TREE DISEASES 



157 



can find plenty of food, water, warmth and darkness. 

 As these conditions generally exist in wounds and cavities 

 of trees, it is wise to keep all wounds well covered with 



FIG. 110. The Birch-fungus rot. (Polyporus betulinus Fr.) Note the 

 similarity in the color of the fruiting body and bark of the tree. 



coal tar and to so drain the cavities that moisture cannot 

 lodge in them. This subject will be gone into more fully 

 in the following two studies on " Pruning Trees" and " Tree 

 Repair." 



While the majority of the fungi grow on the trunks 



