A STUDY OF HEART-ROT IN WESTERN HEMLOCK. 



11 



can not be used to express this relation, since it varies with all the 

 factors influencing the progress of the decay. As a rule, it would 

 be safe to add to the linear estimate of the cull 1^ feet beyond the last 

 recognizable punky area or area showing the slightest yellowish dis- 

 coloration. The typical rot (figs. 4, 8, and 9) is readily recognizable 

 and has a characteristic reddish brown to brownish yellow color, 

 often spotted with areas of a more vivid rust color and occasionally 

 showing streaks or Hnes of a dark red to reddish brown hue. Its 

 texture is very pronomiced and this, combined with its color, forms 

 the basis for the scaler's common name for the defect ''stringy 

 brown-rot." In the last stages of decay the heartwood is entirely 

 disorganized, giving place to large cavities in the butt logs and some- 

 times in the logs above. The stringy nature of the rot can be readily 

 seen in this stage and also in- the ends of logs badly but not hollow 



Fig. 8. — Longitudinal section of Un old sporophore of EcMnodontium tinctorium on hemlock, showing its 



relation to branch stubs. 



rotted, especially in the grass-stubble effect (figs. 4 and 10) produced 

 by the sawing. The brick-red color of the sporophores is often found 

 distributed through the typical rot and in the branch stubs in the 

 final stages of decay. 



AREAS STUDIED AND FIELD METHODS USED. 



The areas selected for study lie in the drainage basin of the Priest 

 River in Idaho. Throughout this region western hemlock is rather 

 evenly distributed, extending downward from the sub alpine zone 

 into the upper limits of the yellow-pine zone. The species attains 

 its best development on damp north slopes and is found greatly 

 suppressed when growing as an understory in the dense bottom 

 stands. 



One of the factors promoting the development of forest-tree fungi 

 of the region is the high annual precipitation. The dry periods of 



