Impacts of Prescribed Fire on Overstory Tree Quality and Stand Volume in Oak Dominated Forests in Southern Indiana
The use of prescribed fire for ecosystem restoration presents numerous questions for natural resource managers. One of these questions, the impact of prescribed fire on overstory tree quality and stand volume, is explored here prospectively and retrospectively. A long-term study is being installed in 20 oak-dominated stands across central and southern Indiana to monitor effects of repeated prescribed fire on overstory tree quality. Prior to the initial prescribed fire, 20 average quality and 10 highest quality trees in each stand were measured for grade and defects below breast height. Each prescribed burn is monitored with thermal paints and thermocouples at variable heights on a subset of stems. Assessment of wounding from fire is also conducted two growing seasons after each fire. Within the study’s founding two stands, 37 percent of sample trees sustained fire damage (n = 59), but no trees had died or received a reduction in United States Forest Service tree grade after two years. Additionally, fire scar formation on overstory tree quality and stand volume was explored in 54 oak-dominated stands with variable prescribed fire histories and aspects in southern Indiana. We measured fire scar size and frequency, then quantified the residual stand volume and tree grade with and without deductions from fire scars to determine the relative stand volume lost to prescribed fire damage. Generally, as the number of prescribed fires in a stand’s history increased, more trees were scarred, the relative volume lost increased, and more trees declined in grade. Aspect surprisingly appeared to have little effect on the responses until a stand had four or more prescribed fires. Overall, relative volume lost was less than 10%, and less than 3% of trees lost quality through any amount of prescribed fire. Across both studies, prescribed fire had minimal impact on the volume and value of the timber trees in this study. My research suggests that prescribed fire does not have as great of economic impact to standing timber as generally perceived.^
Michael R. Saunders, Purdue University.
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