辽东山地山杨天然次生林空间结构分析

Spatial structural characteristics of natural Populus davidiana secondary forest in Liaodong Mountain

【目的】研究辽宁老秃顶子国家自然保护区内天然山杨林的空间结构特征,为其经营与保护提供依据。【方法】在保护区内选择有代表性的山杨天然次生林建立50m×50m的标准地3块,通过分析标准地中山杨、蒙古栎、黄桦、刺楸的胸径结构和树高结构,来反映其林分水平的竞争状态,同时利用空间结构分析软件Winkelmass1.0对标准地内各树种的混交度、角尺度进行综合分析。【结果】山杨、蒙古栎、黄桦、刺楸的胸径和树高分布特征表现出一致性,整体上都呈现正态分布的特点,且山杨具有显著的竞争优势。全林分平均混交度为0.65,处于强度和极强度混交的林木比例达60.0%,作为优势树种的山杨混交度最小,仅为0.45。林分平均角尺度为0.48,整体呈随机分布。【结论】在调整森林结构时,应针对顶极或主要伴生树种的角尺度、竞争树胸径和树高分布、混交度来进行空间结构调整,使经营对象具有竞争优势或不受到挤压的威胁,使整个林分的格局趋于随机分布。

【Objective】The study aimed to explore the spatial structural characteristics of the natural aspen forest in the Liaoning Laotudingzi National Nature Reserve.【Method】Three representative standard plots of 50m×50mwere established in natural Populus davidiana secondary forest.The structure of diameter at breast height（DBH）and tree height of P.davidiana,Quercus mongolica,Betula allegheniensis and Septemlobate kalopanax were analyzed to reflect the competition level of stands.The spatial analysis software Winkelmass 1.0was used for comprehensively analyzing the mingling degree and the uniform angle index in sample plots.【Result】The DBH and tree height distribution of P.davidiana,Q.mongolica,B.allegheniensis,and S.kalopanaxwere consistent with normal distribution,and P.davidianahad significant competitive advantage.The average mingling degree was 0.65 and the individuals at high and extremely high mingling degrees accounted for 60.0%.As the dominant tree species,Populus davidiana had the minimum mingling degree of 0.45.The average uniform angle index of the whole stand was 0.48 witharandom distribution pattern.【Conclusion】When adjusting the forest structure,the mingling degree,neighborhood comparison and the uniform angle index of climax or major associated species should be considered so that the target species can have competitive advantage and do not suffer the threat of being squeezed and the forest plantation can tend to be random.