.02
.07 0.06
.09 0.02
.03 0.45
-------
A similar pattern is observed with respect to the nitrogen
cycle. Examination of results for ammonia, nitrite and nitrate
indicates that Cement Creek was consistently higher than Big
Timber Creek. The West Fork shows increase in ammonia only,
nitrate and nitrite changing insignificantly or lowering as
the stream enters the fire area. Changes in the Dennison Fork
are slight and not considered to be significant.
pH does not appear to reflect changes due to the fire.
Changes in Cement Creek and the West Fork appear insignificant.
In general, this is also true of the Dennison Fork; although
station D-200 shows a considerably higher pH than D-300, this
trend does not continue to station D-100.
In summary, it would appear that the only significant changes
observed in the streams under regular flow conditions would
be increases in chemical oxygen demand, resulting from added
organics, and possibly potassium.
It might be expected that during periods of increased runoff,
suspended sediment would increase in streams draining the fire
area due to increased erosion. This was not noticed during
any of our sampling periods; however, as is mentioned elsewhere,
deep erosion ditches were observed where cat trails were made
in attempts to control the fire. In addition, a local resident
who operates a lodge on the Dennison River below the fire area
remarked that the river, which is used as a water source, could
-------
not be used during high runoff periods after the fire because of
the sediment loads.
Stream Biology
To evaluate the effects of a large scale forest fire on
the aquatic organisms within the burned area becomes an ecological
study. Broadly defined, ecology is the study of interrelations
between living organisms and their environment. Therefore,
to understand the reason why change has or has not taken place,
one must study not only the organisms, but also the environment.
In a forest fire such as this, the aquatic environment
was disrupted during and after the fire. During the fire, smoke
reduced the amount of sunlight entering the stream, which could
interfere with the emergence pattern of the aquatic insects.
Soot, ash and other debris entered the water and the water temperature
itself may have been raised because of the fire. After the
fire, the burned-over soil and duff layer had been altered.
Sooner or later these changes manifest themselves in the chemical
constituents of the water in the streams. These changes, if
drastic enough, affect the aquatic organisms within the streams.
These aquatic organisms are an extremely diverse conglomeration
of animals and plants that forms a closely knit community, each
member of which is affected in some manner by every other organism
-------
69
in the community. Ideally, to evaluate the effects of such
a fire, one should be able to look at this entire community;
however, this is virtually impossible because of restrictions
in time and resources. Therefore, a portion of the whole must
be examined with the hope that what has happened to the entire
group can be predicted from that portion. The decision of which
portion to examine is not easy in itself. Since the primary
producers are the start of the food chain, should they be studied?
If so, what can be told about the intermediate links or the
end of the food chain, the fish? Perhaps the fish population
should be studied, since it is that portion of the community
in which man is most interested. Unfortunately, the fish populations
within the streams in the study area do not lend themselves
to the type of study to which we were restricted. For example,
there is a movement of fish up and downstream in relation to
temperature and other factors, and since it was only possible
to take samples at predetermined times, a distorted picture
might be obtained.
So, after these considerations, the macro fauna portion
of the benthos was chosen for study. This lends itself nicely
to such a study because its organisms are quite stable, with
life cycles ranging from several months to several years. They
can be adversely affected because the fire interferes with emergence
and may have other effects. They are able to reestablish themselves
-------
70
rapidly. Arid finally, they are a very important portion of
the community because they are Important food items of fishes.
The benthos is in reality a community within the larger
aquatic community, consisting of a very diverse group of animals
for which the degree of diversity is dependent upon water quality.
For example, in clean, unpolluted mountain streams such as those
in this study, the benthos consists of many different species
with no great numbers of individuals within one species.
When something happens to the environment which changes
the quality of the water, making it more desirable for one species
than another, that species or group of species becomes dominant
in number and the entire community composition changes. If,
on the other hand, a condition develops which wipes out a section
of the entire community and that condition is subsequently removed,
the area becomes repopulated quite rapidly by drifting organisms,
upstream migration, repopulation by flying adults or egg-laying
adults, or other means (Larrimore, 1959; Frey, 1961J Macan,
1963).
Generally speaking, this aquatic community is fundamentally
different from terrestrial plant communities, where one or a
few plants establish dominance and become a potent influence
upon the other members of the community (Macan, 1963). This
is logical since the animals which constitute this community
are motile and are not so restricted in their diet that they
-------
71
cannot take advantage of changing food supplies. They also
differ from plant communities in that their numbers fluctuate
greatly during the course of a year, and this is a disadvantage
when using them as indicators of pollution. However, if there
is an awareness of this fluctuation and its causes, it can be
overcome. To do this, a sampling schedule must be established
that will sample the population at its various stages and will
compare like populations. With this in mind, the sampling schedule
was established.
As mentioned before, it is very likely that the population
was affected somewhat during the actual fire. This is especially
true since many of the forms studied have an emergence pattern
coinciding with the fire. However, it was impossible to study
the population during or immediately after the fire, so the
first sampling period was set for the following spring just
prior to breakup. This period was selected in an attempt to
establish the condition of the population before it was exposed
to whatever effects the fire might have had on the population
through the flushing action of melting snow during breakup.
Prior to this sampling period, a buildup of bottom ice in the
streams made collecting a representative bottom sample impossible.
The next sampling period was set for approximately June
1967, or such a time when the river returned to normal after
breakup. This sampling period was selected to evaluate any
effects which were brought about by runoff from the burned area.
-------
72
It was to take place immediately after breakup, but before the
population had an opportunity to readjust itself after runoff.
This series of samples was never collected because helicopter
transportation was not available. However, in an attempt to
salvage something from this sampling period, samples were collected
from one station on the West Fork which was in the burned area.
These were not from stations designated in the original plan.
The third or fall sampling period was selected to measure the
reproductive capacity and over-wintering populations within
the stream. This sampling trip was successful in all ways.
The fourth sampling date was again before breakup in the
spring of 1968. Once again, icing conditions made it impossible
to collect reliable biological samples.
The last sampling period was after breakup in 1968 and
again established to determine whether there were any further
effects due to runoff the second year after the burn. This
again was only partially successful because of extremely heavy
rains in the area, which made it impossible to collect representative
samples from Cement Creek and Big Timber Creek.
The exact sites of the nine stations described earlier
were carefully selected to insure similarity of bottom type,
riffle versus pond area, and bank cover. Since the composition
of the benthic community is determined by these and other factors,
it was important that all sites be similar in order to have similar
-------
73
community composition. Apparently there was a high degree of
success in the site selection, since sample communities from
the various sites were closely related. Figure 16 portrays an
example of the method used for quantitative sampling of the
benthic community with a Surber sampler.
The schedule of sampling periods and stations just described
was selected to sample the benthos at important intervals in
the post-fire history of the area and would have produced valuable
information on the effects of such a fire on the aquatic fauna
had it been followed. Unfortunately, the schedule could not
be followed and as a result, the data are scattered to the extent
that it is hazardous to draw definite conclusions. However,
several factors are worthy of note.
When utilizing the community concept as a tool to evaluate
the effects of a catastrophe on the aquatic environment, it
is necessary to examine the community both qualitatively and
quantitatively. If the catastrophe has had a drastic effect,
the diversity of the community will have been disrupted and
it will have changed, with new species entering, or groups of
organisms missing. If, on the other hand, the effect has not
been drastic, it is possible that no groups have been eliminated,
but that the standing crop has been affected. In that case
the quantitative data are of value. However, quantitative data
are difficult to analyze and evaluate since the standing crop
-------
tends to fluctuate considerably during the course of a year
and truly representative samples are difficult to collect.
In this study we utilized both methods in an attempt to
evaluate the effects of this fire.
In analyzing the data, we find there were only three tax-
onomic groups (from this point forward they will be referred
to as taxa groups) present above the fire, while there were
seven taxa within the fire area and five below the fire area
in the Dennison Fork in September, 1967 (Table 11). In June
1968; there were 12, 18, and 12 taxa respectively (Table 11).
Close scrutiny of the-tables reveals no significant differences
within the stations. The difference in numbers of taxa between
the two sampling dates is probably due to the time of the year.
The quantitative data from Dennison Fork also show no significant
differences.
In September the numbers ranged from 33.1 organisms per
square meter in the station in this upper unburned area to 79.1
in the middle station and 202.4 in the lower station (Table
12). Annelids and dipterans dominated the lower two stations,
but the percentage of plecopterans was high in the upper station.
This probably resulted from environmental conditions unrelated
to burning, since the same condition did not exist in June 1967.
In June 1968 numbers per square foot ranged from 1357.9
in the upper station to 4164.8 in the middle station and 201.5
-------
TABLE 11
A QUALITATIVE COMPARISON OF ORGANISMS COLLECTED
FROM THREE STATIONS ON THE DENNISON FORK, CHICKEN, ALASKA
September 14, 1967 June 26, 1968
ORGANISM D-1QO D-200 D-300 D-1Q0 D-2QO D-300
01igochaeta
Naididae XX XXX
Hi rudinea
Piscicola sp.
Arachnida
Hydracarina X
Plecoptera
Isoperla sj). XX XX
Alloperla sp. XX
Ephemeroptera
Ephemerella sp. XX XX
Rhithrogena sp. X
Ironodes s£. XX
Ameletus X
Trichoptera
Polycentropus s.p. X
Lepidostoma sp. XXX
Micrasema X
Ptilostomis X
Phryganea X
Limnephi lus XXX X
Brach.ycentrus X
Coleoptera
Helodidae
Diptera
Tipulidae
Prionocera sp. XXX
Tipula S£. X
Simuli idae
Prosimulium XXX
Chironomidae
Cricotopus sjd. A X X
Smittia XXX
Procladius X X
Nanocladius X
Cricotopus sp. B. XX
Ablabesmyia X
Pseudochironomus X
Micropsectra X X
Chironomus X
Tabanidae X
Ceratopogonidae
Dasyhelea X
Mollusca
Pisidium X
GROUP FREQUENCY 5 7 3 12 18 12
-------
TABLE 12
NUMBER AND PERCENTAGE OF ORGANISMS PER SQUARE METER OF BOTTOM
FROM THREE STATIONS ON DENNISON FORK IN 1967 AND 1968
ORGANISM
September 14, 1967
June 26, 1968
D-100
D-20
0
D-300
D-100
D-200
D-30
3
1*
2**
1
2
1
2
1
2
1
2
1
2
Annelida
128.8
63.6
30.4
38.4
6.4
19.4
67.2
33.3
36.8
0.9
416.8
30.7
Plecoptera
0.0
0
2.8
3.5
9.2
27.8
9.2
4.6
34.0
0.8
2.8
0.2
Ephemeroptera
12.0
5.9
0.0
0
2.8
8.3
39.6
19.6
168.4
4.0
34.0
2.5
Trichoptera
15.6
7.8
15.6
19.7
2.8
8.3
18.4
9.2
110.4
2.7
18.4
1.4
Diptera
46.0
22.7
30.4
38.4
12.0
36.2
67.2
33.3
3815.2
91.6
886.0
65.2
TOTAL
202.4
100
79.1
100
33.1
100
201.5
100
4164.8
100
1357.9
100
*1—Number of organisms per square meter
**2—Percentage of total numbers per square meter
-------
77
in the lower station. This would seem to be a significant difference.
However, there was an influx of blackfly larvae before this
sampling period. Blackfly egg clusters are attached to rocks
and when they hatch, the larvae tend to remain attached to the
rocks in great numbers. Therefore, if the sampler, when placed
at random in the stream, covers one of the rocks that harbor
the blackfly, great numbers are collected. On the other hand,
had the sampler failed to cover the rock where the great mass
of larvae was attached, only a minimal number or even one would
have been collected. This probably explains the great variation
in number. Once again, the annelids and dipterans dominated the
community in all stations (Table 12).
As expected, the data from the West Fork show the same
trend of larger numbers of taxa in June 1968 than in September
1967. In 1967 there were five groups in the upper unburned
area and six in the burned area, while in 1968 there were 15
in the unburned and 18 in the burned area (Table 13). It is
highly improbable that the fire was responsible for the larger
numbers of groups within the burned area, even though this is
consistent within all of the streams. It is more probable that
this is because of ecological differences in the environment,
due perhaps to elevation, groundwater intrusion or stream gradient.
Annelids and dipterans once again dominated the quantitative
data in the West Fork (Table 14) as they did in the Dennison Fork.
-------
TABLE 13
A QUALITATIVE COMPARISON OF ORGANISMS COLLECTED FROM
TWO STATIONS ON THE WEST FORK, CHICKEN, ALASKA
ORGANISM
September
14, 1967
June 26, 1968
WF-100
WF-200
WF-100
WF-200
Annelida
Naididae
X
X
X
X
Arachnida
Hydracarine
X
X
Plecoptera
Hastaperla sp.
X
Isoperla sp.
X
X
X
Pseudocloeon sp.
X
Ephemeroptera
Ephemerella sp.
X
X
X
Ameletus sp.
X
Ironodes sp.
X
Centroptilium sp.
X
Trichoptera
Lepidostoma sp. A
X
X
X
X
Lepidostoma sp. B
X
Brachycentrus sp.
X
X
Platycentropus sp.
X
Ptilostomis sp.
X
Micrasema sp.
X
Polycentropus sp.
X
Diptera
Deuterophlebiidae
Deuterophlebia sp.
X
Tipulidae
Prionocera sp.
X
X
Simuliidae
Prosimulium sp.
X
X
Chironomidae
Pentaneura sp.
X
X
Cricotopus sp.
X
X
X
Crionomus sp.
X
Smittia sp.
X
Diamesa sp.
X
Tan.vtarsus sp.
X
Dolichopodidae
X
X
Group Frequency
6
5
18
15
-------
TABLE 14
NUMBER AND PERCENTAGE OF ORGANISMS
PER SQUARE METER OF BOTTOM FROM TWO STATIONS
ON WEST FORK IN 1967 AND 1968
ORGANISM
WF-1
September 14, 1967
00 wf-;
?00
WF-
June 2(
100
5, 1968
WF-2
>00
1*
2**
1
2
1
2
1
2
Annelida
67.2
52.5
6.4
11.1
138.0
11.8
110.4
8.6
Plecoptera
2.8
2.2
2.8
4.8
0.0
0.0
Ephemeroptera
0.0
0.0
124.2
10.6
55.2
4.3
Tri choptera
12.0
9.4
12.0
20.6
41 .4
3.5
100.4
8.6
Di ptera
46.0
35.9
36.8
63.5
869.4
74.1
1002.8
78.5
TOTAL
127.9
100
58.0
100
1173.0
100
1278.8
100
1* - Number of organisms per square meter
2** - Percentage of total numbers per square meter
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80
However, where the Plecoptera were the next most frequent organisms
in the Dennison, the Trichoptera held that position in the West
Fork. In neither of the two sampling periods was there a significant
difference in either the diversity or the total number of organisms
per meter.
The next four stations that were compared consist of two
stations on Big Timber Creek lying outside the burned area and
two stations on Cement Creek lying inside the burned area. Since
the gradient in these streams is quite steep, it is necessary
to compare stations from comparable areas on the two streams.
Group frequency in all cases was very low, since the data consist
of only the September 1967 sampling period. There is, however,
no significant difference in either the qualitative or quantitative
data (Tables 15 and 16). Of ecological interest is the fact
that the Annelida are no longer a significant portion of the
total number in these two creeks, but the Plecoptera are the
dominating group.
When it became apparent that we would not be able to collect
samples from the prescribed sampling points during the June
1967 sampling period, a series of samples was collected from
one site on the Mosquito Fork draining an unburned area and
one set of samples from the West Fork, draining a portion of
the burned area. These rivers were not wholly comparable, but
were closely enough associated to supply some data for that time
-------
TABLE 15
A QUALITATIVE COMPARISON OF ORGANISMS COLLECTED
FROM BIG TIMBER AND CEMENT CREEK, CHICKEN, ALASKA
September 14, 1967
STATION
ORGANISM
T-100
C-100
T-200
C-200
01igochaeta
Naididae
X
Hirudinea
Piscicola sp.
X
Plecoptera
Isoperla sp.
X
X
X
X
Brach.yptera sp.
X
X
Ephemeroptera
Epeorus
X
Ciriygmula sp.
X
Trichoptera
Ecclisom.yia sp.
X
X
Brachycentrus sp.
X
Limnephilus sp.
X
Diptera
Tipulidae
Tipula sp.
X
Chlronomidae
Cricotopus sp.
X
Rhagionidae
Antherix sp.
X
X
X
Group Frequency
5
7
4
3
-------
TABLE 16
NUMBER AND PERCENTAGE OF ORGANISMS
PER SQUARE METER OF BOTTOM FROM TWO STATIONS
ON CEMENT AND BIG TIMBER CREEK ON SEPTEMBER 14, 1967
ORGANISM
T-lOO
C-100
T-2C
)0
C-200
1*
2**
1
2
1
2
1
2
Annelida
0.0
0.0
6.4
2.7
6.4
3.3
2.8
0.7
Plecoptera
174.8
86.4
122.4
50.6 .
150.0
77.6
199.6
53.5
Ephemeroptera
15.6
7.7
12.0
4.9
2.8
1.4
2.8
0.7
Trichoptera
2.8
1.4
0.0
0.0
0.0
0.0
2.8
0.7
Diptera
9.2
4.5
101.2
41.8
34.0
17.7
165.6
44.4
TOTAL
202.4
100
242.0
100
193.2
100
373.5
100
1* - Number of organisms per square meter
2** - Percentage of organisms per square meter
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83
of the year. The qualitative data indicate no difference in
the two streams. There were 12 taxa representing the unburned
area and 11 in the burned (Table 17). It is of interest to
note that on the West Fork, a burned area was represented by
11 taxa in 1967, but a similar area in 1968 was represented
by 18. There is a possibility that this might be the result
of fire or the original runoff from the fire. This is only
conjecture, however. The quantitative data (Table 18) is again
biased by large numbers of blackflies. If they are removed
from the data, there is no significant difference.
The quantitative data represented in this paper consist
of three 0.092m2 {1 ft.2) samples for each station and sampling
period. All of these data were subjected to the t-test for
related measures. In no case was there a difference in the
two groups at the 95% confidence limit. The qualitative data
are represented by 1/2 hour of concentrated effort with a dip
net, covering all representative areas in a sampling site.
The data discussed above suggest that the effects of the
fire on the benthic macro-organisms were negligible or so ephemeral
that they returned to normal in a short time before it was possible
to evaluate the effects. There is some indication that there
may have been fleeting effects due to the fire or fire control
methods. It is difficult to imagine that the erosion noticed
in the cat trails mentioned earlier in the paper did not at some
-------
TABLE 17
A QUALITATIVE COMPARISON OF ORGANISMS COLLECTED
FROM THE WEST FORK AND THE MOSQUITO FORK ON JUNE 18. 1967
ORGANISM MOSQUITO FORK WEST FORK
Plecoptera
Isoperla sp. X
Alloperla sp. X X
Brachyptera s£. XX
Ephemeroptera
Ephemerella sp. X X
Trichoptera
Lepidostoma sp. X X
Brachycentrus sp. X X
Ptilostomis sp. X X
Diptera
Simuliidae
Prosimuliurn sp. X x
Tipulidae
Tipula sp. X
Chironomidae
Polvcentropus s£. X
Pentaneura sjj . XX
Smittia sp. X
Cricotopus sp. -A X
Cricotopus S]>. -B
Rhagionldae
Atherix s£. X
Group Frequency
12 11
-------
TABLE 18
NUMBER AND PERCENTAGE OF ORGANISMS
PER SQUARE METER OF BOTTOM FROM MOSQUITO FORK AND WEST FORK
ON JUNE 18, 1967
ORGANISM
Mosquil
:o Fork
West
Fork
1*
2**
1
2
Plecoptera
144.4
12.1
14.1
4.5
Ephemeroptera
126.0
10.5
58.0
1.9
Trichoptera
172.0
14.3
223.6
7.2
Diptera
757.2
63.1
2695.6
86.4
TOTAL
1200.0
100
3117.9
100
1* - Number of organisms per square meter
2** - Percentage of organisms per square meter
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86
time increase the turbidity in the streams enough to cause some
damage to the organisms present. However, if there was some
damage, it did not extend into our sampling periods, or it was
so slight that our methods were not sensitive enough to measure
it.
Even though we have been able to show some changes in the
chemical makeup of the water, especially some of the nutrients
and potassium, these changes must have been below the magnitude
necessary to effect a change in the portion of the aquatic population
we examined. To further substantiate this hypothesis, fish
collected from the burned area were no more difficult to obtain
than from outside the area and were in good physical condition,
feeding voraciously on the aquatic insects from the streams.
General Discussion
Data and observations collected during this study failed
to show that the fire had any significant detrimental effect
on soils, waters, or benthic organisms. Despite its size and
the vast numbers of trees killed, very little mineral soil was
exposed by burning all the organic layers. A possible reason
for this is the total thickness of the organic layers; their
lower several inches remain wet even during hot, dry summers.
Moreover, permafrost did not thaw deeper than about 29 inches,
-------
even where burning was most severe, and the entire thawed profile
remained very wet and cold. Another possible reason is that
in these forests, fuel is insufficient to produce a fire hot
enough to dry and burn the lowest duff layer. Most of the trees
are standing and little fuel is lying on the ground.
Analysis of soil did not show any reliable trend in soil
properties caused by burning. Potassium content of the duff
layer might be offered as an exception, although the differences
between burned and unburned soil are small. On the other hand,
analysis of water extracts of these soils did produce evidence
that salts and soluble organic substances are released by burning.
Burning evidently releases organics, potassium, and small quantiti
of calcium and magnesium, but these remain as soluble substances
and do not penetrate into the soil. Instead they remain in
the duff layer and are removed by runoff waters. The presence
of permafrost prevents percolation of soil waters; hence any
soluble material remains near the surface. We conclude, therefore,
that analysis of water extracts is sufficient to detect changes
in soil chemistry caused by forest fires in Alaska.
Even though there was no statistical evidence that the
fire had caused changes in the biota of the streams, there were
some indications that there may have been some early effects
from the fire. It is unfortunate that it was impossible to
collect pre-breakup samples because they would have been most
-------
88
indicative of any immediate effects of the fire. It will be
well to note that early winter samples may be the answer to
problems encountered in pre-breakup sampling.
It is also unfortunate that the entire first set of June
samples could not be collected, since indications from the
two sets not originally in the sampling schedule but collected
•at that time are that populations were lower in June 1967 than
in June 1968. Of course, this is only conjecture, since there
is only one set of samples to compare. This difference in
population could be the effect of the fire through reduction
of standing crop or possibly the inability of the organisms
to reproduce due to the time of the fire.
Chemical and soil data indicate a rise in COD and
potassium. At no time did the potassium concentrations rise
to a level that would be harmful to the aquatic organisms. On
the other hand, COD levels could have a very definite effect.
It is doubtful that the small increase in numbers of organisms
in the burned area can be attributed to the increase in COD;
however, it is possible that an increase in COD in streams
such as those studied here would be beneficial for the entire
food chain of organisms at the levels measured in this study.
Although trees were killed, even with moderate to light
burning, most shrubs remained alive and in September 1967 we
noted that most of the shrubs were growing and that the darkest
-------
89
burned areas were turning green, caused by shrubs and grasses
that had invaded the area (Figure 12). In June 1968 we noted
that over much of the entire burned area the shrub understory
was recovering and with the invading grasses {see appendix)
gave the appearance of rapid recovery from the effects of burning.
However, this did not apply to the trees killed by the fire,
which remained black, standing testimony to the eradication
of this portion of the forest community over much of the burned-
over area.
Burning appears to cause a marked increase in the brown
color of streams draining a burned-over watershed. Observations
from the air during breakup in May 1968 showed that Cement Creek
was distinctly more highly colored than was Big Timber Creek,
above the fire. This verifies the chemical data, both from
soil extracts and water samples. The significance of this increase
in soluble organics is a moot point; however, it is one established
fact that fires do cause this increase.
Erosion arising from the fire appeared to be a minor contributor
to increased turbidity during runoff after heavy rains, except
for the color. Few landslides were observed and these were
on very steep slopes that may slide whether the slope was burned
or not. Although relatively minor from the total effect standpoint,
several cat trails were observed to be contributing high silt
loads to the streams. It was only where the cat trails were
in small valleys or in the stream course that this erosional
-------
90
process was observed (Figure 13). Where these trails were in
shallow soils or on rocky ridges, erosion did not appear to
be significant.
A major contributing factor to the erosion of fire lines
is the melting of permafrost caused by removing the organic
layer in building fire lines. In deep silty soils, generally
•in the bottom of valleys, melting permafrost is the chief agent
responsible for the increased silt load arising from the fire.
Wickstrom (see appendix) observed several areas of more
widespread landslides in a portion of the burn not studied by
us. Here extensive landslides appeared to be the result of
protective cover removal by fire and not due to mechanical means
during fireline construction.
-------
ACKNOWLEDGMENTS
We wish to acknowledge the cooperation of the Bureau of
Land Management in furnishing helicopter transportation within
the fire area and several flights from Fairbanks and the fire
area for reconnaissance, and to Merric Helicopters for providing
excellent air transportation to reduce overland walking to a
minimum in difficult terrain.
-------
LITERATURE CITED
Anonymous. 1965. "Methods of Soil Analysis." Part 2. Amer. Soc.
Agron., Inc., pp. 771-1571.
ADPHA. 1965. "Standard Methods for the Examination of Water and
Wastewater." 12th Ed.
Dyrness, C. T. and C. T. Youngberg. 1957. "The Effect of Logging
and Slashburning on Soil Structure." SSSAP, 21:444-447.
Frey, Paul J. 1961. "Effects of DDT Spray on Stream Organisms in
Two Mountain Streams in Georgia." U.S. Fish & Wildlife Service,
Special Sec. Dep. Fish No. 392.
Jenkins, David and Lloyd L. Medsker. 1964. "Brucine Method for
Determination of Nitrate in Ocean, Estuarine and Fresh Waters."
Anal. Chem; 36:610.
Klemmedson, J.O., A.M. Schultz, H. Jenny, and H.H. Biswel. 1962.
"Effect of Prescribed Burning of Forest Litter on Total Soil
Nitrogen." SSSAP, 26:200-202.
Larrimore, R. Weldon, William F. Childers, and Carlton Heckrotte.
1959. "Destruction and Re-Establishment of Stream Fish and
Invertebrates Affected by Drought." Trans, of the Amer. Fish.
Soc., 88:261-284.
Lutz, H.J. 1956. "Ecological Effects of Forest Fires in the Interior
of Alaska." USDA Tech. Bull. No. 1133, p. 121.
Macon, T.T. 1963. "Freshwater Ecology." John Wiley & Sons, Inc.,
New York, N.Y., p. 338.
Murphy, J. and J. P. Riley. 1962. "A Modified Single Solution Method
for the Determination of Phosphate in Natural Waters." Anal.
Chem. 27:31-36.
Scotter, George W. 1963. "Effects of Forest Fires on Soil Properties
in Northern Saskatchewan." Forestry Chronicle, 39:412-421.
Sweeney, James R. and Harold H. Biswell. 1961. "Quantitative Studies
of the Removal of Litter and Duff by Fire Under Controlled
Conditions." Ecology, 42, 572-575.
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94
Tarrant, Robert F. 1966. "Effects of Slash Burning on Some Soils
of the Douglas Fire Region" SSSAP, 20:408-411.
Wright, H. 1966. "Loss of Nitrogen from the Forest Floor by
Burning" Forestry Chronicle, pp. 149-152.
-------
APPENDIX
-------
FIRE Y-34
FIRE RECOVERY, MATER POLLUTION & EROSION OBSERVATIONS
June 6, 1968
by
Jerry C. Wickstrom,
Bureau of Land Management
Fairbanks District
Assisted by
Dr. Leslie Viereck,
Forest Science Laboratory
University of Alaska
-------
FIRE Y-34 FIRE RECOVERY, WATER POLLUTION AND EROSION STUDY
On June 6, 1968 a trip was made by helicopter to the area of
Fire Y-34 for the purpose of orientation of PSC and Forest Science
Lab personnel as well as to establish transects and photo points.
Present for the trip were myself, Jerry Wickstrom, Fairbanks District
Wildlife Specialist; Glenn Lipscomb, PSC; Jim Hagihara, PSC; and Dr.
Leslie Viereck of the Forest Science Lab at the University of Alaska.
General observations of the fire found that erosion activity
was at that time becoming active. The large erosion channel on the
west side of the fence which was examined in the fall of 1967 was
dumping a large stream of muddy water into the Dennison River.
Cat lines on the east side of the fire in the Liberty Creek
drainage were the most active, although temperatures were not
yet high enough to actively thaw permafrost along the erosion
channels. Numerous slides were observed to have occurred on
severely burned areas of the fire—especially on the Liberty
Creek side. Most of these were the result of natural thawing
and slippage as a result of the fire and not mechanical disturbance.
One large slide on the east side of the fire was initially started
by minor tractor disturbance. This was observed to be starting
in the fall of 1966 at which time the tracks of the cat were
still visible at the head of the slide. The cause of this slide
is no longer apparent.
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100
Vegetation was continuing to come in strong except for
cat lines. The lower two-thirds or more of most slopes were
heavily covered with sedges, grasses (Calamagrostis) and eriophorim.
Intermixed with the grass and sedges were blueberry, cranberry
(Vac. Vitis-idea), dwarf birch, willow and ledum.
On the highest slopes and ridges above 2500 feet, revegation
of blueberry, ground cranberry, dwarf birch and willow was just
beginning. On severely burned areas and cat lines, no revegetation
was noted. In addition to the resprouting shrubs, small mosses
such as Polytrichum are beginning to appear, as well as Epilogium,
scattered fescues and Calamagrostis grasses and, infrequently,
various forbs. One common plant—crowberry (Empetrum nigrum)--
was not noted to have sprouted at any location examined.
It was hoped to establish many more transects and photo
points than the six that were accomplished; however, it was
found to be quite time consuming to locate representative sites
and then establish and read the transects. The transects and
photo points that were established are accessible with some
effort without a helicopter; however, if future observations
of this burn are made, it will probably continue to be most
expedient to utilize a helicopter. The transect and photo point
locations are shown on the 1-inch-to-the-mile map. See also
Illustration #1 for transect layout diagram.
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101
During the summer of 1968 additional flights were made
over the area and persons familiar with the area were questioned
concerning the water quality of the Forty Mile River. It was
observed that after a rain period or heavy rainfall, the Forty
Mile River was turned as brown as the Tanana with silt pouring
in from eroding cat lines and from the burn itself. Outside
the fire area, the Dennison, the West Fork of the Dennison,
the Mosquito Fork, Dewey Creek, Walker Fork and Liberty Creek
remained completely clear or became only slightly off-color
during these periods. Mr. and Mrs. Bob McComb of South Fork
Lodge, long-time residents of the Chicken area, stated that
the water quality of the Forty Mile River was worse at times
than they had seen during days of active mining. The McCombs
have used Forty Mile River water for domestic purposes for years;
however, since the fire, sediment has been so heavy on occasion
that the water is scarcely usable.
Walker Fork of the Forty Mile River, which borders the
fire on the east, is another clear water stream which exhibits
extreme muddiness during periods of rainfall. This stream borders
a BLM campground and was never observed to be muddy at any time
before the fire, according to information that could be gathered
from local residents and from personnel and other BLM observations
of this stream previous to the burn. Starting from the campground,
a fire line was cut up the valley approximately 2-1/2 miles to
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102
the burn. This line is severely eroded and was actively dumping
sediment into Walker Fork in 1968. Liberty Creek, which dumps
into Walker Fork, also carries a heavy load of silt during runoff
periods.
As a result of observation on this fire and on others on
which 1 participated in control operations, I have come to the
conclusion that much of the damage caused by erosion as a result
of control methods is unnecessary and could be prevented through
adoption of some simple guidelines for cat line construction
and rehabilitation. Erosion can be prevented or lessened on
permafrost areas, steep slopes and loess materials by doing
the following:
1. Put cat lines on ridges, not in drainage bottoms. Even
if the bottom is dry, it may not be the comnon situation. The
most active erosion occurring on V-34 is the result of a cat
line in a drainage bottom. The small stream in the bottom was
dry in 1966, but now, .especially in spring, it runs strongly
and has transferred its path into the cat line, which is rapidly
eroding and dumping silt into the Forty Mile River.
2. Construct cat lines on ridges and slopes in such a manner
as to prevent water from running more than 30-50 yards. Methods
of constructing line on permafrost to prevent erosion are shown
in Illustration #3. Standard water barring will not work on
permafrost ground.
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103
3. Construct standard water bars on non-permafrost areas.
These will be sufficient in most cases to prevent erosion.
4- Halt all cat line construction at least 50 feet and
preferably 100 feet from the edge of all lakes and streams
(Illustration #3). Timber in the remaining strip can be walked
or cut down, burned out or a hand line cut through if necessary.
Stream banks have been areas of extreme erosion in the past.
5. Seed the critical areas on the cat lines with adapted
species such as Polar Brome, meadow foxtail, or bluegrass.
This can be accomplished by crews who are patrolling the fire
line. Seeding rate should be 15-20 lbs. per acre or to 1/4
mile of 33-ft. cat line. It would also be a good idea to
apply 10-20-20 fertilizer at a moderate rate if possible.
Planting of grasses should not in most cases be carried out
past the middle of August.
If seeding cannot be accomplished at the time of the
fire, it should be delayed until probably late April or early
May of the following year and then seeded by helicopter.
6. Rehabilitate cat lines if at all possible while heavy
equipment is on the fire. If preventive work is not accomplished
immediately, the lines will be too soft to work on until freeze-
up in October. Trial rehabilitation efforts were started on
fires 0-E-7, Z-40, and Z-76 at Chicken in September 1968 using
the method shown in Illustration #4. It was found that the cat
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lines were much too soft to operate on and work was postponed
until after freeze-up. The principle to be employed on post-
fire rehabilitation of critical areas involves pushing the berm
across the line at 35- to 50-yd. intervals, depending on slopes.
Seeding is planned to follow on these areas in the spring of
1969. Inasmuch as this has been planned as a trial effort,
a number of variations in seeding and barrier construction will
be tried and evaluated during the next year.
Conclusion
It is my conclusion that Fire Y-34 has destroyed approxi-
mately 200,000 acres of good to excellent caribou winter range.
It is now rapidly revegetating itself, following the general
vegetative ecological succession pattern as outlined by Lutz
(1956). The amount of potential moose range created is felt
to be minimal and a poor trade for the caribou range lost.
From observations of this fire during its course and for two
years afterward, it was observed that:
(a) revegetation starts inmediately on the lower slopes and
wetter areas with the sedges, fire weeds and willows beginning
to sprout almost immediately.
(b) In the fall following the fire, these foregoing species and
grasses will be strongly prevalent on at least the lower 1/3 of
all slopes.
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(c) Revegetation in the upper slopes and ridges can be
expected to begin to occur in the second season following the
fire, especially Calamagrostis grass, dwarf birch, Vaccinium
Vitisidea and Vaccinium uliginosum, and Epilobium.
(d) Severely burned areas will not show any revegetation
by two years following the burn.
(e) Cat lines can be expected not to start any meaningful
revegetation within two seasons of the fire. On the wetter
lines when erosion was not active, a scattered growth of very
small mosses wajs apparent in the fall of 1968.
Cf) Erosion can be expected to start almost immediately
on cat lines on permafrost areas and be especially active for
the first two seasons following from the permafrost melt and
intermittently active thereafter as the result of light to
moderate rainfall.
(g) Erosion on cat trails probably is not serious on over
10% of the total lengths.
(h) Considerable slippage, leaching, slides and erosion
channels develop on severly burned slopes without mechanical
disturbance. In many cases the silt from such erosion does not
reach drainage waters because of the isolated pattern of slip-
page and the vegetal debris Interrupting its flow.
(i) Cat line erosion has contributed significantly to the silt-
ation of formerly clear streams.
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(j) Prevention of cat line erosion is possible if the pro-
cedures outlined in this report ary followed in fire line
construction.
(k) Rehabilitation of cat lines is felt to be possible.
Final analysis of current rehabilitation work will give a
basis for judgment and decision on procedure.
(1) Intermittent studies of this fire should be continued
to actually determine the ecological succession rates of
lichens. Complete aerial photos of the area are available,
which will enable later reference as to location, degree
of burn and general vegetative type present at the time
of the burn.
(m) Continued studies should be made on the rate of erosion
progress and recovery of the fire. The current Alaska Water
Laboratory study and report should give a good indication of
what has happened to water quality.
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FIRE Y-34
WATER POLLUTION-FIRE ECOLOGY STUDY (SEPTEMBER 1968)
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FIRE Y"34
WATER POLLUTION-FIRE ECOLOGY STUDY (SEPTEMBER 1968)
The third scheduled sampling period for the water pollution
study was completed on the Chicken burn the week of September
12-15, 1967. Persons taking part included Dr. Fred Lotspeich,
Ernst Mueller and Paul Frey of the Alaska Water Laboratory,
and Jerry Wickstrom of the Bureau of Land Management. This
sampling was actually the first complete sampling, since biological
sampling was also completed. No biological samples had been
taken in the previous spring sampling, and the second sampling
period in June was cancelled because of the fire outbreak. In
addition to the sampling, some time was available for general
observation by the Wildlife Specialist of vegetative recovery
of the burn and effect of erosion on the burn.
Originally, it was planned to continue the project two
more days to provide the time to study the vegetative aspects
of the area and establish some plots, transects, and photo points.
Water flow measurements were also to have been taken by the
University of Alaska Water Institute. Members of the Alaska
Department of Fish and Game and the Forest Science Laboratory
were unable to take part in the study, as originally hoped for.
None of this extra study was accomplished because of the
mechanical failure of the helicopter on September 15, which caused
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it to be crash landed on the south side of the Dennison River
near South Fork Lodge, with moderate damages.
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Observations
During the course of the water study, most of the cat lines
on the north side of the fire were flown over. Vegetative recovery
of these lines has been slight. The only vegetation present
are patches of very small mosses. Most of the lines cut in
the bottoms along the contour line are very wet, with water
standing in much of the swath. Little erosion has occurred on
these areas or on the higher ridge sites, which are for the
most part rocky and dry. Some slumping has occurred on the
trails crossing permafrost areas in the bottom. Severe erosion
has occurred on creek banks at crossing points and on trails
on the north slopes that cut across contour lines.
Some erosion observed was already 5-15 feet deep and 5-
20 feet wide and over a mile long. This is coming about because
of the melting of the ice lenses and permafrost and the active
erosion of the melted water, plus the natural drainage waters
of the slopes. It is likely that such erosion is now uncorrectable
and that erosion will continue to increase until the sides slump
to a natural angle of repose or until bedrock is reached. In
some spots, bedrock has already been exposed; however, in other
places the overlying soil, composed primarily of loess, may
be 50-100 feet deep.
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Little erosion was noted in the burn where mechanical disturbance
had not occurred. There was some weeping of silt on burned
sedge-black spruce slopes where the fire had burned intensely.
Severe erosion was noted by other BLM personnel near Walkers
Fork, and erosion involving large portions of hillsides has
been observed, starting in the fall of 1966 when the first examination
of the fire was made. These two areas were not examined on
this trip, because of the helicopter failure.
It does not appear that severe erosion is occurring on
or over 10% of the total length of cat trails; therefore, it
is felt that prevention or prompt correction of a similar situation
is feasible.
Vegetative recovery on the burn has been rapid on parts
of the burn itself, but very slow on the cat lines. On the
burn, recovery has been rapid in the bottom and lower half of
the slopes, but negligible on the ridge tops and upper drier
slopes.
Sedge and grasses are coming back in well and provide 50%
or more covering on the wetter slopes. Willow (believed to
be Sebb) has returned very well and in some locations it is
estimated that a willow plant or sprout occurs on approximately
every 10-20 square feet. These plants were very obvious from
the air because of their yellow green color. Plants have sprouted
to maximums of 20 inches. Tom Paine drainage, which was uniformly
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burned over Its entire area, appears very green with regeneration
of sedges, grasses (Calamagrostis) and willows. Other species
noted that have reappeared are Ledum and dwarf birch.
The 53 Mile Taylor Highway burn of the early 19501s was
flovjn over to evaluate the vegetative recovery of an area similar
to Y-34. It was originally intended to land and make a close
evaluation of this burn; however, this could not be accomplished
because of the helicopter failure. From the air, the Taylor
Highway burn appeared to be completely covered with vegetation--
mainly grasses, sedges, and shrubs. Trees that have come back
on this site are made up, it appears almost entirely of aspen
and birch; little willow was noted.
Recommendations
It is recommended that the study be continued next spring
to complete the ecological and erosion observations not completed
this fall.
In the future, cat trails on north slopes or following
drainages should be covered following the fire with the old
vegetative material scraped aside. This may not be possible
in the case of an early fire. If the trail is not covered, erosion
will proceed so rapidly that preventive measures will have little
chance of success.
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It is recommended that plans be investigated by fire control
to alter control methods in permafrost areas, north slopes and
bottom areas so that erosion is prevented. Methods must also
be investigated as to the feasibility of erosion prevention
on cat trails that must be cut on permafrost areas. This is
especially important in stream bank areas where trails enter
river bottom.
The best time to engage in rehabilitation work is while
the trail, construction of water barriers, covering limited
areas with straw mulch or wood chips, and seeding. The last
solution is probably suitable for only limited areas such as
stream banks.
Attached to this report are a number of pictures showing
erosion damage and vegetative recovery. Most of these pictures
were taken in the small drainage in Sections 1 and 12, T 25
N., R. 17 E., CRM, and Section 7, T 25 N., R. 18 E., CRM (see
attached map). It is planned to establish a permanent measurement
system on this erosion area to measure the rate at which it
proceeds and stabilizes.
As use of heavy duty equipment increases, there will be
increasing occurrence of erosion with destructive effects on
fisheries and stream values because of the silting. Potential
cures or preventatives for the problem are needed. The problem
occurs not only on fire cat lines, but on other trails used by
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the Army, miners, and hunters. Permanent scars and vegetative
changes result in the disturbed areas and it is likely that
some type of regulation will be necessary to protect fragile
areas. The BLM should take the lead in preventing or correcting
such damage caused by cross country travel or fire control activities.
Note: The illustrations, maps and photographs which Mr.
mentions are not included here, but are available at the
office of the Bureau of Land Management.
Wickstrom
Fairbanks
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