四川盆地西缘柳杉人工林结构及生长预测的初步研究

运用多元统计分析的方法,研究了四川盆地西缘山地柳杉人工林的密度和直径—株数分布的规律,筛选出了影响林分密度的主导因子(林今年龄、地位指数和林分平均直径),并建立了林分密度预测模型。还根据西泽正久(1978)所提供的求解Weibull分布参数e的gamma和Cud数值表,对48块林令标准地的林木株数调查结果用Weibull分布函数进行了拟合。结果表明:有33块标准地的拟合结果经卡方检验达到极显著水牛(α=0.01),有10块标准地达显著水平(α=0.05),另有5块标准地的拟合结果则不符合weibull分布。在此基础上,对影响柳杉人上林Weibull分布函数的 b、c参数的林分结构因子进行了回归分析,并用易测林分结构因子建立了两个参数的预测模型。 通过建立上述预测模型,作者对柳杉人工林的结构和生长量进行了综合预测。经检验结果表明:本次研究所建立的预测模型达到精度要求,为森林资源预测、森林经营管理、抚育间伐提供科学依据。

A Preliminary Study on the Structure and the Estimation of Growth of Cryptomeria Fortunei Plantation in the Western Borders of the Sichuan Basin

The method of multivariate statistical analysis was applied to study the density and the structure of diameter-tree number of Cryptomeria fortunei plantation in the western borders of the Sichuan Basin. And important factors (age,site index and average diameter of stands) that affected the density of C. fortunei plantation were sifted ou. And the model that estimated the density of C. fortunei plantation was established. On the basis of the table for determining gamma value and coefficient of variation of diameter of c parameter of Weibull function offered by Nishizawa Seikyu( 1978) , Weibull function was fitted with the data from 48 standard plots.The results of X_2-test showed that X_2 values of 33 standard plots came to extremely significant level (a=0. 01).and 10 standard plots came to significant level (a=0. 05).and other 5 standard plots did not fit into Weibull function. The expression of regression was made between b,c parameters of Weibull function and the structure factors of C. fortunei plantation. And the predicted model was es tablished that estimated b.c parameters with structure factors easy to be measureted in the stands.Based on the models above,the structure and the growth of C. fortunei plantation were estimated.The tested result showed that the estimted values of the models came to the precision demand.and the models can be used for the prediction of resources,management and thinning of forest.