Using SlideforMAP and SOSlope to identify susceptible areas to shallow landslides in the Foreste Casentinesi National Park (Tuscany, Italy)

SlideforMAP and SOSlope are part of a suite of software available through ecorisQ (www.ecorisq.org), an international, non-profit association promoting solutions for risk reduction of natural hazards. SlideforMap is a probabilistic model that quantifies the stabilizing effect of vegetation at the regional scale and localizes potential areas where forest protection could be improved. SOSlope is a hydro-mechanical model that computes the factor of safety at the slope scale, using a strain-step discrete element method, which includes the effects of vegetation root structure and composition. The research aims at investigating the landslide susceptibility at two different spatial scales, using both models. 

The study area is located on a vegetated slope near an interregional connecting road (Tuscany, Emilia-Romagna, central Italy), which crosses the Foreste Casentinesi National Park (Tuscany) an important natural area for both touristic and recreational activities. 

A shallow landslide susceptibility analysis was performed at two different spatial scales, combining the use of the two previously mentioned models. In particular, SlideforMap was applied to identify the main susceptible areas to landslides at regional scale. Next, the identified unstable areas were investigated at detailed scale using SOSlope which simulated an intense rainfall event. Specifically, both distributions of root and soil forces along the slope were analyzed; for the sake of comparison, beech (Fagus sylvatica L.) and spruce (Picea abies L.) parameters were used. Finally, a back-analysis was performed on real landslides. 

The results showed the activation of root reinforcement spatially distributed in the studied slope. The basal root reinforcement map highlights significant differences, with beech showing higher reinforcement values compared to spruce. According to the factor of safety map, landslides may occur along the investigated unstable area. 

SlideforMap and SOSlope may be useful tools to support land and forestry planning, allowing the localization and quantification of the protective effects of forests, root reinforcement included. Results demonstrated that the factor of safety can be used as benchmarks for silvicultural interventions, thus improving the whole planning activities in both forest and surrounding natural and man-made systems.