Tropical peat swamp forests contain huge amount of carbon in the substrate as peat. The amount of carbon fixed is strongly related to the amount of primary production. In general, the amount of litterfall that strongly determines the primary production, which is expected to vary significantly depending on a number of factors such as watertable, dryness, peat depth and solar radiation. Tropical peat swamp forests are known to show multiple plant communities on a single dome, with vegetation varying with peat thickness. Each community also differs in size and species composition. However, the primary production and seasonality of each forest community are unknown.
　Therefore, in this study, litterfall monitoring was conducted in tropical peat swamp forests in the Sabangau River Basin, Central Kalimantan, Indonesia, from 2018 to elucidate the actual condition of litterfall mass in tropical peat swamp forests. Fifteen litter traps were installed and litter mass was monitored in each of the study areas: riparian forest, mixed forest, mixed forest-low pole transitional type, low pole forest and interior low pole forest.
The results showed that there were differences in the amount of litterfall among the forest type and the month. In particular, the monthly variation was greater than that of the forest type. Annual fluctuations were also observed. Most notably, litterfall increased during the period of severe fires in tropical peatland in 2019. This was presumably as a result of damage to plant communities due to light blockage caused by smoke. It was inferred that this was caused by dry conditions that facilitated fire rather than fire. The results of this study show that the amount of litterfall in peat swamp forests varies significantly with the plant community, but is also strongly influenced by other external factors such as fire and drought.