—_ Ft >  —_ 
a en a a, ae | 
14 BULLETIN 658, U. S. DEPARTMENT 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, 
the presence of sporophores, the number of dead branches or in- 
Fic. 15.—Fomes annosus, root Fomes. 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 
