NOAA/WDS Paleoclimatology - Stambaugh fire data from Kisatchie Hills - IMPD USKSH001

Question: How frequent and variable were fire disturbances in longleaf pine ecosystems? How has the frequency and seasonality of fire events changed during the past few centuries?
Location: Kisatchie National Forest, Western Gulf Coastal Plain, longleaf pine-bluestem ecosystem, in relatively rough topography adjacent to the Red River, Louisiana, USA.
Methods: Nineteen cross-sections of remnant dead pines exhibiting 190 fire scars were collected from a 1.2 km2 area. Tree-rings and fire scars were dated and analyzed for the purpose of characterizing past changes in fire and tree growth. Temporal variability in fire occurrence and seasonality was described for the pre- and post-European settlement periods. Seasonality of historic fires was determined by the scar position within the rings. The relationship between fire and drought was investigated using correlation and superposed epoch analysis.
Results: The mean fire return interval for the period 1650-1905 was 2.2 years (range 0.5 to 12). Significant new findings include: evidence for years of biannual burning, temporal variability in fire seasonality, an increase in fire frequency and percent trees circa 1790, and synchronous growth suppression and subsequent release of trees coinciding with land use changes near the turn of the 20th century. Drought conditions appeared unrelated to the occurrence of fire events or fire seasonality.
Conclusions: Few multi-century fire history records exist in longleaf pine ecosystems due to the species' high resistance to scarring; however, our results indicate new potential for reconstructing fire history in this ecosystem. Fire scars quantitatively documented one of the most frequent fire regimes in the U.S. New information such as the temporal variability in fire intervals, late-growing season dominated events, biannual burning, and changes in tree-growth provide a new perspective on the dynamics of longleaf pine fire regimes.