Soleha, Endang2021-07-282021-07-282020-08wahyu sari yenihttps://repository.unri.ac.id/handle/123456789/10046Siamang (Symphalangus Syndactylus) is primate speciesclassified as arboreal since it does all of daily activities on tree canopies closely.This study was carried out from April to July 2017 in Suaka Margasatwa Bukit Rimbang Bukit Baling Region, Kampar Regency shouthern part, Riau Province. This study aimed to analyse the composition and structures of trees in habitats of Siamang in Suaka Margasatwa Bukit Rimbang Bukit Baling Region. This study used purposive sampling method, with a total of three transects, five plot (40x40 m in size) each transect. The parameters observed in this study were density, frequency, and dominance. A total of 57 species from 25 families and 264 individuals were identified in this study. Species with the highest value of density, ferquency, and dominance were Callophyllum pulcherimum (8,33), Callophyllum pulcherimum and Dipterocarpus gracilis (0,53), andTetramerista glabra (10930), respectively. The important value index in Siamang’s habitat was at low category, and ranged from 1.19– 20.82%.enSiamang (Symphalangus Syndactylus)VegetationSMBRBBArticle