A Stand-Replacement Prescribed Burn in Sand Pine Scrub
This paper describes fire characteristics and the immediate effects of a prescribed, high-intensity bum on a 12.2 hectare portion of a stand of Ocala sand pine scrub. The fire team on the Seminole District, Ocala National Forest used the BEHAVE fire model to predict the conditions needed to accomplish a stand-replacement bum. Suitable conditions arose on May 11, 1993 with temperature 26" Celsius°, relative humidity 50%, wind 3 kilometers per hour, and fuel moisture (l-hour fuel) 7%. The area was burned by establishing a 40 meter blackline with backfires and then setting a headfire. The prolific smoke produced was not a problem due to selection of proper atmospheric conditions. Fire intensity was variable and affected by position and fuel loading, but on average was twice as high in the interior compared to the edge. The crowns of nearly all sand pine were severely scorched, and all trees subsequently died. Twenty-seven percent of the preburn snags were felled by the fire. Fire eliminated the shrub layer and reduced the litter layer thickness by 50%. The amount of bare ground was 0.1% in control plots and 17% in the burned area. Following the burn, light increased from 6 to 17% at ground level but only from 16 to 22% at breast height, because most needles remained on the overstory sand pine.