Date of Award
Master of Science
Funding and manpower dedicated to prescribed burning programs are often limited, and information on the re-accumulation rates of fuels after burning and appropriate burning schedules is needed for prioritization and planning. I investigated the effects of community type and site productivity on the re-accumulation of forest fuels after prescribed burning. This was done on the Cherokee National Forest by sampling a five year chronosequence of stands with different periods of time since burning within three different community types. The community types were: dry mesic pine/hardwood, xeric pine/hardwood, and dry-mesic hardwood sites. Five replicate stands representing 1, 2, 3, 4, and 5 years since burning and five controls with no recent burning were studied within each of the 3 community types. In all stands, coarse woody debris, fine woody debris, duff depth and litter depths were sampled using standard U.S. Forest Service FIA (Forest Inventory Analysis) methods for sampling fuels. Increment cores were obtained within each stand to establish site index and estimate stand age. Effects of different frequencies of prescribed burning on fuel loading were investigated using replicate stands that have been burned annually and every 5 years for the past 41 years on the University of Tennessee Highland Rim Forestry Experiment Station. The same fuel measurement protocol used on the Cherokee National Forest was used to measure these plots. Dry-mesic pine/oak sites and xeric pine/oak sites both contained greater amounts of coarse woody debris (CWD) and fine woody debris (FWD) after burning than the dry-mesic oak sites. There were no significant differences between years since burning in amounts of coarse woody debris. The low intensity prescribed bums used by Cherokee National Forest managers significantly reduced FWD on site, but did not affect CWD quantities. Within the FWD category, 1 and 10 hour fuels were undoubtedly consumed by the prescribed burns, but differences between years since burning and between burned stands and controls were not statistically significant, suggesting rapid re-accumulation to control levels within the 5-years since prescribed burning. In contrast, 100 hour fuels were significantly reduced by prescribed burning and did not re-accumulate to control levels within 5-years since burning. Duff depths were highly variable, but differed significantly across years since burning. Quantities of duff were significantly greater 5 years since burning than in controls and 1, 2 and 4 years since burning. Litter depths increased significantly with increasing numbers of years since burning, but remained significantly less than in controls 5 years after burning. The dry-mesic and xeric pine/hardwood sites contained greater quantities of litter than dry-mesic hardwood sites. There were no significant differences in CWD distribution between the annual and periodic burning treatments on the Highland Rim Forestry Experiment Station. Significant differences in the amount of fine fuels occurred between the annual burn treatment, periodic burn treatment, and control, with the least amount of fine fuels in the annual burn treatment. Control sites contained significantly greater amounts of FWD than the annual and periodic burning treatments. Similar significant patterns were also found for both duff and litter depths.
Ellis, David Matthew, "Effects of Community Type and Site Productivity on Re-Accumulation of Forest Fuels after Prescribed Burning in East Tennessee. " Master's Thesis, University of Tennessee, 2004.