RHVIEWS 713 



It is along these lines that Chandler's study is of particular value, 

 bringing together under a single cover the results of all previous in- 

 vestigations on the subject of form factors and by his contributions 

 extending our knowledge very materially. 



After demolishing, by an iconoclasm based on relentless logic, our 

 trust in all methods of estimating hitherto developed, the author states : 



"If, then, an adequate volume table based on diameter and height is 

 to be attained, it will be necessary to develop an expensive and com- 

 plicated system. The data must be kept in the taper curve form and 

 be rescaled whenever a new log rule is used or market conditions 

 change. At least two sets of taper curves must be available for each 

 species, for each quality site — one for old growth and one for second 

 growth. Probably more than two would be needed later, divided on the 

 basis of age. Such a system would be costly, complicated, and im- 

 possible." 



He then goes on to cite actual examples of stands within the same 

 forest type wherein the divergencies of form are so great as to make 

 it practically impossible to construct a height curve which will be a true 

 average, or to determine the average taper. 



"In such stands," says the author, "it becomes necessary to abandon 

 the type as a unit of area for estimation. The trees of each form must 

 be tallied separately and to each form must be accorded its own height 

 curve and volume table or form factor. The use of one volume table 

 with separate height curves alone will not answer here any more than 

 for different sites, for all bole forms and tapers are averaged together. 

 This results in an overestimate of the more poorly formed trees with 

 heavy taper and an underestimate of the full-boled trees." 



The author proceeds to discuss the factors which control volume. 

 Diameter and height have been considered the only volume factors 

 with which it was necessary to deal in the construction of volume 

 tables. The author believes that there are two other factors which 

 must be taken into consideration — taper and bole form. 



"In order to obtain a clear idea of the real meaning of taper the 

 merchantable length of a tree above diameter breast high must be con- 

 sidered as the frustum of a perfect cone. Taper then becomes the 

 rate of decrease in diameter in this frustum. The degree of departure 

 from the perfect cone frustum is the other new factor to be considered, 

 namely, that of bole form. 



"Of the four factors directly influencing merchantable volume, 

 namely, diameter (diameter breast high), height, taper, and bole form, 

 the latter is the only one which is unnecessary for computing the vol- 



