12 BULLETIN 871, U. S. DEPARTMENT OF AGRICULTURE. 



always indicate that there is well-developed dry-rot in the heartwood. 

 In such infections it is generally possible to distinguish three stages in 

 the affected heartwood, with upper and lower limits. These stages 

 for convenience are termed total extent, unmerchantable extent, and 

 maximum concentration. "Total extent" is expressed by giving 

 the height in feet in relation to the ground level of the lowest and 

 highest point in the bole of the tree invaded by the fungus without 

 regard to radial extent. By "unmerchantable extent" is meant the 

 portion of the bole rendered valueless for lumber by the dry-rot, 

 while "maximum concentration" covers that portion of the bole in 

 which the decay seems to be at its worst. The upper and lower limits 

 of all three of these stages may at times coincide, but especially 

 that of the unmerchantable extent and maximum concentration. It 

 is self-evident that these last two mentioned can never exceed the 

 total extent. 



The sporophores and shot-hole cups invariably appeared between 

 the upper and lower limits of the maximum concentration. The 

 lower limits varied from 3 to 25 feet below the sporophores or shot- 

 hole cups, and the upper limits from 4 to 45 feet above them. In every 

 case except one the lower limit of the unmerchantable extent was at 0. 

 In other words the bole of every tree was unmerchantable, at least 

 from the ground level to the sporophore or shot-hole cup. In the one 

 exception the unmerchantable extent did not commence until 8.2 

 feet from the ground level. This was due to the presence of a large 

 open fire scar extending from to 10.8 feet. The fungus distinctly 

 avoids the dried-out wood around open wounds, which habit will be 

 fully discussed later in this paper. The upper limits of the unmerchant- 

 able extent were variable. In the two abortive sporophores the un- 

 merchantable portion extended for 10 and 24 feet, respectively, 

 above the sporophores, while the extent above the shot-hole cups was 

 23 and 53 feet. 



The total extent in every tree with sporophores except one (see 

 above, under unmerchantable extent) reached from the sporophore or 

 shot-hole cup to the ground level, but the upper extent was variable, 

 being for the two sporophores 24 and 25 feet, respectively, and for the 

 shot-hole cups ranging from 24 to 53 feet. 



From the figures available it is impossible to make an exact state- 

 ment as to the range of the total extent, unmerchantable extent, and 

 maximum concentration of the dry-rot in trees with sporophores or 

 shot-hole cups, except that it may be safely assumed not only from 

 the figures at hand but from observations on logging areas that the 

 bole of a tree will always be unmerchantable from the ground level 

 to a variable height above a sporophore or shot-hole cup. But it 

 must be remembered that an old shot-hole cup indicates a greater 

 development for the fungus plant in the tree than does the first 



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