Abstract
A diameter-distribution prediction system (DDPS) was previously developed for pure even-aged hinoki (Chamaecyparis obtusa Sieb.) plantation. In this study, we examined the applicability of this DDPS to sugi (Cryptomeria japonica D. Don) plantation. We estimated the parameters for the DDPS mainly using a data set obtained from permanent sample plots in western Japan and validated the parameters using a data set obtained from permanent sample plots in the Kanto and Kinki regions. We also compared predicted and observed diameter distributions. We found that when the length of the prediction period was shorter than 16 years and initial stand age was larger than or equal to 31 yr, the predicted and observed density and basal area were not significantly different. The difference between predicted and observed distributions were minor and the goodness of fit appeared sufficient to allow this method to be used for prediction of sugi stand variables and diameter distributions for stands aged over 30 years. Considering the independency of the two data sets used for parameter prediction and validation, it is concluded that the DDPS would accurately predict stand growth in other regions.
