FORESTED WETLAND: Background

Within the mid-Atlantic Coastal Plain, forested wetlands (system - palustrine, class - forested wetland) include a diverse gradient of forest types. These forests are dominated by woody species that are adapted to tolerate saturation of the root zone for various periods during the growing season. Because different plant species are adapted to different hydrologic regimes, the forest that forms within a given site is determined largely by hydrology. Cypress swamps form within areas that are saturated with water throughout most or all of the growing season. A complex gradient of other forest types form as the hydroperiod is decreased. The boundaries of forested wetlands are frequently difficult to delineate because forests that form within areas with short hydroperiods are very similar to upland hardwood forests.

Within the United States, forested wetlands are experiencing dramatic reductions in area and changes in plant composition. Nationwide, forested wetlands account for the greatest amount of wetland loss. Between the 1950's and 1970's, nearly 2.5 million ha of forested wetland were lost. Much of this loss was due to the harvest of wetland forests or to filling or draining of forested wetlands for conversion to agriculture or urban development. In 1991, the mid-Atlantic Coastal Plain contained more than 550,000

ha of forested wetlands or nearly 7.4% of the nations total. As with upland forests, occupation of forested wetlands by birds is influenced by a number of factors including patch size, vegetation structure, and hydrology.