Hydrology of Flooded and Wetland Forests
| Authors: | L.J. Bren, T.M. Williams, Devendra M. Amatya |
| Year: | 2025 |
| Type: | Book Chapter |
| Station: | Southern Research Station |
| Source: | In: Forest Hydrology: Processes, Management, and Applications, Amatya, Williams, Bren, and de Jong (Editors), CABI Publishers, UK |
Abstract
Flooded or wetland forests are commonly continuously inundated for many months. Trees that can survive this have specialized mechanisms for allowing roots to respire. The forests can be classified by the source of the water causing inundation – rainfall, groundwater, flow from an adjacent watercourse or tidal inundation. The latter may include specialized vegetation at the ocean salt/freshwater interface known as ‘mangroves’. These seem to require some input of freshwater, although the mechanism of how this assists their survival is unclear. The hydroperiod is the usual annual period for which a forest is inundated. Flooded forests usually contain a range of vegetation aligned to the hydroperiod of specific sites. Flooding of the forests gives them an unusual, distinctive and highly valued character, both in the vegetation and the associated fauna. Often, these forests have large accumulations of carbon in anoxic soils. Many flooded forests are under some sort of threat relating to changes in their inundation due to the value of water for other uses. The resulting problems may be difficult to resolve and require compromise to achieve resolution. The advent of climate change and the impacts of this on rainfall in large catchments pose a particularly serious threat to the long- term survival of this group of forests around the world. Oxidation of dried- out ‘wetland soils’ can be a major source of greenhouse gases.