Prescribed burns help land managers create forage, habitat for wildlife

Historically, fire has provided the perfect habitat for various species of wildlife. Native people used prescribed burns in their land management processes as well. They understood how fire could be used for good, and put it to good use.

In recent decades, however, fire has come to be seen as a bad thing most of the world. But, the truth is, it still has a place in land management. Prescribed burns or “controlled burns,” as some call them, are used to improve habitat where the landscape has changed and in areas where conditions are no longer as favorable for wildlife as they once were.

Prescribed burns should only be conducted by professionals who are trained in keeping these fires under control. However, those looking to manage their land for a variety of wildlife species, including white tailed deer, would do well to understand how prescribed burns can work into an overall land management plan.

Professionals who conduct prescribed burns carefully plan out where the fire should start, where it should stop, and where the fire breaks should be that will help to keep the fire in the right area.

Black areas, or fire breaks are created before the actual burn is started. These areas, as the name implies, stop the fire at a particular point by being void of any fuel that would allow the fire to continue past that desired end point. These breaks are usually at least 10 feet wide.

Fire can provide the perfect conditions post-fire for forage for deer and other species. The point is to take the landscape from shrubby, wooden plants and low quality cover and food to native grasses that would provide high quality cover and food.

Post-disturbance, woody species of trees come to dominate the landscape within seven to 10 years. This limits available forage for white tailed deer. When managing for deer, it is recommended to burn on a three-to-seven-year rotation. This allows for plenty of early successional vegetation deer need to be healthy. 

Managing a forest with prescribed burns brings about deer food naturally. It can be done for a fraction of the cost of creating food plots.

When deciding on the timing of prescribed fires, land managers should think not only of forage, but also of bedding cover. 

It is also important to remember that a closed-canopy forest will do little to provide the browse and vegetation white tailed deer need. Cutting to allow for at least 20-30 percent sunlight should be done first. Then a prescribed burn can follow. Sunlight penetration to the forest floor is important for those herbaceous species that are desirable when managing for deer. Killing of small oaks, hickories and other less beneficial species that are crowding out herbaceous species is important to get the right plants at the right time when the deer need them. When burning is done correctly, few big trees will be damaged or killed. For that reason, thinning, as described above, should be done before a prescribed burn is put on the landscape.

Timing is the second important factor in prescribed burns, right after the interval of burning. Burning during the dormant season, for example, will knock back the vegetation, but it will not change the composition of what is growing in that part of the forest. During the winter, all of the plants’ water and carbohydrates are stored in the roots. When burning is done during the growing season, woody species can be decreased and herbaceous species increased. This is especially true with late growing season burns. According to prescribed-fire.com, 30-70 percent of ground cover should be browse or forbs when managing for deer. While grasses are less important for deer, they do provide fuel for future burns. 

Burning at different times of the year can be beneficial to deer as well. New growth is the most nutritious, so that first growth after a burn can be extra beneficial for deer. New growth is also the easiest for deer to digest. Growing season fires allow land managers to better mimic natural fires, and bring about the benefits of a natural fire occurrence. 

A word about turkey

Wild turkey, too, can benefit from prescribed burns, just as other species such as grouse can. A combination of dormant season and growing season fires can benefit these birds as well. It should be noted that early growing season fires can destroy turkey nests. However, according to the National Wild Turkey Foundation, studies have shown no population-level effects to turkeys from nests destroyed by fire. A study in Georgia found that, in 75 percent of the cases where a turkey nest was destroyed by a prescribed burn, female turkeys simply renested that year. 

Female turkeys prefer vegetation communities that are present approximately two to three years post burn, when that habitat is available. For that reason, shortening the intervals between burns may be even more beneficial for wild turkeys. Broods need the early successional vegetation that is present post-burn. Turkeys may even forage in burned areas, sometimes while they are still smoldering. 

Managing for bats

Prescribed fire can also be used to manage the landscape for bats. Nick Sharp, a non-game biologist for Alabama Wildlife and Freshwater Fisheries presented his talk regarding just that recently. With National Bat Awareness Week being Oct. 24-31 this year, it is a good time to think about managing for these nocturnal critters as well.

Bats are in decline across the country, just as they are here in Wisconsin. White nose syndrome alone has killed approximately 90 percent of northern long-eared, little brown and tri-colored bats in less than 10 years. Most species of bats are in decline due to not only white nose syndrome but also habitat loss and other issues.

Bats are important to the ecosystems in which they are found, but they are important to humans as well. A single bat can eat over 1,000 insects per night.  They also contribute $4 billion in pest control service to our agricultural economy. They mean $1 billion to the global corn crop alone.

Like many animals bats rely on forests for their survival. The eight species of bats in Wisconsin use forests for food, water and shelter throughout their lives. Cave dwellers such as the Northern long-eared bat, the little brown bat and the tri-colored bat can use hollow trees or even slash piles as roosts. Keeping these things on the landscape can be important for bats. Prescribed fire can be beneficial for bats, too, by improving forest conditions.

Prescribed fire can reduce the understory and midstory clutter. This can make foraging conditions easier for bats. They then have more space to fly around eating those bugs and pests. An open understory can also make conditions better for the prey of bats, meaning the forage base can support more bats in general.

Fires such as this can also create more high-quality snags and basal cavities in trees. That means more roosting and nesting places for bats, too.

One thing for land managers to keep in mind is the timing of burns, when it comes to bats. Bats do not fly below 45-50 degrees. Pups also cannot fly for the first month of their lives. For that reason, burns should not be conducted in areas where bats live from May 1 to July 31. This is pupping season and baby bats will not be able to fly away from fire. Also, because many bats in Wisconsin will spend their winter in caves, it is important to keep caves smoke-free for the health of the bats inside.

Another technique that can be used, if burning must be done for some reason during pupping season, is the reduce of the fire’s intensity. Wind can be used to transfer heat across the land instead of the transfer up the trees. Low humidity and light wind days should be avoided when burning. Back fires can also be used to reduce the intensity of a burn.

Before burning, land managers can protect large snags by raking away and leaf litter or anything that can provide fuel for a fire. These areas should be raked down to bare soil to keep them intact and on the landscape. 

Sharp also spoke about some best practices land managers can use when managing for bats as well as other wildlife. He said the forest should retain at least 16 trees of nine inches in diameter at breast height (DBH). All standing snags that measure greater than three inches DBH should be retained as well. Trees with exfoliating bark, cavities and/or basal opening should be kept whenever possible as well. In areas with continuous canopy cover, Sharp recommends maintaining a small forest opening with abundant snags as well.

Land managers should also keep in mind any water features incorporated into the landscape. Forest cover and snags in riparian areas should be protected and maintained. Continuous canopy cover over water areas can also be important.

These land management techniques allow the land manager to work with the natural elements present on the landscape, rather than attempting to add things that would not normally grow in a location or that work against the natural ecosystem. Also, prescribed fire has the additional benefit of keeping natural wildfires at bay by removing fuel from the landscape.

Beckie Gaskill may be reached via email at [email protected].