Effects of prescribed fire on soil physicochemical properties in a mediterranean Pinus halepensis plantation: a case study in the Montgrí Massif.

Fire has long shaped Mediterranean ecosystems. However, changes in fire regimes, a major consequence of globalenvironment change, have led to increasingly frequent and more intense wildfires in these regions. Sustainableforest management is, therefore, today critical for reducing the risk of ignition and minimising the damagecaused by wildfires. In Spain, management tools as pruning and felling, silviculture, and prescribed fire (PF) areemployed individually or in combination to address this challenge. But the use of PF is controversial due to therisks of provoking uncontrolled fire episodes, increasing greenhouse gas emissions, and altering soil properties ifsuch fires are not properly managed. This study reports the results of the annual monitoring of the physical andchemical properties of a calcareous soil after a PF. We document changes in a Pinus halepensis plantation of theMontgrí massif (NE Spain) to determine whether this forest management approach has any short-term (two-yearperiod) effects. In year zero, i.e., immediately after the PF, a significant increase in the soil’s electrical conductivityand water repellency was observed in the burned plot (vs. control). In the first year, soil pH wassignificantly higher in the treated plot relative both to its first-year pH levels and to those of the control. By thesecond year, no significant differences were observed in the physicochemical properties of the soils of the treatedand control plots. These results suggest that PF did not cause significant short-term changes in soil properties,supporting its role as a sustainable management tool for reducing accumulated biomass in forests while maintainingsoil resilience in Mediterranean ecosystems.