6o Forest jy Quarterly. 



of -f- 2.8%. Baur's tables (based on height, diameter and age 

 classes) gave 1009.8 cubic feet or an error of + 15.4'^. The re- 

 sult with Schiffel's tables inspires the suggestion that, where vol- 

 ume tables are wanting these volume tables ma)' be u.sed for any 

 coniferous species without any considerable error where the con- 

 .stant for the species is known. 



A partial difi&culty was met, however, in that different species 

 may be essentially different in their relative height and diameter 

 dimensions. I found no great difficulty in using Schiffel's tables 

 for the Balsam Fir, but in an attempt to do the .same with the Red 

 Spruce I was constantly finding combinations of dimensions for 

 which there was no corresponding volumes worked out in the 

 tables, due to the fact that such combinations do not occur in the 

 Norway Spruce. For example, a Red Spruce cut on Moose Mt. 

 gave the following measurements: height, 21 meters; diameter, 

 41 cm ; qy^, 74. On referring to Schiffel's table (p. iii) I found 

 that he gave volumes for trees of 2 1 meters height and a form 

 quotient of 74. but only for diameters from 17 to 27 C7n ! 



JuDSON F. Clark. 



Since the above article was sent to the printer a kind friend has 

 expressed the opinion that the reader has not had a sufficient 

 explanation of the character of Schiffel's volume tables to ap- 

 preciate my suggestion that they might be used for our species, 

 provided the constant for the different species were determined. 

 I shall therefore review and add a few words to the explanation 

 given in my previous paper. 



The data for these tables were obtained by very careful section- 

 wi.se measurement of 2529 stems of Norway Spruce. These 

 measurements were classified according to height, diameter at the 

 middle point, and diameter breast-high. From these data curves 

 were drawn enabling the investigator to correctlj^ average his re- 

 sults and to interpolate for dimensions which were not met in the 

 preliminary taking of the data. From these curves a series of 

 tables were constructed from which the volume of an}' tree of 

 known height, form quotient, and breast-high diameter might be 

 readily read off without calculation. 



The individual trees of any species vary greatly in form, but it 

 stands to reason that if two trees of the same species measure the 



