Ecological impacts of fuel reduction treatments in the Piedmont and southern Appalachian mountains.
Callaham, Mac*,1, Waldrop, Thomas1, 1 USDA Forest Service, Athens, GA, USA
ABSTRACT- Systematic exclusion of fire from fire-adapted ecosystems has resulted in dense vegetation and heavy fuel loads across the North American continent. Forest health has deteriorated in some ecosystems and fuels are reaching dangerous levels in terms of risk for wildfire occurrence. Mechanical fuel treatments and prescribed fire are important tools for reduction of wildfire risk, but the ecological consequences of implementing these practices at large scales are unknown. The National Fire and Fire Surrogates study was established for the purpose of examining the effects of fuel reduction techniques involving a factorial arrangement of prescribed fire and mechanical fire surrogate treatments in a variety of ecosystems. We conducted studies of fuel reduction practices in two southern ecosystems: the southern Piedmont and the southern Appalachian mountains. In the southern Piedmont, prescribed fire and thinning are used primarily in the context of southern pine pulp and timber production, whereas objectives for the southern Appalachian site were somewhat different, and focused on removal of the dense understory of ericaceous shrubs (primarily rhododendron and mountain laurel) which represent a hazardous fuel type in the system. Preliminary results for both sites suggest that the treatments had dramatic effects on the cover of shrubs and resulted in dramatic changes in vegetation structure and composition. Forest floor depths were also influenced by the treatments with reductions of the Oi layer with fire and mechanical treatments. There was no effect on depth of Oe and Oa layers of the forest floor except when the treatments were used in combination. First year results from the Piedmont site indicated that decomposition of pine litter was significantly slower in thinned stands than in burned or control stands, and that soil respiration was lower in burned stands than in the other treatments. Similar data from the Appalachian site will be summarized and presented. These early results suggest that the fuel reduction treatments utilized in the study are effective for the short term reduction of shrubs and woody fuels, but careful monitoring over the longer term is needed to understand the potential consequences of these treatments for other components of ecosystem function.
Key words: thinning, Piedmont, fire, Appalachian
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