A FORML'LA METHOD FOR ESTIMATING TIMBER 



419 



III. THE BOARD-FOOT FORM FACTOR 



But it will be observed that, no matter what unit of length be used 

 in estimating, the tally sheets may be worked up without using any 

 volume table. All that is necessary is to compute the total length of the 

 trees tallied in each diameter class and multiply that sum by the cor- 

 responding value of b, which will give the total volume in board feet 

 for the trees of that diameter. Column b in Table 2, therefore, is in 

 itself a table of what may be called board-foot form factors. 



In collecting the data it is unnecessary to measure the height of stump 

 or the top of the tree beyond the upper cut (or the point that is taken 

 as the upper limit of the merchantable bole if that should not coincide 

 with the upper cut). The only measurements necessary to take on 

 each tree are the length of each log to the nearest whole foot and the 

 diameter inside bark of the stump and top end of each log, rounded to 

 the nearest whole inch, as is the practice in scaling. Greater refinement 

 is wholly unnecessary for any volume-table work. It is necessary to 



