The current increase in large wildfires is a socio-economic and ecological threat, particularly in populated mountain regions. Prescribed burning is a fuel management technique based on the planned application of fire to achieve land management goals; still, little is known about its potential impacts on tree physiology and soil properties in the European Alps, where it has never been applied. In spring 2022, we tested the effects of prescribed burning for fire hazard reduction in a dry conifer forest dominated by Scots pine (Pinus sylvestris L.). We generated an intensity gradient by manipulating surface fuels at the base of selected trees and evaluated prescribed burning effects on branch hydraulic conductivity, wood anatomy and soil physico-chemical properties in the short- and mid-term, up to one year after the treatment, with controls outside the treated area. The results showed that prescribed burning led to an effective surface fuel load reduction, and the plant-soil system was resistant, despite being affected by a considerable lack of rainfall. We conclude that even a high-intensity prescribed burning can be considered sustainable for reducing fire hazard in Scots pine forests of the European Alps, with these findings being extendable to similar forest ecosystems.

Soil surface moisture (SSM) is a critical indicator of agricultural drought, yet high-resolution projections under climate change remain scarce. This study develops a machine learning framework to predict and project SSM at 1 km resolution across five European Living Labs (LLs), encompassing vineyards, olive groves, and fruit tree systems. Historical Sentinel-1 SSM observations (2014–2024) were used to train ensemble models (Random Forest, XGBoost, ExtraTrees, LightGBM) incorporating climate variables, soil texture, topography, and land use. Tree-based models achieved R² values of 0.63–0.87. Vineyards showed the highest predictability (R² ≈ 0.87), reflecting their sensitivity to short-term atmospheric demand and surface water availability, whereas olive groves were the least predictable (R² ≈ 0.63–0.68), consistent with deeper rooting systems and greater drought buffering capacity. When forced with bias-corrected CMIP6 projections under SSP1-2.6 and SSP5-8.5 for 2041–2070, models indicate minimal changes under SSP1-2.6 but pronounced SSM declines of 8–24% under SSP5-8.5, with historically wetter regions experiencing the largest absolute losses. SHAP analysis confirmed precipitation and potential evapotranspiration as dominant predictors across all crops. This framework provides spatially explicit, crop-relevant SSM projections to support climate adaptation in European agricultural landscapes.

Background: Wildfires are natural disturbances that impact the soil altering the biogeochemical cycling of many elements. The European Alps are being increasingly affected by extreme wildfires, but little is known about the persistence of fire-induced changes in these soils, and the relationship with fire severity in this environment. We sampled an Alpine Scots pine ( Pinus sylvestris L.) forest affected by a mixed-severity wildfire (tree mortality range 15–100%) and assessed the recovery of several soil properties three years after the event in surface and sub-surface horizons of unburnt and burnt plots belonging to different severity classes (mapped with a combination of remotely sensed and field data). Results: The burnt plots differed from unburnt plots by having greater bare soil exposure, and the dark-colored surface horizon was characterized by significantly higher pH and pyrogenic carbon content compared to the unburnt plots. The sub-surface horizons had significantly lower organic carbon content than the unburnt plots, higher pH, and less sand-sized aggregates. There was no proportionality between fire-induced changes in soil properties and fire severity class. The soils with the greatest water repellency (water drop contact angle > 110°) were mostly located in low severity plots. Conclusions: Most soil properties, including those that usually recover quickly (e.g., pH), were still different in burnt plots three years after the wildfire. Severity maps produced in these environments, although detailed, can fail in identifying the sites where the soil was most severely burnt, and recovery of soil properties is not proportional to the severity degree obtained with this approach.

Wildfires play the role of ecosystem shapers in the majority of terrestrial biomes, altering canopy and litter cover and imposing strong modifications on soils. Organic matter (OM) content and composition, mineralogy, pH, aggregate stability and water repellency (WR) are among the main edaphic properties to be affected by heat. Various studies dealt with occurrence, extent and persistence of burning-induced soil WR, but the dynamics at the basis of its formation (and loss) are still widely unclear. In addition, the vast majority of research on this topic has been carried out in the Mediterranean, even if alpine environments are far from being untouched by fires. Our aims were therefore to provide insight into the key mechanisms regulating WR thermal alterations in a relatively understudied environment.Our sampling design aimed at collecting soils representative of the Western Italian Alps. Charring was simulated in the lab, at increasing temperatures (up to 300° C), on a set of A soil horizons developed under pine and beech forest covers. Water drop penetration time (WDPT) was employed to test WR persistence. Soils were analyzed in terms of organic carbon (OC) and nitrogen contents, pH, texture and iron (Fe) oxides composition (Fe-DCB and Fe-pyrophosphate extracted). Fe-speciation and OM composition of some selected samples were further characterized using Fe K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy and Fourier transform-infra red (FT-IR) spectroscopy, respectively.WR was found to be extremely variable, event at room temperature. For samples exhibiting an increase in WR upon burning intensity, maximum repellency was observed at 200° C. OC abundance (%) and coarse texture were found to be the main drivers of hydrophobicity in soil. WR was drastically lost when samples were exposed to temperatures higher than 200°C. Above this threshold, pH systematically increased and OC (%) sharply decreased. The increasingly negative charge of mineral surfaces, mirrored by pH increase, seems to result in a significant C volatilization by OM desorption, eventually leading to a super-hydrophilic behavior in soil.Fe EXAFS allowed to evaluate different thermal-dictated pathways of Fe-speciation. The formation of more crystalline Fe-forms (e.g. hematite, meghemite) was observed above 200° C. Even though a reduction in surface area should be expected when observing an increase in crystallization degree (potentially giving rise to greater WR), OM adhesion to mineral surfaces seems to be inhibited by the change induced in their charge. A reduction in the OM-bound Fe pool (pyrophosphate extracted) above 200° C could be appreciated, supporting the interpretation of oxy-hydroxides transformations and OC (%) loss.  The current investigation has been carried out to capture an in-depth picture of wildfire impacts on alpine soils, targeting factors responsible for WR enhancement and shred. Identifying the mechanisms regulating wildfire-related WR is a key issue, as the formation of hydrophobic layers in soil highly favors its erosion. Addressing such matters is crucial to tackle the issue of ecosystems recovery, considering that climate-change-related alterations in wildfires regimes are already causing the occurrence of more frequent and disruptive fires.