STRUKTUR DAN KOMPOSISI HUTAN DI KAWASAN LINDUNG RANTAU BERTUAH, KABUPATEN SIAK, PROVINSI RIAU

A study on structure and composition of old secondary forest (OSF), young secondary forest (YSF), and old scrub forest (OScF) in Rantau Bertuah Protected Area, Siak Regency, Riau Province, was conducted in September 2018. The purpose of this study was to analyze species composition and structure of forests.The research plot measuring 100 x 100 m (one ha) each was made at OSF, YSF, and OScF. The OSF plot held 33 families, 55 species, and 642 trees with a diameter of ? 10 cm; in YSF 31 families, 56 species, and 450 trees; and in OScF 28 families, 52 species, and 235 trees. At the tree level the OSF was dominated by Calophyllum macrocarpum, Shorea sp., and Gironniera nervosa; the YSF by Palaquium amboinense, Shorea macroptera, and Gironniera nervosa; and the OScF by Macaranga hypoleuca, Gironniera nervosa and Lithocarpus gracilis. Based on the main dominant species and full distribution in the plot, the forest is called the Gironniera nervosa-Lithocarpus gracilis association.