108 SHADE TREES. 



HEART ROTS. 



Heart rots are extremely destructive to both living and 

 dead trees. They are due to a number of fungi, many of 

 which are both parasitic and saprophytic. The fact that 

 many of these organisms will live on the dead wood from 

 which they readily pass to the living trees makes it very 

 important that all such dead and decaying material be re- 

 moved and burned. 



WHITE HEART ROT. 



This is a true disease caused by the false tinder fungus, 

 Fomes igniarius (L.) Gillet. It attacks the beech, aspen, 

 Trees willows, maples, birches, walnuts, oaks, hickory, 



attacked. apple, etc. The organism gains entrance 



through wounds and grows in the heart wood which it trans- 



Fig 40. Fomes igniarius on a living aspen. (From Bui. 

 149, Bureau of Plant Industry, U. S. Dept. of Agricul.) 



forms into a white pulpy mass bounded by one or more black 

 layers. During this period of decay the disease cannot be 

 detected from the outside but after the fungus has progressed 

 two or three feet from the point of entrance it comes to the 



