ABSTRACT
Wetlands in the United States are defined as areas that are transitional between terrestrial and aquatic systems, where the water table is usually at or near the surface or the land is covered by shallow water. A great variety of wetlands are formed under different hydrological, water quality, climatic, or edaphic conditions, each with its distinctive vegetation and biota. This chapter considers forested wetlands only, where a closed-canopy tree cover forms the dominant vegetation, or if immature, the trees have the potential of becoming closed-canopy forests. Although northern forested wetlands were extensive in the past, the great majority of them supported only scattered, stunted trees of black spruce and tamarack. Unlike the northern conterminous United States and the southern and eastern portions of Canada, the impacts of human activities on Alaska’s wetlands have been relatively minor.
