Positive regeneration responses of oak, hickory, and american chestnut to repeated prescribed fires and mechanical thinning 22 years after study initiation

Since the 1960s, there has been an increasing trend in oak (Quercus spp.) dominated forests exhibiting poor oak regeneration and recruitment, and associated hickories (Carya spp.) are likely undergoing a similar trend. Additionally, American chestnut (Castanea dentata) responses to management have been poorly studied. Silvicultural treatments to increase oak regeneration include prescribed fires and stand thinning, but often show mixed results. One potential issue is grouping oaks and hickories when analyzing treatment responses. This may obscure species- or genus-specific responses, making the long-term efficacy of silvicultural treatments difficult to identify. Thus, oak and hickory seedling and sapling responses to mechanical thinning, repeated prescribed burning, combined thinning and burning, and unmanipulated controls were analyzed at the species and genus level. Treatment plots also included American chestnut regeneration, were included in the genus-specific analyses. There was no evidence of species-specific responses to individual treatments in oak, while species-specific responses were observed in sapling hickories with Carya glabra and Carya tomentosa densities being 2.5 times greater than Carya ovata. When grouped by genus, oak and hickory have similar responses to individual treatments, thus analyzing their responses as a collective group is appropriate. The combined burning and thinning treatment was most effective with average sapling densities increasing by 2362 %, 1277 %, and 500 % for oak, hickory, and American chestnut, respectively, as of 2022 compared to 2000 (pre-treatment). Long-term forest management to increase understory light levels and decrease the competitive strength of mesophytes appears equally capable of promoting oak, hickory, and potentially American chestnut regeneration.