NUTRIENT STOCKS IN FOUR STAGES OF A LOWLAND RAIN FOREST AT PASIRMAYANG, JAMBI, CENTRAL SUMATRA,

Studies of nutrient cycling of tropical forests should differentiate between dynamic stages of the
forest. We studied the nutrient concentration (N, P, K, Ca and Mg) and phytomass of aboveground (living
and non living parts) and belowground compartments (soil) in four dynamic stages, namely Building (Bl and
B2), and Mature (Ml and M2) stages, for a lowland rain forest.
Nutrient concentrations in various compartments differed between the dynamic stages. Bark contains
higher nutrient concentration than wood parts, both in stems and branches. Leaves contain higher nutrient
concentration than wood parts, both in litterfall and litter. The concentration of K in throughfall is the
highest, Ca and Mg perform similar value. Throughfall exhibits lower nutrient concentration than open
area rain water. The nutrient concentration of 10-20 cm is higher than in the 0-10 cm soil depth.
The phytomass values are highly variable among tree parts, diameter classes and dynamic stages.
The phytomass is generally the highest in M2 and significantly different from Bl ,  Ml and B2. The
phytomass of leaves in litterfall and litter is higher  than wood parts. More litterfall and litter are
accumulated in mature than building phases.
Key words : nutrient / phytomass / dynamics / rain / forest