COMMUNITY RESPIRATION IN A LOWLAND RAIN FOREST IN PASOH, PENINSULAR MALAYSIA

Abstract

The total community respiration rate was estimated in undisturbed stands in the Pasoh Forest Reserve, Negeri Sembilan, Malaysia. Dark respiration rates were determined with a large number of detached samples of leaves and woody parts taken from plants of various sizes ranging from a 55m-tall emergent tree to undergrowth herbs. Respiration rates in leaves tended to decrease toward the lower layers of the forest canopy, the mean leaf respiration rate per tree thus increasing with increasing tree size. Respiration rates of woody parts depended on both their diameter and the size of the tree they were taken from. Inter-species differences were relatively small in both cases. A procedure for assessing the total respiration of a tree solely from its DBH was formulated taking all these factors into consideration. Combining the formulation with a DBH census, the rate of total respiratory consumption of dry matter by the whole community was estimated at 75.2 t ha^<-1>y^<-1>, of which 94% was accounted for by trees (DBH&ge;4.5 cm). Leaf, branch, trunk, and root parts contributed, respectively, 50%, 21%, 15%, and 15% to the total tree respiration.