Quantitative analysis of mixed-age forest structure

Author: An Huijun / Zhang Tao (editors)
Publisher:
Publish Date: 2004-12-01
Features: This book focuses on broad-leaved Korean pine forests in Jiaohe, Jilin Province, with varying levels of human disturbance, analyzing the forest stand characteristics, particularly spatial structures, of pioneer tree-dominated stages, associate tree-dominated stages, and climax community stages. The aim is to provide theoretical and technical support for the sustainable management of broad-leaved Korean pine forests. Based on the characteristics of positioning data, the book proposes a method to eliminate boundary effects in calculating aggregation indices. In the study of forest stand spatial structure, it for the first time introduces the parameter "layer ratio" to express the multi-layer structure of forests. This parameter aligns with other spatial structure indices such as mixing degree, size ratio, and angle scale, thereby supplementing forest stand spatial structure parameters. It also identifies that the optimal structural unit for spatial structure research in broad-leaved Korean pine forests consists of a reference tree and its four nearest adjacent trees. The optimal standard angle for angle scale is determined to be 72 degrees. Research based on the optimal structural units shows that the spatial structure parameters of different tree species in broad-leaved Korean pine forests vary to varying degrees at different developmental stages. As the forest stand progresses toward a stable climax community stage, the layer ratio and mixing degree gradually increase. By using some indicators of angle scale and aggregation intensity, as well as aggregation indices, to analyze the spatial pattern of trees, the results are consistent: trees are aggregated in the pioneer tree-dominated stage, develop into a random distribution pattern in the associate tree-dominated stage and climax community stage, and the average distance of nearest neighbors and the average distance of structural units increase progressively. Spatial structure parameters can be used to select logging trees. During implementation, based on the analysis of forest stand spatial structures at different developmental stages, the main objectives of adjusting relevant structural parameters at different stages are determined, priority structural units for logging are selected, and a comprehensive balance is conducted to finalize the logging trees.