Syringaldazine did not turn purple on cross sections of tree branches or saplings or on cambial tissue cultures unless hydrogen peroxide was added; this indicated the absence of laccase but presence of peroxidase in lignifying cells. Peroxidase, therefore, apparently is the only en enzyme that polymerizes p-coumaryl alcohols to lignin in trees.

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Chemical and microscopic features of wood decay by several ascomycetes in axenic culture are described. The tested ascomycetes caused significant weight losses in birch wood. Daldinia concentrica was especially active, causing a weight loss of 62.9% after 2 months. While lignin and carbohydrates were both degraded, carbohydrates were preferentially attacked. As measured by alkaline nitrobenzene oxidation, syringylpropane units of the lignin were removed selectively. AU of the tested ascomycetes eroded fiber cells walls beginning from the lumen. Some also caused cavities in the secondary walls, typical of soft-rot decay. Pine wood was generally resistant to decay; some of those species which were capable of forming soft-rot cavities in birch caused significant weight loss in pine. Alstonia scholaris, a tropical hardwood with a guaiacyl-rich lignin, was resistant to degradation.

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