Peat swamp forest

Satellite image of the island of Borneo on 19 August 2002, showing smoke from burning peat swamp forests

Peat swamp forests are forest wetlands in tropical and subtropical areas. They have poor drainage. Waterlogged soil prevents dead leaves and wood from decomposing fully. Over time, this creates a thick layer of acidic peat. They are made up of trees which are broadleaved (not conifers), and many other types of flowering plants.

Peat swamp forests are usually surrounded by lowland rain forests on better-drained soils. There may be brackish or salt-water mangrove forests near the coast.

These tropical swamp forests are quite different from the north temperate peat bogs in climates such as in Ireland. Temperate peat bogs are not caused by forests, but mostly by mosses such as Sphagnum, grasses, sedges and shrubs.

Ecology

Peat swamp forest in Kalimantan

About 62% of the world’s tropical peat lands are in southeast Asia. In this area 80% is in Indonesia, 11% in Malaysia, 6% in Papua New Guinea, with pockets in Brunei, Vietnam, the Philippines, and Thailand.[1][2] They have trees up to 70 m high. The spongy, unstable, waterlogged, anaerobic beds of peat can be up to 20 m deep with low pH (pH 2.9 – 4) and low nutrients. The forest floor is seasonally flooded.[3] The water is stained dark brown by the tannins that leach from the fallen leaves and peat – hence the name ‘blackwater swamps’. During the dry season, the peat remains waterlogged and pools lie among the trees.

Tropical peatlands coexist with swamp forests in these tropical and subtropical moist broadleaf forests. In this biome vast amounts of carbon as soil organic matter store up – much more than natural forests contain. They are among the largest near-surface reserves of terrestrial organic carbon.[4] Unfortunately, regardless of their importance, peat swamp forests are one of the most threatened, yet least studied and most poorly understood biotypes.

Draining and logging

Large areas of these forests are being logged at high rates. Since the 1970s, peat swamp forest deforestation and drainage have increased greatly. In addition, El Niño and Southern Oscillation (ENSO) drought and large-scale fires are accelerating peatland devastation. This destruction increass the carbon release to the atmosphere as carbon dioxide. Tropical peatlands have already become a large CO2 source, but data is limited.[5]

Tropical peat swamp forests are home to thousands of animals and plants, including many rare and critically endangered species such as the orangutan and Sumatran tiger, whose habitats are threatened by peatland deforestation.[6]

References

  1. ↑ Rieley J.O; Ahmad-Shah A.A. & Brady M.A. 1996. The extent and nature of tropical peat swamps. In: Maltby E et al (eds) Tropical lowland peatlands of Southeast Asia, proceedings of a workshop on integrated planning and management of tropical lowland peatlands held at Cisarua, Indonesia, 3–8 July 1992. IUCN, Gland, Switzerland.
  2. ↑ Page S.E; Rieley J.O. & Wüst R. 2006. Lowland tropical peatlands of southeast Asia. In: Martini I.P. et al (eds) Peatlands: evolution and records of environmental and climate changes. Elsevier B.V. pp 145-172.
  3. ↑ Yule C.M. 2008. Loss of biodiversity and ecosystem functioning in Indo-Malayan peat swamp forests. Biodiversity and Conservation. doi:10.1007/s10531-008-9510-5
  4. ↑ Paige, Susan E. et al 2002. The amount of carbon released from peat and forest fires in Indonesia during 1997. Nature 420 61–65. [1]
  5. ↑ Hirano, Takashi et al 2006. Carbon dioxide balance of a tropical peat swamp forest in Kalimantan, Indonesia. Global Change Biology. 13 (2) [2]
  6. ↑ "Peatland Treasures". Wetlands International. Archived from the original on 2019-02-12. Retrieved 2019-02-15.