长白山2种针阔混交林空间结构多样性研究
Spatial structure diversity of semi-natural and plantation stands of larix gmelini in Changbai Mountains, northeastern China.
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摘要: 为研究云冷杉过伐林的恢复和保护,本文选取落叶松云冷杉林和云冷杉针阔混交林2个林分,应用传统林分直径因子结合空间多样性指数和空间结构参数的二元分布,对长白山落叶松云冷杉林和天然云冷杉林的整体结构进行分析。结果表明:1)云冷杉针阔混交林的径阶分布近似为反“J”型曲线,落叶松云冷杉林的径阶分布为多峰的反“J”型曲线,呈现出同代林的特征;2个林分的空间多样性指数分别为5.546 0和4.149 4。2)2个林分空间结构的二元分布特征差异不显著,落叶松云冷杉林中胸径和树高处于中庸且呈随机分布的林木所占比例为14%和13%,云冷杉针阔混交林中为11%和13%;落叶松云冷杉林分中处于强、极强度混交且胸径和树高占据中庸势态的林木分别占总林木的12%和10%,云冷杉针阔混交林中为13%和14%。3)落叶松云冷杉林分中处于不同优劣程度和混交等级的林木株数比例相差较大;云冷杉针阔混交林分中,相同混交状况的林木在不同优劣等级的株数比例相差不大,林分胸径和树高差异不明显。天然云冷杉针阔混交林处于相对稳定状态,落叶松云冷杉林需要采取抚育措施以提高其空间结构多样性。研究结果可应用于落叶松云冷杉林抚育设计,调整其林分结构,实现林分的空间结构化经营。Abstract: The objective of this study was to study the recovery and protection of over-logged forests. Based on survey data of two plots, the structure of larch-spruce-fir stands and natural spruce-fir and broadleaf mixed forests was analyzed using traditional approaches, species spatial diversity and a bivariate distribution of three commonly used diversity indices, i.e. uniform angle index (W), dominance (U) and mingling (M). The results indicated that: 1) The diameter distribution of the spruce-fir and broadleaf mixed forests was similar to a “J-shaped” curve. The diameter distribution of the larch-spruce-fir stands was similar to a multimodal “J-shaped” curve and showed the characteristics of stands of the same generation. The value of species spatial diversity of larch-spruce-fir stands (4.149 4) was smaller than that of spruce-fir and broadleaf mixed forests (5.546 0). 2) There were no significant differences in the structure of the bivariate distribution between the two plots. As for two indices DBH and height, the frequency of the trees with random distribution pattern and middle dominance degree was 14% for DBH and 13% for height in the larch-spruce-fir stands, and 11% for DBH and 13% for height in the spruce-fir and broadleaf mixed forests. As for the same indices, the frequency of the trees with high mingling and middle dominance degree was 12% for DBH and 10% for height in the larch-spruce-fir stands, and 13% for DBH and 14% for height in the spruce-fir and broadleaf mixed forests. 3) The frequency of trees with different dominance and mingling degree was different in the larch-spruce-fir stands. Trees with same mingling degree were almost the same between different dominance degrees in spruce-fir and broadleaf mixed forests. There was also little difference in DBH and height. The natural spruce-fir and broadleaf mixed forests were in a relatively stable state. Immediate measures are needed to improve spatial structure diversity in the larch-spruce-fir stands. The results of our research could be used for the design and tending of larch-spruce-fir stands and adjustment of its structure, and thus to achieve the effects of structure-based forest management of larch-spruce-fir stands.