Abstract
I tested whether or not BEHRE'S and KUNZE'S relative stem taper curves in coniferous species can be estimated theoretically only from tree height and diameter at breast height through a theoretical two-way volume equation, and compared the accuracy and precision of the estimated taper curves. The estimation procedure was fitted to 50 Cryptomeria japonica D. DON and 50 Chamaecyparis obtusa ENDL. trees. The estimated BEHRE'S relative stem taper curve showed higher accuracy and precision than KUNZE'S. In BEHRE'S relative stem taper curve, the mean relative errors of estimated diameter were less than ±3.2% for C. japonica and ±11.8% for C. obtusa, except on the upper stem near the tip. The standard errors of estimated diameter ranged from 0.7cm to 1.2cm for C. japonica and from 0.5cm to 1.9cm for C. obtusa. In conclusion, BEHRE'S relative stem taper curve can be well estimated theoretically only from tree height and diameter at breast height, except on the upper stem near the tip.
