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林木分布格局是森林结构的重要组成部分,直接影响森林生态系统的健康与稳定,维持森林结构多样性被认为是保护生物多样性的最佳途径。本研究探讨了林木分布格局多样性的测度方法,以期为揭示森林结构多样性提供理论依据。格局多样性研究的关键在于选择合适的生物多样性测度方法和具有分布属性的格局指数。本研究通过统计角尺度分布频率和Voronoi多边形边数分布频率,运用Simpson指数分别计算角尺度多样性和Voronoi多边形边数分布多样性,作为表达林木分布格局多样性指数的方法,并以我国东北吉林蛟河的3个100 m×100 m的阔叶红松(Pinus koreansis)林长期定位监测标准地为例,分析了林木分布格局的多样性。结果表明:无论是角尺度分布还是Voronoi多边形的边数分布都接近正态分布,角尺度分布中随机分布林木的频数最多,占55%以上;Voronoi多边形的类型多达10个以上,50%以上的林木有5–6株最近相邻木。利用Simpson指数衡量林木格局多样性,角尺度分布与Voronoi多边形的边数分布都显示出聚集分布的林分比随机分布林分的格局多样性高。研究还发现,两种格局判定方法得出的Simpson指数值有所不同,角尺度分布的多样性数值明显低于Voronoi多边形的边数分布的多样性数值,主要原因是二者的等级数量不同。可见,林木分布格局多样性研究应选择具有分布属性的格局指数,但由于各指数反映的角度不同,所以在分析比较不同林分格局多样性时应采用相同的分析方法。
Forest distribution pattern is an important part of forest structure. It directly affects the health and stability of forest ecosystem. Maintaining forest structure diversity is considered as the best way to protect biodiversity. In this study, we discussed the method of measuring the diversity of forest distribution pattern, in order to provide a theoretical basis for revealing the diversity of forest structure. The key to the study of diversity is to select suitable measures of biodiversity and pattern indices with distributional attributes. In this study, the angular distribution of frequencies and Voronoi polygon edge frequency distribution frequency, the use of Simpson index to calculate the angular scale diversity and Voronoi polygon edge number distribution diversity as a method to express the diversity of forest distribution pattern index, Taking Long Jiao (Pinus koreansis) forest of 100 m × 100 m in Jiaohe as an example, the diversity of forest distribution patterns was analyzed. The results show that both the angular distribution and the Voronoi polygon have a normal distribution. The distribution of trees in the distribution of angle scales is the largest, accounting for more than 55%. The types of Voronoi polygons are more than 10 and 50% The trees have 5-6 recently adjacent wood trees. Using the Simpson index to measure diversity of forest pattern, both the angular distribution and the edge distribution of Voronoi polygons showed that the distribution pattern of the stands was higher than that of the random distribution. The study also found that Simpson index values obtained by the two methods are different. The diversity of angular scale distribution is significantly lower than that of the Voronoi polygon. The main reason is that there are different levels of the two. Therefore, we should choose the pattern index which has the distribution attribute. However, as each index reflects different perspectives, the same analysis method should be used in analyzing and comparing the diversity of different stand patterns.