EFFECTS OF SELECTIVE MANAGEMENT SYSTEM ON BIOMASS STRUCTURE AND FOREST SUSTAINABILITY: A CASE STUDY OF A TROPICAL RAINFOREST IN PENINSULAR MALAYSIA

Abstract

We analysed the effects of a selective management system (SMS) on the biomass structure (frequency distribution and spatial distribution of biomass) of a tropical rainforest in Peninsular Malaysia. The biomass structure of total biomass, i.e. the sum of the aboveground and belowground biomass of all individuals ≥ 5 cm diameter at breast height, was analysed in a forest logged under a SMS and compared with that of an unlogged natural forest. We also analysed new approaches to improve the logging system using unlogged natural forest census data. Mean total biomass value and its variance were lower in the logged forest (256 ± 52 Mg ha^-1) than in the unlogged natural forest (464 ± 120 Mg ha^-1). Logging operations also changed the spatial pattern of the total biomass, as spatially clustered and random distributions were observed in the logged forest and the reference forest respectively. To mitigate the impacts of logging on the original biomass structure, we recommend reducing the logging ratio by adopting a maximum cutting limit, as well as a uniform logging intensity throughout a stand. This will ensure a spatially random arrangement of remaining emergent trees and vital forest regeneration processes.