Relationships among wildfire, prescribed fire, and drought in a fire-prone landscape in the south-eastern United States

Concern over increasing wildfire activity in the last few decades has prompted increased investment in fuels reduction treatments worldwide. Prescribed fire is a commonly used management tool for reducing fuels and modifying subsequent wildfire dynamics, yet the influenceof prescribed fire on wildfire is difficult toevaluateempirically due tothe oftenunpredictablenatureofwildfire.Inthisstudyweevaluateda30-yearrecordofwildfire,prescribedfireanddroughtat Fort Benning, a 74 000-ha military training installation inwest-central Georgia, USA. Annual wildfire incidence declined sharplyfrom1982to2012as prescribedfirehectaresincreased. Multipleregressionmodelsincludingbothprescribedfire and drought (assessed using the Keetch-Byram Drought Index; KBDI) explained ,80% and 54% of the variation in annualwildfireincidenceandarealextent,respectively.Current-andprevious-yearprescribedfirewerestronglyinversely related to current-year wildfire, suggesting that the cumulative area burned by prescription is important in explaining current-year wildfire incidence. Wildfire activity overall (both incidence and areal extent) was highest during drought yearswhencumulativeprescribedfirehectareswerelow.Ourresultssuggestsomeinevitabilityofwildfireduringdrought, but also provide evidence for the positive effects of sustained landscape-scale prescribed fire in reducing wildfire activity over time.