HERMAN H. CHAPMAN 67 



true age of the tree. The volumes of trees are measured 

 by foresters at 4| feet from the ground, or breast high, to 

 avoid the swelling of the stump. This swelling is not regu- 

 lar in different trees of the same diameter at breast high, 

 and the volumes are more consistent for diameters at the 

 latter point. By measuring a large number of felled trees, 

 the average contents may be determined. If the trees are 

 classified by height as well as diameter, and the contents 

 of the different classes found, these values may be tabu- 

 lated, giving us a volume table based on the diameter and 

 height. 



Timber Estimating. 



Such tables are very useful in determining the cos- 

 tents of standing timber. The work in the field consists 

 in measuring the diameters of trees and enough heights 

 to determine the average. The volume of an average tree 

 is found from the table, and multiplied by the number of 

 trees of that diameter. If the diameter of every merchant- 

 able tree can be actually measured, and a volume table is 

 available, an accurate estimate of the standing timber can 

 be obtained. But in most cases, time and expense do not 

 permit of so much labor. Professional timber estimators 

 resort to many short cuts to get at the result. The short- 

 est and least accurate is to guess at the total, which can 

 sometimes be done quite accurately by experienced men, or 

 a strip is traversed on which all the trees are counted to 

 a definite distance, say four rods on each side. In this way 

 the estimator, or timber cruiser, seeks to get an average 

 which will give him, without actually counting them all, 

 the total number of trees on the tract. The volume of his 

 trees is also gotten by an average, the cruiser merely 

 guessing at the contents of the average tree. Each man 

 may have a different method, but experience is the basis 

 of them all, and the more painstaking men attain an accu- 

 racy greater than could be expected by the use of such 



