喀斯特常绿落叶阔叶混交林林木空间分布格局及关联性研究

基于茂兰喀斯特常绿落叶阔叶混交林1.28 hm²的固定样地每木检尺调查数据，将树木按树高分为不同林层，采用成对相关函数g(r)和标记点函数k_mm(r)对树木基于个体和标记点的空间分布格局及关联性进行分析。结果表明：在40 m研究尺度上，林下层、次林层和主林层树木分别在0~18、0~26 m和0~2 m的尺度上表现为聚集分布，其他尺度表现为随机或均匀分布。林下层林木胸径在小尺度上呈现显著的空间负关联，次林层林木胸径、冠幅与地上生物量的标记点在中尺度上呈现显著的空间负关联，主林层林木的各标记点在整个研究尺度上均没有显著关联性。林下层与次林层个体在2 m的尺度内呈现显著空间正关联，次林层与主林层个体在0~3 m尺度呈现显著空间正关联。总体而言，喀斯特常绿落叶阔叶混交林不同林层林木在小尺度呈聚集分布，层内竞争主要出现在林下层和次林层，不同林层个体间关联性主要表现在次林层与主林层及次林层与林下层之间。

Spatial Distribution Patterns and Correlation of Trees in Karst Evergreen Deciduous Broad-leaved Mixed Forest

Trees were divided into different forest layers according to tree height based on the survey data of each tree in a 1.28hm2 fixed plot in a karst evergreen deciduous broad-leaved mixed forest in Maolan. Then the spatial distribution pattern of trees based on individual and marker points was analyzed by using g(r) and kmm(r). The results showed that on 40 m scale, trees in understory, substory and main story showed aggregation distribution at 0–18, 0–26 m and 0–2 m scales, respectively, while trees at other scales showed random or uniform distribution. The DBH of understory trees showed a significant negative spatial correlation at small scale. There was a significant negative spatial correlation between DBH, canopy width and biomass markers in substory at mesoscale, while there was no significant correlation between markers in the main story at the whole research scale. There was a significant positive spatial correlation between individuals of understory and substory at 2 m scale, and a significant positive spatial correlation between the individuals in substory and main story at 0–3 m scale. In general, affected by microtopography and diffusion restrictions, trees in different forest layers in karst evergreen deciduous broad-leaved mixed forest show aggregation at small scale, and intra-competition mainly occurs in the understory and the substory. The correlation between individuals in different forest layers were mainly between the substory and main story, and between the substory and undestory.