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Natural disturbances like windthrows or forest fires alter the provision of forest ecosystem services like timber production, protection from natural hazards or carbon sequestration. After a disturbance, forests release large amounts of carbon and therefore change their status from carbon sinks to carbon source for some time. Climate-smart forest management may decrease forest vulnerability to disturbances and thus reduce carbon emissions as a consequence of future disturbances. But how to prioritize stands most in need of climate-smart management? In this study we adopted a risk mapping framework (hazard × vulnerability) to assess the risk to climate-related forest ecosystem services (carbon stock and sink) in forests prone to windthrow (in the Julian Alps, Italy) and forest fires (in the Apennines, Italy). We calculated hazard by using forest fire and windthrow simulation tools, and examined the most important drivers of the respective hazards. We then assessed vulnerability by calculating current carbon stocks and sinks in each forest stands. We used these values together with the calculated hazard to estimate "carbon risk", and prioritized high-risk stands for climate-smart management. We show that combining disturbance simulation tools and forest carbon measurements may help in risk-related decision making in forests, and taking planning decisions for climate-smart forestry. This approach may be replicated in other mountain forests to help understanding their actual carbon vulnerability to forest disturbances. [ABSTRACT FROM AUTHOR]

As an initial step in more extensive research into the links between biological and cultural diversity in present-day Italy, we reviewed Biocultural Diversity studies that explore the relationship between biological and cultural patterns of diversity to determine whether any direct causal relationships or common drivers could be inferred. We found no significant attempts to quantitatively measure biocultural diversity in the country as a whole. Italy shows a high number of mutual interactions, but common drivers and patterns between biological and cultural diversity were not evident. This could be either a problem of quantification due perhaps to an inherent incommensurability between the two dimensions, or different causative patterns that drive biological and cultural diversity. [ABSTRACT FROM AUTHOR]

Surface biomass characterization plays a key role in wildfire management. It allows classifying vegetation fuels flammability for fire risk analysis, to define silvicultural prescriptions for fire hazard reduction, to plan prescribed burning, or to model fire behavior and its effects, such as greenhouse gas and pollutant emissions. To facilitate fuel classification and analysis of potential fire behavior and effects in Italy, we harmonized 634 measurements of surface wildland fuels from Alpine, temperate and Mediterranean environments. The dataset provides quantitative data for duff, fine dead fuels and downed woody material, live grasses and shrubs fuel components. Surface fuel data were harmonized by subdividing loads (Mg ha-1) to standard size classes for dead (0-6, 6-25 and 25-75 mm) and live (0-6, 6-25 mm) fuels, collecting percent cover and depth/height (cm) of the various fuel components, and classifying observations into 19 fuelbed categories. To ensure comparability with existing vegetation classification systems, we classified each observation according to the European Fuel Map, the Corine Land Cover classes (level IV), the European Forest Types, and the forest categories of the Italian National Forest Inventory. The dataset and a photo description of each fuelbed category are available as Supplementary material. This dataset is the first step to develop several products at the national scale such as: (i) fuel type classification and mapping; (ii) carbon stock and wildfire emission estimates; (iii) calibration of fuel models for the simulation of fire behavior and effects. [ABSTRACT FROM AUTHOR]

Forests of the Apennines are characterised by high canopy cover and high tree species diversity (being at the interface between two major climatic zones of Europe), and provide important ecosystem functions to millions of people. They exemplify cutting-edge themes such as forest ecology in warmer climates, consequences of heavy land use, and resilience at the trailing edge of the distribution of many European forest species (Silver fir, Norway spruce, Beech, Black pine, Birch). We introduce the setting under the geological and climatological point of view and review the literature on the interactions between these long-term drivers and the specific, structural, and genetic diversity of these forest communities (e.g., effects of glacial refugia or tectonic/volcanic activity), followed by a brief outline of what little is known about natural disturbance regimes and their range of variability. Anthropogenic disturbances (fire, grazing) and land use changes (abandonment of cropland and pasture) have been by far the main drivers of forest dynamics at least for the last two millennia, determining for examples overageing of coppices, treeline advances, forest encroachment on former agricultural land. We suggest considerations about the interplay between these land use changes and disturbance drivers (e.g. fuel continuity), summarize comparisons between managed and unmanaged forests (e.g., increase in tree size, deadwood, biodiversity indicators), and elaborate on current proposals for climate-adapted management, highlighting specific and genetic diversity as an important source of resilience and adaptive potential. [ABSTRACT FROM AUTHOR]

During the last millennia, all forests of the Italian Alps have been heavily affected by human land-use. Consequently, forest structures have been modified, and there are no old growth remains. In the last decades, however, many forests have been withdrawn from regular management, because wood production was unprofitable, and left to develop naturally. At the same time, in currently managed forests, silvicultural systems able to develop or maintain old-growth characteristics are being required. The aim of this paper was to assess the status and developmental dynamics of old-growth characteristics in mixed beech, silver fir, and Norway spruce montane forests of the eastern Italian Alps. We selected along a naturalness gradient (a) three old-growth forests in Bosnia and Montenegro (due to the lack of old-growth forests in the Italian Alps), (b) two forests withdrawn from regular management for at least 50 years, and (c) three currently managed forests. In each forest, we analysed 17 structural attributes, in order to assess their value as indicators of old-growth condition. Old-growth forests were characterized by significantly higher amounts of live and dead biomass, share of beech in the dominant and regeneration layers, and number of large trees. The diameter distribution was best described as a rotated sigmoid, differently from currently and formerly managed forest. We discuss the differences in old-growth characteristics across the management gradient and use our results to evaluate the effectiveness of retention prescriptions currently applied in the studied regions in maintaining or promoting old-growth structural attributes in managed forests. [ABSTRACT FROM AUTHOR]

Forest fire is a common concern in Mediterranean watersheds. Fire-induced canopy mortality may cause the degradation of chemical–physical properties in the soil and influence hydrological processes within and across watersheds. However, the prediction of the pedological and hydrological effect of forest fires with heterogenous severities across entire watersheds remains a difficult task. A large forest fire occurred in 2017 in northern Italy providing the opportunity to test an integrated approach that exploits remote and in-situ data for assessing the impact of forest fires on the hydrological response of semi-natural watersheds. The approach is based on a combination of remotely-sensed information on burned areas and in-situ measurements of soil infiltration in burned areas. Such collected data were used to adapt a rainfall–runoff model over an experimental watershed to produce a comparative evaluation of flood peak and volume of runoff in pre- and post-fire conditions. The model is based on a semi-distributed approach that exploits the Soil Conservation Service Curve Number (SCS-CN) and lag-time methods for the estimation of hydrological losses and runoff propagation, respectively, across the watershed. The effects of fire on hydrological losses were modeled by adjusting the CN values for different fire severities. Direct infiltration measurements were carried out to better understand the effect of fire on soil infiltration capacity. We simulated the hydrological response of the burned watershed following one of the most severe storm events that had hit the area in the last few years. Fire had serious repercussions in regard to the hydrological response, increasing the flood peak and the runoff volume up to 125% and 75%, respectively. Soil infiltration capacity was seriously compromised by fire as well, reducing unsaturated hydraulic conductivity up to 75% compared with pre-fire conditions. These findings can provide insights into the impact of forest fires on the hydrological response of a whole watershed and improve the assessment of surface runoff alterations suffered by a watershed in post-fire conditions. [ABSTRACT FROM AUTHOR]

Forest ecosystems are threatened by different natural disturbances. Among them, the irruption of large herbivores represents one of the most alarming issues. Several local-scale studies have been carried out to clarify the mechanisms governing ungulate–forest interactions, to understand the effect of wild ungulates overabundance, and to apply conservation plans. However, information at large scales, over long periods of observation and from unmanipulated conditions is still scarce. This study aims to improve our knowledge in this field by using repeated inventories to investigate: the types of damage produced by ungulate populations on young trees, the drivers that stimulate browsing activity and its consequences on the specific composition of seedlings and saplings. To reach these goals, we used data collected during a twenty-year monitoring program (1994–2014) in the forests of Paneveggio-Pale di San Martino Nature Park (Italy). We applied descriptive statistics to summarize the data, GLMs to identify the drivers of browsing activity and Non-Metric Multidimensional Scaling (nMDS) ordinations to investigate the changes in specific composition of young trees across 20 years. We detected increasing browsing activity from 1994 to 2008 and a decline in 2014. Ungulates browsed preferentially in mature stands, and fed mostly on seedlings and saplings under 150 cm of height. The analysis of the environmental drivers of browsing pressure on the smallest size classes of plants suggests that foraging behavior is influenced by snowpack conditions, ungulate density and seasonality. Moreover, results underline the fact that ungulates feed mostly on palatable species, especially European rowan, but can also use unpalatable plants as emergency food under high competition levels. nMDS results suggest that rowan seed dispersion might be promoted by deer movements, however, saplings of this species were not able to exceed 30 cm of height because of heavy browsing. This bottleneck effect led to the dominance of unpalatable species, mostly Norway spruce, reducing diversity during forest regeneration. If prolonged, this effect could lead to a reduction of tree species richness, with cascading effects on many parts of the ecosystem, and threatening the resilience of the forest to future disturbances. [ABSTRACT FROM AUTHOR]

Wildfire regimes affected by global change have been the cause of major concern in recent years. Both direct prevention (e.g., fuel management planning) and land governance strategies (e.g., agroforestry development) can have an indirect regulatory effect on wildfires. Herein, we tested the hypothesis that active land planning and management in Italy have mitigated wildfire impacts in terms of loss of ecosystem services and forest cover, and burned wildland-urban interface, from 2007 to 2017. At the national scale, we assessed the effect size of major potential fire drivers such as climate, weather, flammability, socio-economic descriptors, land use changes, and proxies for land governance (e.g., European funds for rural development, investments in sustainable forest management, agro-pastoral activities), including potential interactions, on fire-related impacts via Random Forest modelling and Generalized Additive Mixed Model. Agro-forest districts (i.e., aggregations of neighbouring municipalities with homogeneous forest and agricultural characteristics) were used as spatial units of analysis. Our results confirm that territories with more active land governance show lower wildfire impacts, even under severe flammability and climatic conditions. This study supports current regional, national, and European strategies towards "fire resistant and resilient landscapes" by fostering agro-forestry, rural development, and nature conservation integrated policies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)