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ABSTRACT: The objective was to determine the effectiveness of a regular prescribed burning program for reducing tree mortality in southern pine forests burned by wildfire. This study was conducted on public and industry lands in northeast Florida. On the Osceola National Forest, mean mortality was 35% in natural stands and 43% in plantations two growing seasons after a June 1998 wildfire. Burn history significantly affected mortality with those stands prescribe-burned 1.5 yr prior to the wildfire having the lowest mortality, while stands prescribe-burned 2 or more years prior had higher mortality. Although significant tree mortality did occur on the Osceola National Forest, with all trees killed in some stands, many trees in other burned stands did survive. The overall mortality was lower in both plantations and natural stands on the Osceola than at Tiger Bay where prescribed burning had been less frequent. The highest mortality rates occurred on the Lake Butler Forest where prescribed burning had not been used since plantation establishment. Thus, a regular prescribed burning program will reduce mortality following wildfires in both natural and planted stands of southern pines on flatwoods sites, even when wildfires occur under severe drought conditions. South. J. Appl. For. 28(1):28-34.
Key Words: Prescribed burning, wildfire, longleaf pine, slash pine, mortality.
As noted by DeBano et al. (1998), there is a general trend in many forest types of increasing fuel buildup and therefore fire intensity with a lengthening of the fire-return interval. Thus there exists an implied relationship between overstory tree mortality and time since the last burn. Mortality can result from high-intensity crown damaging fires or from highseverity ground fires consuming accumulated litter around the bases of trees (Ryan and Frandsen 1991).
Fuel buildup is quite rapid the first 10 yr following disturbance in the saw palmetto (Serenoa repens [Bartr.] Small)/ gallberry (Ilex glabra L.) fuel complex found on flatwoods sites in the southern coastal plain (Sackett 1975, McNab et al. 1978). For decades, frequent, regular judicious use of prescribed burning has been promoted as a practical method to limit the accumulation of these fuels. Past research supports the assumption that wildfires would be kept small and damage limited with regular use of prescribed burning. Davis and Cooper (1963) found a strong relationship between the...