Biodiv Sci ›› 2023, Vol. 31 ›› Issue (11): 23219.  DOI: 10.17520/biods.2023219

• Special Feature: Semi-humid Evergreen Broad-leaved Forests • Previous Articles     Next Articles

Patterns and causes of forest gap disturbance in a semi-humid evergreen broadleaved forest in the Jizu Mountains, Yunnan

Xi Tian1, Wencong Liu1, Jiesheng Rao1, Xiaofeng Wang1, Tao Yang1, Xi Chen1, Qiuyu Zhang1, Qiming Liu2, Yanxiao Xu2, Xu Zhang3, Zehao Shen2,1,*()   

  1. 1 School of Ecology and Environmental Science, Yunnan University, Kunming 650091
    2 Key Laboratory of MOE for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871
    3 Yunnan Youtu Biotechnology Co., LTD, Kunming 650599
  • Received:2023-06-25 Accepted:2023-10-12 Online:2023-11-20 Published:2023-12-22
  • Contact: * E-mail:


Aims: Forest gaps are a common form of forest disturbance and play an important role in forest regeneration and species coexistence. The forest gaps serve as the basis for the forest landscape’s shifting mosaic structure. We aim to provide the scientific basis for better conservation and management of the semi-humid evergreen broad-leaved forests in the Jizu Mountains.

Methods: This study analyzed the species composition and DBH class structure of all woody plants (including all standing living trees and coarse woody debris (CWD) based on a survey of the forest dynamics plot in a semi-humid evergreen broad-leaved forest in the Jizu Mountains starting in 2022. The spatial patterns of the basal area of all woody plants and the number of forest gap makers (FGM) in the plot were mapped using ArcGIS. An environmental interpretation using a generalized linear model combined with variance partitioning analysis was performed.

Results (1) The number and the basal area of CWD were about 13.6% and 15.8% for all standing living trees, respectively. A total of 57 woody species contributed to CWD formation, with a total of 12,317 individual trees; among which 12 species acted as FGMs, with a total of 2,280 individual trees. (2) The DBH class structure of standing living trees and CWD was like an inverted “J” type: with more individual trees having smaller DBH classes and fewer larger classes, indicating the main source of tree mortality was the self-thinning process during the early stage of community succession. (3) The number and average density of the FGM decreased as follows: trunk snapping (TS), dead fallen tree (DFT), standing dead tree (SDT), and leaning live tree (LLT); The sum of basal area for the standing living trees, CWD, and FGM differed significantly within the plot, with the hillsides on both sides of the gully being higher and at the gully bottom being lower; the number of all four types of FGM were abundant on the hillsides on both sides of the shallow gully, while it was lowest in the bottom of the shallow gully, all three types of FGM were distributed in the bottom and the hillsides on both sides of the deep gully except for LLT. (4) The variance of environmental factors increased as follows: 16.7% for SDT, 25.6% for DFT, 37.2% for TS, and 76.0% for LLT. Biological competition and a self-thinning process caused the formation of SDT and DFT. Soil nutrient contributed the most to the number of LLT, while topographic factors and biological factors drive the formation of TS.

Conclusion: The semi-humid evergreen broad-leaved forest in the Jizu Mountains has small-scale disturbances, the number of SDT and DFT is closely associated with the tree density within the forest community. For LLT, soil nutrient influences the rate of tree survival more than topographic factors. Areas in the forest where TS occurres are driven by topographic factors and biological factors.

Key words: semi-humid evergreen broad-leaved forest, coarse woody debris, forest gap maker, sum of basal area, spatial pattern, environmental interpretation