Wildfires have been observed to significantly impact hillslope stability through the combustion of vegetation and changes in soil properties, mainly resulting in an increased proneness to post-fire rainfall-induced erosion and debris flows. In this regard, the existing literature on the fire-induced effects on soil properties has yielded divergent results mainly due to the inherent site-specificity that characterizes both wildfire and post-fire soil mobilization phenomena. To shed a light into the post-fire changes in both physical and hydromechanical properties of volcanic soils, an experimental laboratory study was conducted on soil samples collected from the Mt. Saro area in the Sarno municipality (Pizzo d’Alvano massif, Campania region, Italy). Here, a wildfire occurred on March 23, 2022. The experimental campaign pursued the geotechnical characterization of three classes of soil samples i) unburned, ii) wildfire-burned, and iii) laboratory thermally treated. The results unveiled pronounced changes in soil properties under both wildfire- and laboratory-burned conditions. In general, the fire-affected soil showed decreasing values of soil organic matter content, root content by weight, and soil shear strength when compared to the unburned control samples. Conversely, as the severity of the fire increased, we observed increases in soil hydraulic conductivity and cumulative infiltration. These findings can provide novel insights to enhance the comprehension of those processes presiding over post-fire slope instability and erosion in similar geo-environmental contexts.
Fire-induced changes in the geotechnical properties of a volcanic soil
L. Iervolino;D. Peduto
;V. Foresta
2025-01-01
Abstract
Wildfires have been observed to significantly impact hillslope stability through the combustion of vegetation and changes in soil properties, mainly resulting in an increased proneness to post-fire rainfall-induced erosion and debris flows. In this regard, the existing literature on the fire-induced effects on soil properties has yielded divergent results mainly due to the inherent site-specificity that characterizes both wildfire and post-fire soil mobilization phenomena. To shed a light into the post-fire changes in both physical and hydromechanical properties of volcanic soils, an experimental laboratory study was conducted on soil samples collected from the Mt. Saro area in the Sarno municipality (Pizzo d’Alvano massif, Campania region, Italy). Here, a wildfire occurred on March 23, 2022. The experimental campaign pursued the geotechnical characterization of three classes of soil samples i) unburned, ii) wildfire-burned, and iii) laboratory thermally treated. The results unveiled pronounced changes in soil properties under both wildfire- and laboratory-burned conditions. In general, the fire-affected soil showed decreasing values of soil organic matter content, root content by weight, and soil shear strength when compared to the unburned control samples. Conversely, as the severity of the fire increased, we observed increases in soil hydraulic conductivity and cumulative infiltration. These findings can provide novel insights to enhance the comprehension of those processes presiding over post-fire slope instability and erosion in similar geo-environmental contexts.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.