孟滦林场白桦群落空间结构特征研究

本研究通过对孟滦林场4种不同立地条件下的白桦次生林的林木点分布状况、直径分布及空间结构参数(角尺度和混角度)的研究,来分析其群落空间结构特征。结果表明:研究区白桦林分直径总体上分布仍不合理,中小径阶林木较多,有明显人为干扰痕迹。除样地2直径分布特征值q偏低,在(1.3～1.7)范围外,其余样地的直径分布特征值q都在(1.2～1.5)之外,直径分布变化较大,没有规律;样地1、3个体分布角尺度分别为0.483和0.502,整体上呈随机分布,样地2、4的平均角尺度为0.532和0.583,其林木水平分布表现为团状分布;4块样地的平均混角度大小为:样地3样地1样地2样地4,由于人为及牲畜活动干扰对其树种组成及种间竞争的影响使其混角度都较低,同时不合理的人为干扰活动违背了树种自然演替规律,也是其结构不合理的重要因素。

Birch community characteristics of spatial structure in Mengluan forest farms

This paper analyzes the community spatial structure by exmining the spatial distribution of trees,diameter distribution and spatial structure parameters(angle scale and mixed angle) of 4 different site conditions in Mengluan.The results show that the distribution of Birch is still unreasonable,with overgrown trees in the path order,and the signs of human disturbance are obvious.The value of the diameter distribution of q varies too much in four plots(1.2-1.5) except for plot 2(1.3-1.7).The distribution of larger diameter path-order trees vary even more;For plots 1 and 3,individual plot-scale distribution angle for the 0.483 and 0.502,respectively,was on the whole randomly distributed;the average angle for plots 2 and 4 were 0.583 and 0.532,whose horizontal distribution of trees characterizes Bulk distribution.Human and livestock activities on right its species composition and inter specific competition in the low angle of the impact of its mix,while irrational anthropogenic interference with the activities of the law contrary to natural succession tree species on the distribution of stand structure exert significant impact.