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在木论自然保护区极小种群单性木兰(Kmeria septentrionalis)群落木本植物每木调查的基础上,采用混交度、角尺度和大小比数3个林分空间结构参数,分析单性木兰生存群落木本植物物种组成及其空间结构特征。结果表明,样地内共有木本植物树种95种,隶属于55科82属,为典型的阔叶混交异龄林。群落林木以小径级占绝对优势,林木个体随着径级的增大急剧减少,整体呈倒J型分布。群落中大部分树种处于强度混交,树种间混交程度较高,林分平均混交度达0.742;群落林分大小比数为0.508,不同等级的林木在空间结构单元内分布较均匀;大部分林木介于随机分布和不均匀分布,均匀分布比例较少,林分平均角尺度为0.549,群落空间分布格局为轻度聚集分布。单性木兰种群径级结构呈倒J型,种群从幼苗向幼树生长过程中林木个体急剧减少。单性木兰种群混交度为0.796,处于高度混交状态;平均大小比数为0.400,处于亚优势偏向中庸状态;角尺度为0.528,呈轻度聚集分布状态。单性木兰群落不仅亟须有效保护,同时需采取适当的人为干扰措施促进种群的延续与发展。
Based on the investigation of woody plants in the Kmeria septentrionalis community in the Mulin Nature Reserve, the spatial structure parameters of three forest types, including the degree of mixing, the angle scale and the size ratio, Community Woody Species Composition and Spatial Structure Characteristics. The results showed that there were 95 species of woody plants in the sample, belonging to 55 genera and 82 genera, which were typical broad-leaved mixed-aged stands. Community trees take the absolute advantage of the path of small size, individual tree size decreases sharply with the increase of diameter, the overall inverted J-type distribution. Most of the species in the community were mixed in intensity, and the mixed degree among the species was high. The average mixed degree of the stands was 0.742. The ratio of the stand size to the community size was 0.508. The different grades of forest trees were more evenly distributed in the spatial structure units. In random distribution and uneven distribution, the proportion of uniform distribution is small, the average angular dimension of stand is 0.549, and the spatial distribution pattern of community is lightly aggregated. The diameter-class structure of the single-sex magnolia was inverted J-shaped, and the number of trees in the population decreased sharply from the seedling to the young tree. Mingle of Magnolia biondii population was 0.796, which was in a high degree of mixed state. The average size ratio was 0.400, which was in the middle state of subdominant preference. The angular scale was 0.528 with a slight aggregation distribution. It is not only necessary to effectively protect Monotypic Magnolia community, but also to take appropriate human intervention measures to promote the continuation and development of the population.