KERAGAMAN DAN POTENSI JENIS SERTA KANDUNGAN KARBON HUTAN MANGROVE DI SUNGAI SUBELEN SIBERUT, SUMATERA BARAT

Abstract

This research conducted at Siberut Island Biosphere Reserve, West Sumatra in June 2007, was aimed at investigating biophysics potential and carbon contents of mangrove forest. Two sampling plots each 0.25 hectares were built at 1,300 m distant from coastal line to analyze vegetation composition, carbon potency and soil fertility. The inventory of mangrove species was conducted along 1-km of a 2-km riverine-mangrove forest. The results showed there were 10 species of mangrove trees grew in the forest, i.e. Rhizophora apiculata Blume, R. mucronata Blume, Bruguiera cylindrica W.et.A., B. gymnorrhiza (L). Savigny, Xylocarpus granatum Koen, Barringtonia racemosa Blume, Ceriops tagal C.B Rob., Aegyceras corniculatum Blanco, Luminitzera littorea Voigl., and Avicennia alba L. The result of soil chemical analysis showed that, high of concentration of carbon (C) of 23.22%, nitrogen (N) of 0.73%, natrium (Na) of 10.4 me/100 g, potassium (K) of 4.51 me/100 g, however lower concentration of phosphat (P) of 3.9 ppm and cation exchange capacity of 18.93. Vegetation analysis, showed that mangrove species was dominated by R. apiculata with density of 80 trees per hectare, R. mucronata of 28 trees per hectare, and B. gymnorrhiza of 12 trees per hectare. Biomass and carbon contents of mangrove stands composed of R. apiculata, R. mucronata, and B. gymnorrhiza were low: 49.13 ton per hectare and 24.56 ton C per hectare or equivalent to 90.16 ton CO 2 per hectare.