Natural Succession Of Secondary-lowland Dipterocarp Forest After Selective Logging In Long Pahangai, West Kutai, East Kalimantan

Selective logging in West Kutai may raise vegetation and environmental destruction in lowland Dipterocarp forest, and this will naturally run into succession. The purposes of this research were to study secondary succession in lowland Dipterocarp forest after 8 months and 6 years of Selective Logging in Long Pahangai, West Kutai regency, East Kalimantan and to study the relationships between plant abundance and soil nutrients and other environmental factors. The research had been done from May to November 2012. Nine study plots were chosen randomly within 3 selected study areas: primary Dipterocarp forest; and two secondary Dipterocarp forests, including 8 months, and 6 years forest after selective logging with three replicates each. Vegetation analysis was carried out using 20 x 20 m2 quadrat method, and 36 soil samples were taken and analyzed its soil nutrients, including total content of C-organic, total as well as available content of nitrogen, phosphorous, and potassium. The results showed that 8 months secondary forest had dominated by pioneer plant of grass (Scleria sp.). Six-year secondary forest had dominated by pioneer trees such as Macaranga and climax species such as Shorea and Adenanthera. High abundance (20% and 26 %) of climax vegetation saplings in 6-year­old secondary forest increased its similarity index close to primary forest. The high available phosphorus content in soil may induce the growth of both pioneer and climax plant species in the 6-year secondary forest compared to other forests. The different trend showed in the 8 month secondary forests that selective logging practices enriched soil nutrients contents except for available phosphorous