TREES AND TIMBER 



437 



New York City is placed at five to ten million dollars. The 

 chinquepin and chestnut alone are susceptible. The attack 

 is made upon the bark through wounds, but t^dgs and 

 leaves are not directly affected. From the point of attack 

 it spreads in all directions until the diseased parts meet on 



Fig. 191. — Map showing the distribution of the chestnut bark disease; black shows 

 area of severe infection ; round dots, presence of disease prior to 1909 ; + indicates 

 the spread of the disease during 1909. After Metcalf. 



the opposite side of branch, thus girdling the twig. Dead, 

 discolored, sunken patches with numerous yellow, orange, 

 or reddish-brown pustules are produced ; spores are extruded 

 in greenish or yellow horns. The appearance of the fun- 

 gus upon the trunk indicates speedy death, but if small 

 branches are first diseased, the tree may hve for a few years. 



