PE EIE[R-Rg RESEARCH ON - HJ Andrews Experimental Forest

extracted was determined by the weight differences
before and after extraction .
Water soluble materials were determined in
a similar manner using boiling water .
As employed by Cowling (1961), a 1 per -
cent NaOH solubility test was used to determine
rate of cellulose decomposition .
In an effort to isolate fungi involved in the
decomposition processes needles were cultured
in two ways : A portion of each sample
was plated on 2 percent malt extract agar and
onto an antibiotic medium consisting of 2
percent malt extract agar plus 1 :30,000 Rose
Bengal and 50 p .p.m. streptomycin. A second
portion of each sample was washed in sterile
water for 2 minutes and the needles plate d
onto these same agars . The plates were incubated
at 26°C for 7 to 14 days. Isolation s
were made from the resulting fungi .
Results
Table 1.-Frequency of occurrence of
genera of fungi isolated from
needle sample s
Months
Genera
0 Phomopsis sp .
Mucor sp .
Penicillium spp .
Trichoderma spp .
Botrytis sp .
Graphium sp .
6 Phomopsis sp . 2
Mucor sp . 3
Penicillium spp . 4
Trichoderma spp . 4
Aspergillus spp . 3
12 Penicillium 4
Trichoderma spp . 4
Mucor sp . 4
1 1 = Very infrequent
2 = Infrequen t
3 = Frequent
4 = Very frequent
Frequency o f
isolation'
Discussion
Several genera of fungi have been reporte d
to exhibit the capability to utilize waxe s
(Martin and Juniper 1970) . From the data i n
figure 1 it appears that fungal action on th e
needle waxes causes these materials to be -
come more soluble in hexane after a period o f
time. There is a large weight loss in hexan e
extractables after a six month period and a
smaller weight loss after 12 months . I t
appears from this trend that during the first
6-month period, waxes are acted on initiall y
during primary processes of decomposition .
This was followed during the second 6-mont h
period by the processes of increasing solubilization
of cellulose and saccharides .
Dice (1970) reported that annual production
of organic matter for Douglas-fi r
litter is 359 kg/ha . The density data in figure
1 shows that at 12 months there is a 60 per -
cent reduction of organic matter or approximately
213 kg/ha .
The fungi listed in table 1 are being studie d
to determine what role they play in th e
physiochemical processes illustrated in figure
1 .
1 . 6
1 . 5
1 . 4
1 . 3
1 . 2
1 . 1
1 . 0
.9-
.8 /
.7 /
. 6
. 5
.4
.3
. 2
. 1
0
6 1 2
MONTHS
- DENSITY
- HEXANE ELTRACTAN.ES
- I3T WATER EXTRACTABLES
1% MOM EXTRACTAHLES
1 . 6
1 . 5
1 . h
1 . 3
1 . 2
1 . 1
1 . o
Figure 1 . Density and weight loss of extractables of
Douglas-fir needles after decomposition .
. 9
. 8
. 7
.6
.5
.4
.3
. 2
.1
0
3
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