Fire as an Ecological Factor in Northeastern Minnesota

Abstract

Research during the past four decades has shown that fire is a natural agent which has been shaping the composition and boundaries of forests and prairies long before the appearance of modern man in such areas. In America, Indians often set fires for purposes such as driving game, clearing forest underbrush and prairie farmland, obtaining firewood, signaling, controlling insects, and increasing the berry crop (Ahlgren and Ahlgren, 1960). Failure to recognize that ecosystems may be fireadapted has resulted in management practices that threaten the balance of living organisms within such ecosystems. Odum (1971) includes fire as an important limiting factor along with other agents such as water, light, moisture, and air. Two extreme types of forest fires are crown fires and surface fires. The former often destroys all vegetation and may consume humus so as to expose mineral soil. Surface fires can move through groves of mature trees without noticeably damaging them, eliminating some components of the understory and creating favorable conditions for the development of others. Light surface fires often reduce the flammability of the forests, speeding the decay process, and creating a seedbed favorable for the reseeding of species requiring lesser humus accumulation. Scientists and the public have regarded fire as a destructive, wholly negative event which is to be avoided at all costs. Reversing such prejudices has generally progressed well enough among scientists, and the relatively young area of study known as fire ecology now has many disciples. Recent events in certain National Parks suggest that the public, given the facts and concepts, is willing to accept the current views regarding the importance of fire. The first project to include the use of wildfire as a management tool on National Forest lands was initiated in 1972 for a portion of the Selway-Bitterroot Wilderness (SBW) of northern Idaho and western Montana (Aldrich and Mutch, 1972). Under this policy, fire control is brought into operation when fires threaten to cross the boundary of the study area and when fire danger rating is high. Extensive investigations in plant ecology indicate that the vegetational composition of the SBW is showing characteristics which threaten the continued existence of the highly diversified vegetation of this region, due to the fire control policies effective since the 1930's (Habeck, 1972). The purpose of this paper is to investigate the nature of the role of fire in northeastern Minnesota, regarding its influence primarily on vegetation. Paleobotanical research in the Boundary Waters Canoe Area (BWCA) and study of vegetational characteristics provide a history of fire and plant cover for certain areas of northeastern Minnesota.