天然红松阔叶林不同径阶林木的空间分布特征分析

为进一步揭示天然红松阔叶混交林的空间结构规律,为合理经营天然红松阔叶林提供借鉴,本研究在吉林省蛟河林业实验区大坡经营区设立面积为1 hm2的样地,利用全站仪对高度1.3 m以上的林木进行每木调查,然后利用角尺度、大小比数和混交度等3种结构参数,分析了样地内不同径阶林木的空间分布特征.结果表明:天然红松阔叶林中小径阶(胸径≤10 cm)林木占总株数的59.4%,其周围林木呈随机分布,与林分的总体分布格局一致.大径木的平均角尺度呈急剧下降的趋势,说明其相邻木挤在一起的现象大幅度减少,相邻树木在其四周趋于均匀分布.林木大小比数随胸径的增大呈迅速减小的趋势,小径木多明显受压,中径木处于中庸状态或亚优势地位,大径木全部处于优势地位.林木混交度随着胸径的增大呈逐渐递增的趋势,竞争压力逐步减小,林木空间分布特征渐趋优化.

Analysis of Spatial Distribution Characteristics of Trees with Different Diameter Classes in Natural Korean Pine Broad Leaved Forest

To further explore the spatial structure pattern of natural Korean pine broad leaved forest and provide references for managing the natural forests, this study established a 1 hm^2 plot in Dapo Region of Jiaohe Forestry Experimental Area, using TOPCON-GTS-602AF to survey every tree higher than 1.3 m, and then employing three parameters-angle index, neighborhood comparison and mingling-to analyze the spatial distribution characteristics of trees with different diameter classes in this plot. It showed that the trees with diameter classes smaller than 10 cm accounted to 59.4% of all tress in the forest, with the trees around them distributing in random pattern, similar to the distribution pattern of the whole forest. On the contrary, trees with larger diameter classes had remarkable decreasing angle indices, with the neighboring trees uniformly surrounding them. Neighborhood comparisons decreased with increasing diameter classes, with the small trees being suppressed, the large trees being superior, while the middle trees being in some kind of intermediate or above status. Meanwhile, mingling increased with increasing diameter classes, showing that as their diameter increased, trees would face lessening competitive stress and that the spatial structure of the forest was gradually getting optimized.