6种生长方程在杉木人工林林分直径结构上的应用

对Richards等6种生长方程的数学解析性及其应用于杉木人工林林分直径结构模拟的理论依据进行了分析和探索，并应用此6种生长方程模拟了林分直径累积分布。发现在描述林分直径累积分布时，Richards方程绝大多数表现为Logistic型，Weibull方程的参数c均大于1，曲线存在拐点；除Mitscherlich式外，各生长方程的模拟精度均相当高，Richards、Weibull、Logistic、Gompertz、Mitscherlich、Kod等6种生长方程样本选优率依次降低；Richards、Logistic、Weibull、Gopertz、Korf及Mitscherlich等6种生长方程总体模拟精度依次降低；相对生长率表现为变量指数函数方程的精度较相对生长率表现为变量幂函数方程的精度高，且3参数方程的精度较2参数的高。

Application of Six Growth Equations on Stands Diameter Structure of Chinese Fir Plantations

The mathematical characteristics of six growth equations and the theoretical basis of these equations applied to model stands diameter structure are analyzed and explored, and the long term observation data of permanent sample plots of Chinese fir are sorted out. The six equations are used to simulate stands cumulative diameter distribution, in order to clearly master the simulation parameters of every equation and what properties growth eqations have when used in the field of diameter structure. The results show: Richards equation at most time presents as a kind of Logistic and Weibull equation has its inflection point; except for Mitscherlich function, modelling precision of all growth functions are very high; the optimum seeking rate of Richards, Weibull, Logistic, Gompertz, Mitscherlich and Korf successively get down; the whole precision of Richards, Logistic, Weibull, Gompertz, Korf and Mitscherlich successively get down; the functions, relative growth rate of which is the index of variable,have the higher precision than those that relative growth rate is the power of variable; equations with three parameters have the higher precision than equations with two.