Vegetative Response to 37 Years of Seasonal Burning on a Louisiana Longleaf Pine Site

From 1962 through 1998,20prescribed burns were applied in a natural stand of longleafpine (Pinus palustris Mill.) to determine the ejfects of variousfire regimes on theforestplan t community. The original longleaf seedlings regeneratedfrom the 1955 seed crop and were growing in a grass-dominated cover when the study began. By 1999, prescribed burning in March and May resulted in a significantly greater stocking of longleafpine (203 trees/UC) than on the unburned and July burned treatments (72 trees/UC) (a = 0.05). Fire arrested the growth of natural loblolly pine (P. taeda L.) and hardwoods, but loblolly pines and hardwoods of at least 4 in. dbh added 7Oft2/ac of basal area on the unburned plots. Thus, total woody basal area was significantly greater on the unburned (117@/ac) and May burned (132@/ac) treatments than on the July burned treatment (66@/ac); basal area was intermediate on the March burned treatment (97@/ac). Pine volume was 4,315,2,870,2,652, and 1,97Oft3 inside-bark/at on the May burned, March burned, unburned, and July burned treatments, respectively, but these differences were not statistically significant (P = 0.06). There was only 1 I lb/at of herbaceous plants on the unburned plots. Herbaceous plants averaged 993 lb/at on the three burned treatments, withpinehill bluestem (Schizachyrium scoparium var. divergens (Hack) Gould} being the most common herbaceousplant. We believe the chief influence ofbuming in this natural longleafpineforest was not on pine yield but how fires influenced overall stand structure and species composition. South. J. Appl. For. 25(3):122-130.