FOREST DISEASE SURVEYS. 3 



In most cases the appraisal of a timber-sale area is based somewhat 

 low in respect to the total feet board measure of sound material, 

 principally on account of the unknown amount of defect or rot to be 

 encountered and sometimes partially for other causes, foremost of 

 which is the desire to prevent ovcrestimation. 



In timber surveys the estimating of timber is performed by mem- 

 bers of the party who have been trained to estimate stands of varying 

 mixtures, age, and soundness and who are thoroughly capable of 



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Fig. 2. — Fruiting bodies of Trametes pini on lodgepole pine. Notice the swell- 

 irg of the trunk where the fruiting bodies are attached. (Photographed by 

 G. G. Hedgcock.) 



judging the board-feet contents of trees within reasonable limits of 

 error. The addition to the party of an expert cruiser has been 

 made as a means of aiding the estimators in this work and checking 

 their results. The determination of the correct cull percentage due 

 to rot is the aim of this arrangement in the crew. 



In certain types and ages of stand the estimate may come close to 

 the true scale, but, again, too small a percentage is deducted for cull 

 due to rot, and consequently the estimate runs too high. A sale con- 

 tractor figuring possibly on a conservative margin and accepting the 



