Fire in North American Wetland Ecosystems and Fire-Wildlife Relations: An Annotated Bibliography
103. Heinselman, M. L. 1981. Fire intensity and frequency as factors in the
distribution and structure of northern ecosystems. Pages 7-57 in
H. A. Mooney, T. M. Bonnicksen, N. L. Christensen, J. E. Lotan,
and W. A. Reiners, tech. coords. Proceedings of the conference: fire
regimes and ecosystem properties. 11-15 December. 1978, Honolulu, HI.
U.S. For. Serv. Gen. Tech. Rep. WO-26.
Presettlement forests of much of North America were strongly fire-dependent. Historical changes in fire regimes, the role of fire in regulating vegetation structure, the reciprocal influence of community structure on fire frequency, and variations in ecosystem development (succession) under presettlement, contemporary, and managed fire regimes for five ecosystems are presented. The large peatlands and smaller bogs and swamps of the northern Lake States, Canada, and Maine support boreal vegetation, but their fire regimes are different from those of areas with mineral soil. Forested peatlands with a moss ground layer will not readily carry spring ground fires because they are too wet and there is no highly flammable layer. In contrast, sedge and grass fens, even those with partial tree cover, burn best in spring before succulent vegetation develops. Thus, most fires in forested peatlands occur in July, August, or September of severe drought years, and most fires in sedge-grass fens occur in April, May, or early June. The presettlement fire regime for large forested spruce bogs in Minnesota was one of long return interval crown fires with a fire cycle of perhaps 100-150 years. The vast grass-sedge fens of north-central and northwestern Minnesota burned at more frequent intervals of periodic surface fires with fire cycles of 5-30 years. Removing fire from northern ecosystems would be among the greatest upsets in the environment that man could impose. [K-L-S]
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