Single and repeated fires affect survival and regeneration of woody and herbaceous species in an oak-pine forest

Since the 1940's, fire suppression has contributed to changes in the plant species composition of oak-pine communities in the Cumberland Plateau, exemplified by a lack of oak regeneration and an abundance of fire-sensitive species. Returning fire to these communities could promote oak regeneration by inhibiting regeneration of fire-sensitive species. We examined the effects of two single fires (1993 or 1995) and a repeated fire (1993 and 1995) on herb, shrub and tree strata, including sprouting response, on an oak-pine ridgetop in eastern Kentucky. Overstory (>10 cm dbh) species composition was dominated by Quercus spp., whereas the midstory (2-10 cm dbh) was dominated by red maple and blackgum. Oak regeneration was well-represented in the herb layer, but was not nearly as prolific as red maple. Single and repeated fire reduced stems 2-10 cm dbh by 60 to 80%; stump sprouting by individual trees was promoted by fire. On the twice-burned site there were fewer red maple and blackgum sprouts per hectare than on a site burned in 1995, despite greater numbers of sprouts per tree. Species richness in all strata was increased by fire, from 19 species on the unburned site to 35 species on the twice-burned site. Our data suggest that periodic prescribed fires may reduce regeneration of red maple and other non-oak species sufficiently to promote chestnut oak regeneration; regeneration of more shade intolerant species, including scarlet oak and the hard pines, would require a disturbance of greater intensity.