The morphology of decay by white rot and soft rot fungi (Bjerkandera adusta, Trametes versicolor, Chaetomium globosum, Daldinia concentrica)

Ten hardwood species of both normal and tension wood were used to conduct decay tests with white rot fungus Bjerkandera adusta or Trametes versicolor, soft rot fungi Chaetomium globosum and Daldinia concentrica.; Weight loss results demonstrate that there is no significant difference between normal and tension woods in white, soft and Daldinia concentrica decay. However, it is possible that there are significant differences in specific wood vs. fungus combinations, and the weight loss could be either higher or lower in tension wood than in normal wood.; U-shaped erosion/notches and rounded pit erosion in white rot Bjerkandera adusta and Trametes versicolor, and V-shaped erosion/notches, angular pit erosion and cavity formation in soft rot Chaetomium globosum are consistently produced. Daldinia concentrica produces V-shaped erosion/notches and angular pit erosion consistently in all samples. Different enzymatic systems in white, soft and Daldinia concentrica are responsible for the different shapes they created.; Hyphal sheaths were observed in all white, soft and Daldinia concentrica decay and their possible functions are discussed. “Rounded protrusions” were observed in white rot decay Bjerkandera adusta . Possible functions of the rounded protrusion were also postulated. Hyphal sheath plays an important role in aiding the enzymatic activities in white, soft and Daldinia concentrica decay.; Calcium oxalate crystals were observed in Bjerkandera adusta decay. They were not present in all other test fungi species including another white rot fungus Trametes versicolor. The crystals were embedded within hyphae/hyphal sheaths rather than exposed. It is suggested that the formation of calcium oxalate crystal is affected by environmental conditions, which would follow two different pathways.; Daldinia concentrica should be considered as a soft rot (type 1 and type mixed) fungus based on the existence of cavity formation, V-notch lumen erosion, angular pit erosion, fine hyphae, and small bore hole.