History of fire in a southern Ohio second-growth mixed-oak forest

The role of fire in shaping the composition and structure of Quercus (oak)-dominated communities in the deciduous forests of eastern North America is becoming clearer but fire regimes are less well known. I analyzed the fire-scar patterns in 14 oak cross sections from a mixed-oak stand in Vinton County, southeastern Ohio, to determine the frequency and seasonality of fire. This oak stand was even-aged and originated in the mid-1850s, so the fire history is representative of the period after Euro-American settlement. The tree rings were crossdated, calendar year of the fire sears was assigned, and season of burning noted. The fire-scar dates are Weibull-distributed, and the median probability interval is 3.6 years. The 95% and 5% Weibull probability exceedance intervals were 0.4 and 12.1. Spatially extensive (major) fires occurred every 7.5 years, and the 95% and 5% exceedance intervals for these fires were 0.9 and 24.3. The fires probably were ignited by people. Fire scars indicated that most fires (69%) occurred during the dormant season or in the spring (25%) and were rare (6%) during the summer (May 1 to July 30). These patterns are not significantly different from dates of observed wildfires in Vinton County. Seasonal climate has no apparent relationship to fire occurrence.