Classification and Habitat Adaptability Analysis of Evergreen Broad-Leaved Forest Formation in Zhejiang Province

Formation classification and habitat adaptability analysis can quantify species’ responses to environmental factors such as climate, soil and topography, reveal their ecological niche characteristics, thereby providing a theoretical basis for understanding species’ geographical distribution patterns. Based on plot data from evergreen broad-leaved forests at the stand age stage 1(<20 years), stage 2 (20 ~ 60 years) and stage 3 (>60 years) in Zhejiang Province, formation types were systematically classified, the interspecific associations among dominant tree species within communities were analyzed, and environmental factors were integrated to explore their influence on community structure. The result indicated that with the forest age increasing, community types were gradually simplified from three to two with clear differences in dominant species composition, understory vegetation, topographic and climatic features. Regarding species association, the interspecific associations in most community types exhibited stronger positive associations, and indicated higher niche overlap and co-distribution, particularly with the significant association between the dominant species such as Cyclobalanopsis glauca, Schima superba, and Castanopsis cuspidata, and their co-occurring species. However, the negative associations in some communities (e.g., Lithocarpus glaber-Quercus fabri and Castanopsis cuspidata-Schima superba) were more prevalent, suggesting the potential interspecific competition or niche differentiation. Environmental factor analysis revealed that mean annual precipitation, mean annual temperature, elevation, litter layer thickness and canopy closure were the primary factors affecting species distribution in communities of the stand age stage 1 and 2, with explanation ratios of 5% and 8%, respectively. In contrast, although the environmental factors in the stage 3 communities exhibited a high explanation ratio (91%), showed no statistical significance except for slope position which had a significant effect on community distribution. This study reveals the structural characteristics, interspecific relationships and the environmental response mechanisms of evergreen broad-leaved forest communities across different stand ages, providing theoretical support for the maintenance and sustainable management of regional forest ecosystem.