Tropical peat forests South-east Asia
South-east Asia has about 27 million hectares of peatland, or 271.000 km2 and 60% of the known tropical peatland resource. This is 10% of the total South-east Asian land area. Indonesia alone has 22,5 million hectares, which is 12% of its land area and 83% of the South-east Asian peatlands area.
Peatswamp forests grow on a thick layer of organic matter. This layer of organic matter or ‘peat’ consists of dead plant materials like leaves, roots, branches and even complete tree trunks that have been accumulating over a period of thousands of years and can develop into thick layers. These layers only form under very special circumstances, as dead plant materials normally are rapidly decomposed by fungi, bacteria and other organisms. Due to the extreme anaerobic, acidic and nutrient poor conditions in peatswamp forests, however, the process of biodegradation is significantly reduced. Environmental conditions are just too extreme for decomposers to do their job, and as a consequence dead plant materials are accumulated in the soil. As such, peatswamp forests act as sinks of huge amounts of carbon. Peat thickness in Indonesia (Sumatra, Kalimantan and Papua) ranges from less than 1 metre to over 12 metres, in some places even 20 metres. While 42% of the peatland area in Indonesia is over two metres thick, these thicker peat deposits store 77% of the total peat carbon.
The process of peat accumulation is highly sensitive to changes in abiotic circumstances like hydrology and (micro-) climate. Small changes can easily lead to a complete shift from peat accumulation to oxidation. As a consequence disturbances of peatlands might have far-reaching consequences for the peat soil and its accompanying flora and fauna.
Peatland ecosystems contain disproportionately more carbon than other terrestrial ecosystems. The forested tropical peatlands in South-east Asia store at least 42,000 Megatonnes of soil carbon, of which 35,000 Megatonnes are stored in Indonesian peatlands. Human interventions can easily disturb the natural balance of production and decay turning peatlands into carbon emitters.