理论生长方程对杉木人工林林分直径结构的模拟研究

APPROACH TO THEORETICAL GROWTH EQUATIONS FOR MODELLING STANDS DIAMETER STRUCTURE OF CHINESE FIR PLANTATIONS

理论生长方程在林分直径结构领域的应用具有重要的理论和实践意义。为探寻影响理论生长方程模拟性能好坏的内外机制 ,从而有所选择和鉴别地使用理论生长方程 ,本文从林分及方程两个角度出发进行了探讨。结果表明 :年龄、立地、密度、间伐强度等因素对Richards等 6种生长方程模拟精度影响不明显 ,而不同方程间的模拟精度差异极明显 ;林分直径累积分布曲线的拐点存在一个主要区间 ( 0 4～ 0 6) ,生长方程拐点的取值情形与方程模拟精度的大小密切相关 ,方程最佳拟合曲线的有效拐点区间愈大、拐点精确度愈高 ,拐点有效性越大 ,则方程模拟精度越高。

The application of theoretical growth equations to the field of stand diameter structure has important significance in both theory and practice.In order to look for the inside and outside mechanism,and be elective and distinguished to use theoretical growth equations,this paper,in the view of stands and equations,studies and discusses this problems.The results showed:that there was not obvious influence of age,site index,density and thinning weight on modelling precision of six growth equations,such as Richards,Logistic and Korf so on,but there was a distinctly difference in modelling precision significant among equations.The inflection points of curve of stands cumulative diameter distribution mainly ranged,from 0.4 to 0.6. There was a close correlation between the value distribution of inflection points of growth equations and the modelling precision of equations,the wider the effective inflection point range of the best fit curve of equations was,or the higher the precision of inflection points was.The bigger the validity of inflection points was, then the modelling precision of equations would be higher.