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White-Hot Winter | Seasonal Prescribed Burns Help Wisconsin’s Marshes And Wetlands

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Gone Sleddin'

Gone Sleddin'

Michele Witecha

Michele Witecha is the prescribed fire specialist for the Wisconsin DNR.

When most people think about winter in Wisconsin, words like cold or dark often come to mind. That’s not always the case for DNR fire staff. For them, winter can mean fire. Prescribed fire, to be exact.

Prescribed fire, also known as controlled burning, is an essential tool for restoring animal habitat, controlling the growth of invasive plants and promoting native species and oak and pine regeneration.

Prescribed burns conducted in late winter provide an ideal opportunity for DNR burn crews to focus on areas where hazardous fuels exist on state lands, particularly on marshes and wetlands. These vegetation communities can build up excess dead vegetation over time, posing a wildfire risk during snow-free periods.

Wildfires in cattails burn more aggressively and at a significantly hotter temperature. They also can be more difficult to control and suppress than fires involving other fuel types.

DNR fire management crews rely on ice cover to reach and ignite interior cattails. Ignitions can proceed faster and are safer for crew members, compared to igniting from an amphibious vehicle in open water.

To reduce the risk to burn crews and the public, burns in these areas occur in winter when snow surrounds the units.

The first prescribed burn of the year can happen anywhere from mid-January to mid-February, as burn crews must wait for the ice cover to be thick enough to safely reach the marsh vegetation on foot before lighting the fires.

Most people are aware of burn activity in the spring, but the thick, black smoke from winter burns can create a surprising sight. The burns might look intense, especially when they occur near populated areas.

A prescribed burn removes excess vegetation above the snow at Horicon Marsh.

Why Burn In Winter?

The primary driver of winter burns is to reduce the risk of wildfire to the public and the local fire suppression community weeks later, during times of higher fire danger.

In addition to reducing hazardous surface fuels, winter burns also play a crucial ecological role. When conducted in marshes, wetlands and wet prairies, these burns can help reduce the dominance of cattails, which grow aggressively and can crowd out native plants and grasses, and therefore stimulate the growth of native grasses, sedges and wildflowers — the base of most food webs in those communities.

The stimulation of root growth in native vegetation increases carbon uptake and storage overall, offsetting the carbon released during the winter burn within 1-2 years.

Removal of the dead vegetation also creates vital open water foraging habitat for waterfowl migrating back north in the spring.

Conducting prescribed burns in the winter does have several caveats. Prescribed burning is a weatherdependent event, and the guarantee of the necessary weather, fuel and ice conditions varies from year to year.

Burn windows also are impacted as climate change continues to influence winter temperatures and snowfall in Wisconsin.

Although winter presents a safe opportunity to conduct surface fuel reduction burns, it’s limited in impacting undesirable brush below the surface. To reduce woody plants, late summer or fall burns might be more effective, according to fire effects research across the Great Lakes.

Prescription Planning

There’s a lot more to prescribed burns than just lighting a fire. Each burn is driven by the specific desired objectives laid out by the property’s wildlife biologist, ecologist or forester.

DNR staff carefully plan how, where and when to conduct a burn to achieve the desired fire behavior and meet objectives, all while ensuring the safety of burn crews, the public and the wildlife in the burn area.

A burn “prescription” is developed that outlines the specific fuel and weather conditions needed for a safe burn. This includes wind speed and direction, temperature, humidity, ice thickness and the presence of snow.

Beyond winter, additional windows of opportunity for prescribed burning occur through spring and open again in late summer and fall (mid-July through November), based on weather.

DNR fire management staff closely monitor conditions throughout the year to find the ideal windows and only burn when weather and vegetation conditions meet the prescription for a safe and effective burn.

Learn More

Find details about when and where the DNR conducts prescribed burns throughout the year via the DNR's Prescribed Burn Dashboard. For information on conducting or contracting a burn on your property, visit the Wisconsin Prescribed Fire Council website, prescribedfire.org.

Winter prescribed burns bring many benefits come spring. Migrating waterfowl and other birds will flock to the recently burned unit to take advantage of the pockets of open water, reinvigorated marsh grasses and wildflowers, and the increased food sources these areas provide.
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