Peatland fires are generally caused by human activities, compounded by natural events that create prolonged droughts such as the El Nino, and the already degraded condition of peatlands.
The most common cause of peat fires is land burning activities that occur when peatlands are being cleared to open a plantation, whether it is a company-owned or community-owned plantation. Land clearing is usually done by drying and then burning land to clear it.
Land burning during a land clearing is common as this method is relatively easy, cheap, and quick. However, land burning can have a negative impact on the peat’s biophysical conditions and can cause peatland fires on a large scale.
Dried peat becomes very susceptible to fire, and can catch fire even from a small ignition source. Furthermore, reduced tree cover on peatlands causes temperature changes which then accelerate the oxidation of peat soils. Oxidation that releases carbon into the air creates conditions conducive to fires.
Peatland fires are dominated by smouldering combustion, which can last for a long time, even months. Fires can also spread to the deeper layers of the peatland, which contain a lot of organic materials such as leaves, branches, tree trunks, serving as fuel to keep the fire burning under the peat surface even though on the surface the fire appears to have been extinguished.