Habitat evolution of a peat swamp forest and belowground carbon sequestration during the Holocene along the coastal lowland in Central Sumatra, Indonesia

Abstract

Habitat evolution of a peat swamp forest and belowground carbon storage was examined in a coastal lowland along the eastern coast of Central Sumatra, Indonesia. Boring surveys using a hand-operated peat sampler for 32 sites and radiocarbon dating for 29 samples revealed that the peat swamp forest had begun formation by 6500 cal BP and expanded rapidly between 6500 and 5000 cal BP and between 4000 and 2000 cal BP to nearly the present distribution area. The thickness of the peat layer formed under the peat swamp forest reached approximately 4 m, even in the margin of the peat dome, and more than 9 m in the center. Stored carbon per unit volume of the peat layer was estimated to be between 30 and 44 kg C m−3 in the margin of the peat dome and approximately 26 kg C m−3 in the center, which was less than the general carbon values of the mangrove peat. The relatively higher amount of stored carbon per unit volume in the margin was possibly caused by an inflow of allochthonous carbon from flood deposits. Belowground carbon burial rate of the peat layer was calculated as between 31 and 105 g C m−2 years−1 in the peat dome margin and between 27 and 76 g C m−2 years−1 in the center, which were identical to mangrove peat. These data suggest that peat swamp forests have played a significant role as places for carbon sequestration belowground as well as mangrove forest with mangrove peat. [Figure not available: see fulltext.].