Self-adjusted Height-Diameter Curves and One-entry Volume Model

It is proved that the error of one-entry volume tables presently used in Yanbian District,Jilin Province mainly comes from the estimate error of the average heights in diameter classes. Three types of multi-entries height-diameter model,named self-adjusted height-diameter curves,are introduced in this paper. The mean height of basal area are measured while the diameter distribution is measured for one subcompartment(or plot). Height-diameter curve will be estimated from the mean height and diameter distribution,and then an one-entry volume model will be obtained. The results of the research show that the first choice of the type of height-diameter curves is the reduced hyperbolic type,H=Hm·D/[D+(Hm/Hg-1)Dg](1) where D-diameter of a tree,H-its estimated height,Hg-mean height of basal area,Dg-basal area average diameter,Hm-height limitation(parameter).The self-adjusted one-entry volume models corresponding to equation(1)are developed. The results show that the error of self-adjusted one-entry models is 50% less than that of the present one-entry volume tables used in Yanbian District.