Category: Wildlife Impacts

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Using Prescribed Fire to Enhance Habitat for White-tailed Deer

Prescribed fire is an excellent tool to stimulate and maintain forage and cover for white-tailed deer. Browse (the leaves and twigs of woody species) and forbs (broadleaf herbaceous plants) dominate the whitetails’ diet throughout their range, and fire can be used to increase available nutrition from these plants in woods and fields. Fire can also be used to maintain relatively dense cover before openness and visibility increase as a result of over-shading and competition.

Frequency of Fire

Forb production is highest in early successional stages where sunlight is not limited. In the eastern US, where rainfall exceeds 30 inches per year, woody species invade post-disturbance and typically dominate within 7 – 10 years, limiting forage available for white-tailed deer. Burning on a 3 – 7-year fire-return interval maintains early successional vegetation, which often provides 2,000 – 6,000 pounds (dry matter) of desirable forage per acre during spring and summer. This forage production rivals that of warm-season food plots and can be maintained at a fraction of the cost of food plots. The exact fire-return interval necessary varies by site and year. When managing for deer, it is desirable to burn when woody encroachment begins to limit forage production. This interval provides not only food, but attractive bedding cover as well.

 

Season of Burn

The fire-return interval influences vegetation composition and structure more than any other factor. However, timing of burning can also influence vegetation composition and associated structure. Within a given fire-return interval, burning during the dormant season sets back vegetation structure, but often does not change vegetation composition appreciably. Most woody species readily re-sprout following fire in any season. Burning during the growing season (especially late growing season) tends to decrease woody species and promote increased herbaceous coverage. Thus, the necessary fire-return interval to maintain the same vegetation structure and composition may be a year or 2 less following dormant-season fire than growing-season fire. Late growing season fire may encourage more forbs in areas where grasses represent >70% coverage. Increased forb coverage (>30 percent groundcover) is desirable when managing for deer. Browse and/or forbs should comprise 30 – 70% of the groundcover. Grasses are not desirable for deer forage, but some grass coverage provides fine fuel and facilitates burning.Both dormant- and growing-season fire have a place when managing for white-tailed deer. Although various browse species are selected over others by whitetails, browse re-sprouting following burning is highly nutritious. Young growth of any plant is more nutritious, more palatable, and selected by deer over older growth because it is more digestible. Nonetheless, as the growing season progresses and plants mature, forage quality declines.

Animal Nutrition

Fire can also be used in woods and woodlands to increase available nutrition and cover for white-tailed deer. However, burning in closed-canopy forests will do little to improve browse availability or fawning cover. Thus, it is important to open the canopy to allow at least 20 – 30% sunlight into the stand prior to burning. Retention cutting, thinning, and shelterwood harvests are often used to reduce canopy closure and enable more sunlight to enter the stand. Forage production (browse and forbs) in the understory of a closed-canopy forest usually averages 25 – 100 pounds (dry wt) per acre. With additional sunlight, forage production is increased to 700 – 1,000 pounds (dry wt) per acre. It is important to note these estimates only include plants commonly eaten by white-tailed deer, not total biomass. This flush of new vegetation not only increases nutritional carrying capacity, but also can help increase fawn survival by enhancing cover. The soft mast (such as blackberry and blueberry) response following fire also provides increased nutrition for deer.

If burning the woods may involve a little more than what it’s worth, consider this: Burning 4 acres of woods typically provides as much warm-season forage as 1 acre of soybeans. The increased forage following burning will persist at least 3 – 5 years, whereas warm-season food plots have to be planted each year. Any serious deer manager cannot afford to not consider using prescribed fire.

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Managing Northern Bobwhite with Prescribed Fire

bobwhite habitat managed through prescribed fire photo

The northern bobwhite is a popular gamebird and many landowners wish to improve populations of this quail on their land. Practices such as timber thinning, disking, herbicide applications, and food plots are commonly implemented for bobwhites. However, prescribed fire is implemented by far fewer landowners. This resistance to use fire is unfortunate because fire benefits bobwhite more than any other practice.

Impacts of fire

Bobwhite require short, dense, woody cover (shrubs), perennial grass cover, bare ground, and abundant forbs (broadleaf herbaceous plants) with an open structure at ground level. Fire is an effective tool to manipulate all of these factors. Fire removes dead plant material, opens the structure of vegetation at ground level, and stimulates annual food-producing forbs to germinate. In a forest, fire can be used following a harvest or thinning that allows at least 50% sunlight into the stand. Burning these stands consumes leaf litter and stimulates a lush understory that provides better cover and more food, especially seed and soft mast.

Frequency

Fire frequency is the most important factor when using fire for bobwhite management. The ideal frequency depends on the plant community, precipitation, and soil type. In general, a short fire-return interval is needed in the eastern portions of the bobwhite range. Areas of the Gulf Coastal Plain may need fire every 1 – 2 years to maintain the early seral stages required by bobwhite quail in these areas. On the western edge of the bobwhite range where precipitation is much less, fire frequencies can be longer. Burning once every 10 years will maintain the plant community in a suitable composition and structure.

This pine savannah is burned every 1 – 2 years and is excellent bobwhite habitat.

Seasonality

Although fire frequency is the most important factor, season of fire can also be influencial. Fire in different seasons will tend to favor certain plants that may be more or less desirable for bobwhite. This is highly variable from place to place. However, in general, summer fires tend to reduce woody plant composition more than dormant-season fires. So, if your goal is to reduce woody plants and increase herbaceous plants, burning during the growing season should be considered.

Additional considerations

Similar to haying, burning during the nesting season can destroy nests. Most bobwhite nesting occurs May-July. So if growing-season fire is needed to control woody species, burning late in the growing season should be considered. Also, if a large area is burned in the spring, perennial grass cover for nesting will be lacking that year. Therefore, only a portion of the landscape should be burned in any one year. However, in areas that receive a lot of rain, such as the Gulf Coastal region, grass cover returns quickly following fire and quail may nest in that year’s burned area. Fire also temporarily removes shrub cover. However, most shrubs resprout and the resprouts are often more dense a year or two following fire.This further implies that only a portion of the landscape should be burned each year.

With a little experience and knowledge, landowners can effectively use prescribed fire to manage bobwhite habitat. Fire historically maintained healthy bobwhite populations and it can continue to do so today.

 

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Managing Firebreaks for Wildlife

Managing native vegetation with prescribed fire should be an integral part of any land management plan. Maintaining adequate firebreaks is necessary to implement a prescribed fire program. Firebreaks serve several functions, including defining the burn unit perimeter and providing access to burn units. However, they can also be used in other ways to benefit wildlife and improve hunting. Food plots are often used to attract wildlife and make various game species more visible and increase hunting success. In some cases, food plots can also provide beneficial forage for species such as wild turkey (Meleagris gallopavo) and white-tailed deer (Odocoileus virginianus).

Managing Herbaceous Cover

Firebreaks may be the only accessible and open areas for food plots. Firebreaks can be disked seasonally, annually, or every few years; thus, they can be used for annual or perennial, warm- or cool-season food plots. Perennial plantings are best suited for firebreaks around areas that are burned on a fire-return interval of >3 years. If the firebreak is planted in the season prior to burning, a “green” firebreak may provide suitable protection, depending on plant moisture, dead plant material, etc. Otherwise, firebreaks should be disked (optimally) or at least mowed just prior to burning. Thus, it is may be necessary to re-plant the firebreak after burning. 

Firebreaks do not have to be planted. They can be left fallow to allow native forbs to germinate. Often, native species such as sunflowers (Helianthus spp.), crotons (Croton spp.), and ragweeds (Ambrosia spp.) germinate in fallow firebreaks depending on the time of year they were disked. Fallow food plots, both in fields and in woods, can be very attractive to wildlife. When firebreaks occur in woods, it is not uncommon for woody species to sprout and grow in the firebreak. That’s OK. Browse and cover from low-growing woody plants are important sources of food and cover for several species, especially white-tailed deer and wild turkeys. Woody species can be kept in check by disking, mowing, or selective herbicides.

Firebreaks can be managed for both fallow vegetation and food plot forages. By creating a firebreak 2-disk-widths wide, one half (or side) can be planted and the other left fallow. This can be a very attractive arrangement, depending on what is planted and what the seedbank holds, for species such as cottontail rabbits and northern bobwhite.

Another strategy when creating firebreaks in areas where the seedbank is likely to hold undesirable species is to establish the firebreak the width of a sprayer, not the width of a disk. This allows the use of selective herbicides, whether the firebreak is managed with planted forages or for fallow vegetation.

 

This firebreak has been planted to oats to provide additional forage during the cool season. The extra width aids in controlling prescribed fires within the adjacent pine stand while allowing adequate sunlight for the food plot.

This food plot was created by disking a firebreak. Notice the sunflower, croton (dove weed), and ragweed which provides forage for white-tailed deer and seed for mourning dove and Northern bobwhite.

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Minimizing Mortality to Wildlife from Prescribed Fire

For most wildlife species, mortality from prescribed fire is small. Some species of reptiles such as this Western glass lizard appear to be more susceptible to mortality. However, failure to use fire will eventually result in the plant community being insufficient for these same species. Thus, some level of wildlife mortality is necessary to sustain the populations that are dependent on these fire adapted plant communities.

Prescribed fire is an important wildlife management practice that influences the structure and composition of plant communities.  This influences wildlife distribution and abundance across the landscape.  However, there are some concerns to consider when using prescribed fire, such as direct wildlife mortality.  While direct mortality is rare, there are some things that can be considered to minimize its occurrence.  However, the overall positive effects of fire outweigh any potential negatives in most instances.

While the vast majority of wildlife are able to avoid fire (either by escaping the burn unit or going underground), young wildlife will be particularly vulnerable.  Limited information exists on how much mortality fires cause, but it appears to be minimal in areas where fire historically occurred.  Ground nesting birds are susceptible to fire and this has long been recognized. However, limited research suggests that loses to ground nesting birds from fires conducted during the nesting season is minimal.  Yet, avoiding the primarily nesting period is advisable when possible, assuming the land manager can still maintain the appropriate fire frequency. 

For most of the U.S., the primary nesting season for grassland birds is May-July.  While there is still reproduction taking place during August and September, the vast majority of nests are complete by this time.  Therefore, waiting until late July or August will avoid most chick mortality. Additionally, many bird species will renest if their first nest is lost to a fire.  Similarly, May and June have high numbers of deer fawns and young rabbits.  Reptiles are also at risk during early spring.  They are not as mobile as mammals and birds, and are more frequently killed by fire right after they come out of hibernation.  Some species in particular have shown high mortality rates such as glass lizards.  Reptiles and amphibians are most active during the summer months.  Summer fires often leave a refugia of unburned area that reptiles and small mammals may be able to escape to. However, it has been concluded that a landscape with a mosaic of burned and unburned areas has a higher diversity of reptile species.  Thus, while some reptile and amphibian mortality will occur, providing a diversity of plant composition and structure with fire would be beneficial in the long-term to the reptile and amphibian community as a whole.  Therefore, only a portion of the landscape should be burned each year.  This will also ensure that all species have the habitat requirements needed in that year.  

While it is impossible to avoid wildlife mortality from prescribed fire, steps can be taken to reduce the incidence.  However, as mentioned earlier, maintaining the appropriate plant community for a species is much more critical than individual incidental mortality.  Thus, fire frequency must be the overriding factor for proper wildlife management.

 

 

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Utilizing Prescribed Fire to Create “Food Plots”

Land managers often wish to plant food plots to increase forage or serve as an attractant for wildlife. At times this may be a beneficial practice, particularly as an attractant for hunting.  An alternative is to use prescribed fire to stimulate food producing native plants. Depending on the soil type, location, season of year, and precipitation, prescribed fires often stimulate plants that are utilized by wildlife.

Growing Season Fire

Growing season fires can be especially productive for creating food plots for mourning dove hunting, this favors several species of desirable food plants such as snow-on-the-mountain, croton or dove weed, and sunflower, as well as creates ample bare ground to allow doves to forage. These plants are also desirable for Northern bobwhite, ring-necked pheasant, and wild turkey.  Additionally, late summer or early fall fires reduce grass litter going into the dormant season which can make certain important cool season plants more accessible. Scribner’s panicum, which is important winter deer forage in many areas, is a good example. This plant is commonly foraged on by white-tailed deer during the winter in areas that were burned during the previous growing-season.

Dormant Season Fire

Dormant season fires can be equally important.  Wild turkey in particular are attracted to areas that were burned in later winter or early spring as they have actively growing grasses for the first few weeks following the fire.  Later as annual forbs (broadleaf herbaceous plants) increase in abundance the area become important for insect production for hens and poults. These same forbs will have seeds later in the summer and into the fall that wild turkey feed on.  White-tailed deer will utilize many of these same forbs as forage.  Further, burned areas that contain woody plants will have abundant resprouts that offer excellent browse for white-tailed deer.  Plants such as greenbrier, elm, and blackberry are particularly attractive following a fire.

Final Considerations

While, these native “food plots” may not produce the quantity of forage per acre that a cultivated plot would, the cost is much less per acre, thus many more acres can be treated maximizing the benefit to wildlife. Land managers will not see the same results from year to year or place to place as weather and soil differences will influence the outcomes. Experimentation with various seasons of burns on a particular property will provide the manager guidance as to how to increase the attractiveness of a site to target wildlife. The important thing to remember is that you can successfully manage for wildlife without planting anything on your property. This requires an understanding of how to manipulate native plants with disturbances such as fire.  To be successful with this type of management, it is imperative to learn to identify key plants that wildlife utilize.

Prescribed fire can create natural food plots at little cost to the landowner. These white-tailed deer are concentrated on a fire that was conducted in July, the photo was taken the following January. The deer are feeding on the winter rosettes of Scribner’s panicum which is a native cool season perennial grass.

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How does fire impact wildlife?

Fire can be both positive and negative for wildlife. Wildlife evolved in plant communities that had fire. Man has changed the fire regime which has had negative impacts on many species. Some species require frequent fires while others require less frequent fires. Thus, the impacts on species of plants and animals are highly variable and to determine the impacts on a particular place you need a good understanding of individual species responses.
There are some general notes to consider regarding wildlife: 1) Fire temporarily increases the palatability of many plants which increases forage for herbivores. 2) Fire temporarily increases the amount of annual forbs which many birds require. 3) Fire temporarily reduces the amount of cover for nesting and escape.
How long these conditions last depends on the productivity of the site. It could be as little as 3 years or as many as 200 years. Fire is critical for wildlife biodiversity. The key is selecting the appropriate scale (time interval between fires and size of fire) to match the wildlife species of interest.

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