Responses to mechanical wounding and fire in tree species characteristic of seasonally dry tropical forest of Bolivia

Short-term responses to stem wounding were measured over a 60-day period on six tree species found in seasonally dry tropical forest in Bolivia. Three types of wounds were inflicted to simulate mechanical bark damage and bark damage caused by low- and high-intensity fires. Extent of wood discoloration associated with wounding varied with wound type and severity, with high-intensity burns associated with the greatest amount of discoloration, low-intensity burns the least, and mechanical wounds intermediate. Two thin-barked species produced a distinct ligno suberised boundary zone in the bark earlier than thicker barked species; however, all species produced a distinct wound periderm by 60 days postwounding. The amount of wood discoloration associated with wounding appeared to be independent of the thickness of the lignosuberized boundary zone. Bark thickness provided a useful measure of species' resistance to wood discoloration with low-intensity burns but not with high-intensity burns where bark occasionally separated from the cambium or developed cracks and fissures. Variability in short-term responses to wounding and other factors may result in differences in the composition and abundance of microorganisms that colonize the wounds, with implications for reductions in wood quality and decay development.