Fire's Role in Nature

Much of life on Earth has evolved with fire. Like storms and floods, fire is a powerful force that has the ability to give life or smother it. Fire has shaped many of the ecosystems and life forms we know today, here in Wisconsin and also worldwide.

Wild lupine is a plant native to Wisconsin's jack pine barren communities.

Wisconsin's natural plant communities at the time of settlement were a mix of grassland, oak savanna and oak forests in the south and southwest, and conifer-hardwood forests and pine savannas (or barrens) in the north. These ecosystems evolved over thousands of years under many influences. One of the most influential factors was fire. Fire returns nutrients to the soil, exposes soil so that seeds may germinate, releases seeds from cones or hard seed covers, removes the thatch layer that shades small-statured species, and plays many other ecological roles.

While lightning strikes started many fires, many more acres in North America were burned intentionally by Native Americans. Fire was used to clear the land for agriculture, improve forage for game species, direct game migration, and clear brush to ease travel or prevent hostile forces from approaching.

In The Vegetation of Wisconsin, John Curtis writes: "In the early years of settlement, the most important vegetational effects were caused by the elimination of fire." European settlers limited the extent of wildfires with their plowed fields, dirt roads and forest clearings, causing major changes in the frequency and extent of free-running fire. Eventually, fire control efforts were organized, and today between state and local efforts, most wildland fires are suppressed before they affect more then a few acres. While this has made living in rural Wisconsin safer for the human community, it has greatly changed the natural community.

In the absence of fire, pine barrens can quickly fill in with trees.

The strongest evidence for the change in fire regime is seen in the prairie and savanna regions of the state. Land that was described as treeless by early settlers quickly became covered with brush and forests as major settlements were established. Changes in our fire-dependent natural plant communities were rapid after about 1850; this is especially true of the prairies, pine barrens and oak savannas where a closed forest canopy quickly eliminated most of the light-loving species. Many of these formally common plants and animals, and their habitats, are now uncommon, and quite a few are formally listed as threatened or endangered.

With this great reduction in wildland fire, as well as other human disturbances, the land area of those plant communities that require frequent fire has been greatly reduced. Even with the conservation efforts of state, federal and private entities, only a small percentage of land has vegetation representing the original natural state. Within those conserved lands, we find many acres that require fire in order to maintain the native community types. Land managers today frequently use fire - as prescribed burns - as part of their land management strategy.

Prescribed burning is a commonly used management tool for restoring and maintaining prairie, savanna, and barrens communities.

Natural resources managers work to mimic, as closely as possible, the fire regime that a plant community experienced naturally. Since most significant natural fires burned when the vegetation was dry in the spring and fall, this is when management fires are usually applied. Using natural fire breaks such as rivers or lakes, or man-made breaks such as roads, mowed paths, or plowed fire lines, land managers generally only burn a small portion of a protected area at one time in order to avoid damage to animal populations.

While state and federal agencies conduct most management fires, private organizations such as The Nature Conservancy, The Prairie Enthusiasts, and many nature centers have prescribed burn programs as well.