柏木人工林立地质量与林分结构规律的研究

本文通过对柏木人工林林分结构时、空间变化规律的研究,发现林木株数按径级的分布在幼龄期呈倒“丁”型,在中龄前期低指数级呈倒“丁”型,高指数级近似正态分布,而中龄后期为近似正态和正态型,随年龄和指数级的增大其径级分布从倒“丁”型向正态分布里有序的过渡;分析了不同立地质量下林分(?)、(?)、(?)及生物量等生长指标的变化规律,并建立了指数级和各指标之间的函数回归式,以实现对不同立地质量林分的评价预测;分析探讨了不同经营目的下林分的合理密度,为柏木人工林经营提供了技术指标和依据。

A Study of the Site quality and Stand Structure of Mourning Cypress Plantations

Through studies of the changing laws of mourning cypress plantations in line with time and space it is found that the distribution of forest trees according to their diameter-class appears a re versed "J" in the juvenile period,and so does that of the low index class in the earlier middle-aged period. The forest trees of high index class are similar to a normal distribution, but present a normal and an approximate normal distribution in the later middle-aged period. As a result,the diameter-class distribution of forest trees shows an ordered transition from the inversed "J" to the normal dis tribution along with the rise in their age and index class. The changing laws of such growth indexes of stand as average diameter,height,volume and biomass under different site quality are analysed in this paper. Functional regression formulae between the index class and indexes are established for the evaluation and prediction of stand under different site quality. Moreover, the rational density of stand for various management purposes is discussed to provide technical basis for the management of mourning cypress plantations.