DRY-ROT OF INCENSE CEDAR. 19 
decays caused by Trametes pini and by Fomes laricis (the chalky 
quinine fungus) intermingled in the v/ood of living Douglas firs on 
several occasions, while down logs in the woods are often mycological 
gardens of wood-destroying fungi with the decays completely 
intermingled. 
Both the dry-rot in small pockets and the Trametes pini decay are 
nearly always found around decayed knots or following along healed 
wounds, mainly those caused by fire. Where the infections occur 
around knots the decay is almost invariably confined to the imme- 
diate neighborhood of the knot, resulting in little or no loss in the 
merchantable contents of the tree. YvTiere any appreciable quantity 
of wood was rendered unmerchantable, the decays were almost 
invariably in intimate connection with healed-over wounds caused 
by fire, frost, or lightning, particularly the first, throughout their 
extent. Exceptions to this rule did occur. In one tree, for example, 
the Trametes pini decay extended for a distance of 23.5 feet in the 
center of the tree above an open fire scar without being in connection 
with any other wound. But the fire scar was very large, extending 
deeply into the tree and undoubtedly had a far-reaching influence 
on conditions in the heartwood. In another tree (tree No. 40 on the 
intermediate area; see p. 17) this same decay extended for 22.1 
feet in between two areas of typical dry-rot without following along 
any wound. The dry-rot in small pockets was found in one instance 
to extend for a distance of 8.2 feet, not in connection with a wound 
but merely as an extension of typical dry-rot. This case has already 
been cited (tree No. 392 on the intermediate area; see p. 18). 
The above fact suggests that the dry-rot in small pockets may be 
the result of the influence on the dry-rot fungus of changed condi- 
tions in the heartwood, either physical, chemical, or both, induced 
by the presence of wounds or knots. 
In further support of this hypothesis, it is almost invariably the 
rule wherever typical dry-rot is found along healed fire scars in the 
butt of a tree that instead of the pockets of normal size, one or more 
long continuous pockets of the dry-rot follow immediately along the 
scar throughout its length and invariably run out close to the end of 
the scar. A maximum length of 10 feet has been attained. Such 
pockets have never been found except in connection with wounds. 
This seems to prove that variations in the typical form of dry-rot 
may be induced by certain types of wounds in the tree. 
The fact that the Trametes pini decay is usually found in the 
immediate vicinity of knots or healed-over wounds may be taken to 
indicate that incense cedar is an unsuitable host for Trametes pini 
and that the organism can rarely progress much beyond the point of 
infection. This would also explain the rare production of sporo- 
phores and the fact that in the only known collection, to cite Weir's 
