In the line of fire: the peatlands of Southeast Asia

Abstract

Peatlands are a significant component of the global carbon (C) cycle, yet despite their role as a long-term C sink throughout the Holocene, they are increasingly vulnerable to destabilization. Nowhere is this shift from sink to source happening more rapidly than in Southeast Asia, and nowhere else are the combined pressures of land-use change and fire on peatland ecosystem C dynamics more evident nor the consequences more apparent. This review focuses on the peatlands of this region, tracing the link between deforestation and drainage and accelerating C emissions arising from peat mineralization and fire. It focuses on the implications of the recent increase in fire occurrence for air quality, human health, ecosystem resilience and the global C cycle. The scale and controls on peat-driven C emissions are addressed, noting that although fires cause large, temporary peaks in C flux to the atmosphere, year-round emissions from peat mineralization are of a similar magnitude. The review concludes by advocating land management options to reduce future fire risk as part of wider peatland management strategies, while also proposing that this region's peat fire dynamic could become increasingly relevant to northern peatlands in a warming world.This article is part of the themed issue 'The interaction of fire and mankind'.

Managing fire risk during drought: the influence of certification and El Niño on fire-driven forest conversion for oil palm in Southeast Asia

“…Removal of forest vegetation is critical for establishing an oil palm plantation, but combustion completeness may be lower for these fires, given higher fuel moisture and less need for complete combustion of aboveground biomass than for expansion of row crop agriculture . Fuel moisture also has a substantial influence on trace gas emissions from fire, including smouldering fires in peatlands (Miettinen et al, 2012;Page and Hooijer, 2016). By combining active fire detections with satellite observations of trace gas emissions, it may be possible to characterize regional GHG emissions directly associated with fires on oil palm plantations.…”

Peatland Fires in Riau, Indonesia, in Relation to Land Cover Type, Land Management, Landholder, and Spatial Management

“…Intact peat swamp forests are resistant to fire because the ecosystem is moist throughout the year [2]. Soil moisture in peat swamp forests is high because of the tree canopy, while in shrubland, sunlight directly reaches the ground's surface [51].…”

“…Peatlands store 500 -700 G ton of carbon, yet it only covers 3% of the Earth's surface [2]. The majority of this carbon is stored in temperate and boreal peatlands, but tropical peat swamp forests also store a significant amount of carbon at around 80 -90 G ton, 69 G ton of which is stored in Southeast Asia.…”

How temporal patterns in rainfall determine the geomorphology and carbon fluxes of tropical peatlands

“…The carbon stored as peat in these domes has been sequestered by photosynthesis of peat swamp trees (2) and preserved for thousands of years by waterlogging, which suppresses decomposition. Human disturbance of tropical peatlands by fire and drainage for agriculture is now causing reemission of that carbon at rates of hundreds of megatons per year (2)(3)(4)(5): Emissions from Southeast Asian peatlands alone are equivalent to about 2% of global fossil fuel emissions or 20% of global land use and land cover change emissions (6,7). Because peat is mostly organic carbon, a description of the growth and subsidence of tropical peatlands also quantifies fluxes of carbon dioxide (1,4,8).…”