Natural Disturbances

Natural Disturbances

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Purpose:

Description of the Great Lakes Assessment Fire Project

In 1995, the Landscape Ecology Research Unit of USDA Forest Service, North Central Forest Experiment Station (NCFES), initiated a study of Modern Lake States fire patterns initiated a study of modern Lake States fire patterns and the factors that might influence their occurrence and frequency. The study was conducted primarily at the University of Wisconsin-Madison, Land Information and Computer Graphics Facility, through a cooperative agreement between the University and NCFES, as part of the Great Lakes Ecological Assessment.

Data development for this project included two major new databases covering the entire northern regions of Minnesota, Wisconsin, and Michigan. The first, the Lake States Fire Database contains information for thousands of wildfires that occurred across the region in recent years. The second, called the Fire Factor Database, consists of a large set of spatially explicit biotic, abiotic, and human factors that may affect fire patterns.

Forests of the Northern Lake States Region

The forests of the Lake States occur within the Laurentian Mixed Forest Province (Bailey 1995), and almost all areas have been logged at least once (Pyne 1982). The province lies between the boreal forest to the north and deciduous forests to the south and east (Bailey 1995, Heinselman 1978). Vegetation includes upland conifer forests, peatlands and conifer swamps in northern and eastern Minnesota; aspen parkland and prairie in northwestern Minnesota; and northern hardwood forests, white pine / red pine forests and jack pine barrens in northern Wisconsin, the Upper Peninsula of Michigan, and the northern Lower Peninsula of Michigan (Albert 1995).

The pre-settlement cycles of forest growth and disturbance were influenced by fire in many parts of the northern Lake States region. Lightning-caused fire once drove the succession of forested land in northeastern Minnesota to such an extent that Heinselman described the natural ecosystem containing the Boundary Waters Canoe Area as "fire-dependent". Further west in Minnesota, Frissell (1973) used fire scars to estimate fire return interval and concluded that "fire was a dominant factor in the establishment and maintenance of the natural biotic communities of Itasca State Park". In Wisconsin, Vogl (1970) found that fire frequency was apparently "critical in determining the kinds and numbers of conifer species occurring in the overstory of pine barrens". Frelich and Lorimer (1991) pointed to light and medium disturbance more characteristic of windstorms as the probable dominant disturbance in parts of the Upper Peninsula of Michigan but also noted that some study stands did contain fire evidence. Loope (1991), also studying part of the Upper Peninsula, found systematic fire evidence on well-drained, sandy soils near Pictured Rocks National Lakeshore. In the northern Lower Peninsula of Michigan, Whitney (1986) found a "close association of fire frequency and forest type"; his study categorized pine forests and hemlock-white pine-northern hardwoods forests at the high and low ends (respectively) of a flammability spectrum.

Public Land Management and Native American Reservations in the Northern Lake States Region

Public land management and Native American Reservations cover a significant portion of this part of the Lake States. In Minnesota, a large portion of the forested area is managed as the Superior and Chippewa National Forests, and the Koochiching, Kabetogama, and Pine Island State Forests (McGhie et al. 1996). Reservations within the Minnesota's borders include the Red Lake, White, and Leech Lake Indian Reservations. Major public land management in Wisconsin includes the Chequamegon and Nicolet National Forests, as well as the Northern Highland State Forest, among others. Public management in the Upper Peninsula of Michigan in dominated by National and State Units, including the Ottawa National Forest, Pictured Rocks National Lakeshore, the Hiawatha National Forest and many State Forests. Public management in the northern Lower Peninsula of Michigan is dominated by the Huron-Manistee National Forest and an extensive set of State Forests.

Human Influence on Modern Fire Patterns of the Northern Lake States Region

Although lightning remains a major cause of wildfire in the western U.S. (Marsden 1982, USDA 1987), it plays only a small role in the modern Lake States fire regime. Haines et al. (1975), presenting a National Forest wildfire atlas for the entire 1960--1969 decade, found human influence throughout the northeast and north central states. In all of the Lake States forests, lightning was responsible for less than half the forest fires; in most cases, this natural cause was associated with fewer than 25% of fires. On Lake States National Forests in that decade, major causes included smoking by hunters and fishermen, pyromania, refuse burning, recreation cooking fires, and railroad sparks and exhaust.

Through development of roads, railroads, utility corridors, and urban areas, humans have greatly affected fire cycles in and near the Lake States region (Heinselman 1981). For example, Harrington and Donnelly (1978) discovered that over half the fires in Ontario in the 1920s were centered on a single rail line; they called the link between human habitation and fire starts "undeniable". Main and Haines (1974), found that between 1960 and 1969, over half of all fires on northeastern National Forests were started by local permanent residents. Stocks et al. (1996), recounting recent studies of Canadian forest fires of the 1970s and 1980s, found that areas of high human habitation witnessed a high number of fires, though they had relatively little area burned due to human suppression. In their view, humans have a major effect both by influencing the origin of fires, and then by suppressing them, resulting in a complex fire pattern.

Analysis of both state-level and national summary statistics indicate that humans continue to play a powerful role in starting fires in and near the Lake States. In 1986 (USDA 1987), humans caused only 47% of fires larger than 10 acres (4 ha) across the full set of U.S. National Forests. During that same period in Lake States National Forests, however, humans caused 93% of all such fires.

Active fire suppression has had a major effect on the patterns of fires in the Lake States. Heinselman (1973) warned that without the reintroduction of fire in northern Minnesota, "major unnatural, perhaps unprecedented changes" in the ecosystem could occur. Swain (1980) agreed, predicting that continuing fire control may allow spruce and fir to replace broadleaf species in the area. Frelich and Lorimer (1991) found that suppression has doubled the fire rotation period in the Upper Peninsula of Michigan. Clark (1990), working in northwestern Minnesota, concluded that without fire suppression, fire frequency there would have otherwise increased by 20-40% in the 20th century because of warmer and drier conditions. In the Upper Peninsula of Michigan, Loope (1991) found that since the advent of European settlement, there have been no significant forest fires within the Pictured Rocks National Lakeshore area, whereas the area had previously averaged a fire every 22 years. Frissell (1973), studying Itasca State Park in Minnesota, aptly described the role of fire suppression, saying it has created "a serious departure from natural conditions".

The pervasive influence of humans on fire patterns in the Lake States region is best summarized by Heinselman (1981), who said that human impacts of all kinds have "so greatly lengthened and modified natural fire cycles, that they are no longer relevant" except to understand the natural ecosystem and work with nature reserves.

References

Analysis Team:

North Central Research Station, Rhinelander, WI
Dave Cleland, Ecologist

Private Consultant
Richard L. Watson, Forest Ecologist

North Central Research Station
Jim Jordan

USDA Forest Service, Chippewa National Forest, Cass Lake, MN
Dave Shadis

USDA Forest Service, Huron-Manistee National Forest, Cadillac, MI
Alix Cleveland, Forest Ecologist

North Central Research Station, Rhinelander, WI
Paula Anderson

USDA Forest Service, Hiawatha National Forest, Escanaba, MI
Peggy Burkman, Fire Ecologist

University of Wisconsin, Land Information and Computer Graphics Facility, Madison, WI
Jeff Cardille
Ron McCormick

North Central Research Station, Houghton, MI
Maureen Mislivets, Landscape Ecologist

Michigan Technological University, Houghton, MI
Sari Saunders, Landscape Ecologist

Available GIS Maps:

Reports

Annotated Bibliography of Lake States Natural Disturbances. Paula J. Anderson, David T. Cleland, John C. Zasada. Draft 9-02 (Working Document).
PDF version: AnnotatedBibliographyLSNaturalDisturbances.pdf (1.22 mb)

Fire return intervals and fire cycles for historic fire regimes in the Great Lakes Region: a synthesis of the literature. Donald I. Dickmann and David T. Cleland. Draft 8/02.
PDF version: LSFireCycles.pdf (518 kb)

Toward a Theory of Meso-scale Wildfire Modeling- A Complex Systems Approach Using Artificial Neural Networks; Ronald J. McCormick, Thomas A. Brandner, Timothy F.H. Allen (available only in PDF format) Fire.pdf (157 kb)