| Summary: | A study into the distribution of thermophilic and thermotolerant fungi in a spruce-pine wood chip pile in Prince George was carried out. Five treatments consisting of pine, spruce, incorporation of wood fines into spruce, sterilized spruce and sterilized spruce inoculated with a Ptychogaster sp. were examined. Samples of wood chips buried at six different locations in the chip pile were examined after 3, 6 and 12 months storage periods. From 100 randomly selected chips from each sample the fungi were isolated on 2% malt, 0.5% malic acid and 2% agar at 25° and 45°C. Data on temperature during storage and acidity of wood chips, moisture content and weight loss at the time of sampling were recorded for the six positions in the wood chip pile.
Thermophilic fungi colonized the inner regions while thermotolerant fungi inhabited the outer regions of the wood chip pile. Among the thermophilic fungi, listed according to frequency of isolation were Byssochlamys emersonii Stolk-Apinis, Allescheria terrestris Apinis, Sporotrichum thermophile Apinis, Thermoascus aurantiacus Miehe and Humicola lanuginosa (Griffonand Maublanc) Bunce. The most common thermotolerant fungi were Aspergillus fumigatus. Fresenius and Chrysosporium pruinosum (Gilman and Abbot) Comb. Nov.
Fungal distribution was generally related to position in the wood chip pile. Of the associated factors temperature (17°-45°C) was most strongly related to fungal distribution, whereas acidity of wood chips and moisture content did not vary greatly between positions.
Incubation of wood samples on cultures demonstrated the ability of all the common thermophilic and thermotolerant fungi to cause weight loss of lodge pole pine Pinus contorta Dougl. varlatifolia, ponderosa pine Pinus ponderosa Laws. and spruce Picea glanca (Moench) Voss sap wood samples. These weight losses varied from 0.65% to 25% after six weeks incubation. Temperature, medium and type of wood affected the ability of the fungi to cause weight loss. No synergistic or antagonistic effects' existed between the thermophilic fungi.
Chemical analysis of degraded wood indicated that the thermophilic fungi utilized the arabinose fraction of the hemicellulose preferentially. === Forestry, Faculty of === Graduate
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