金沟岭林场杨-桦次生林空间结构研究

Study on spatial structure of poplar-birch secondary forest in Jingouling Forest Farm

以金沟岭林场杨-桦次生林为研究对象,分别研究各演替阶段基本测树因子,对样地调查数据进行处理分析,用角尺度、混交度和大小比数来表达林分的水平结构,用林层指标来反映林分垂直方向的结构特征,从而得出杨-桦次生林各演替阶段林分空间结构特征以及随着演替的进行林分空间结构的变化趋势。结果表明:(1)在演替初期林木分布为随机分布,演替中期与演替的亚顶级阶段林木分布为团状分布;林木混交程度随着演替由中度混交逐渐转变为强度混交和极强度混交;随着演替进行,先锋树种的优势程度逐渐减小,顶级树种的优势程度逐渐增大。(2)演替初期,各林层伴生树种比例逐渐增加,先锋种比例逐渐减少;演替中期,则顶级树种比例逐渐增加,先锋树种比例逐渐减少;演替亚顶级阶段,各林层的先锋树种,伴生树种,顶级树种的比例为1∶3∶6。

The basic tree measurement factors in various succession stages of poplar-birch secondary forest in Jingouling Forest Farm were investigated, the sample plots survey data were processed and analyzed. The stand＇s horizontal structure was characterized by angular scales, mingling index and neighborhood comparison of DBH, the stand＇s vertical structure was characterized by the forest story index, thus obtaining the spatial structure characteristics of the forest stands in different succession stages and the variation tendency of the stands spatial structure. The results show that（l） in the early succession stage, the tree distribution was random, and it appeared reunion distribution in both the middle and third succession stages; as the development of succession, the degree of forest mixed changed gradually from moderate to strength and then extreme strength mixed; the pioneer species advantage of gradually reduced, the advantage of top trees gradually increased.（2） In the early succession stage, the proportion of associated tree species increased gradually, the proportion of pioneer species reduced gradually in each forest story; in the middle succession stage, the proportion of top species increased gradually, the proportion of pioneer species reduced gradually; in the third succession stage, The proportion of the early, middle and third succession stages was 1 ： 3 ： 6 in each forest story.