THE PROBLEM OF THE REGIONAL VOLUME TABLE 



By Donald Bruce 



Division of Forestry, University of California. 



Not so very many years ago decided differences of opinion existed 

 between foresters as to the relative merits of regional and local volume 

 tables. In the early days of the profession few of the former had 

 been prepared and as each man needed a table for some specific 

 end he was forced to compute one for himself. Thus it came about 

 that in this early period the local table was very prevalent. Many of 

 them, however, were hastily prepared from inadequate data and were 

 none too reliable, so that a reaction towards the second type was a 

 quite natural consequence. A few years later the Forest Service had 

 published a fairly complete set of regional tables, each based on a 

 substantial number of tree measurements, and the local table became 

 nearly obsolete. 



Many arguments have been advanced in favor of each type, but 

 these arguments have usually been supported by purely deductive 

 reasoning unaccompanied by conclusive experimental evidence, and 

 the change which came about seems to have been more the result of 

 circumstance than of investigative research. The modern regional 

 table itself is accordingly not beyond suspicion. A salient point of 

 doubt, of course, is in the definition of region. It has been tacitly 

 assumed that the entire range of such species as western yellow pine 

 or Douglas fir must be subdivided, but the decision as to the number of 

 regions to be recognized and the determination of the boundaries be- 

 tween them have been too often handled on an opportunist basis. The 

 boundaries of National Forest districts have been scrupulously respect- 

 ed, while pronounced physiographic frontiers have sometimes been 

 ignored. The western yellow pine of northeastern California, for 

 example, is far more similar to that of the Klamath region of Oregon 

 than to that of the western Sierras, yet for volume table purposes it is 

 the last two that have been combined. 



It would seem that the experience of a decade of use should have 

 told us which tables are good and which are not. Unfortunately, how- 

 ever, the form of the table has not been sufficiently standardized to per- 

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