Preliminary evaluation of physical characteristics of soils from Mediterranean cork oak forests: post fire long term assessment

Abstract

Fire is an agent that promotes considerable changes in the physical, chemical and biological characteristics of soils and, consequently, in the landscape. Fire severity and duration, and intrinsic characteristics of the soils lead to different trajectories of soil recovery. Numerous studies focus on short term fire effects on soils but, the long-term post fire dynamics remains unclear. The present study was conducted in soils mainly Leptosols, from cork oak forests at Serra do Caldeirão (Algarve region, southern Portugal). Two severe wildfires occurred in this area, in 2004 and 2012. Undisturbed soil samples (<5 cm of depth) were collected in 2020 on plots burned in 2004, burned in 2012 and unburned (a total of 47 plots). The soil samples were analysed for the physical properties namely, bulk density, porosity, % of coarse/fine fraction and moisture. For all the studied parameters, the results showed no significant differences between burned and unburned areas, indicating considerable soil system resilience to forest fires. The study suggests the need of further analyses in order to understand the recovery processes of this forest system.