FOREST INSECTS AND FUNGI 



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for two or three feet above and below the fruiting bodies. In 

 its final stages the heartwood is completely destroyed so that 

 the tree is weakened and Hable to be broken off by windstorms. 

 On examination the center of the tree will be found of a pulpy 

 consistency definitely limited on the outside by one or more 

 narrow black layers. 



Fig. 46. — The fallen chestnut, now 6 inches in diameter, was formerly injured by fire 

 which allowed a fungus to enter. This fungus hollowed out the stem for over 2 feet 

 from the ground leaving untouched a mere shell of wood on the outside. The first 

 heavy wind broke the tree. 



This disease causes greater damage to poplar than to other 

 trees, but is by no means confined to the poplar. It occurs on 

 more species of broadleafs than any similar fungus. It has been 

 found on poplar from Maine to Oregon and from Canada to 

 New Mexico, and undoubtedly exists wherever poplar lives. 

 In New York and New England the beech also is very commonly 

 affected. 



It is one of the most conspicuous of our so-called punks, or 

 shelf fungi, which grow upon living trees. The fruiting body is 

 commonly more or less hoof shaped, the thickness being about 

 equal to the width. The upper surface, at first smooth, becomes 



