172 A MANUAL FOR NORTHERN WOODSMEN 



board feet, or cords); the results have been averaged, 

 evened by curves, and then the board-foot tables have 

 been discounted by a small percentage to allow for normal 

 defects of form and quality. Cutting practice that is 

 economical, but not extreme, has been supposed through- 

 out, the idea being to get, as nearly as possible, a conserva- 

 tive figure for good and economical practice. 



In applying all these tables, considerable defects must be 

 allowed for in the form of a discount. It is further to be 

 clearly understood that they apply to timber as it runs 

 and may be considerably off as applied to single trees. 



In volume tables for hard woods merchantable length 

 is in most cases preferable to total height as a factor 

 because these trees characteristically spread out at the 

 top, at once rendering total height hard to measure and 

 destroying utility for lumber. Such tables also, because 

 of greater irregularity of form and greater liability to 

 defect in hard woods, are in general less trustworthy than 

 soft wood tables. Several "graded volume tables," 

 classifying the yield of trees by lumber grades, are in 

 existence, but their utility apart from the local conditions 

 in which they were constructed does not seem clear. 



The way in which these volume tables may be tested 

 and made to conform to the practices of any given locality 

 is illustrated as follows: 



A spruce property is to be explored on which cutting and 

 scaling methods are as follows : Timber runs up to about 

 20 inches in diameter and 75 feet in height ; trees are cut 

 down to the size of 12 inches on the stump or 11 breast high. 

 Logs cut for saw lumber, one log from a tree, cut off where 

 it will scale best. Logs are therefore seldom over 40 feet 

 long and run from that down to 28 or 30. Scaling done 

 with Maine log rule. If a log is 26 feet long or under, it is 

 scaled as one log with the top diameter inside bark ; if 27 

 to 30 feet, as two logs of equal length giving the butt log 

 an inch larger diameter than the top ; from 31 to 35 feet in 

 the same way but allowing 2 inches "rise," and 3 inches on 

 log lengths of 36 to 40 feet. In addition a level discount 

 of 10 per cent is made on all logs to cover defects. 



A half day's time spent following the logging crew and 



