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融合无人机多光谱与机器学习的洮河中游云杉人工林林窗识别

万姣姣, 陈国鹏, 尚嗣梁, 鲜骏仁, 杨永红, 王飞   

  1. 甘肃农业大学林学院, 甘肃 730070 中国
    四川农业大学环境学院, 四川 611130 中国
    甘肃省白龙江林业科学研究所, 甘肃 733000 中国
  • 收稿日期:2025-06-18 修回日期:2026-05-14

UAV Multispectral and Machine Learning-Based Forest Gap Detection in Mid-Reach Tao River Spruce Plantations

WAN Jiao-Jiao, CHEN Guo-Peng, SHANG Si-Liang, XIAN Jun-Ren, YANG Yong-Hong, WANG Fei   

  1. College of Forestry, Gansu Agricultural University 730070, China
    College of Environment, Sichuan Agricultural University 611130, China
    , Gansu Bailongjiang Forestry Research Institute 733000, China
  • Received:2025-06-18 Revised:2026-05-14
  • Supported by:
    Supported by the National Natural Science Foundation of China(32260281); the Science and Technology Innovation Fund of Gansu Agricultural University(GAU-QDFC-2023-08); and the College Students' Innovation and Entrepreneurship Training Program of Gansu Agricultural University(202308017)

摘要: 【目的】林窗是驱动森林更新的关键因子,其精确识别对森林生态系统结构分析与可持续管理具有重要意义。传统方法难以高效获取林窗的精细空间信息。【方法】本研究利用无人机多光谱影像和冠层高度模型(CHM),结合面向对象影像分析(OBIA)与机器学习算法,构建了一套高精度的林窗信息提取方法,旨在揭示洮河中游云杉(Picea asperata)人工林林窗的分布特征。【主要结果】结果表明:(1) 最优影像分割参数组合为形状因子0.3、紧致度0.5、尺度26,能够有效平衡过分割与欠分割问题;(2) 在对比的四种机器学习算法中,贝叶斯分类器表现出最优的分类性能与稳定性,在测试样本上的总体精度达0.963、Kappa系数为0.913;(3) 从林窗组成结构看来,面积大于200 m2的林窗占总面积比例超过35%,表明该区域林窗形成可能主要受风倒、病虫害等干扰事件主导。【结论】研究证实了融合无人机多源数据与贝叶斯算法的OBIA方法可有效实现云杉人工林林窗的精准识别,所揭示的林窗分布格局为理解该区域人工林的干扰历史与更新动态提供了重要依据,研究成果可为退化人工林的结构优化与近自然经营提供技术参考。

关键词: 林窗, 无人机, 面向对象, 多光谱, 分割尺度, 机器学习

Abstract: Aims Forest gaps serve as a key driver of forest regeneration, and their accurate identification is of great significance for assessing forest ecosystem functions and supporting sustainable management. Traditional methods are often insufficient for efficiently acquiring detailed spatial information on forest gaps. Methods In this study, using UAV multispectral imagery and a canopy height model (CHM), combined with object-based image analysis (OBIA) and machine learning algorithms, a high-precision method for forest gap information extraction was developed. The aim was to reveal the distribution characteristics of forest gaps in a Picea asperata plantation in the middle reaches of the Taohe River. Important fingings The results showed that: (1) The optimal image segmentation parameter combination was a shape factor of 0.3, compactness of 0.5, and scale of 26, which effectively balanced over-segmentation and under-segmentation; (2) Among the four compared machine learning algorithms, the Bayesian classifier exhibited the best classification performance and stability, achieving an overall accuracy of 0.963 and a Kappa coefficient of 0.913 on the test samples; (3) In terms of gap composition, gaps larger than 200 m² accounted for more than 35% of the total gap area, suggesting that the formation of forest gaps in this region may be primarily driven by disturbance events such as windthrow, pests, and diseases.This study confirms that the OBIA approach integrating UAV multi-source data and the Bayesian algorithm can effectively achieve accurate identification of forest gaps in spruce plantations. The revealed gap distribution pattern provides an important basis for understanding the disturbance history and regeneration dynamics of plantations in this region. The findings can serve as a technical reference for structural optimization and close-to-nature management of degraded plantations.

Key words: Forest Gap, drone, Object-Oriented, Multispectral, segmentation scale, Machine learning