Detection of Geochemical Markers to Monitor the Recovery of Soils After Wildfire Events

Forest fires are considered the main disturbance in the Mediterranean basin (Naveh, 1990) and exerts both immediate and lasting ecological and environmental impacts. This is in part caused by a depth transformation of soil physical, chemical and biological characteristics associated to qualitative and quantitative changes in the most functional fraction of soil such is organic matter (González-Vila and Almendros, 2003; González-Pérez et al., 2004; Knicker et al., 2005). Changes exerted to soil organic matter (SOM) is reflected in the structure of the whole system and negatively affects soil health and quality (Arias et al., 2005) favouring the occurrence of erosive processes and the lost of a non-renewable natural resource such is soil. However, the effects of fire on soil colloidal properties and on the microbial community are reversible. After the passage of fire soil properties may naturally revert to a situation close to that before fire; erodibility is reduced and soil functionality is again achieved. This is especially evident in the so-called cold fires including controlled burnings and fires in open forest at semiarid environments with pyrophytic vegetation (Mutch, 1970; Pyne, 1996). The starting hypothesis is that if reversible effects do occur, then we may be able to find out biogeochemical surrogated indicators informing on the recovery of soil quality. An earl