A STUDY OF HRART-ROT TN WESTERN HEMLOCK. 13 



separate plats were laid out, comprising 5.7 acres. The river-bottoin 

 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 



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Fig. 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 determioing the age corresponding to the stump height of the felled trees. 



