Tropical forests play a critical role in mitigating climate change. However, there are many uncertainties in carbon (C) estimation, because of large variations in tropical forests. For this reason, we quantified C stocks and flux in an intact lowland mixed dipterocarp forest (MDF) of Brunei Darussalam. Tree, deadwood, and soil C stocks were estimated using the allometric equation method, the line intersect method, and the sampling method, respectively. The tree DBH was re-measured at intervals of 3 years for the growth rate, and the soil respiration rate was measured at 54 points. For litter falls and litter decomposition rate, litter traps (n=30) and bags (n=18) were used. The total C stock was 321.4 Mg C ha-1 and tree, dead wood and soil C stocks accounted for 67%, 11%, and 23%, respectively, of the total. The results reveal that there was a relatively high C stock, even compared to other tropical forests. The average tree growth rate and soil respiration rate were 3.3 mm yr1 and 2.5 μg mol m-2 s-1, respectively. In addition, the annual litter fall was 3.4 Mg ha-1 year-1, and 70% of the litter had been decomposed for 1 year.

* Supported by research grants from the Korea Forest Research Institute (S121313L130100).