Form-class volume tables for ponderosa pine, Douglas-fir and white fir in California
| Authors: | V.A. Clements, C.W. Stevens, D.F. Roy |
| Year: | 1949 |
| Type: | Research Note |
| Station: | Pacific Southwest Research Station |
| Source: | Res. Note 60. Berkeley, CA: U.S. Department of Agriculture, Forest Service, California Forest and Range Experiment Station |
Abstract
Presented in this Research Note are form-class tables for estimating the volume in board feet, Scribner Rule, of ponderosa pine, Douglas-fir, and white fir in California. This single series of tables fits all three species within acceptable limits of error. It is hoped that this series may satisfactorily replace the many existing tables for single species, both old growth and young growth, and for various sites.
The wider application of sales by tree estimates in the national forests of California raises the need for more accurate volume tables. Those now available are based on the two variables, d.b.h. (diameter breast high) and height. The limitations of such tables become especially critical in small sales of a few trees. For this purpose variation in estimates of individual trees must be reduced to a minimum.
A third variable, form class, to measure the shape of the tree has been included in the present tables to improve individual tree estimates. Such improvement unfortunately incurs increased difficulty in applying the tables. This difficulty arises from the need for accuracy in determining form class itself. Unless form class is carefully determined, its introduction accomplishes no improvement in volume estimates.