Wildfire effects on soil quality: application on a suburban area of West Attica (Greece)

Abstract

On the occasion of the July 2018 wildfire in the West Attica region (Kineta area, Geraneia Mountain) this study aimed to the assessment of soil quality in Kineta area and the effect of fire on soil properties and the bioavailable forms of copper (Cu), iron (Fe), manganese (Mn) and zinc (Zn), which is a topic poorly documented. Topsoil (0–5 cm depth) and subsoil (5–25 cm depth) samples were collected from burned sites and unburned control sites two months after the wildfire event. The area is mainly covered by pine trees (Pinus halepensis). Statistical analysis and Geographical Information System (GIS) database elaboration proved successful tools for this research. The type of methodology applied in this study consists of Diethylene-Triamine-Penta-Ace-tic acid (DTPA) chemical extraction, pH, Cation Exchange Capacity (CEC), Electric Conductivity (EC) and soil organic matter (OM) evaluation, factor analysis, GIS database and comparison of soil parameters with quality standards and levels given from the literature. Results of this study indicated that wildfires significantly (p < 0.05) increased pH values, as well as, OM, FeDTPA and MnDTPA higher contents in topsoil at burned sites than topsoil in unburned locations. This higher availability of elements in the soil may be associated with the addition of ash during a fire. At the same time, relationships between various parameters have been identified from factor analysis and reflect genetic association. A GIS elaboration showed the spatial relationship among high positive factor scores, lithology, Mn-oxides and soil condition (burned or unburned soil). In particular, ZnDTPA contents in Kineta soils constitute a case of lithogenic contamination, while high concentrations of MnDTPA demonstrate the role of wildfire in enhancing levels of available elements in topsoil.