What have we learnt?
What have we learnt?
Over the past decade, research on forest disturbances has deepened our understanding of how ecosystems respond to climatic and anthropogenic pressures. Three broad disturbance types have been the focus of empirical and modeling studies, yielding insights for both basic ecology and applied management.
Late‐spring frost and drought are increasingly recognized as critical constraints on forest productivity. Chen et al. (2023) compared the immediate and carry-over impacts of late-spring frost (LSF) and growing season drought on gross primary productivity (GPP) capacity across 34 Northern Hemisphere eddy-covariance sites. They found that LSF caused sharp, immediate drops in light-saturated GPP capacity in both needle-leaf and broadleaf forests, while drought had a stronger effect on needle-leaf sites (Chen et al., 2023). No significant interaction between the two extremes was observed, but LSF exhibited a more persistent carry-over effect than drought. Path analysis revealed that differences in canopy conductance underlie the varied drought sensitivity between forest types, underscoring the need to account for species-specific hydraulic traits when predicting carbon cycle feedbacks under climate change.
Path erosion pose a subtler but persistent threat to forest understoreys and soils. In Koli National Park, Finland, Selkimäki and Mola-Yudego (2011) measured trail width and depth across 201 sample plots and modeled erosion against slope, visitor numbers, and substrate. They demonstrated that steeper slopes and higher visitor densities drive greater path widening and incision, with rocky-site forests on hilltops showing the lowest resistance and meadows the highest (Selkimäki & Mola-Yudego, 2011). Their generalized linear models of width and depth provide park managers with predictive tools to steer trail design and visitor flow, mitigating soil loss while preserving recreational access.
Wildfires remain among the most severe disturbances in Mediterranean and temperate forests, and a suite of studies has dissected their ignition, spread, and post-fire dynamics. Using multiscale spatial analysis, González-Olabarria et al. (2011) showed that human-caused ignition density in Catalonia is strongly aggregated at hexagon, municipal and county scales, driven by population access, road and path densities, and land-cover interfaces . González-Olabarria et al. (2012) further leveraged airborne LiDAR to map stand variables (e.g., canopy bulk density, shrub cover) across 500 m² grids and fed these into FlamMap simulations under varied moisture and wind scenarios, producing continuous maps of fire intensity and burn probability . By contrast, González-Olabarria, Mola-Yudego, and Coll (2015) found that different ignition causes (e.g., burning pastures, accidental fires) exhibit distinct spatial aggregation patterns, implying that prevention measures must be cause-specific. On the severity side, Cardil et al. (2019) reviewed remote sensing burn indices (dNBR, RdNBR) against field–based Composite Burn Index measurements, highlighting the importance of timing and calibration to capture peak severity accurately and recommending combined linear and non-linear modeling approaches for Mediterranean fuels. Peris-Llopis, González-Olabarria, and Mola-Yudego (2020) showed that topographic (altitude, slope), fuel (pine vs. shrub), and socio-economic variables (population, road density) influence burned area differently across fire size classes—small, medium, and large—suggesting size-targeted prevention strategies . Finally, Peris-Llopis et al. (2024) demonstrated that mixed species stands (e.g., Pinus halepensis–Pinus nigra) can suffer higher post-fire mortality than pure stands, challenging assumptions that diversity always confers greater fire resistance and calling for nuanced mixture management. González-Olabarria et al. (2017) distilled stochastic simulation optimizations into flexible, threshold-based management rules for Pinus nigra stands, specifying basal area limits for thinning and regeneration cuts under varying fire probabilities, thus providing practitioners with decision triggers that adapt to changing fire regimes,
Other disturbances and adaptive responses round out this disturbance portfolio. In Finland, young stands (density < 1400 trees ha⁻¹) dominated by birch, pine, or mixed species, especially those with higher species diversity and recent silvicultural treatments, are most susceptible to browsing damage, with stand size also playing a contributory role (Díaz-Yáñez et al. 2017). In Norway, we developed wind and snow damage hazard models across, finding that stand structure and site factors (slope, species composition) far outweigh individual tree species in predicting damage, and they illustrated applications for hazard mapping and vulnerability simulations (Díaz-Yáñez et al., 2019) . In a complementary study, Díaz-Yáñez et al. (2019b) integrated these hazards into forest management planning, providing a framework for risk-based thinning and harvesting regimes that reduce vulnerability. The spread of Hymenoscyphus fraxineus (ash dieback) adds a biotic disturbance: Díaz-Yáñez et al. (2020) showed that this pathogen triggers high ash mortality and niche replacement, further altering structural vulnerability to other disturbances . At the policy and stakeholder level, Khanam et al. (2025) surveyed 129 forest stakeholders across Finland, Lithuania, Romania, Serbia and Greece, revealing region-specific threat perceptions—storms and pests in the north, illegal logging in Eastern Europe, fires and grazing in the Mediterranean—and highlighting the need for tailored adaptive strategies, active management, and policy reforms to bolster resilience.