This study examines the independent and combined effects of canopy gaps and fire on tree regeneration in southern Appalachian mixed hardwood stands by analyzing an area in northern Georgia that burned in the fall of 1999. Two hypotheses, the gap-partitioning and density hypotheses, that explain how spatial variation in regeneration following canopy gap disturbance maintains species diversity in mature forests were tested. In the understory, species diversity, density, the mean height of understory stems, and species composition differed significantly between burned and unburned plots. Species diversity and the mean height of understory stems were lower in burned plots, although density was higher in burned plots relative to unburned plots. Shade-intolerant species, Liriodendron tulipifera L., Robinia pseudo-acacia L., and Sassafras albidum (Nuttall) Nees., had much greater abundance in the burned understory, while moderately shade-tolerant species exhibited mixed responses to burning. Neither the gap-partitioning nor the density hypothesis were supported by evidence collected for this research, and the effect of burning did not influence the rejection of these hypotheses.