Altering successional trends in oak forests: 19 year experimental results of low- and moderate-intensity silvicultural treatments

Abstract

Intensive silvicultural treatments can sometimes prevent the conversion of an oak (Quercus spp.) forest to a forest composed of mesophytic competitors following harvest, but the required labor is a disincentive for many private landowners. In this study, shelterwood removal, commercial clear-cutting, understory control, and oak underplanting were conducted on mesic and dry–mesic sites in southwestern Wisconsin to evaluate the effect of these treatments on forest composition and to identify the least intensive combination needed for successful oak regeneration. Commercial clear-cutting, with or without prior herbicide spray of low vegetation and oak underplanting, resulted in nearly complete dominance by a wide array of non-oak species on both mesic and dry–mesic sites. In contrast, 153–903 ha–1of the oaks that were underplanted on shelterwood – understory removal plots successfully achieved dominant or codominant status by age 19. Control of tall understory saplings was essential for successful oak regeneration on both sites. On the mesic site, oak underplanting was an additional necessary treatment, whereas natural regeneration was adequate in shelterwood plots on the dry–mesic site. The study suggests that successful oak regeneration can be obtained on productive sites in this region after a single application of a moderately intense silvicultural treatment, although the effort required for understory control may still be an obstacle to widespread application without external incentives.