Effects of prescribed fire on physiology and growth of Acer rubrum and Quercus spp. seedlings in an oak-pine forest on the Cumberland Plateau, KY

Poor survival of oak regeneration has been attributed to fire suppression and the physiological limitations imposed by the increasing dominance of competitors, especially red maple (Acer rubrum L.). We examined the physiological responses of red maple, chestnut oak (Quercus prinus L.) and scarlet oak (Q. coccinea Muenchh.) seedlings following a prescribed fire in an upland oak-pine forest in eastern Kentucky. Immediately following fire, seedlings on burned sites had significantly greater foliar concentrations of N, P, K, and Mg than seedlings on unburned sites; this effect of treatment diminished over the first growing season. Seedlings on burned sites also demonstrated significantly higher photosynthetic potential and had greater relative growth rates of diameter and height through the second and third growing seasons post-fire. Among species, chestnut oak consistently had the greatest foliar concentrations of all nutrients, with red maple being intermediate and scarlet oak the lowest. Both oaks had significantly greater maximum photosynthesis than red maple, but there were no significant differences among species for diameter or height relative growth rates. Treatment by species interactions indicated that red maple seedlings were significantly taller than oaks on the burned site, while there were no differences in height among species on the unburned site. Although a single fire improved the performance of all species, our results suggest no improvement in the status of oak regeneration based on post-fire seedling physiology and growth.