Fungi causing cull 



The fungi that caused cull in the study trees are listed for 

 each tree species in table i|. This table shows the relative 

 importance of each fungus in producing cull. 



For example, table h shows that in spruce trees the brox^m rot 

 caused by the red belt fungus (Fomes pinicola) was found in more than 

 one-fourth of the study trees and caused about 88 percent of the 

 total brown rot, or nearly three-fourths of the total cull in that 

 tree species. Nearly three-fifths of the decay caused by this fungus 

 was in the typical stage. Cull of this type (fig. 3) is useless for 

 either lumber or pulp. In contrast, table U shows that in western 

 redcedar 98 percent of the total cull was caused by white rot, of 

 which 77 percent occurred in the incipient stage. In other words, 

 more than three-fourths of the total cull in redcedar consisted of 

 white rot in the incipient stage of decay — a type of cull material 

 (fig. I;) that may have limited use in both lumber or pulp manufacture. 



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