摘要:利用小兴安岭凉水自然保护区内10.4 hm²样地的调查数据，统计并分析样地内乔木树种的组成与分布，借助混交度计算方法探究大径级个体周围同种邻木分布情况，并分析其产生的原因及大径级个体在其中发挥的作用，研究结果表明：（1）大径级个体（DBH ≥ 50.0 cm）与其周围5-6 m范围内的邻木的混交程度最低，易形成围绕大径级个体（以下简称中央木）的同种邻木环形结构，该环形结构在一定程度上推动着未来的森林演替与更新；（2）距离中央木15 m范围内的中小径级个体（1级木（1.0 cm ≤ DBH < 5.0 cm）、2级木（5.0 cm ≤ DBH < 10.0 cm）、3级木（10.0 cm ≤ DBH < 30.0 cm））与中央木均保持较高的混交程度，而4级木（30.0 cm ≤ DBH < 50.0 cm）、5级木（DBH ≥ 50.0 cm）与中央木的混交程度明显下降，以5级木最低，这种现象的产生与密度制约及物种共存机制存在密切关系。通过研究不同物种及不同生长阶段（不同径级）的林木分布，揭示了凉水地区阔叶红松林中大径级个体周围邻木分布格局特征及其成因，论证了大径级个体在控制周围林分结构、维持物种多样性及推动森林演替中的重要作用，为阔叶红松林的经营及管理提供了数据支撑。



Abstract:The spatial pattern of forests depends on their internal characteristics, interspecific relationships, external environmental characteristics, and interactions with different individuals of the same species plant. At the same time, it also determines the spatial situation of growth competition among trees and provides habitats of animals, plants, and microorganisms and it is one of the important research contents of forest ecology. We used the survey data of 10.4 hm² plots in the Xiaoxing'an Mountains Liangshui Nature Reserve to analyze the composition and distribution of arbor species in the plots. We used the calculation method of mixed degree to explore the distribution of same species adjacent trees around large-diameter individuals, and analyzed the causes and the role of large-diameter individuals. Research indicates:(1) Large diameter individuals (DBH is greater than 50.0 cm) have the lowest degree of mixing with neighboring trees in the range of 5-6 m around it, and it is easy to form the same species adjacent trees circular structure surrounding large diameter individuals (hereinafter referred to as the central tree), which promotes the future forest succession and renewal to a certain extent; (2) The middle and small level individuals within the range of 15 m from the central trees (diameter class 1 of adjacent trees (1.0 cm < DBH < 5.0 cm), diameter class 2 of adjacent trees (5.0 cm < DBH < 10.0 cm), and diameter class 3 of adjacent trees (10.0 cm < DBH < 30.0 cm)) maintain a high degree of mixing with the central trees. However, the degree of mixing of diameter class 4 of adjacent trees (30.0 cm < DBH < 50.0 cm) and diameter class 5 of adjacent trees (DBH ≥ 50.0 cm) with the central trees were significantly decreased, and diameter class 5 of adjacent trees was the lowest. This phenomenon is closely related to conspecific negative density dependence (CNDD) and species coexistence mechanism. In this paper, by studying the distribution of trees in different species and different growth stages (different diameter classes), we revealed the forest spatial pattern characteristics and the cause of formation of the trees around the large diameter individuals in broad-leaved Korean pine forests in Liangshui, and demonstrated the important role of large diameter individuals in controlling the structure of surrounding forests, maintaining species diversity and promoting forest succession, which provides data support for the sustainable management of broadleaved Korean pine forest. In addition, this study adopted single-time forest data. Whether the influence of large diameter individuals on the surrounding forest structure and species diversity will change with time remains to be further studies. Therefore, long-term dynamic observation study of forest community is urgently needed.





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