In Singapore, more than 95% of the original forest has been
cleared, most of it prior to the 1870s (Corlett, 1992). Much of the
remaining forest cover is secondary, although a few small patches
of protected primary forest remain. Here we report carbon stocks
in long-term forest dynamics plots in primary and secondary forests
in Bukit Timah Nature Reserve, one of the few areas of protected
forest on the island of Singapore. The site supports
dipterocarp forest growing on infertile soils developed on granite
bedrock (Burslem et al., 1994). We estimate carbon stored in living
trees, coarse woody debris, and soil. Importantly, we estimated soil
carbon to 3 m depth; most studies only sample to 1 m, but tropical
forest soils, including those at Bukit Timah, can be very deep (e.g.
>5 m in Bukit Timah; see Supplementary material) and previous
studies may therefore have underestimated soil carbon stocks.