华北落叶松人工幼龄林生长特征分析

Growth characteristic analysis of Larix principis-rupprechtii young plantation

为了研究华北落叶松人工幼龄林的生长规律,在河北塞罕坝机械林场设置了33块标准地,研究华北落叶松幼龄林树高、胸径和材积生长特点以及密度对材积生长的影响。结果表明,华北落叶松在5年生树高生长开始加速,胸径生长在11年生前处于快速增加阶段,材积生长量在9年生开始进入高速生长阶段,树高、胸径和材积生长都在15年生时达到最大值,然后降低。不同地位级、不同密度其每公顷材积年均生长量不同;在密度一定的情况下,年均生长量随地位级的提高而增加;而针对某一地位级,随密度增加,材积增长速度呈降低趋势。

In order to study the growth of height,diameter at breast height（DBH）and volume of timber,as well as the relationship between volume of timber and density of Larix principis-rupprechtii young growth plantation,33 survey plots were established in Saihanba,Hebei province,and the results indicated that the growth trend of height of Larix principis-rupprechtii individual increased from 5 years old after planted,growth of height stepped into accelerate growth stage from 11 years old,and the start of volume of timber was 9 years old.Growth of height,DBH and volume of timber reached the largest value at the year of 15 and became less after that. Volume of timber and annualmean growth per hectarewere different in different site classes and density,in the case of a certain density, annual mean growth increased as the increase of site classes,while in the case of a certain site class,growth of volume of timber decreasedwith the increase of density.