芦芽山阴坡华北落叶松-云杉天然次生林林分空间结构特征

  目的  分析芦芽山国家级自然保护区阴坡典型天然次生林的林分空间结构，为当地天然次生林的科学经营和相似立地条件下人工林的培育提供参考依据。  方法  以芦芽山自然保护区阴坡5个不同海拔的华北落叶松Larix principis-rupprechtii-云杉Picea spp.天然次生林群落调查数据为基础，通过计算群落的角尺度、大小比数、混交度和林分空间结构指数，分析不同海拔群落的空间结构特征。  结果  华北落叶松-云杉天然次生林平均角尺度为0.51~0.53，林木空间分布格局以聚集分布为主，但聚集程度较低，优势树种在林分中属于随机分布；各海拔林木的大小分化程度整体均接近中庸状态，林木大小分化程度较小，华北落叶松的大小比数小于云杉，表明华北落叶松的竞争力较大；随海拔高度的上升，林木空间隔离程度呈下降趋势；林分空间结构指数随海拔升高而下降，低海拔林分的整体结构较其他海拔更好。  结论  研究区华北落叶松-云杉天然次生林群落均处于演替后期阶段，海拔1 950 m处林分的空间结构最好，稳定性最高。图1表4参20

Spatial structure of Larix principis-rupprechtii-Picea spp.secondary forests on shady slope of Luyashan National Nature Reserve

  Objective  The objective is to analyze the spatial structure of typical secondary forests on shady slope of Luyashan National Nature Reserve, and provide reference for scientific management of natural secondary forest and artificial forest in similar habitats.  Method  Based on the survey data of Larix principis-rupprechtii-Picea spp. secondary forest communities at five different altitudes on the shady slope of Luyashan National Nature Reserve, the spatial structures of the communities at different altitudes were analyzed by calculating the angle scale, size ratio, mingling degree and forest spatial structure index.  Result  The average angular scale was 0.51?0.53. The spatial distribution pattern of the forests was dominated by aggregation distributions, but the degree of aggregation was low. The dominant tree species were randomly distributed in the stand. The size differentiation degree of the trees at all altitudes was close to the mean state, and the size differentiation degree of L. principis-rupprechtii was smaller than that of Picea spp., indicating that L. principis-rupprechtii was more competitive. With the increase of altitude, the spatial isolation degree and the spatial structure index decreased. The overall structure of lower altitude stand was better than that of other altitudes.  Conclusion  The communities of L. principis-rupprechtii-Picea spp. secondary forests in the study area are in late state of succession. The stand at 1 950 m above sea level has the best spatial structure and stability. Ch, 1 fig. 4 tab. 20 ref.]