A STUDY OF HEART-ROT IN WESTERN HEMLOCK. 13 
separate plats were laid out, comprising 5.7 acres. The river-bottom 
and slope types were first selected for investigation, for the reason 
that at these elevations and under the existing conditions grand 
fir and hemlock are heavily diseased. The plats represented a 
variety of age classes, mixtures, and successions. 
The investigations on grand fir and hemlock were carried out 
simultaneously, but the data on the former are reserved for a future 
report. The influences of site and elevation on the distribution and 
amount of decay were considered, and the data were consequently 
divided according to the two sites indicated. In order to get the 
percentage of rot of hemlock and grand fir, a clean cut of these species 
Fic. 10.—Section through a trunk of hemlock, with an old sporophore attached. The stringy nature of 
the heart-rot and the grass-stubble effect due to sawing are both characteristic. 
was made. The trees were bucked in such lengths (16 feet and 
shorter) as to determine the transverse and longitudinal extent of 
the decay; also the point at which the decay was greatest. That 
section of the trunk containing the upper extension of the decay was 
fully dissected, in order to determine the exact upper limit. The 
diameter of the rot at each log end was measured and recorded. 
The rot in each tree was measured in detail. A full analysis of the 
stump was also made. A uniform stump height of 18 inches was 
maintained throughout. The age of the tree was determined at this 
point, and four years added to the age at the stump, giving the 
entire age! Before the trees were felled, full notes on the external 
1 This average age at stump was secured by taking data on a number of seedling hemlocks in the same 
stand and determining the age corresponding to the stump height of the felled trees. 
