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



particularly likely to be followed on double-length logs (20, 24, 28 

 feet, etc.)- But invariably the dry-rot will commence just at the 

 top of the fire scar and almost immediately spreads out over the 

 entire radius of the heartwood. In other words, in a log with an 

 open fire scar showing on the base but otherwise sound and with 

 pockets of dry-rot in the top end, the decay should be considered as 

 beginning at about the top of the fire scar and extending from there 

 to the upper end of the log in practically the same degree and radial 

 extent with relation to the heartwood as is shown on the top end. 



Advance rot (see p. 13) should be treated just the same as mature 

 dry-rot. 



In the case of a large swelling on the bole caused by mistletoe it 

 is best to have the tree bucked in such a manner as to exclude the 

 swelling rather than have such a defect reach the landing as part 

 of an otherwise sound log and then be scaled out. 



Timber sales at present offer the only extensive means of prac- 

 ticing intensive silviculture on our National Forests, and the entire 

 results are absolutely based on correct marking. Fundamentally, 

 the object of marking is to leave the stand in the optimum condition 

 for its future welfare and development. This goal should never be 

 lost sight of, no matter how clouded the issue may be by a com- 

 plexity of immediate and often pressing considerations. To attain 

 this end requires a high degree of skill, grounded on a thorough 

 understanding of all the factors involved, not the least of which are 

 those making for total loss in the species under consideration. 



The fundamental object of marking has been far from completely 

 attained if, after cutting, diseased individuals are left standing to 

 carry infection to otherwise sound trees of merchantable size, besides 

 menacing the future of the advance growth and reproduction. 

 Obviously, then, trees with sporophores or shot-hole cups should 

 invariably be marked for cutting, for these are positive proofs of 

 damaging dry-rot. Such trees are as a rule not only a total loss, 

 being unmerchantable from the butt to varying distances of 10 to 

 50 feet above the highest sporophore or shot-hole cup, but are the 

 most potent factors in spreading infection to other trees, since infec- 

 tion can only be brought about by spores coming from sporophores 

 on diseased trees. True enough, shot-hole cups in themselves do 

 not menace surrounding trees with possible infection, but they do 

 indicate that the fungus has reached fruiting maturity and is very 

 likely to develop more sporophores, as is attested by the not un- 

 common occurrence of two or more shot-hole cups of varying ages 

 on the same tree. Furthermore, the fungus mycelium in any in- 



