352 JOURNAL OF FORESTRY 



accuracy in estimating the total volume content of white pine and red 

 pine, and spruce stands in Canada, providing that the diameter breast 

 height is measured just above the root swelling, if such is present, and 

 providing of course that the average form class of the stand is ascer- 

 tained correctly. 



The following series for form classes 60, 65, 70, 75, and 80, made 

 from measurements at Petawawa, as demonstrated above, agree closely 

 with Jonson's series, and the inference is that tables based on these 

 series will prove accurate when applied generally, but, of course, such a 

 statement cannot be made until measurements have been secured from 

 trees of all ages and sizes, spread over the entire range of the tree. 

 To this end, we invite the co-operation of foresters in Canada and the 

 United States to take form quotient measurements of typical trees 

 and send in their figures. The assistance thus received will be of great 

 value and will be much appreciated. 



The final series were obtained from the averages of the white and red 

 pine series by graphical interpolation. The average values at the eighth 

 and ninth cross section in form classes 70, 75, and 80 have been some- 

 what raised for reasons which have been discussed above. 



Average Taper Series Inside Bark for White Pine and Red Pine Ob- 

 tained from Measurements oti Felled Sample Trees in 

 Young and Medium Aged Stands. 



Form class Diameter in per cent of d. b. h. at each tenth of stem above b. h. 

 d b.h. 1/10 2/10 3/10 4/10 5/10 6/10 7/10 8/10 9/10 



D 



0.60 100 93.2 85.8 77.9 69.4 60 50 38.4 25.9 12.9 



0.65 100 94.3 88.0 81 73.6 65 55.4 43.8 30.6 15.6 



0.70 100 95.3 90.2 84.3 77.8 70 60.7 49.5 35.8 19.2 



0.75 100 96.2 91.8 87 81.8 75 66.7 56 41.5 23.2 



0.80 100 97 93.7 89.7 85.4 80 73 62.7 48.5 28.7 



INVESTIGATIONS IN BRITISH COLUMBIA 



A considerable amount of investigation has been carried on in Brit- 

 ish Columbia on Douglas fir, white pine, white spruce, Engelman's 

 spruce, balsam, and hemlock. The measurements were not taken at 

 each tenth above d.b.h. as in the East, but at breast height and at each 

 16 feet. These measurements (inside bark) were then plotted on 

 cross-section paper and the diameter at each tenth read oflf and the 



