Factors affecting post-fire regeneration after coppicing of cork oak (Quercus suber) trees in northeastern Algeria

Abstract

Wildfires may have serious and long-lasting impacts in Mediterranean Basin oak forests. Although cork oak (Quercus suber L.) is usually considered a highly fire-resistant tree species, post-fire recovery is not guaranteed. We assessed the mortality and regeneration of 729 cork oak trees that burned and were cut in six sites with the objective of identifying the main factors affecting the short- to medium-term post-fire recovery. We used linear mixed models to investigate potential relationships among tree stump status at the end of the second and fifth growing seasons and several tree- and site-level variables. Overall tree mortality in the second year was 44% and was negatively affected by bark thickness and positively affected by root exposure, trunk injuries, and diameter, in decreasing order of importance. Between the second and fifth years, mortality increased to 53%, but this increase was only observed in sites with high grazing pressure. Grazing also had a strong negative impact on the growth of basal resprouts, thereby compromising tree recovery. The results give useful information on the need for application of adequate forest management practices (particularly avoiding debarking injuries, soil erosion, and grazing pressure) to increase the resilience of these ecosystems and reduce the negative economic and ecological impacts of wildfires.