Kisatchie Hills - USKSH001 Additional Site Information Michael C. Stambaugh, Richard P. Guyette Dating Method: Crossdated Sample Storage Location: Missouri Tree-Ring Laboratory, Department of Forestry, 203 ABNR Building, University of Missouri-Columbia, Columbia, MO 65211 USA. Reference: Stambaugh M.C., R.P. Guyette, and J.M. Marschall. In review. Longleaf pine (Pinus palustris Mill.) fire scars reveal new details of a frequent fire regime. Journal of Vegetation Science. Abstract: 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. Comments: These samples were collected for fire scar history reconstruction. Samples were collected from tree stumps and dead standing trees. Although the species is unknown they are likely longleaf pine (Pinus palustris). Fire History Graphs: Fire History Graphs illustrate specific years when fires occurred and how many trees were scarred. They are available in both PDF and PNG formats. The graphs consist of 2 parts, both of which show the X axis (time line) at the bottom with the earliest year of information on the left and the latest on the right. The Fire Index Plot is the topmost plot, and shows two variables: sample depth (the number of recording trees in each year) as a blue line along the left Y axis, compared with the percent trees scarred shown as gray bars along the right Y axis. Below, the Fire Chronology Plot consists of horizontal lines representing injuries by year on individual sampled trees. Symbols are overlain that denote the years containing the dendrochronologically-dated fire scars or injuries. The sample ID of each tree is displayed to the right of each line. The Composite Axis below represents the composite information from all individual series. The symbols used to represent the fire scars or injuries, and the filters used to determine the composite information, are shown in the legend. These graphs were created using the Fire History Analysis and Exploration System (FHAES). See http://frames.nbii.gov/fhaes/ for more information.