Fire Return Intervals and Fire Cycles for Historic Fire Regimes in the Great Lakes Region: A Synthesis of the Literature

Discussions and descriptions of a “fire regime ” require consideration of ecological context. As such a fire regime is defined by not only by the meteorological, physical, and biological properties of an ecosystem, but also by the spatial, temporal, and behavioral characteristics of the fires that burn in it. Although wildland fires are affected by many variables, the fire regime of a particular ecosystem usually is quite distinctive when defined within a particular historic time period. The fundamental premise for this discussion is that fire has been ubiquitous in all Great Lakes ecosystems during the Holocene Epoch, although the characteristic periodicity varies by several orders of magnitude according to regional and landscape ecosystem. Sooner or later—in some cases much sooner, in others much later—every ecosystem experiences fire. While usually considered an exogenous process, the very idea of a fire regime presupposes that fire is an integral part of ecosystem functioning and, in fact, may often be governed by endogenous ecosystem properties (White 1979). The relatively short fire-return intervals and fire cycles for many Great Lakes ecosystems, and the widespread adaptability of plants and animals in this region to fires, supports this contention. As White and Pickett (1985) emphasized, the neat classification of disturbances as endogenous or exogenous is problematic