小兴安岭谷地云冷杉林主要种群及林隙形成木的空间格局

Spatial distribution pattern of main populations and gap makers in Picea koraiensis and Abies nephrolepis forest of Xiaoxing'an Mountains,Northeast China

调查了小兴安岭谷地云冷杉林1.5 hm2(100 m×150 m)固定样地内的物种组成和径级结构,用点格局方法分析样地内主要种群的空间格局和空间关联性以及林隙形成木的空间格局.结果表明:样地内胸径≥2 cm的乔木有13种,种群密度差异大,重要值在前4位的为臭冷杉、红皮云杉、白桦和花楷槭.种群的径级结构近似倒"J"形.臭冷杉和红皮云杉空间分布相似,随空间尺度的变化趋势为聚集-随机-均匀分布.白桦在≤40 m尺度为聚集分布,>40 m尺度变为随机分布,而花楷槭在整个研究尺度上均为聚集分布.除白桦和花楷槭两者间在整个研究尺度上均为负相关以外,其余种群间均为小尺度上正相关、大尺度上负相关.臭冷杉和白桦种群间正相关的显著性强,其他种群间正相关性普遍较弱.样地内林隙形成木的空间格局表现为中小尺度聚集分布,随尺度增大趋于随机分布.掘根形成的林隙形成木的空间点格局呈单峰型分布,随机、聚集和均匀3种分布均有出现.折干形成的林隙形成木的空间点格局分布整体波动不大,小尺度上在随机和聚集分布间交替出现,到大尺度则归于随机分布.两者间的空间关联性分析表明,≤32 m尺度为显著正相关,>32 m尺度为不显著的负相关.

Species composition and diameter class structure were investigated in 1. 5 hm2（ 100 m ×150 m） permanent plot in Picea koraiensis and Abies nephrolepis forest of Xiaoxing＇an Mountains.The spatial distribution pattern and spatial association of main populations and gap makers were analyzed by using point pattern analysis. The results showed that there were a total of 13 species with diameters at breast height greater than 2 cm in tree layer,and great differences were observed in the densities of main populations. The importance values of A. nephrolepis,P. koraiensis,Betula platyphylla and Acer ukurunduense were ranked in the first 4 in the plot. The diameter class structure of their populations presented an inverse ‘J＇curve. The spatial distribution patterns for A.nephrolepis and P. koraiensis were similar,which changed from aggregated,random to uniform distribution with the spatial scale. For B. platyphylla,the distribution was aggregated at ≤ 40 m scale,and random at 40 m scale,whereas A. ukurunduense presented an aggregated distribution pattern at the whole research scale. Except that the negative correlation between B. platyphylla and A. ukurunduense existed at the whole research scale,positive correlation between the other populations at small scale and negative correlation at large scale were observed. Only A. nephrolepis and B. platyphylla had significant positive correlation,and generally no significant correlation existed between other populations. Spatial distribution pattern of gap makers was characterized as aggregated distribution at small and middle scales,and random distribution with increasing scale. Spatial point pattern of gap makers formed by uprooting exhibited unimodal type distribution,and random,aggregated,and uniform distribution also occurred. Spatial point pattern of gap makers formed by breaking overall presented a little fluctuation,random and aggregated distributions alternatively appeared at small scale,and random distribution happened at large scale. Their spatial correlation analysis indicated that significant positive correlation existed at ≤32 m scale,and non-significant negative correlation at 32 m scale.