354 JOURNAL OF F0RE;STRY 



A number of white spruce (Upper Fraser Valley), Engelmann 

 spruce, western hemlock, and balsam fir were analyzed. It would make 

 this article altogether too long, however, to describe in detail the series 

 obtained. This must be said, however: Whenever root swelling 



reached above breast height we obtained an absolute form quotient ( ^ ) 

 or form class which was lower than the form class indicated by 'ihe form 

 of the bole above the root swelling. 



The analysis of the sample trees has shown, however, that if we base 

 the taper series on the "normal" d.b.h. of the tree we obtain series that 

 correspond very closely with the eastern series and with Jonson's 

 mathematically computed series. 



It is found that root swelling does not as a rule materially affect the 

 breast height diameters in trees less than 12 inches. For instance, 41 

 western white spruce, with an average d.b.h. of 10 inches, gave series 

 that agreed almost exactly with Jonson's series for Norway spruce of 

 the same form class. The same is true in regard to balsam fir, Douglas 

 fir, and other species. 



Prof. Jonson and Mattson-Marn have found that normal Norway 

 spruce, Scotch pine, and larch, whether large or small, are similarly 

 built, provided they have the same absolute foun quotient. Froni ihe 

 limited number of measurements taken in Canada it would appear as if 

 the same could also be said about our Canadian conifers. 



The falling off in the top sections which was found in the young, fast 

 growing trees examined in the East was not noticed in the series for the 

 western species, where all trees examined were larger and older than 

 in the East. From the series constructed for each form class, which 

 give us the dimensions in per cent of diameter at breast height at any 

 point of the stem, it is of course possible to construct taper tables and 

 any kind of volume table, whether in cubic feet, board feet, or ties. If 

 we know the form class, the d.b.h., and the total height, we know 

 from our taper tables what the diameter is at the top of each JG-foot 

 log, we know at what height on the stem the diameter is 8 inches, 6 

 inches, or 4 inches, etc. 



In using a form class table it is of course necessary to know the 

 diameters, the heights, and the form class of the trees in the stand. 

 Diameters are measured, heights are obtained from a height curve 

 constructed from measurements of a few representative trees in each 

 important stand, and the average form class is obtained either from 

 felled sample trees by Jonson's form point method or by judging the 



