Responses of hardwood advance regeneration to seasonal prescribed fires in oak-dominated shelterwood stands

Effects of seasonal prescribed fires of varying intensities on density, mortality, stem form, height, and height growth of hardwood advance regeneration were investigated. Three mixed-hardwood stands on productive upland sites were cut using a shelterwood technique, each forming a block of spring burn, summer burn, winter burn, and control treatments. Advance regeneration was inventoried from permanent plots before and after burning. Fires top-killed nearly all hardwood regeneration, forcing the rootstocks to sprout. Fire treatments reduced densities of all hardwood species relative to not burning, with spring and summer fires causing greater density reduction than winter burning. Among species, oak (Quercus spp. L.) and hickory (Carya spp. Nutt.) were more resilient sprouters than yellow-poplar (Liriodendron tulipifera L.) and red maple (Acer rubrum L.), especially as fire intensity increased. All prescribed fires improved oak stem form and stimulated height growth of hickory and oak. Overall, prescribed fires improved oak advance regeneration with spring burning providing the most benefit. This approach of following a shelterwood harvest with prescribed fire may be a viable method of regenerating oak-dominated stands on productive upland sites.