14 



BULLETIN 658, U. S. DEPAETMENT OF AGRICULTURE. 



agencies, such as fungi, mistletoes, smoke, frost, wind, and snow 

 injury, their outward recognition, and their possible and actual dam- 

 age to the trees. Sample plats of small dimensions can often be 

 resorted to in order to ascertain the extent of a heart-rot in a certain 

 age class. Borings can be made with an increment borer on a few 

 sample trees and thus the kind of rot and in the case of butt rots 

 the extent of decay can be determined. Soundings on the trunk, 

 tin- presence of sporophores. the number of dead branches or in- 



FlG. 15. — Fomcx annosus, root Fonies. Typical fruiting bodies. 



juries, and the presence of the unmistakable swells and pitch flows 

 occurring at old branch whorls all aid in the determination of the 

 presence and extent of decay within a tree. The amount of decay 

 bears a certain relation to the age of a stand, becoming greater as 

 the stand grows older. 



Owing to this fact, a table similar to the cull table given on page 

 25 of the Reconnaissance Manual of District 1, United States Forest 

 Service, but giving the rot percentage only for a range of age classes 

 for each tree species would prove of value in judging the decay in 

 the stand. Such a table would give a range in rot percentages to be 



