Lowland dipterocarp rain forest is a major resource for timber in Bornean SE Asia. Forests are heavily exploited and regeneration of canopy species is slow. knowledge of primary forest ecosystems remains very limited. Especially for dynamics - rates of growth, mortality and recruitment. It is necessary to model the primary forest to understand the (lack of) recovery of the logged forest. The dipterocarp forests of borneo have a high regional and global biodiversity value. This proposal aims to remeasure two 4ha permanent plots in the Danum valley conservation area, Sabah, 8-9 years after their initial enumeration in 1985-86 (c. 18k trees >10 cm girth, all identified); to extend sampling of smaller trees (10-50 cm gbh) in several new 0.2ha plots in the primary forest and in neighbouring forest which was logged c. 25 years ago; to study in detail the sapling (<10 cm gbh) populations of key understorey species in the main and satellite plots; and to examine edaphic factors particularly soil depth and moisture variables.
From the first enumeration a strong association between certain understorey species (mostly euphorbiaceae) with small ridge tops was found. It is hypothesized that this is an adaptation to drought in drier years, a factor which is part of the general e Bornean environment. our attention will be directed to the distribution of, and interactions between, understorey species and dipterocarp pole trees on ridges and lower slopes in primary and logged forest. This new hypothesis suggests that the understorey species provide important protection for canopy trees and especially so when the canopy is opened by logging and the lower strata are more lighted and prone to dryness. It is hoped that this research will give fresh insights into modelling tropical forests and the management of their exploited areas.
Funding SchemeCSC - Cost-sharing contracts
6703 BV Wageningen
2311 EZ Leiden