Fire effects on soil quality in Quercus suber forests: a long-term assessment

Abstract

Wildfires, despite being a major disturbance factor, have also an essential role in shaping the Mediterranean landscape and its ecological processes. Post-fire soil properties can change significantly, depending on fire charactheristics. However, long term fire effects on soil are still not well understood, particulary in the Mediterranean region and in cork oak forest systems. This study aimed to provide a long-term assessment of soil chemical characteristics in cork oak forests 16 years after a wildfire, at different depths, and of soil resillience to wildfire. The study was conducted in 2020 at Serra do Caldeirão (southern Portugal, Algarve), mainly in Leptosols. Soil sampling was carried out at two depths (0–5 cm and 5 cm–to maximum depth) in plots burned in 2004 (n=25) and unburned plots (n=12), which were used as control. Soil samples were chemically anallysed in the laboratory. Similar results were obtained for burned and unburned plots, for most of the parameters. The exceptions were extractable P (0-5 cm depth) and organic C (both depths), which were significantly higher in burned plots. The results show a natural recovery of soil characteristics after wildfire and, consequently, indicate a considerable soil resilience and the important role of vegetation on the dynamics of post-fire soil recovery.