A Preliminary Study on Dynamic Laws in Coefficient Variation of the Tree Diameter Even-aged stands

The dynamic models in stand-level are developed for square coefficient variation of the tree diameter, which can be used to describe three states(decrease, stabilization, and increase)of square coefficient variation of the tree diameter, so it is an efficient way to predict arithmetic mean diameter via the quadratic mean diameter in stands. A satisfactory fitting has been obtained based on the growth data of even-aged plantations of Chinese fir(Cunninghamia lanceolata). Compared with another method proposed by Knoebel and others, the models are of both certain mechanism and better prediction precision on the whole. It has been found that the fitting can be improved as the initial value is added. The result of this paper could be used to predict the arithmetic mean diameter and coefficient variation of the tree diameter in unthinned and thinned even-aged plantations of Chinese fir.