Characteristics of spatial distribution of throughfall in a lowland tropical rainforest, Peninsular Malaysia

The spatial distribution of throughfall in a tropical rainforest in Peninsular Malaysia was evaluated using 100 bucket raingauges placed along a line as well as two large raingauges (collection areas of 9.58 and 7.08 m2). Throughfall was clearly large in a treefall gap although it was not significantly different between a typical old-growth area with big trees and another area without big trees. A cyclic variation, the scale of which was 10–15 m, was detected in the entire forest through Fourier analysis, and this scale roughly corresponded to the index of canopy cover openness. The observations gave the spatial mean value of throughfall with enough accuracy considering that the distribution of throughfall in the forest was controlled by different scale effects consisting of the size of disturbance areas such as gaps as well as the size of individual canopies.