SO eae ae 
18 BULLETIN 658, U. S. DEPARTMENT OF AGRICULTURE. 
It is readily seen that Table I will aid greatly in determining the 
rot in the tree by means of external characters, and after the class of 
defect and the cause have been determined by its use it will be com- 
paratively easy to select the proper rot column in the table of rot 
percentages for any one tree species. In this manner the two tables 
can be used conjunctively in securing a more accurate rot percentage — 
for the stand.t Until it is possible to obtain accurate data from a 
large number of trees of all the species composing the prevalent 
forest types of this 
region, no table of 
rot percentages will 
be presented. 
Since the type 
lines are sketched on 
the topographic map 
on the basis of age 
class, it will be 
found advantageous 
to study and record 
the rot data upon 
such a basis. This 
will make it easier 
to produce patholog- — 
ical. maps,of. tire 
area by using white 
prints from the type- 
sheet tracings of the 
timber survey maps. 
SYSTEM 2) a el In a unit crew 
ree VE consisting of two 
Fic. 18.—Typical rot of the scaly Pholiota in grand fir. : 
Note the horizontal streaks formed by the yellowish felty Men (an estimator 
muyceltut: / and a topographer), 
the estimator can be trained to determine the cause of the dis- 
ease and the amount and therefore the rot percentage, recording 
such data accurately for the strip which is being surveyed. Since 
the estimate sheets have blank spaces for the recording of all disease 
and other injuries suffered by the stand, as well as for the estimated 
loss in cull due to each, the only change that a more intensive disease 
survey will incur will be the additional work done by the topog- 
rapher. He will be required to indicate upon his map the boundaries 
pL VU wu NEAL ji 
“METRIC! 
1Weir, J. R. Difficult problem of the control of fungus diseases in the forest. In 
Timberman, y. 14, no. 9, p. 27-29, illus. 1913. : 
Weir, J. R. Some problems in conservation with reference to forest hygiene. Jn Tim- 
berman, y. 14, no. 11, p. 28-31, illus. 1913. 
Meinecke, E. P. Forest tree diseases common in California and Nevada. Washington, 
D. C. 1914. These publications may be found useful in the determination of various 
kinds of defects. ; 
