Evaluating the Burn
United States Department of Agriculture, Forest Service Southern Region, February 1989; Technical Publication R8-TP 11.
The purposes of a burn evaluation are to determine how well the stated objectives of the burn were met and to gain information to be used in future burns. An initial evaluation should be made immediately after the burn, perhaps the following morning. A second evaluation should be made during or after the first postfire growing season.
Points to be Considered
If, however, loblolly pine stands are burned in the fall (September or October), after the trees have undergone their last needle flush of the growing season but prior to the onset of dormancy, research indicates that 100 percent crown scorch is likely to kill them Slash pine appears to be more tolerant of severe crown scorch during the fall.
If more than 15 percent of a southern pine tree's needles are actually consumed by flames, the tree's chances of survival would be poor even if very little of the rest of the crown is scorched. Young vigorous trees are more likely to survive severe crown damage than are older individuals.
Magnitude and duration of growth responses in southern pines due to various levels and seasons of defoliation are not well documented. Both negative and positive responses have been observed, but the preponderance of evidence shows a direct relationship between diameter and height growth loss and crown scorch.
Providing no crown consumption took place, the above table will help in estimating potential growth loss in loblolly and slash pines over 3 inches dbh. These "ball park" estimates can be used for other southern pines as well, until more specific results become available.
A good indicator of hardwood control is a series of bark cracks extending into the cambium near ground level. This indicates sufficient heat was applied to penetrate the bark and kill the cambium. Although large hardwoods can be damaged by periodic fires they are difficult to kill.
Judge the success of burning for brownspot control by the number of longleaf seedlings with all infected needles burned off, but still having a protective sheath of green needles around the unharmed terminal bud.
whenever burns are conducted over dry soils (drought conditions) or when a deep litter layer is present, even though some duff remains.
New root growth in vigorously growing pines can usually offset these losses, but older trees, having survived such fires without crown damage, often die six months to a year later for no apparent reason.
Smoke behavior must be continually evaluated from the time the fire is ignited until smoldering ceases. Unusual or unexpected smoke effects should be noted and correlated with other parameters of the burn for future use. Any public complaints should be recorded as part of the evaluation.
Timing and Points to Evaluate
Evaluation should take place immediately after the burn and again during the first postfire growing season. In the case of late summer prescribed fires, the second evaluation should take place the following spring after the next growing season has begun.
Points in First Evaluation
Points in Future Evaluation
Future evaluation can best be made after the start of the growing season to determine the following:
| The Bugwood Network and Forestry Images Image Archive and Database Systems|
The University of Georgia - Warnell School of Forestry and Natural Resources and
College of Agricultural and Environmental Sciences - Dept. of Entomology
Last updated on Monday, March 24, 2003 at 02:17 PM
Questions and/or comments to the