Apr. 1, 1925 
* The Construction of Taper Curves 
619 
appropriate percentage to the proper 
diameter inside the bark (fig. 9). To 
anybody familiar with curves of similar 
form made by the conventional system, 
a striking difference will be noted in the 
upper part of the tree, where all the 
curves converge into one. A wide 
spread is the rule in the curves made by 
the usual system. In effect, this 
harmonize the whole curves themselves 
by the graphic methods employed by 
Barrows. The results are, further¬ 
more, very much more dependable. 
This method also obviates any necessity 
of working out mathematically the 
equation of these curves. 
It is interesting to compare the taper 
found by the method here used for 
Fig. 7.—Subordinate form quotients at ten equal intervals from the base of the tree to the top for Douglas 
fir trees having form quotients from 0.64 to 0.80 
method gives the form or taper curve 
of all trees having the same form quo¬ 
tient, and each size class of trees is 
assigned its tree form simply by work¬ 
ing the form quotient into a regular, 
orderly seq uence. It is obviously much 
easier to brin g these simple figures into 
order than to arrange, rearrange, and 
Douglas fir and the taper found by 
Behre for western yellow pine, using his 
modification of Hojer’s equation. The 
difference is very slight. Taking Behre’s 
form class 70 and comparing it with the 
values for form quotient .700 in Table 
I, which is based on the most complete 
data, the following results are obtained. 
