12 
BULLETIN 1163, U. S. DEPARTMENT OF AGRICULTURE. 
CONK-ROT. 
The decay causing by far the greatest loss in Douglas fir is relatively 
easy to detect. Sporophores of this decay occur abundantly. This 
is indicated by the local name of conk-rot used in the Pacific North- 
west. Lumbermen observed the unusually common occurrence of 
sporophores, or " conks," on infected trees, as compared to those 
with other decays, and the name followed. The prolific development 
of sporophores is shown by the fact that of 83 trees with sporophores 
there was an average of 14.4 per tree, or a total of 1,196. Considering 
all infections both with and without sporophores there was an average 
of 10.1 sporophores per infection, or 1 for every 6.34 cubic feet of 
conk-rot in the trees and 1 for every 65 board feet. 
It is of interest to consider the orientation of these sporophores. 
Moller (£), working with the same fungus, found 89.4 per cent of the 
sporophores on the westerly side of the trees. He explained this by 
the facts that the prevailing winds were from the west and the trees 
were most strongly struck by rain on the west side, and consequently 
the branch stubs (a very common point of infection) were more moist 
on that side. Weir and Hubert (7, p. 30) , in their work with the Indian- 
paint fungus (EcJiinodontium tinctorium E. and E.) on western hem- 
lock (Tsuga heterophylla (Raf.) Sarg.), found that most of the 
sporophores had a northwest to north-northeast orientation. The 
same workers (8, p. 18), studying conk-rot in western white pine 
(Pinus monticola Doug.), found the largest percentage of the sporo- 
phores develops ^ on the west side of the tree, with the smallest per- 
centage on the southeast side. Table 12 shows the orientation of 
the sporophores on the trees studied. 
Table 12. — Orientation of sporophores of conk-rot in Douglas fir. 
Character of data. 
Orientation of sporophores. 
NW. 
N. 
NE. 
E. 
SE. 
s. 
S\V. 
W. 
212 
17.8 
291 
24.4 
202 
17.0 
91 
7.6 
144 
12.1 
77 
6.5 
96 
8.1 
79 
Percentage of total 
6.6 
The largest percentage of sporophores occurred on the north side 
of the trees and the smallest percentage on the south side. Adding 
the sporophores on the north, northwest, and northeast it is seen 
that 59.2 per cent were in the northerly grouping. Following this 
system gives 36.7 per cent easterly, 26.7 per cent southerly, and 32.5 
per cent westerly. The northerly direction clearly predominates. 
This is logically explained by the fact that there is less light on the 
northerly side and consequently more moisture, particularly during 
the growing season, which in this region is a long dry period inter- 
rupted by occasional thundershowers of brief duration. Conditions 
on the northerly side of the trees are therefore more favorable for 
infection and the subsequent development of sporophores. 
As a rule very little rot develops in a tree before a sporophore 
appears, or if not a sporophore at least a swollen knot, or " blind 
conk," as it is colloquially termed. The sporophores can not pene- 
trate the unbroken bark and issu^ only through knots or branch 
