SHADE TREE AND TIMBER DESTROYING FUNGI. 215 



and ridges which mark off the annual layers. The fungus is 

 thus perennial. 



It is very generally distributed through hardwood forests. It 

 is especially abundant in certain hardwoods in the Adirondacks. 

 In some sections a large percentage of the beech, birch and 

 maple is affected. A quantity of the wood of affected trees was 

 collected both at Childwood, St. Lawrence Co., in 1896, and at 

 Clearwater, Herkimer Co., in 1898. At the latter place, the 

 second flag station north of Fulton Chain, on the N. Y. C. R. R., 

 there were excellent opportunities for studying it on the maple, 



and for determining 



the conditions which 

 favor the entrance of 

 the fungus into the 

 heart of the tree. 

 Since the mycelium 

 cannot enter through 

 the living cambium of 

 the tree, an "infec- 

 tion court " must first 

 be provided. ' These 

 infection areas are 

 provided in a variety 

 of ways, in general 

 their origin being the 

 same as for other tim- 

 ber destroying fungi 

 which enter through 

 wounds. 



The conditions pre- 

 vailing in a large portion of the mixed forests of the Adirondack 

 region are such that a very common point for entrance is provided 

 by the falling of the lower limbs. In the mixed forests the 

 spruces : and pines tower so far above the hardwood as to cut off 

 much of the light. The hardwoods are thus so shaded that the 

 area of foliage is considerably lessened, many of the trees having 

 few limbs, and then bearing few leaves compared with trees in 

 the open, or even in a hardwood forest where all the trees have 

 an equal chance for light. 



74. Section of fruit body of Polyporus 

 igniarius. 



