576 JOURNAL OF FORESTRY 



defect or breakage, to errors in the width of the survey strip, height 

 measurement, or some other easy source of error in crusing. Because 

 volume table defects have been overshadowed by the other perhaps 

 larger and more easily corrected sources of error in timber surveys, 1 

 believe we have somewhat neglected the careful study of volume table 

 preparation. 



American foresters have been confronted with a tremendous prob- 

 lem in supplying themselves with volume tables for the hundreds of 

 species of the country and for the wide range of conditions under which 

 some of our trees grow. In Europe, with only a half-dozen commer- 

 cial species, it is no wonder that each table can be based on 50,000 trees. 

 In this country we have been forced to use a volume table on one 

 species which was made for another without any knowledge of the 

 relative form factors of the two species, or, for lack of a better, we 

 have put into general use a little local volume table made for temporary 

 use only. 



While volume tables are altogether lacking for some species, there 

 is duplication with other species. This duplication comes partly from 

 the independence and isolation of the districts, each of which desires 

 to make its own tables without collaboration or reference to its neigh- 

 bors. It also comes from the practice — which, I think, is now less 

 common — of each cruiser making tables for each project, namely, local 

 tables. 



Granted, then, that there is room for improvement in the volume- 

 table system on the National Forests, and that the Branch of Research 

 should assume responsibility for making these volume tables, what 

 kind of tables are wanted and how should they be made? 



The first point that must be decided is whether we should adhere 

 to the conventional form of table or whether we should adopt a rad- 

 ically different form. By conventional form of table I mean one which 

 shows the contents in board feet, or cubic feet for specialized purposes, 

 of trees of various diameters and of various heights. Whether the 

 conventional form of table or a radically different form is used depends 

 basically upon the method of timber estimating to be employed. If 

 experienced estimators of the type of the high-paid private cruiser are 

 to be used, it would clearly be best to have volume tables which show 

 the contents of trees by component logs and which give the taper for 

 each log — tables which permit of grading the timber as it is estimated : 

 quality of volume tables. But if inexperienced estimators are em- 



