Conducting a post-burn evaluation is a great way to assess the efficacy of a prescribed fire and determine whether your management objectives were met.
But examining information collected from fires at the end of the season can also shape tweaks to burn block prescriptions and can also be a good way to approach reducing potential costs of post-burn treatments like mowing, roller chopping or herbicides.
The extent of evaluations varies just as much as the types of properties across the Southeast. Not everyone does them and no two reviews are the same.
At Tall Timbers, the review process is quite thorough as the data collected are often used in research projects.
Typically, we mark data points including last burn, ground cover type, basal area, topography, and at 200-yard intervals calculate percent of complete burn, crown scorch percentage, hardwood stem and pine seedling density.
Tall Timbers’ Director of Land Management Eric Staller said before he became familiar with individual tracts and under what conditions they burned best, evaluations helped him adjust burn prescriptions and get a better sense of how fire shaped the landscape.
“When you first start seeing active fire on the ground, most people don’t know is that hot or is that cool? What are you actually doing? What are you accomplishing?” he said. “I think that these are very helpful for that.”
Thirty years ago, before post-burn evaluations became commonplace at Tall Timbers, there were areas where woody-stemmed shrubs were only being top killed at about 50%.
Those areas kept getting thicker and thicker and by the time those blocks came back in the two-year burn cycle, they had a four-year rough in which it became tough to get a more complete burn.
Coupling evaluations with weather on the day of the burn can help a manager make changes to coincide with better conditions such as differing humidity, wind speed and days since rain for the next burn.
“At the bare minimum, everyone should be going out there and saying did I accomplish my goals? Whatever goals those are and then you tweak your prescriptions for the next time you go to burn that unit,” Staller said. “That’s how I see it as the best of use.”
Other managers may do a simple visual review of their burns and some plan to mow or roller chop no matter how complete a fire burns.
Tall Timbers Game Bird Program Director Dwayne Elmore said for managers looking to reduce cost and prioritize efforts, or one who manages a smaller property, analyzing a fire can help make changes to a burn program to cut back on the need for post-burn treatments.
Additionally, the weeks following a burn are a great time to gain access to areas previously inhibited by brushy growth and apply herbicide to larger hardwoods that were unaffected by fire. That is especially important on properties without a long history of fire that may require hack-and-squirt methods to address unwanted species.
In that same vein, assessing a burn and delaying mowing or roller chopping can help save costs by allowing a manager to prioritize efforts.
Pine regeneration that may have been scheduled to be sprayed with herbicide or dealt with mechanically could be killed in the burn, eliminating the need for more costly intervention efforts that were planned.
Post-burn is also a good chance to address quickly resprouting invasive plants like Japanese climbing fern, Bahia grass or cogon grass, Elmore said.
Those and other problem plants will be obvious and herbicide can be targeted with less interception by other desirable vegetation or litter. Further, whether or not you apply herbicide immediately, you’re able to map out their locations to return to later.
Elmore also suggested assessing areas that didn’t burn as complete as you’d hoped. Maybe there is a hardwood patch or a ditch that always seems to exclude fire and becomes thick because of soil differences or topography changes.
“Remap the areas and make that another burn unit,” he said. “Then come back when conditions are harsher and burn it after the surrounding area has been burned. This is very effective for burning wetlands that are often flooded during the late winter and early spring.”
Whatever your management goals, there is a lot to be learned from doing a post-burn assessment that could result in savings or time and money as well as more effective prescribed fire.
