9E. 10, NO. 5
WATER RESOURCES RESEAR
PLEASE DO NOT REMOVE FROM
FILES
The Biochemical Oxygen Demand of Finely Divided
Logging Debris in Stream Water
STANLEY L. PONCE'
School of Forestry, Oregon State University, Corvallis, Oregon 97331
The impact of Douglas fir needles and twigs, western hemlock needles, and red alder leaves on dissolved
oxygen and thus on the quality of mountain stream water was examined. • The mean COD, 90-da' BUD,
and BOD rate coefficients were, respectively. 454 mg 0 2 /g, 110 mg 0 2 /g, and 0.125 for Douglas fir
needles, 947 mg 0 2 /g, 110 mg 0,/g. and 0.056 for Douglas fir twigs, 570 mg 0 2 /g, 200 mg 0 2 /g. and 0.049
for western hemlock needles, and 882 mg 0 2 /g, 286 mg 0 2 /g, and 0.047 for red alder leaves. The 90-day
values of BOD and A', for the leaf material could be estimated accurately by tests of 20. 20. and 60 days,
respectively, for Douglas fir needles, western hemlock needles, and red alder leaves. The BOD of leaf
material exposed to fluctuating temperature exerted a 5-day BOD 4.0, 2.4, and 4.2 times greater than the
standard temperature BOD, for Douglas fir needles, western henilock needles, and red alder leaves,
respectively. Toxicity of a leachate extracted from each species was determined on guppies and steelhead
trout fry. The concentration of material needed to produce toxic effects s■ as very high, so high. in fact.
that oxygen depletion probably would be responsible for death long before the leachate effect. Data on
oxygen depletion obtained in this study will be useful in developing a predictive model for water quality
management on forested lands.
The economy of the Pacific Northwest has been built
around water and timber resources of the region. Small
streams originating in timbered coastal watersheds serve as
prime producers of anadromous salmon and trout. Growth,
development, and survival of the young fish produced in these
streams are related to quality of the aquatic environment in
which they reside. The quality of this aquatic environment, in
turn, is dependent upon the management practices applied to,
and the condition of, the adjacent terrestrial environment.
The principal timber species of the region is Douglas fir, and
to a lesser extent, western hemlock and red alder. West coast
Douglas fir, because of its regeneration and growth
characteristics, is harvested by clear-cutting. A common
byproduct of clear-cut logging, as well as other timber
harvesting techniques, is slash, which is composed of limbs,
branches, and needles or leaves of trees. Often this material is
deposited directly in stream channels. In general, large
material is removed. Finely divided material, however, such as
needles, leaves, and broken twigs, often remains. This material
may be responsible for the reduction in dissolved oxygen (DO)
concentration.
Recent field and laboratory studies indicate that tree foliage
is subject to biological oxidation. Chase and Ferrullo [1957]
studied the effect of autumn leaf fall on oxygen concentration
in lakes and streams. They reported that after 1 yr, maple
leaves demanded about 750 mg 0 2/g of their initial dry
weight, but oak leaves and pine needles required about 500 mg
02/g of their initial dry weight. The oxygen uptake was rapid;
by day 100, maple had achieved about 70%, and oak and pine
had achieved about 55% of the demand exerted in 1 yr.
Slack and Feltz [1968] examined the effect of leaf fall on
quality changes in a small Virginia stream. They reported no
significant change in oxygen consumption due to leaf fall as
the rate increased from 0 to 2 g/m 2 day -1 . As the rate increased
from 2 to 12 g/m 2 day-', however, there was a corresponding
drop in oxygen concentration from 8 to less than 1 mg/I. Upon
' Now at the Department of Forest Sciences, Utah State University,
Logan, Utah 84322.
Copyright © 1974 by the American Geophysical Union.
natural flushing by a storm event the DO responded by climbing to a level greater than 11 mg/I.
Hall and Lantz [1969] reported the effects of logging on
habitat of coho salmon and cutthroat trout in coastal streams
of Oregon. Two small watersheds were studied, one completely clear-cut and the other patch-cut with buffer strips, and
compared with a third watershed that served as a control. Felling on the clear-cut watershed began in the spring. Timber was
felled along the stream, and logs were yarded uphill by cable
across the stream to landings. This practice resulted in the accumulation of a considerable quantity of debris, limbs. twigs,
needles, and bark in the channel, which restricted flow and
formed pools. The large material remained in the channel
throughout the summer. In early fall the channel was cleared
of the large material to permit free flow.
A substantial reduction in the DO concentration w as
observed in surface and intragravel waters of the clear-cut
watersheds. DO concentrations from late spring through most
of the summer were too low to support salmon and trout in
one third of the stream available to the salmonids; juvenile
coho salmon placed in live-boxes there survived less than 40
min. The lowest oxygen concentration reported, 0.6 mg/1, w as
observed in a pool resulting from a darn composed of debris.
During this period, oxygen concentration of the control
stream and the stream draining the patch-cut watershed
remained at levels near saturation. Upon removal of large
debris from the channel and establishment of free-flowing conditions the DO concentration rapidly returned to near prelogging conditions in the surface water. Intragravel ox\gen
concentrations, however, remained about 3.0 mgil lower than
the prelogging concentrations for the next 2 yr and continued
to decline over the next 4 yr to levels less than 2.0 nig/I at
several locations.
It is apparent that finely divided logging material may be
responsible for severe oxygen deficits within a small stream
system after deposition in a stream by poor logging practices.
Although such changes have been observed, no quantitative
information describing the potential for oxygen extraction by
decomposition of logging slash typical of the Pacific
Northwest has been reported.
983
PONCE: POLLUTION FROM LOGGING WASTES
984
TABLE 1. Mean BOD of Different Concentrations of Douglas
Fir Needles as a Percentage of the Mean BOD of the 4
Grams per Liter Concentration
Time, days
Concentration
2
4
6
8
10
2.1
4.1
8.2
16.4
113
100
275
413
48
100
148
164
52
100
163
133
54
100
129
110
54
100
118
104
The purpose of this study was to quantify the impact of
Douglas fir (Pseudotsuga menziesii [Mirb.] Franco) needles
and twigs, western hemlock (Tsuga heterphylla [Raf.] Sarg.)
needles, and red alder (Alnus rubra Bong.) leaves on dissolved
oxygen and thus on the quality of mountain stream water.
The study, conducted in the laboratory, consisted of four
principal components. First, to define the total quantity of oxygen required for complete oxidation, the chemical oxygen
demand (COD) was determined for the material. Second, an
experiment was performed to determine whether the BOD exerted by Douglas fir needles under standard temperature conditions was related directly to the mass of vegetation in the
sample water. Third, to quantify the amount of oxygen required by microorganisms and the rate at which it was used,
long-term (90-day) biochemical oxygen demand (BOD) was
determined for the material. A 5-day BOD was also determined by using simulated stream conditions in which the
temperature was fluctuated daily. Fourth, toxicity of material
leaching from debris into stream water to guppies (Poccilia
reticulata) and steelhead trout (Salmo gairdneri gairdneri)
fingerlings was determined. The toxicity test defined the direct
toxicity of the leachate to fish under test conditions.
M ETHODS
Sampling methods. The stream water used in this study was
obtained from a typical stream in the Oregon Coast Range.
It was assumed that this water supported established
microorganism populations that would consume the test
material. As a result the stream water served as the sole source
of seed in the BOD experiments.
The vegetation sampling procedure was determined experimentally to eliminate sampling bias because of differences
in tissue chemistry in leaves of different ages from different
parts of the tree crown. As a result of these preliminary experiments, all vegetation was taken from the lower one third of
the crown. Douglas fir and western hemlock needle samples
were composed of a mixture containing an equal number of
needles from north and south crown aspects of three different
trees in proportion to their average number in each age class
(H. G. Smith, personal communication, 1970). Red alder
leaves were taken at random from three different trees.
Douglas fir twigs were taken from north and south crown
aspects of the lower one third of the crown from three different
trees. Twigs of different ages were not mixed, but instead,
first-, third-, and fifth-year age classes were formed. Twigs
within each age class from different trees were mixed, however.
The form of vegetation used in the following experiments was
as follows: whole Douglas fir and western hemlock needles
and red alder leaves cut into 2-cm segments and quartered
longitudinally.
Analytical methods. Values for COD were determined by
the rapid COD method described by Jeris [1967].
The mass concentration dependency of Douglas fir needles
was determined by the Hach manometric technique [Hach
Chemical Company, 1971]. Proportional concentrations of
needles were placed in the test containers:
The long-term standard temperature BOD of the material
also was determined by the Hach manometric technique. A
concentration of about 4 gm/I was used in the test containers.
The test was run 90 days for leaf material and 45 days for
Douglas fir twigs. To differentiate between carbonaceous and
nitrogenous BOD in leaf material, half the samples were
treated with an equivalent of 10 mg/1 of 2-chloro-6(trichloromethyl) pyridine to inhibit nitrification.
The 5-day fluctuating temperature BOD test with leaf
material was performed in a water bath in which the water was
agitated continuously. The values for BOD were determined
by standard dilution technique [American Public Health
Association, Inc., 1971]. The temperature range and cycle
selected were 12.8°-35.0°C over an 8-hour period, followed by
a drop from 35.0° to 12.8°C over the next 16 hours. This
temperature pattern replicated values observed in clear-cut
watersheds of the Oregon Coast Range [Brown and Krygier,
1970].
Toxicity of the various leachates to guppies and steelhead
trout fry was determined on the basis of 24-, 48-, 72-, and
96-hour tests and expresed as median lethal concentration.
(LC50). The 'static bioassay method,' described by the
American Public Health Association, Inc. [1971], was used in
these tests. Leachates used were derived from vegetation
placed in water poisoned with 2.0 mg He'll as HgC1 2 over 5
days. He* was removed from the solution with a chelating
compound before proceeding with the bioassay. Poisoning and
depoisoning procedures followed in this test were developed
by Schaumburg [1971].
TABLE 2. Cumulative Standard Temperature BOD Exerted in
Milligrams of 0 2 per Gram (Dry Weight) by Douglas Fir,
Western Hemlock, and Red Alder Leaves in Stream Water
Time, days
Bottle
No.
5
10
20
45
60
90
80
128
140
82
108
82
133
144
82
110
82
145
150
.82
115
192
194
170
79
159
197
197
176
79
162
202
197
178
79
164
220
278
216
278
248
266
278
262
289
274
282
278
278
309
287
8
10
10
9
10
10
22
14
10
10
22
14
Douglas Fir Needles
1
2
3
4
Mean
71
59
71
50
63
6
7
8
9
Mean
34
40
40
30
36
76
124
70
68
84
11
12
13
14
Mean
77
81
79
79
79
108
152
121
126
126
5
10
15
Mean
0
0
0
0
0
74
81
106
51
78
74
120
134
78
102
Western Hemlock Needles
132
175
99
68
118
Fed Alder Leaves
5
5
2
148
216
156
174
174
Controls
5
5
8
6
985
PONCE: POLLUTION FROM LOGGING WAS1ES
TABLE 4. Mean Cumulative BOD Exerted in milligrams of 0 2 per
Gram (Dry Weight) by Douglas Fir and Western Hemlock
Needles and Red Alder Leaves Under Conditions of
Temperature Fluctuation
RESULTS
COD test. The COD test consisted of three replications for
each material. Replications for each leaf treatment as well as
those for the Douglas fir twigs were averaged. Mean values for
Time, days
COD on a dry-weight basis were 454 mg 0 2/g for Douglas fir
Vegetation
needles, 947 mg 02 /g for Douglas fir twigs, 570 mg 0 2 /g for
4
3
5
2
1
TYPO
western hemlock needles, and 882 mg 0 2/g for red alder
leaves.
187
131
202
51
67
Douglas fir
Mass concentration BCD test. Results of the mass concen- Western hemlock
104
88
109
29
60
219
249
191
136
77
tration BOD test are presented in Table 1, which summarizes Red alder
12
7
12
5
5
the mean BOD of Douglas fir needles in percent in relation to Controls
the 4.1-g/1 concentration used in the standard temperature
BOD tests. The 2.1-g/1 concentration show ed a proportional species the mean values for 5 days (BOD E ) represent only 54,
drop in the BOD, about one-half the BUD of the 4.1-g/I 21, and 27% of the BOD90 values for Douglas fir, western
concentration from day 4 to 10. On the other hand, higher hemlock, and red alder, respectively. The value for BOD.5
concentrations did not produce a proportionate increase in within each species represents about 90% of the value for
BOD. Initially, values of BOD for 8.2- and 16.4-g/1 concen- BOD2o.
trations were significantly greater than BOD for the 4.1-g/I
Results of the BOD test for Douglas fir twigs are given in
concentration, but as time progressed, BOD exerted by the Table 3. The first-year twigs exerted the greatest BOD over 45
higher concentrations approached the values for the 4.1-g/I days, slightly more than 13% of their dry weight. Third- and
fifth-year twigs followed with a BOD,, equal to 9.3 and 7.8% of
concentration.
Although BOD of the 8.2- and , 16.4-g samples did not re- their initial dry weight. The BOD, was equivalent to about
main 2 and 4 times higher than BOD of the 4.1-g sample, BOD 25% of the BOD., for all age classes, but the value for BOD2O
exerted by the 4.1-g/I concentration probably was not mass was equivalent to about 65% of that for third- and fifth-year
concentration dependent. At concentrations greater than 4.1
twigs and about 90% of the value for first-year twigs.
g/1, however, mass concentration dependency may occur and
A test for NO, - in the Douglas fir twig samples was also
thus limit the BOD exerted by the material per unit time.
performed. No NO, - nitrogen was found in either the control
or the sample solution.
BOD test. Results of the standard temperature BOD test
Results of the 5-day fluctuating temperature BOD test are
with leaf material are given in Table 2. Table 2 is composed of
given in Table 4. In 5 days, red alder leaves exerted an oxygen
samples treated with the nitrification inhibitor (bottles 3, 4, 8,
demand equivalent to 23.7% of their initial dry weight, but
9, 13, 14, and 10) and samples that were untreated. It is evident
that there is little difference between BOD exerted by the Douglas fir and western hemlock needles exerted a demand
treated and untreated samples, an indication that nitrification equivalent to 19.0 and 9.7%, respectively, of their initial dry
either was not inhibited or did not occur.
weights.
To determine quantitatively whether nitrification took
Leachate toxicity. The concentration necessary to kill half
the initial fish population (LC;0) from the leachate of a 50-g
place, all solutions in test bottles were examined for nitratenitrogen by the Brucine method [American Public Health (fresh weight) sample of vegetation placed in a liter of water
was determined by bioassays. Results are given in Table 5.
Association, Inc., 1971]. In all instances the mean NO,--N
Guppies generally were more tolerant to the three leachates
concentration of NO,- nitrogen in control bottles 5 and 15
was greater than the concentration observed in any of the than trout; the 96-hour LC50 for guppies in Douglas fir,
samples, whether treated with inhibitor or not. There was also western hemlock, and red alder leachate was 35, 65, and 18%
little variation between NO,- nitrogen values of different by volume, as compared with 26, 7.5, and 24% by volume for
treatments within a species. It was assumed from these results trout.
Douglas fir and western hemlock leachates in the steelhead
that nitrification did not occur in any of the leaf samples run at
standard temperature. Thus results for each of the four trout bioassay were not treated with HgC1 2 to examine the
possibility of mercury poisoning (Table 5). It can be concluded
replications for each species were combined, and the mean was
from these data that sufficient mercury was removed from the
calculated for each time period.
leachate of red alder by the chelating compound. Toxicity
Several trends are apparent upon examination of the mean
values given in Table 2. Douglas fir and western hemlock values for Douglas fir and western hemlock are of the same
needles exert a 90-day oxygen demand 40 and 57% less than order of magnitude as those for red alder. In addition, fish in
that of red alder leaves over the same period. Within each the poisoned alder leachate would have been killed very
quickly if mercury had been present in sufficient quantities. As
Douglas fir and western hemlock leachates were not treated
TABLE 3. Mean Cumulative Standard Temperature BOD Exerted
in Milligrams of 0 2 per Gram (Dry Weight) by First-, Third-,
with HgC1 2 to inhibit microorganism decomposition of the
and Fifth-Year Douglas Fir Twigs in Stream Water
leached substances, the LC50 values may be high.
DISCUSSION
Time, days
Twig Age
First year
Third year
Fifth year
Control .
5
10
15
20
30
45
39
21
18
1
74
37
31
89
48
39
1
116
62
48
1
127
81
63
1
132
93
78
1
Results of the mass concentration dependency test with
Douglas fir needles under standard temperature conditions
were of particular importance. This test examined the
possibility that high concentrations of material may inhibit the
rate of nutrient transfer by diffusion into stream water or may
be toxic to aquatic microorganisms. It was concluded from the
986
PONCE: POLLUTION FROM LOGGING WASTES
00
TABLE 5. Percentage Dilution of Leachate From 50 Grams of
Leaves per Liter of Water to Result in LCSO for Guppies
and for Steelhead Trout Fry
0
00
E
0 .0.0 •
^^0 CO •
44 44 C y •
4-
a
C
O
Time, hours
48
24
Vegetation Type
72
96
C-
-0
Douglas fir needles
Western hemlock needles
Red alder leaves
Guppies
78
59
30
Steelhead
Douglas fir needles*
Western hemlock needles*
Red alder leaves
Trout
26
7.5
27
66
42
18
65
35
18
65
35
18
0
Fry
26
7.5
24
10 Q N
V. •
4.4c 0
•
000
C
0
26
7.5
24
26
7.5
24
00
0
0
r- 1
a
0
C
u
0
0
a
0)
■-■
results (Table 1) that the 4.1-g/1 concentration used in the
BOD tests probably was not mass concentration dependent. In
other words, the BOD defined by the long-term tests using the
4.1-g/I concentration may be considered to be an accurate
representation of the maximum BOD that Douglas fir needles
would exert under such conditions.
Concentrations greater than 4.1 g/1 may be mass concentration dependent. The implication of such a condition on the
BOD test per unit mass would be a lower 90-day demand and a
lower reaction rate coefficient.
Values for BOD were of primary concern in this study.
Initial results were presented earlier (Table 2). Because
nitrification did not occur in standard temperature samples,
the four replications within each species of the leaf samples
and the three replications within each age group of Douglas fir
twigs were combined. Composite curves for BOD were constructed through • these data by using a least squares fit. It was
assumed that the data followed a first-order process that may
be expressed mathematically as
y = L(1 - Kit)
(1)
where y is the oxygen demand in milligrams per gram at time t,
t is the time in days, K i is the reaction rate coefficient (base e)
in liters per day, and e is the base of natural logarithms
(2.71828).
The composite curves for BOD were constructed by using 90
days of data and also usin g data for shorter time intervals but
extended to 90 days. The 90-day BOD was chosen as the ultimate BOD-exerted value L because it is representative of the
average time interval between spring runoff and fall freshets.
This is the period when logging debris is most likely to accumulate in small streams of logged watersheds in the Pacific
Northwest. Curves fit through shorter time intervals and extended to 90 days serve as a prediction of the ultimate BOD.
The prediction curves may be considered in much the same
manner as the 5-day BOD that is used to estimate from 60 to
80% of the ultimate demand for sewage wastes.
The reaction rate coefficient was determined by solving (I)
for K,:
K, = (In L — In L t )/1
'
0
N M 40
t,40
1 •
44 CD CD ••
000
0
.0
4-■
00
0
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n cc C
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11..
-o
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C
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In 0.
-0
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—1 +4
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c
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c c cc
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be
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CD
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00
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m1
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M F-4
X X 44 ../1
C. 440
. .
N •-•
ro
4 4
1 1
4
0 0
0
6■1
X XN X
CD 00 N 00
M +0 0 V'
•
iO
C
= •
o
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0o
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o
o
CC
0 0
co cc
0)
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4, 4,
E
4 ,M
a
0
0
0w
4
0W
.■
o / =
0
0
ul 0.0
0)> 3
4.,
6' '6'
(2)
where L, = L — y.
Values of K, and L for selected time intervals are summarized in Table 6. Red alder leaves exerted the greatest oxygen demand over 90 days, 28.6% of their initial dry weight,
CI •
a
ro
*These samples were not treated with HgC12.
00N OD •
0 .0 .0 •
•
4-■
t.
0)
'4'4
0 a .0, o
0 0W0
C S be c
,
;'
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4,
'0 0
41
00
4, 4,
ID
0 0)
4.
0
44 4+
00
CC
*
+-
P ONCE: P OLLUTION F ROM L OGGING W AS"! FS
I
300
I
DOUGLAS FIR
20- DAY FIT
30% ENVELOPE
2
0N
0
200
.......
0
0
co
100
/
•
7 =C
CONTROL
—1
20
40
60
80
TIME, DAYS
Fig. 1. The best-fit BOD curve with a 30 q envelope fit over 20 days
through the composite data for Douglas fir needles.
followed by western hemlock and Douglas fir needles, which
exerted 16.6 and 11.0% of their initial dry weights, respectively.
Douglas fir needles have the highest reaction rate coefficient,
0.125, which is about 2.0 and 2.5 times greater than those for
western hemlock needles and red alder leaves, respectively.
It is evident from Table 6 that the 5-day projected values of
K, and L for leaves are poor indicators of the ultimate BOD.
The ultimate BOD can be predicted accurately, however, from
a 20-day fit for Douglas fir and a 60-day lit for red alder. These
relations are illustrated in Figures I and 2. BOD curves in
Figures I and 2 are enclosed with a 30% envelope for Douglas
fir and a 20% envelope for red alder to illustrate the degree of
variation between replications.
It would seem from Table 6 that the BOD 9O of western
hemlock could he predicted accurately by the 45-day fit. Upon
observation of the data, however, it is obvious that one sample
(bottle 9, Table 2) exerted a BOD much lower than that of the
other samples. The BOD of this atypical sample was nearly
satisfied by day 10 and completely satisfied by day 40. As a
result, a different and probably more precise estimate of the ultimate BOD for western hemlock was obtained by using only
the first 20 days of data to 'construct the composite curve
(Figure 3). There was close agreement among all four samples
during this time period; deviation of the fourth sample did not
begin until after day 10. The composite curve projected from
the 20-day period estimated the BOD 9O as 200 mg 02/g; the
three similar samples were included in a 10% envelope about
the composite curve.
It is evident from Table 6 that the 5-day projected values for
Douglas fir twigs are poor indicators of the 45-day predictions
of the BOD 9O . The projected BOD„ value for the twigs,
however, is similar to the projected 45-day value and identical
to the 90-day BOD value for Douglas fir needles. The twigs
have a much lower value.for K 1 , an indication that their demand will be exerted over a longer time.
The composite curve for Douglas fir twigs is illustrated in
Figure 4. There is a high degree of variation among samples;
four of the nine samples are not included in the 30% envelope.
Seven orrlie nine samples are bunched closely and dominate
987
the shape of the curve. The ultimate demand predicted b y using the 45 days of data, however, may he slightly high because
of the effect of the two high samples.
To interpret the long-term BOD tests under standard
temperature conditions, an attempt was made to define the
quantity of sugars and polyphenolics leaching from the debris
over 90 days. Because of fungal intesference the test was terminated after 20 days and proved of little value in explaining
the BOD results. This test is discussed in detail by Ponce
[19741.
Neither the values for K, nor those for L were determined
for the BOD data collected under conditions of fluctuating
temperature. Some general conclusions, however, can be
drawn by comparing the mean values for BOD, obtained by
using fluctuated temperature with those obtained under standard temperature conditions. The standard temperature BOD,
values were taken from the best-fit BOD 9O curve through the
composite data. The mean values for BOD, of leaves exposed
to conditions of fluctuated temperature were much greater
than values of those exposed to standard conditions: 75%
higher for Douglas fir, 58% higher for western hemlock,
and 76% higher for red alder.
It is apparent from these comparisons that organic debris
exposed to conditions of temperature fluctuation in comparison with those observed in a small stream exposed to solar
radiation by clear-cutting has a much higher oxygen demand
in 5 days than the same vegetation incubated at standard
temperature.
The BOD/COD ratio was computed to obtain a general estimate of how completely the microorganisms oxidized the
material. Specific values of BOD for each species were taken
from the best-fit curves through the composite data, but mean
values for COD were used. The ratios were 0.24, 0.29, 0.32,
and 0.12 for Douglas fir needles, western hemlock needles, red
alder leaves, and Douglas fir twigs, respectively. These ratios
indicate that in all instances, less than one third of the material
was oxidized by biological agents of decomposition over 90
days. These relations provide only a general indication of the
ease with which leaves, needles, and twigs are decomposed by
■••■• • •
RED ALDER
300
MEAN /
0
200
0
co
0
c
co
60- DAY F I T
20% ENVELOPE
100
tl
CONTROL
4-0
20
40
60
60
TIME, DAYS
Fig. 2. The best-fit 130D curve with a 207c envelope tit
days through the composite data for red alder lea\ es.
er 60
P ONCE: P OLLUTION F ROM L OGGING W ASTES
988
WESTERN HEMLOCK
300
300
20- DAY
10%
FIT
ENVELOPE
—
2
t■J
0
200
MEAN
•
c0
0
0
m
1:$
I 00
•
0 200
■■
■1
0
2
0
0
to
— /
\
100
CONTROL
0
0
20
40
60
0
80
TIME, DAYS
0
20
40
60
80
TIME, DAYS
Fig. 3. The best-fit BOD curve with a 10% envelope fit over 20 days
through the composite data for western hemlock needles.
Fig. 4. The best-fit BOD curve with a 30% envelope fit over 45 days
through the composite data for Douglas fir twigs.
microorganisms. Materials containing high concentrations of
cellulose, such as logging debris, often have a highly variable
COD and thus an inconsistent COD/BOD relation.
accumulation studies are data essential to development of an
oxygen depletion model that will enable foresters to predict
on-site and downstream DO levels with time after the introduction of a known amount of logging slash. Such a model
will be a useful tool to foresters making management decisions
that may affect adversely the quality of the aqUatic ecosystem.
SUMMARY
Results of this research have provided several important
facts about COD and BOD of needles, leaves, and twigs,
nature of substances leaching from these materials, and toxicity of these leachates to fish.
Mean values of COD and 90-day BOD under standard conditions and associated BOD rate coefficients were 454 mg
02/g, I10 mg 02/g, and 0.125 for Douglas fir needles, 947
mg 0 2/g, 110 mg 0 2/g, and 0.056 for Douglas fir twigs, 570
mg 0 2/g, 200 mg 0 2/g. and 0.049 for hemlock needles, 'and
882 mg 0 2/g, 286 mg 0 2/g, and 0.047 for red alder leaves.
Further analysis showed that the 90-day values for BOD and
K, could be estimated accurately by tests of shorter duration: 2
days for Douglas fir needles, 20 days for western hemlock
needles, and 60 days for red alder leaves. The standard 5-day
BOD was a poor estimator of the BOD.o and associated K.
Nitrification did not occur in any of the standard
temperature BOD tests, and the standard temperature BOD
samples of Douglas fir needles were not mass concentration
dependent.
Leaf material exposed to conditions of fluctuating temperature exerted a 5-day BOD 4.0, 2.4, and 4.2 times
greater than the standard temperature BOD, for Dou g las fir
needles, western hemlock needles, and red alder leaves, respectively.
Toxicity of a leachate extracted from 50 g (fresh weight)/I of
water of each species was determined on guppies and steelhead
trout fry. The concentration of leachate needed to produce
toxic effects was very high, so high, in fact, that demand for
oxygen probably would be responsible for death.
Results of this study combined with reaeration and debris
Acknowledgments. This paper is a summary of an M.S. thesis cornpleted at Oregon State University. The research was supported by U.S.
Forest Service grant P.N.W. 3, 1971, and is paper 942, School of
Forestry, Oregon State University,
REFERENCES
American Public Health Association, Inc., Standard Methods for the
Analysis of Water and Waste Water, 13th ed., 874 pp., Washington,
D. C., 1971.
Brown. G. W., and J. T. Krygier, Effects of clear-cutting on stream
temperature, Water Resour. Res., 6(4). 1133-1139, 1970.
Chase, E. S., and A. F. Ferullo, acygen demand exerted by leaves
stored under water, J. N. Engl. Water l'orlss Ass., 71, 307-312,
1957.
Hach Chemical Company. Instructions for the Hach Model 2173
Manometric BOD Apparatus. 13 pp., Ames, Iowa, 1972.
Hall, J. D., and R. L. Lantz, Effects of logging on the habitat of coho
salmon and cutthroat trout in coastal streams, in Symposium on
Salmon and Trout in Streams, edited by T. G. Northcote, pp.
355-375, University of British Columbia, Vancouver, B. C., 1969.
Jeris, J. S., A rapid COD test, Water Wastes Eng., 4, 89-91, 1967.
Ponce, S. L., The biochemical oxygen demand of Douglas-fir needles
and twigs. western hemlock needles, and red alder leaves in stream
watei, M.S. thesis, 141 pp., Oreg. State Univ., Corvallis, Oreg.,
1974.
Schaumburg, F. D., A new concept in sample preservation—
Poisoning and depoisoning, J. Water Yollut. Contr. Fed., 43(8),
1671-1680, 1971.
Slack, K., and H. R. Feltz, Tree leaf control on loW flow water quality
in a small Virginia stream, Ent:iron. Sci. Technol., 2(2), 126-131,
1968.
(Received August 9, 1973;
revised May 14, 1974.)