Prescribed burning can improve grazing habitat for livestock, wildlifeWritten by Gayle Smith
Prescribed burning is thought to be a relatively new way of improving grazing habitat for livestock and wildlife, even though this method of grass improvement dates back to the 1960s in the southeastern U.S.
In the mid-plains, prescribed burning is gaining popularity as scientists focus on ways to improve grass growth, reduce parasites and enhance habitat for both livestock and wildlife.
According to Derek Scasta, Extension rangeland specialist with the University of Wyoming, prescribed burning can boost the crude protein in range plants, which creates a healthier grazing habitat for livestock.
One study in Montana showed an increase in western wheatgrass productivity after a prescribed burn, while another study in Oklahoma showed an enhancement in the amount of bluestem grama after native pine and bluestem rangeland were burned. Native plants have adapted to fire and the benefits of grazing afterward, with increased forage and utilization.
“When we use fire to improve habitat, we have to think about forage quality, quantity and crude protein,” Scasta said.
In the Oklahoma study, the burned areas produced higher quality forages, but the unburned patches had more quantity. These results were similar in a short grass study in eastern Colorado. There was no reduction of blue grama in the burned areas, but it enhanced the digestibility of the blue grama forage base.
In fact, burned areas showed about 16 percent crude protein after fire, compared to lower amounts of crude protein in unburned areas.
Scasta says the boost in crude protein after burning is caused by the rapid cycling of nutrients and the pulse of nitrogen prescribed burns provide.
“Crude protein is based on nitrogen content,” Scasta said. “Fire removes all the dead grass from previous years, allowing photosynthesis to occur rapidly.”
When an area is burned, Scasta says the heat moves upward, and 95 percent of the carbon moves up and out, so only five percent penetrates into the soil.
“These fires are not like wildfires,” he explained. “They do not burn hot enough to kill the micro-organisms and organic matter. In fact, prescribed burns only get to about 120 degrees, where wildfires can be over 1,000 degrees. Prescribed burns can actually help prevent wildfires from occurring and prevent the soil sterilization wildfires can cause.”
“Prescribed fires have a short residence time, so a lot of the soil’s organic matter and plant residue is left,” Scasta continued. “They move relatively quickly, and they are not as intense, so fuel consumption is lower. The best time to have a prescribed burn is during late winter or early spring, right before rapid green up.”
History has shown grazing animals, like bison, follow these fires because of the palatability and high quality of vegetation that develops after the fire.
“As fire and grazing move around a landscape, it creates a variety of diverse landscapes and habitat,” Scasta said. “For grassland birds, like the prairie chicken and sage grouse, that is important.”
“In tall grass prairie, cattle will spend 70 percent of their time in burned areas,” Scasta said. “From a management standpoint, prescribed burns could be used to help improve utilization in areas the cattle usually avoid by burning off the coarse or rank vegetation.”
In addition to improving the nutrient content of the grasses, prescribed burning can also reduce the number of parasites.
External parasites account for $2 billion in livestock losses each year. Animals endure blood loss from blood feeding insects, in addition to diseases transmitted by parasites. Scasta says many animals spend more time swatting flies than grazing, which adds up to reduced gains.
Finding a reliable method of parasite control can be difficult because the parasites develop resistance to chemical control methods too quickly.
Scasta referred to a study in Oklahoma, where researchers observed a 57 percent reduction in the tick population by implementing prescribed patch burns in pastures where cow/calf pairs graze.
“When fire moves through, it changes the habitat of the parasites,” Scasta explained.
Prescribed burns can also reduce horn and stable fly infestations, by eliminating their breeding grounds.
“Fire alters their overwintering habitat by burning up the litter,” Scasta said. “In fact, burning attracts livestock and wildlife because they consider it a parasite-free area. It alters woody plants and litter – changing the micro-habitat for ticks and other parasites.”
When to burn?
“When there is a lot of precipitation, burning everything every year has the most upside potential,” Scasta says. “That is when producers will realize the greatest livestock gains.”
During more average years, prescribed burning and patch burning converge.
“During dry years, burning everything has the greatest downside risk,” Scasta continued. “If we burn everything, we are really rolling the dice. I would recommend burning smaller patches and leaving areas as a barrier against drought.”
Scasta said patch burning can easily be incorporated into a management plan.
“The best strategy for patch burn grazing is to burn a patch within a pasture each year and allow the animals to graze it,” he said. “The most important part of the learning process is to conduct prescribed burns.”
When asked how to decide what to burn, Scasta responded that in tall grass prairie, he would target burning everything within a three year period, so he would divide it into thirds and then start over. In drier climates, Scasta said producers may want to spread prescribed patch burns out over a five-year period.
Risk management tips
University of Wyoming Extension Rangeland Specialist Derek Scasta provided seven tips for risk management when conducting prescribed burns, listed below.
First, identify smoke-sensitive areas like roads, hospitals and neighbors with respiratory issues.
Then, plan the ignition sequence. Consider the direction of wind, where to start burning, how to allow fire to back-burn and building additional fire break.
Third, identify hazards like oil and gas enterprises on the ranch.
Next, consider fire weather and behavior, including wind speed and humidity. Never burn when the humidity is less than 20 percent because it increases the chances of escaping embers.
Prepare equipment and a crew prior to the burn.
Also, share resources with prescribed fire associations or co-ops. Ranchers can pool resources to get approved burn plans from the association. Check into prescribed burning insurance.
Finally, seek experience with fire by taking landowner training and student training.