| Abstract: |
Peatland is one of the largest terrestrial carbon storehouses. However,
the carbon it contains is only protected from decomposition by the wet
conditions of the peat. Under special conditions where decomposition
is slow owing to low oxygen supply (water saturated), low nutrient
concentrations, and acidity, dead organic matter from trees or other
vegetation can start to pile up and accumulate, creating conditions
that further slow decomposition. Specialized trees, sedges and other
vegetation start to dominate and a peat swamp forest is formed. When
this starts to hold enough water, it can become a semi-autonomous
landscape unit, depending on rainfall and atmospheric nutrient inputs,
independent of the mineral soil and groundwater. The belowground
carbon stocks can reach 10–100 times those of the most lush tropical
forest. However, when the forest is cleared and the peat is drained the
stored carbon is readily decomposed and released as CO2, the most
important greenhouse gas. In addition, excessive drainage of peatland
increases its vulnerability to fires and, in turn, the peat loses its function
of buffering the surrounding environment from drought by the gradual
release of water stored in the peat ‘dome’. What took thousands of years
to accumulate can be burnt within a few days and decompose in a few
years or decades.
With the increase of human populations, land resources are becoming
scarcer. Peatlands that were once formerly regarded as wasteland are
increasingly being developed for various economic purposes such
as agriculture and settlements. As a consequence, the carbon sink of
actively growing peat becomes one of the most important carbon
sources associated with land uses, land-use changes and forestry.
Tropical peat alone is estimated to contribute 1–3% of global CO2
emissions owing to human activity. In Indonesia, the country that has the largest area of tropical peat, emissions from peatland are around
one-third of the total, although the exact numbers are debated and
uncertain. Therefore, in the context of Nationally Appropriate Mitigation
Actions (NAMAs) and efforts to Reduce Emissions from Deforestation
and Degradation (REDD+), conservation and sustainable management of
peatland has become one of the main concerns. |
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