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.Penelitian struktur dan komposisi hutan sekunder tua (HST), hutan sekunder muda (HSM), dan hutan belukar tua (HBT) di Kawasan Lindung Rantau Bertuah, Kabupaten Siak, Provinsi Riau dilaksanakan pada bulan September 2018. Penelitian ini bertujuan untuk menganalisis komposisi jenis dan struktur tegakan hutan. Plot penelitian berukuran 100 x 100 m (satu ha) dibuat di HSM, HST dan HBT. Hasil analisis menunjukkan bahwa di plot HST tercatat 33 suku, 55 jenis, dan 642 pohon berdiameter ? 10 cm; di HSM tercatat 31 suku, 56 jenis, dan 450 pohon; dan di HBT 28 suku, 52 jenis, dan 235 pohon. Pada tingkat pohon di HST, hutan didominasi oleh Calophyllum macrocarpum, Shorea sp., dan Gironniera nervosa; di HSM oleh Palaquium amboinense, Shorea macroptera, dan Gironniera nervosa; dan di HBT oleh Macaranga hypoleuca, Gironniera nervosa, dan Lithocarpus gracilis. Berdasarkan jenis dominan utama dan sebaran penuh dalam plot, tipe komunitas ini dinamakan asosiasi Gironniera nervosa-Lithocarpus gracilis