﻿DECAYS AND DISCOLORATIONS IN AIRPLANE WOODS. 43 



The discolorations resulting from incipient decay may be found 

 in the sapwood or heartwood. Incipient decay extends for varying 

 distances beyond the typical decay. In cutting out this defect it- is 

 advisable to leave a margin of safety of at ieast 2 feet in a longi- 

 tudinal direction beyond the last visible evidences of the incipient 

 decay, in order to remove all infected wood. This margin ojE safety 

 is particularly important with brown or red-brown friable decays, 

 since infected wood may be dangerously weakened by them while the 

 incipient stage is still practically invisible. 



Many decays other than those described in this paper are found 

 in living trees, in logs, and in manufactured timber, but the examples 

 cited include both the most important decays and the principal types. 

 For most purposes it is sufficient to recognize incipient decay as 

 distinguished from other discolorations or defects without deter- 

 mining the causal fungus. 



