Influence of Fire on Long-Term Patterns of Forest Succession in Alaskan Boreal Forests

The cold climate and resulting low decomposition rates in the ground layers of boreal forests (such as those found in interior Alaska) result in the development of deep organic soils. In turn, these soils have an important role in many physical, chemical, and biological processes (Van Cleve et al. 1986). In combination with the slope, aspect, elevation, and composition of the underlying mineral soil profile of a specific site (Swanson 1996), organic soils are particularly influential in regulating ground temperature and moisture. As a general rule, the presence of a deep organic soil layer serves to insulate the forest floor during the growing season, causing colder temperatures than would otherwise occur. In many forested sites, autogenic cooling resulting from deepening organic soil layers eventually leads to the formation of permafrost, which, in turn, impedes drainage and substantially increases soil moisture (Van Cleve and Viereck 1981; Van Cleve et al. 1983a, b).