Effects of cutting and regeneration on microbial activity of natural forest in east Kalimantan

Abstract

To clarify the effect of cutting and regeneration on microbial activity, natural forest and selective cutting forest were compared to Gmelina arborca Roxb. plantations, shrubs, and arang-arang (Imperata cylindrica) in terms of microbial biomass Carbon (C), Nitrogen (N) concentration, C mineralization, Net N mineralization, Gross N mineralization, and N immobilization. Difference among natural forest, selective cutting forests, plantation, shrubs and arang-arang obviously changed microbial activities rather than amount of soil organic matter. The microbial biomass decreased about 50% in plantations and shrubs. The ratio of N immobilization to gross N mineralization in natural forest and selective cutting forest was low about 50-70%, although it was high (more than 90%) in plantations and shrubs. The N supply was low in plantations and shrubs and much lower in arang-arang area.