A crackling sound resonates as high flames slither across the field. Small trees and bushes are quickly engulfed, providing more fuel for the fire.

Nearby a small group of highly trained fire officers with the Michigan Department of Natural Resources are moving with the fire in protective clothing, hard hats and firefighting equipment.

This is not a wild fire; it is a prescribed burn, which has been deliberately ignited to restore a natural ecosystem.

Prescribed fire is increasingly being used by the DNR and other public-land managers and private landowners to manage vegetation. If implemented when conditions are just right and in an appropriate environment, prescribed fire is a valuable, safe, critical tool for restoring and maintaining important wildlife habitats such as prairies and savannas, oak barrens, jack pine forests and wetlands.

"Prescribed fire is a misunderstood management technique," said Mark Sargent, Private Lands coordinator in the DNR's Wildlife Division. "We understand that it can appear frightening to have a fire racing across a landscape, but we do not light them unless conditions are perfect. Prescribed burns are very effective in restoring some amazing habitats."

Michigan often is thought of as a state historically dominated by its forests. However, when the Europeans first settled here, a significant component of the landscape consisted of more open communities such as prairies and barrens. Most of these grassland sites occurred where trees and shrubs had difficulty growing because of the droughty and infertile soils.

Frequent wildfires (often set by Native Americans or lightning) kept these areas open by killing or stunting shrubs and trees. Wildfires occurred irregularly across the landscape. Fire frequency varied greatly depending on vegetation type, fuel load and flammability, soil moisture, weather and topography.

It is estimated that of the 11 million to 13 million acres of savanna found in the Midwest in the early 1800s, less than 0.02 percent remain. In addition, invasive species, such as spotted knapweed, autumn olive and common buckthorn, are crowding out and killing the little bits of remaining prairie and savannas that exist.

Modern-day fire suppression has transformed prairies and savannas into brush land and young forests because grasses and flowers that cannot grow in shade are unable to thrive under the tall shrubs and trees.

"Since we can no longer allow wildfires to do their job naturally, the DNR uses prescribed burns to mimic those effects because fire is extremely beneficial to a variety of plants and animals," Sargent said. "Without the use of fire, we may lose biological diversity."

Native wild flowers like wild lupine, bird's-foot violet, black-eyed Susan, and blazing star plus grasses like Indian grass, big bluestem and little bluestem thrive in open, grassland/oak forest communities.

A diverse group of wildlife species utilize prairies, savannas and barrens, including the federally endangered Karner blue butterfly, and the grasshopper sparrow, meadowlark, box turtle, wild turkey and fox squirrel.

According to Wildlife Biologist John Niewoonder, the seasonal timing of a burn is one of the most important factors in determining the effects of a fire.

"Fire has the greatest impact on undesirable plants that are actively growing," Niewoonder said. "An early spring fire, for example, may burn off vegetation and shrubs, but because roots are full of reserves, they re-sprout vigorously. In contrast, if burned when root reserves are at their lowest in late spring or summer, sprouting may be significantly less."

Depending on conditions and degree of competition, Niewoonder said today's prairies and savannas may require prescribed burns every two to fives years in order to achieve restoration or management goals. Other less degraded sites may require burning only once every 20 years.

Currently, most prescribed burns are conducted between late March and early May when humidity is low, winds are light and fine fuels (grasses, sedges, oak leaves, etc.) burn readily without getting out of control. Occasionally burns also are conducted in early- to mid-fall but appropriate burn days with suitably low humidity and light wind can be limited at this time of year.

"Remember, it's always best for a prescribed burn to be conducted by professionals who are trained, equipped and experienced in controlling these burns safely," Niewoonder said. "Landowners should not attempt to do significant-sized burns on their own. Always talk to professionals first."

So, this spring or fall, if you hear a familiar crackling or see contained flames in the distance, a crew of natural resource professionals may be restoring lost habitat.

We recommend returning to that same area next year. You will be amazed at the beautiful grasses and wildflowers that may reappear.