Planet of Fire

Prescribed fire is one of the most important tools available to land managers today. Although much of the 20th century was a period of fire suppression, the deliberate ignition of dry vegetation has been taking place across our local landscapes for thousands of years. Long before there were ecologists to carry the flame, indigenous people lit the landscape on a regular basis. Ever since the last glaciers retreated from the area, our plant communities evolved in the presence of periodic fire. Most of the plant communities that occur in our region are considered to be fire-dependent communities, that is, they replicate themselves and exhibit stability over time as long as landscape fire is part of the ecological equation; in the absence of fire, these communities change into something else—usually they degrade.

 Prescribed fire rejuvenates a prairie.

Prescribed fire rejuvenates a prairie.

So, among the techniques employed in ecological restoration, the application of prescribed fire restores a natural process previously withheld from the land. Stephen J. Pyne of Arizona State University has written widely on the subject of fire (relative to ecology), and while ecologists often characterize fire as a disturbance (like an ice storm or a bison wallow), Pyne asserts, “It makes more sense to imagine fire as a catalyst.”

Pyne sees fire as a contextual reaction, taking its character from its fuel and environment. Fine-textured fuels—like dry grasses—flash and burn fast, while coarse fuels—like fallen trees—require higher levels of heat for ignition and burn more slowly. A wind-driven prairie fire will race up a dry hill, while a slow, low woodland fire will creep through leaf litter, leaving unburned fuel in its wake. In any case, landscape fire feeds upon (consumes) plant matter. And fires have burned across the earth ever since there have been plants that dry out to serve as a flammable fuel source. Pyne has referred to the earth as a planet of fire.

 Prescribed fire in a woodland is characterized by low flames and leaves a patchy mosaic of burned areas.

Prescribed fire in a woodland is characterized by low flames and leaves a patchy mosaic of burned areas.

Fire is one of the elements responsible for humans’ rise to keystone species status. No species other than humans wields fire; no other ecological force shapes the landscape the way fire can. To quote a recent report from the U.S. Fish & Wildlife Service (USFWS):  “There is no ecological equivalent to fire. No other type of natural or man-made action yields the same benefits.”

The benefits of fire, naturally, vary according to the ecosystem or ecoregion affected. Locally, fire removes dead plant material (duff) and supports the rapid growth of plants in spring, the bare soil blackened by fire readily accepting the warming rays of the sun. The fresh green shoots may attract grazers, which may attract predators, thus fueling the nutrient cycle across trophic levels in the ecosystem. Fire hastens the recycling of nutrients back into the soil. Fire kills or injures individual woody plants, with seedlings and saplings among the most susceptible (mature trees, especially our fire-adapted species such as oaks being far less likely to be harmed). Although there are exceptions, and depending upon the timing of the burn, prescribed fire tends to favor the establishment of native plants, selectively deterring invasive species. Burning reduces the buildup of fuels and lessens the likelihood and severity of wildfire.

Since 2003, USFWS has been employing prescribed fire in the management of their lands. At Necedah National Wildlife Refuge in central Wisconsin, habitat improvements ascribed to prescribed fire have resulted in dramatic increases in the local population of Red-headed Woodpeckers, a signature species of Midwestern oak savannas. According to USFWS, “Oak savannas survive and flourish only with the help of occasional grass fires.” Such fires throughout the Midwest favor native warm-season grasses at the expense of nonnative cool-season grasses.

So in the early spring—and again in the fall—you may see smoke on the horizon, lifting toward the heavens; you may visit your favorite natural areas to find them briefly blackened below your feet. Know that it is a good thing. After all, it’s only natural: we live on a planet of fire.