西双版纳热带雨林直径分布模型

传统的直径分布模型虽然能获得统计学上满意的表达结果,但常常忽略了大径阶株数的表达 大径阶内的林木虽然株数较少,但从森林经营的角度来看却比小径阶内的林木更加重要,所以在直径分布模拟和估计中必须充分地加以考虑 本研究建立了一个名为倒J形对数函数的新的直径分布模型,以云南西双版纳热带雨林为对象,通过对负指数函数、限定线函数、Weibull函数和倒J形对数函数4种直径分布模型的模拟和检验,发现倒J形对数函数和Weibull函数对于热带森林的直径分布模拟、尤其是对大径阶部分的林木株数分布有较好的拟合效果

Diameter Frequency Distribution Models in the Tropical Rain Forest of Xishuangbanna, Southwest China

Traditional empirical functions can obtain satisfactory modeling results mathematically even they ignore expressing the stems at the right side of the diameter distribution. But from the view of forest management, the less stem number of larger dbh classes is much more important than that of the smaller ones and must adequately be considered in the modeling and estimate. Permanent plots in the montane tropical rain forests in Xishuangbanna, Southwest China, were established, and different empirical models, based on observation data of these plots, were developed to model diameter frequency distributions. There exist 3 traditional ways of modeling the diameter frequency distribution: the negative exponential function model, limiting line function model, and Weibull distribution model. In this study, a new model, named as the logarithmic J-shape function,together with the others, was tested. Results show that logarithmic J-shape function and Weibull distribution model are as more suitable models for modeling works, especially the stem number of larger dbh classes in the tropical rain forests.