Contribution of Bark to Fire Resistance of Southern Trees

Abstract Time required to kill cambium in situ with a standardized propane flame was a function of both thickness and thermal properties of the overlying bark. There were 14 species tested, including hardwoods and softwoods. Resistance was directly correlated with tree diameter. Within diameter classes, species differences in both thickness and insulating efficiency of barks accounted for resistance differences. Time to a lethal cambium temperature was exponentially related to bark thickness and was also influenced by temperature of the cambium before the flame was applied.