Prescribed burning frequency affects post oak and blackjack oak regeneration

Abstract

We studied post oak (Quercus stellata Wangenh.) and blackjack oak (Quercus marilandica Münchh.) regeneration in xeric upland oak forests burned from 0 to 5.3 times per decade for 19 years. Post oak and blackjack oak represented 76 and 11% of the site basal area. All reproduction was by sprouting; there were no true seedlings. Compared with post oak, blackjack oak had a substantially higher density of clumps and sprouts relative to its basal area, suggesting that basal area was not a good indicator of sprout production capacity across species. The number of sprouts per clump declined with time since last fire for both species, indicating that fire stimulated sprouting. Three growing seasons after fire, sprouts per clump was highest with the lowest fire frequency and declined with increasing fire. The decline was greatest for blackjack oak. This may have been due to reduced vigor of the root systems producing sprouts with increasing fire frequency. Results suggested that post oak and blackjack oak sprouting, growth rates, and response to fire are similar, but blackjack oak sprout mortality may be higher than that of post oak. This information is important for the maintenance of post oak-blackjack oak-dominated forests of the south-central United States. Copyright © 2011 by the Society of American Foresters.