长白山云冷杉林幼苗幼树空间分布格局及其更新特征

长白山云冷杉针阔混交林是我国东北主要的森林类型之一,其乔木树种幼苗幼树的结构和动态决定着未来林分的结构和生长动态。在长白山地区设置一块具有代表性的云冷杉针阔混交林幼苗幼树更新样地,统计分析幼苗幼树更新特征,绘制地径结构图、树高结构图及其空间分布图。运用点格局分析中的单变量O-ring统计方法,分析更新树种的空间分布格局;用双变量O-ring统计方法,分析更新树种种间的空间关联性。研究结果表明:(1)更新树种组成有冷杉(Abies nephrolepis)、色木槭(Acer mono)、紫椴(Tilia amurensis)、红皮云杉(Picea koraiensis)、红松(Pinus koraiensis)、蒙古栎(Quercus mongolica)、春榆(Ulmus japonica)7种,其中以冷杉、色木槭为主,更新幼苗幼树的地径近似呈倒J型分布,树高结构近似呈双峰分布;(2)所有更新树种、冷杉、色木槭在小尺度1—10 m的范围内呈聚集分布,随着尺度增加,聚集程度减弱,逐渐趋于均匀分布和随机分布,紫椴、云杉和红松在空间所有尺度上以随机分布为主;(3)更新树种之间的空间关联性在小尺度范围上正关联性比较多,较大尺度范围上负关联性比较多,随着尺度增加,空间关联性减弱。

Spatial distribution patterns of seedling and sapling in a spruce-fir forest in the Changbai Mountains area in northeastern China

To describe the seedling and sapling distribution patterns of a spruce-fir coniferous and broadleaved mixed forest in the Changbai Mountain area, one sample plot covering 60×60 m was established. The spatial coordinates, diameters at ground height (DGH) and heights (H) of all trees with a height exceeding 30 cm and a diameter at breast height (DBH) less than 5 cm were measured. Based on these data from the sample plot, by the method of point pattern analysis, and the univariate O-ring function statistic was used to analyze the spatial patterns of the main regeneration tree species.The bivariate O-ring function statistic was used to analyze the spatial correlations among different regeneration tree species.The following 15 tree species were recorded in this plot: Abies nephrolepis, Picea asperata, Pinus koraiensis, Betula platyphylla, Betula costata, Tilia amurensis, Acer tegmentosum, A. mono, A. ukurunduense, Populus davidiana, Phellodendron amurense, Taxus mairei, Quercus mongolica, Fraxinus mandshurica and Ulmus japonica. The following 7 regeneration tree species were recorded: Abies nephrolepis, Acer mono, Tilia amurensis, Picea koraiensis, Pinus koraiensis, Quercus mongolica and Ulmus japonica.Abies nephrolepis and Acer mono are the most common species, which account for 87.40 percent of total, while Tilia amurensis, Picea koraiensis and Pinus koraiensis take second place, which account for 12.25 percent of total. Only few Quercus mongolica and Ulmus japonica were encountered, which account for 0.35 percent of total. The number of individuals decreased with increasing dgh and height of the regeneration tree species. The distribution of ground diameter follows the shape of an inverse J.The distribution of heights shows a bimodal shape.Abies nephrolepis and Acer mono show an aggregated spatial distribution at distances between 0 and 10 m. With increasing scale the distribution of all regeneration trees is uniform at first, then random. Tilia amurensis, Picea koraiensis and Pinus koraiensis are mostly randomly distributed at all scales, perhaps because of the limited number of these three tree species.Generally, the associations of regeneration tree species show positive correlations at small scales and negative correlations at larger scales.With increasing scale, the correlation intensity is declining. Abies nephrolepis and Tilia amurensis, and Picea koraiensis and Tilia amurensis, do not show a positive spatial correlation; The spatial relationship between Abies nephrolepis and Picea koraiensis, and Abies nephrolepis and Pinus koraiensis is not negative; There are no obvious spatial correlations between Picea koraiensis and Pinus koraiensis.