Fine-scale remote sensing monitoring and interpretation of large-scene vegetation health in the Jiuzhai Valley biosphere reserve:A case study of the Changhai pilot zone
Under the intertwined effects of natural processes,geological disasters,and human disturbances,the health risks of vegetation in biosphere reserves have increased.Accurately extracting and identifying vegetation health information from complex large scenes faces technical challenges.This study investigated the Changhai pilot zone of the Jiuzhai Valley biosphere reserve by leveraging the macro,objective,and quantitative advantages of remote sensing technology.It proposed a fine-scale remote sensing monitoring method integrated with feature extraction and random forest for large-scene vegetation health,achieving the information extraction and target identification of unhealthy trees in typical biosphere reserves.The results show that:① The random forest classification method combined with spectral and texture features can accurately extract unhealthy trees scattered in forests from high-resolution remote sensing images;② The red-green ratio index,normalized difference vegetation index,correlation between red-edge and red bands,and corrected soil-adjusted vegetation index constitute typical features for extracting vegetation health information from remote sensing images;③ The Changhai pilot zone exhibits a generally fair vegetation health status,with unhealthy trees accounting for 0.23%,and geological disasters exert positive effects on the spatial distribution of unhealthy trees.This study provides primary scientific data for vegetation health diagnosis of the Jiuzhai Valley biosphere reserve while showing generalization value for the remote sensing monitoring of ecological security in other biosphere reserves of China.
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