Fire history of a barrier island slash pine (Pinus elliottii) savanna
Abstract
Fire regimes of pine savannas on barrier islands along the coast of the Gulf of Mexico are unknown. We used dendrochronological techniques to precisely date scars from 52 slash pines (Pinus elliottii Engelm.) located within a 370 ha area on Little St. George Island, Florida, USA, an undeveloped barrier island. We determined the years and seasons of fires and turpentine operations, and mapped the spatial distribution of past fires. We identified five separate periods with different fire frequencies. Fires were frequent between 1866 and 1904 (mean fire-return interval of four years). No scars were found from 1905-1923, years during which turpentine operations (1912-1918) protected trees from fires. Frequent fires were again recorded from 1924-1945, (mean fire return interval of four years). During the period from 1945-1962, turpentine operations (1949-1956) again protected trees from fires, and no fire scars were found. The most recent period, 1963 to the present, had a mean fire-return interval of nine years with active, although not entirely effective, fire suppression. Although the trees used in this study were not old enough to determine presettlement fire frequencies, the data reveal that, over the past 145 years, historic fire regimes of this barrier island slash pine savanna consisted of predominately growing-season fires, with short fire return intervals during the two periods with the least anthropogenic activity on the island. Data from this study imply that historic fire regimes of barrier island slash pine savannas, like mainland longleaf pine savannas, may have involved frequent, primarily growing-season fires.