We investigated biotic and abiotic mechanisms that affect Quercus falcata (southern red oak) establishment from seeds in southeastern Pinus paulustris (longleaf pine) forests along a time-since-fire chronosequence (unburned since 1950, the mid-1990s, or winter 2001) and slope gradient. To determine if seed availability limits southern red oak recruitment, we measured seed production, populations of small mammals, and seed removal across sites. To determine if seedling survival limits establishment, we outplanted greenhouse-raised southern red oak seedlings and followed their survival throughout one growing season. We also measured abiotic conditions such as canopy openness, soil moisture, and soil temperature, and censused longleaf pine recruitment. Contrary to expectations based on species' fire-tolerances, longleaf pine recruitment was consistent over the chronosequence, but there was little oak seedling establishment in the long-unburned sites. Sites last burned in the mid-1990s had the lowest oak seed rain, highest small-mammal populations, and highest seed -removal rates; yet, they had the highest oak seedling establishment. Seedling survival was highest in the pre-1950 sites, and was most influenced by intermediate light levels and high soil moisture. We conclude that biotic factors, specifically, seed removal by small mammals, are less important to seedling recruitment than abiotic factors in these forests. Further, the assumption that longleaf pine forests will eventually undergo to succession to hardwoods in the absence of fire is complicated by abiotic conditions associated with landscape position.