Effects of fuel reduction treatments on breeding birds in a Southern Appalachian upland hardwood forest

Abstract

In the past, fires set by American Indians and settlers shaped much of the southern Appalachian forest by reducing the shrub layer and maintaining an open understory. Since the 1930’s, fire exclusion has allowed the development of a thick shrub layer and accumulation of woody debris. This fuel buildup contributes to the potential for wildfire in many ecosystems. Recently, the need for fuel reduction, using techniques such as prescribed fire or mechanical treatments, has received national attention. However, the impacts of such habitat manipulations on breeding birds are not well understood, especially in southern hardwood ecosystems. As part of the multidisciplinary National Fire and Fire Surrogate Research Project, we compared the effects of three fuel reduction techniques and controls on breeding birds, using 50m point counts in four, 14-ha treatments within each of three replicate blocks at the Green River Game Land, Polk County, North Carolina. Treatments were: (1) prescribed burning (B), (2) mechanical felling of shrubs and small trees (M), (3) mechanical felling + burning (MB), and (4) controls (C). Breeding birds were surveyed using point counts during 2001-2004. Mechanical understory felling treatments were conducted in winter 2001-2002, and prescribed burning in spring 2003. Hence, bird responses to all four treatments were compared only for 2003 and 2004. After prescribed fire (2003), leaf litter depth decreased in B and MB, and snag densities and canopy openness increased in MB. Shrub cover was significantly lower in all fuel reduction treatments than in C. Total breeding bird abundance was similar among treatments each year except 2003, when it was higher in C than M. Species richness was similar among treatments except in 2004 when it was higher in MB. Shrub forager abundance was highest in C in 2003, and higher in C than in B during 2004. The abundance of shrub nesters was also lower in B and M than in MB in 2004. Responses were most evident at the species level. Most species showed no detectable response to treatments. During 2003 Worm-eating Warbler abundance was lower in MB than C or M, and, in 2004, it was lower in both B and MB than C or M. Hooded Warblers were more abundant in C than any fuel reduction treatments during 2003 and 2004. Indigo Buntings, which are associated with open habitats, were most abundant in MB during 2004. Fuel reduction treatments affected individual bird species differently, and responses appeared to be associated with changes in habitat structure. To fully understand how fire and fire surrogates for fuel reduction affect breeding bird communities, post-fire surveys of birds and vegetation structure must continue for several years.

Parent Publication

• Restoring fire-adapted ecosystems: proceedings of the 2005 national silviculture workshop

Citation

Tomcho, Aimee L.; Greenberg, Cathryn H.; Lanham, J. Drew; Waldrop, Thomas A.; Tomcho, Joseph; Simon, Dean. 2007. Effects of fuel reduction treatments on breeding birds in a Southern Appalachian upland hardwood forest. In: Powers, Robert F., tech. editor. Restoring fire-adapted ecosystems: proceedings of the 2005 national silviculture workshop. Gen. Tech. Rep. PSW-GTR-203, Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture: p. 285-296