金沟岭天然和半天然混交林林分空间结构比较

Comparison of Spatial Structure for Natural and Semi-natural Mixed Forests in Jingouling Forestry Farm,Jilin Province of China

使用角尺度、混交度和大小比数3个林分空间结构参数,对长白山过伐林区特有的半天然落叶松(Larix olgensis)-云杉(Picea jazoensis)-冷杉(Abies nephrolepis)混交林和未受人为干扰的原始天然混交林进行了空间结构分析和比较。结果表明,两种林分具有相同的平均角尺度0.52,林木皆为团状分布;半天然落叶松云冷杉混交林的平均混交度为0.64,呈现中度混交特征;从胸径大小比数来看,林分中针叶树种具有胸径优势,尤其是云杉的胸径优势最突出,红松(Pinus koraiensis)则分化严重,生长处于劣势。原始天然混交林的平均混交度为0.83,高于半天然落叶松云冷杉混交林,呈现强度混交特征;从胸径大小比数看,阔叶树种胸径优势明显,针叶树种中只有冷杉处于优势,红松和云杉都处于劣势。

Three indices （uniform angle index, mingling index and neighborhood comparison ratio） are used to describe and compare the spatial structure of the natural mixed forest undisturbed by human activities and the semi-natural mixed stand of larch （Larix olgensis）-spruce（Picea jazoensis）-fir（A bies nephrolepis） which only exists in the over-logged forest of Changbai Mountains. Results indicate that two stands have the same uniform angle index of 0.52, with tree distribution being clustered. The average mingling index of the semi-natural mixed forest of larch-spruce-fir is 0.64, with moderate mixed characteristics; the coniferous trees （esp. spruce） in the stand are dominant as seen from the neighborhood comparison ratio based on Diameter at Breast Height （DBH）, while the Korean pine （Pinus koraiensis） is in polarization and inferior position. The average mingling index of the natural mixed forest is 0.83 and higher than that of the semi-natural mixed forest of larch-sprucefir, with intense mixed characteristics and higher stability; hardwood trees in the stand are dominant as seen from the neighborhood comparison ratio based on DBH, while the coniferous trees are in inferior position except spruce. The results could be used to optimize the spatial structure and near natural management of the over- logged forests and plantations.