Abstract
This study examined tree species composition, floristic diversity, and spatial distribution patterns in Malabar Urban Forest, Malang City, Indonesia, a site situated within the Indomalayan biogeographic realm. Vegetation surveys used line transects and 20×20 m quadrat plots across 19 transects in April 2026. 16 transects passed systematic data quality screening. Spatial analysis included Nearest Neighbor Analysis (NNA), Moran’s I spatial autocorrelation, and Sørensen’s similarity coefficient. NNA yielded R = 1.328, indicating a dispersed transect arrangement. Shannon diversity (H’) ranged from 1.552 to 2.265 (mean 1.840). Moran’s I for H’ was -0.095 (pseudo-p = 0.711, n = 8), indicating no detectable spatial autocorrelation in floristic diversity. Of 11 dominant tree species, 9 were exotic (81.8%), and the Sørensen coefficient between sampling zones was 0.286, reflecting high intra-forest compositional heterogeneity. Swietenia mahagoni showed high occurrence frequency (FR = 42.1%) but low relative density (KR = 7.3%), consistent with a spatially distributed planting pattern. These results suggest that historical planting decisions shaped current floristic structure more than biogeographic processes, with implications for zone-specific native species enrichment in urban forest management.