Freshwater swamp forest

Freshwater swamp forests, or flooded forests, are forests which are inundated with freshwater, either permanently or seasonally. They normally occur along the lower reaches of rivers and around freshwater lakes. Freshwater swamp forests are found in a range of climate zones, from boreal through temperate and subtropical to tropical.

Globally, freshwater swamp forests are found in Southeast Asia, tropical Africa, and South America, with the largest areas being part of the Amazon basin. In Southeast Asia, they are found all over the region, frequently close to major rivers like the Mekong, Chao Phraya, and Irrawaddy in Thailand and Myanmar, as well as numerous smaller systems like the Sedili rivers in Johor. Although freshwater swamp forests are frequently found in wet climates, they can also be found in areas that are seasonally drier, such as west New Guinea and east Java.

Freshwater swamp forests are a relatively understudied forest type in Southeast Asia, primarily because they are difficult to access and can harbor diseases spread by insects, such as mosquitoes. In the Amazon Basin of Brazil, a seasonally flooded forest is known as a várzea, and refers to a whitewater-inundated forest. Igapó refers to blackwater-inundated forest. Mangrove and peat swamp forests, for example, have a tendency to draw more attention than other wetland habitats. Peat swamp forests are swamp forests where waterlogged soils prevent woody debris from fully decomposing, which over time creates a thick layer of acidic peat.

A freshwater swamp forest is a type of wetland ecosystem characterized by its unique hydrology and vegetation. These forests are typically found in low-lying areas, riverbanks, and floodplains where there is a consistent supply of freshwater. A forest that is frequently flooded with relatively fresh water rich in minerals is referred to as a freshwater swamp forest. Since tropical freshwater swamp forests are a subset of tropical rainforests, they share a number of environmental traits with other tropical rainforest formations.

Beyond these shared characteristics, however, the environment in freshwater swamp forests and other tropical rain forest formations can vary greatly. In inland, freshwater swamp forests, flooding is typically sporadic, irregular, or seasonal. The depth of the water also varies greatly, from a few centimeters to several meters. These physical factors affect the ecology of freshwater swamp forests, either singly or in combination.

Rain, rivers, and groundwater are all sources of water for freshwater swamp forests, whereas rain is the only source of water for peat swamp forests. The hue of the water in the freshwater swamp forest is typically an indication of the quantities of plant materials present in the water and soil. Contrary to ombrotrophic swamp forests, which only absorb nutrients from rain, freshwater swamp forest soils are relatively nutrient-rich. In freshwater swamp forests, rain and changes in the water table result in the following deposition of nutrients and alluvial soils. Due to the nutrient-rich soils of freshwater swamp forests, wetland rice farming and oil palm plantations have become very prevalent in agriculture.