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Changes in the Chemical Composition of Wood Caused by Six Soft-Rot Fungi. W. E. Eslyn, Forest Products Laboratory, U.S. Department of Agriculture, Forest Service, Madison, Wisconsin 53705; T. K. Kirk(2), and M. J. Effland(3). (2)(3)Forest Products Laboratory, U.S. Department of Agriculture, Forest Service, Madison, Wisconsin 53705. Phytopathology 65:473-476 . Accepted for publication 12 November 1974. DOI: 10.1094/Phyto-65-473.

Standardized blocks of alder, poplar, and pine wood were decayed by six soft-rot fungi (Graphium sp., Monodictys sp., Paecilomyces sp., Papulospora sp., Thielavia terrestris, and Allescheria sp.), all of which had been isolated from pulp chip storage piles. Samples of the woods at different weight losses were analyzed for lignin, glucan (cellulose), xylan, and mannan (hemicelluloses) to allow calculation of the depletion in these major components caused by the fungi. Carbohydrates were depleted faster than lignin in the alder and poplar, cellulose usually faster than the major hemicellulose (xylan). Lignin, which was analyzed by the “sulfuric acid” method, was depleted by all the fungi. Pine was not decayed significantly by three of the fungi, and only to low weight losses (15% or less) by the other three (Paecilomyces sp., Papulospora sp., and Thielavia terrestris). Analysis of blocks that were decayed showed that lignin was depleted faster than the cellulose or the hemicelluloses by Paecilomyces sp. and Allescheria sp.