We document an increase in oak and hickory advance regeneration, depending on landscape position, in the sixth year following mechanical thinning and repeated prescribed fires in southern Ohio, USA. Oak-dominated communities provide a multitude of human and natural resource values throughout the eastern United States, but their long-term sustainability is threatened throughout the region by poor regeneration. This study was established to assess regeneration following midstory thinning (late 2000) and prescribed fire application (2001 and 2005) at two sites in southern Ohio. Each of the four 20+ ha treatment units (two thin and burn, two untreated controls) were modeled for long-term moisture regime using the integrated moisture index (IMI), and a 50 m grid of sampling points was established throughout the units. Vegetation and canopy openness were sampled at each gridpoint before and after treatments, in 2000, 2001, 2004, and 2006. The thin and burn treatment generally resulted in more advance regeneration (>50 cm height) of oak and hickory. The second fires in 2005 created additional landscape heterogeneity by causing variable tree mortality, and thus canopy openness, across the IMI gradient. The drier landscape positions generally had more intense fires, more canopy openness, and more oak and hickory advance regeneration; several other tree species also exhibited marked landscape variation in regeneration after treatments.
Iverson, Louis Rs; Hutchinson, Todd F.; Prasad, Anantha M.; Peters, Matthew P. 2008. Thinning, fire, and oak regeneration across a heterogeneous landscape in the eastern U.S.: 7-year results. Forest Ecology and Management. 255: 3035-3050.