Abstract
I applied the theoretical volume equation (TVE) to 181 Japanese cedar (Cryptomeria japonica D. Don) sample trees collected from three regions, i.e., Yoshino (Nara Prefecture), Nishikawa (Saitama Prefecture) and Obi (Miyazaki Prefecture). The average relative error and standard error of stem volume estimated by TVE were, respectively, 0.923% and 0.015m^3 for Yoshino, 3.191% and 0.006 m^3 for Nishikawa, and 15.908% and 0.143m^3 for Obi. By contrast, the average relative error and standard error of stem volume estimated by EVE were, respectively, -3.820% and 0.042m^3 for Yoshino, 0.536% and 0.006m^3 for Nishikawa, and 4.327% and 0.030m^3 for Obi. It could not be judged which volume equation, TVE or EVE, had smaller average relative error and standard error. Since the EVE had been widely used in estimating stem volume, the result suggested that the TVE could be practically applied to Japanese cedar. In conclusion, the result of the present study would support the universality and goodness of fit of the TVE.
