DRY-ROT OF INCENSE CEDAR. 53 



fected tree possesses the potential capacity of sooner or later pro- 

 ducing sporophores. 



Remembering the great percentage of dry-rot infections entering 

 through wounds, trees with injuries must be treated accordingly. 

 Trees with healed wounds are of less concern than those with open 

 wounds, since the former, if not already infected, are immune except 

 for the inevitable, though fortunately not frequent, attack through 

 branch stubs, while the lattei are still open to infection. Then, too, 

 the area of heartwood exposed by the injury is of grave consequence; 

 the larger the area the greater the opportunity for infection. We 

 already know the high percentage of infections through fire scars 

 which so commonly expose large areas of heartwood; therefore 

 fire-scarred trees, above all, should be marked as heavily as possible. 

 Large lightning wounds are a serious danger, but small superficial 

 injuries, especially if high up on the bole, can be almost disregarded. 

 Frost cracks, though by virtue of the exceedingly small amount of 

 heartwood they expose offering slight chance for infection, often 

 aid in spreading infection established through some other agency, 

 and trees with such wounds should be marked for cutting whenever 

 possible. From the pathological viewpoint spiketops or stagheads 

 may be almost disregarded except for their suppressing influence 

 on the injured individual, but sound silviculture demands the re- 

 moval of such trees from the stand. 



Even if the Utopian dream of a forest community without injured 

 individuals could be attained, this in itself would not result in com- 

 pletely controlling the destruction wrought by the dry-rot fungus, but 

 only in minimizing it in a great measure. There would still be some 

 loss from infections entering through knots. Then, too, no matter to 

 what degree of intensive management a forest in this region may be 

 brought in the future, some injuries will always occur, even from fire, 

 while frost and lightning wounds are inevitable. The unavoidable 

 injuries to a certain number of the seed trees during logging on any 

 yales area must not be overlooked. 



Therefore, all wounded trees must not only be eliminated on sales 

 areas, but trees, even though unwounded and thrifty, must not be 

 left with the expectation that they will be sound at the next cutting 

 if by the time the cutting takes place they will have attained or 

 passed beyond the age at which loss from dry-rot becomes of serious 

 economic importance. It has been shown that the critical age occurs 

 at 165 years and the age of decline at 210 years. Beyond the age of 

 165 years suppressed trees become subject to extensive decay, while 

 up to that age they may be expected, with rare exceptions, to remain 

 relatively sound, the same being true for the dominant trees at an 

 age of 210 years. 



