Growth Response of Pinus ponderosa following a Mixed-Severity Wildfire in the Black Hills, South Dakota

numerous studies have documented a temporary decrease in growth following prescribed burning (e.g., Landsberg et al. 1984, Grier 1989, Sutherland et al. 1991, Peterson et al. 1994, Busse et al. 2000), whereas other studies have reported a positive growth response in ponderosa pine (Wyant et al. 1983, Skov et al. 2005), giant sequoia (Mutch and Swetnam 1995), and Douglas-fir (Reinhardt and Ryan 1988). For giant sequoia, increased growth was most notably evident following moderate-severity ( 50% of subcanopy trees killed) and high-severity ( 50% of subcanopy trees killed but 50% of canopy trees killed; Mutch and Swetnam 1995) prescribed burns. The variability in growth following fire is likely due to the heterogeneity in fire behavior, fire severity, and initial tree-related fire effects associated with both wildand prescribed fire. Tree-specific, fire-related tissue damage including severe cambial, root, and crown damage may negatively affect water and nutrient uptake as well as photosynthetic potential, resulting in growth decreases. In contrast, residual trees with less severe fire damage may benefit from increased plant-available nitrogen (Keyser et al. 2008), as well as reduced competition for water (Skov et al. 2004) and nutrients (Reigel et al. 1992), and may even experience an increase in postfire tree growth and resistance to insect or disease attack. Differences in factors such as fire behavior, fire intensity and severity, degree of fire-related damage, season of burn (dormant versus growing season), and weather conditions that occur during prescribed versus wildfire, as well as differences in geographic region and inconsistent results, make it hard to extrapolate results pertaining to the growth of ponderosa pine following prescribed burning to that expected following a wildfire. Given that wildfires are increasing in size and severity, it would be useful that resource managers understand how forest growth patterns may change as a result (i.e., substantial fire-related mortality combined with reductions in tree growth can result in significant and long-term reductions in standlevel production). We evaluated the effects of a large, mixed-severity wildfire on postfire tree growth and assessed whether growth of surviving ponderosa pine trees differed among trees in unburned stands and those affected by lowand moderate-severity wildfire.