Distribution of Thermophilic and Thermotolerant Fungi in a Spruce-Pine Chip Pile

Abstract

A study into the distribution of thermophilic and thermotolerant fungi in a spruce-pine (Picea spp.—Pinus spp.) wood chip pile at Prince George, B.C., was carried out. Five treatments were examined: pine, spruce, spruce containing a core bag of fines, spruce containing a core bag of sterilized spruce chips and spruce containing a core bag of spruce chips inoculated with a Ptychogaster sp. [probably Chrysosporiumpruinosum (Gilman and Abbott) Carmichael]. Samples of wood chips buried at different locations in the chip pile were examined after 3, 6, and 12 month storage periods. From 100 randomly selected chips from each sample, the fungi were isolated on 2% malt, 2% agar, and 0.5% malic acid medium. Data on temperature during storage, pH of wood chips, moisture content, and weight loss at the time of sampling were calculated for the various sampling positions.Thermophilic fungi colonized the inner regions of the wood chip pile where higher wood substance losses occurred, while thermotolerant fungi inhabited the outer regions. Among the thermophilic fungi listed according to frequency of isolation were Byssochlamysemersonii Stolk-Apinis, Allescheriaterrestris Apinis, Sporotrichumthermophile Apinis, Thermoascusaurantiacus Miehe, and Humicolalanuginosa (Griffon and Maublanc) Bunce. The most common thermotolerant fungi were Aspergillusfumigatus Fresenius and C. pruinosum.Fungal distribution was generally related to position in the wood chip pile. Of the associated factors, temperature (17–60 °C) was most strongly related to fungal distribution, whereas treatment, pH of wood chips, and moisture content did not relate to fungal distribution.