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Wild pollinators are crucial for ecosystem functioning and human food production and often rely on floral resources provided by different (semi‐) natural ecosystems for survival. Yet, the role of European forests, and especially the European forest herb layer, as a potential provider of floral resources for pollinators has scarcely been quantified.In this study, we measured the potential nectar production (PNP) of the forest herb layer using resurvey data across 3326 plots in temperate forests in Europe, with an average time interval of 41 years between both surveys in order to assess (i) the importance of the forest herb layer in providing nectar for wild pollinators, (ii) the intra‐annual variation of PNP, (iii) the overall change in PNP between survey periods and (iv) the change in intra‐annual variation of PNP between survey periods. The PNP estimates nectar availability based on the relative cover of different plant species in the forest herb layer. Although PNP overestimates actual nectar production, relative differences amongst plots provide a valid and informative way to analyse differences across time and space.Our results show that the forest herb layer has a large potential for providing nectar for wild pollinator communities, which is greatest in spring, with an average PNP of almost 16 g sugar/m2/year. However, this potential has drastically declined (mean plot‐level decline >24%).Change in light availability, associated with shifts in canopy structure and canopy composition, is the key driver of temporal PNP changes.Synthesis. Our study shows that if management activities are carefully planned to sustain nectar‐producing plant species for wild pollinators, European forest herb layers and European forests as a whole can play key roles in sustaining wild pollinator populations. [ABSTRACT FROM AUTHOR]

Global change impacts on disturbances can strongly compromise the capacity of forests to provide ecosystem services to society. In addition, many ecosystem services in Europe are simultaneously provided by forests, emphasizing the importance of multifunctionality in forest ecosystem assessments. To address disturbances in forest ecosystem policies and management, spatially explicit risk analyses that consider multiple disturbances and ecosystem services are needed. However, we do not yet know which ecosystem services are most at risk from disturbances in Europe, where the respective risk hotspots are, nor which of the main disturbance agents are most detrimental to the provisioning of multiple ecosystem services from Europe's forests. Here, we quantify the risk of losing important ecosystem services (timber supply, carbon storage, soil erosion control and outdoor recreation) to forest disturbances (windthrows, bark beetle outbreaks and wildfires) in Europe on a continental scale. We find that up to 12% of Europe's ecosystem service supply is at risk from current disturbances. Soil erosion control is the ecosystem service at the highest risk, and windthrow is the disturbance agent posing the highest risk. Disturbances challenge forest multifunctionality by threatening multiple ecosystem services simultaneously on 19.8 Mha (9.7%) of Europe's forests. Our results highlight priority areas for risk management aiming to safeguard the sustainable provisioning of forest ecosystem services. [ABSTRACT FROM AUTHOR]

Recent observations of tree regeneration failures following large and severe disturbances, particularly under warm and dry conditions, have raised concerns about the resilience of forest ecosystems and their recovery dynamics in the face of climate change. We investigated the recovery of temperate forests in Europe after large and severe disturbance events (i.e., resulting in more than 70% canopy loss in patches larger than 1 ha), with a range of one to five decades since the disturbance occurred. The study included 143 sites of different forest types and management practices that had experienced 28 disturbance events, including windthrow (132 sites), fire (six sites), and bark beetle outbreaks (five sites). We focused on assessing post‐disturbance tree density, structure, and composition as key indicators of forest resilience. We compared post‐disturbance height‐weighted densities with site‐specific pre‐disturbance densities to qualitatively assess the potential for structural and compositional recovery, overall and for dominant tree species, respectively. Additionally, we analyzed the ecological drivers of post‐windthrow tree density, such as forest management, topography, and post‐disturbance aridity, using a series of generalized additive models. The descriptive results show that European temperate forests have been resilient to past large and severe disturbances and concurrent climate conditions, albeit with lower resilience to high‐severity fire compared with other disturbance agents. Across sites and disturbance agents, the potential for structural recovery was greater than that of compositional recovery, with a large proportion of plots becoming dominated by early‐successional species after disturbance. The models showed that increasing elevation and salvage logging negatively affect post‐windthrow regeneration, particularly for late‐successional species, while pioneer species are negatively affected by increasing summer aridity. These findings provide a key baseline for assessing future recovery and resilience following the recent occurrence of widespread disturbance in the region and in anticipation of future conditions characterized by increasing heat and drought stress. [ABSTRACT FROM AUTHOR]

The article examines the potential utilization of forest biomass in bioenergy production in Europe, taking into account limiting and developmental factors. The methodology includes a strategic analysis and the use of PEST analysis to evaluate the market for wood biomass. In the context of the current geopolitical situation and the decarbonization goals of the EU, the authors recommend accelerating energy transformation and highlighting forest biomass as an alternative within renewable energy sources. A literature review indicates the need to revise EU assumptions to enable the use of wood for bioenergy production, taking into account the needs of the wood industry. The analysis of economic factors shows competitiveness of forest biomass against coal, yet challenges arise regarding resource availability and competition with other energy sources. Emphasis is placed on the necessity of sustainable forest resource management and technological innovation. In the context of an energy crisis, the article underscores the role of innovation and recycling in alleviating shortages in energy markets. Conclusions highlight the imperative to develop a sustainable energy strategy for forest resource management and engage EU countries in the development of new biofuel and renewable energy sources for energy security and environmental protection. [ABSTRACT FROM AUTHOR]

Coppicing is a form of forest management in European broadleaved forests. While it is still practised in south-eastern Europe, in central and western Europe it was almost completely replaced by high forest management. Currently, there are increasing efforts to reintroduce coppice management into former coppice woods. However, little comprehensive knowledge is available about the extent and management of coppice reintroduction and the processes governing it. In this paper, we present an overview of localities in the Czech Republic where coppice reintroduction was taking place in 2020. We identified 8 localities and conducted 10 semi-structured interviews with experts involved in their management in order to understand what motivated them to restart coppicing and what obstacles they have had to face. The main motivation of site managers is nature conservation, while the most important obstacles are operational issues, such as bureaucracy, complicated land ownership and legal responsibilities or lack of workforce. Other motivating factors identified in other European countries (production of a renewable energy source and potential for rural employment) have so far played a minor role in the Czech Republic. We conclude that a major challenge for future forest policies will be to utilise the economic experiences of regions with active coppicing to foster the spread of coppice woods in order to combine renewable energy production with biodiversity conservation. [ABSTRACT FROM AUTHOR]

Aim: The microclimate and light conditions on the forest floor are strongly modified by tree canopies. Therefore, we need to better consider the micro‐environment when quantifying trait–environment relationships for forest understorey plants. Here, we quantify relationships between micro‐environmental conditions and plant functional traits at the community level, including intraspecific trait variation, and their relationship with microclimate air temperature, light and soil properties. Location: Deciduous temperate forests across Europe. Time period: 2018. Major taxa studied: Herbaceous vegetation. Methods: We sampled 225 plots across 15 regions along four complementary gradients capturing both macro‐ and microclimatic conditions including latitude, elevation, forest management and distance to forest edges. We related the community‐weighted mean of five plant functional traits (plant height, specific leaf area [SLA], plant carbon [C], plant nitrogen [N] and plant C:N ratio) across 150 vascular plant species to variation in local microclimate air temperature, light and soil properties. We tested the effect of accounting for intraspecific variation in trait–environment relationships and performed variation partitioning to identify major drivers of trait variation. Results: Microclimate temperature, light availability and soil properties were all important predictors of community‐weighted mean functional traits. When light availability and variation in temperature were higher, the herb community often consisted of taller plants with a higher C:N ratio. In more productive environments (e.g. with high soil nitrogen availability), the community was dominated by individuals with resource‐acquisitive traits: high SLA and N but low C:N. Including intraspecific trait variation increased the strength of the trait–micro‐environment relationship, and increased the importance of light availability. Main conclusions: The trait–environment relationships were much stronger when the micro‐environment and intraspecific trait variation were considered. By locally steering light availability and temperature, forest managers can potentially impact the functional signature of the forest herb‐layer community. [ABSTRACT FROM AUTHOR]

In the twenty-first century, it is crucial to see climate change not only as a risk that can cause large-scale forest disturbances but also as an opportunity for innovative approaches to forest management and silviculture of new resistant tree species, like the prospective black pine (Pinus nigra J. F. Arnold). This literature review compiles findings from 260 scientific papers. It presents a summary of research results of black pine potential in European forests from 1970 to 2023. It describes the importance of its taxonomy, area of distribution and introduction, ecological characteristics, production, silviculture, wood quality, threats, and pests, as well as the potential of this tree species in relation to global climate change. In Europe, black pine covers an area of over 9.5 million ha and is one of the most frequently planted tree species outside of its original range. This pine is an effective tree species for afforestation management in arid habitats, as well as in areas threatened by pollution or on reclamation sites. Moreover, it resists the negative effects of climate change exceptionally well, such as more intense heat waves and more frequent long-term droughts, especially in young stands with lower tree density. However, the consequences of climate change on growth are not homogeneous across black pine distribution ranges due to interpopulation variability. It also has a high production potential advantage, and the wood is easy to process for various purposes. Overall, black pine can be considered one of the most adaptable pine species to anthropogenic factors and ongoing climate change, and a valuable tree species in forestry for newly cultivated areas in Europe. [ABSTRACT FROM AUTHOR]

Planted monocultures of even-aged coniferous tree species are abundant worldwide but increasingly damaged by biotic and abiotic stressors and disturbances. In Central Europe, a fundamental goal of ecologically oriented forest management is thus the conversion of pure and often even-aged coniferous stands into structurally more diverse and mixed broad-leaved forests. This conversion is often achieved by single-tree selection resulting in small canopy openings that promote artificial or natural regeneration. Consequently, forest conversion aims at altering stand structure and tree communities. In order to describe the status quo of forest conversion and derive implications for forest management, we investigated changes of tree composition and forest structure in the Bavarian Spessart mountains in southwest Germany. We conducted a resurvey of 108 semi-permanent plots in four different coniferous stand types of Norway spruce, Scots pine, Douglas fir, and European larch about 30 years after the initial survey. We found significant differences in the stratification and cover of respective forest layers between the two sampling periods that indicated an increase in stand structural heterogeneity. While species richness of the overstorey remained constant, species richness and diversity of the shrub and lower canopy layer increased significantly. Regenerating "winner" species included late-successional broad-leaved (e.g., European beech, sessile oak), pioneer broad-leaved (e.g., silver birch, rowan) and shade-tolerant coniferous (e.g., silver fir, Douglas fir) species. Although Norway spruce was significantly reduced in the overstorey, it regenerated in parts extensively in the understorey. We conclude that the forest conversion in the Spessart mountains was overall successful in terms of diversifying forest structure and tree species. Its effects are, though, still emerging and the stands are in a transitional phase. Besides the preferred natural regeneration of target tree species, forest management may consider active measures to guide the facilitated diverse tree community of previously pure and even-aged coniferous stands towards stand maturity. [ABSTRACT FROM AUTHOR]

Simple Summary: In a world filled with diverse ecosystems, understanding the behaviour of invasive species is crucial for maintaining balance and health. This study delves into the bioecology of the invasive oak lace bug in Europe, shedding light on its life cycle through a degree day-based model and presenting insights gathered from field-based life tables. Our research addresses key knowledge gaps, offering valuable information for effective pest control in forest ecosystems. By bridging the gap between scientific exploration and practical implications, we aim to empower the public with accessible knowledge on how to protect European forests and maintain the delicate equilibrium of natural environments. Corythucha arcuata, commonly known as the oak lace bug (OLB), is an insect species originally native to North America that has become an invasive species of significant concern in Europe. This invasive pest has been observed in various European countries, raising concerns about its impact on forest ecosystems. In 2015, it was first documented in Romania, further highlighting the need for research on its bioecology and life cycle. This study investigated the bioecology of the OLB in the southern region of Romania, focusing on its life cycle, development, and population dynamics. The results indicated that the OLB has three generations per year and overwinters in the adult stage in sheltered locations. Temperature significantly influenced the timing of egg hatching, nymph appearance, and adult development, with variation observed between generations. Additionally, a life table analysis provided insights into the population dynamics of the OLB in its natural environment, revealing variation in egg laying trends across generations. This research contributes to a better understanding of the OLB's bioecology and provides essential data for forest managers developing science-based management strategies to mitigate its impact. By elucidating the life cycle and development patterns of the OLB in southern Romania, this study aids in the development of predictive models and life tables tailored to the region. These findings empower forest managers with the knowledge needed to make informed decisions for effective OLB management, ultimately preserving the health of forest ecosystems. [ABSTRACT FROM AUTHOR]

Anthropic activities have modelled and simplified southern European forest landscapes for centuries. Over recent decades, new drivers related to human-mediated global change have induced the redistribution of tree species and an increase in more complex forests. However, the current large-scale patterns and drivers of these changes are yet to be fully described for the Mediterranean Basin. In this frame, this work identifies and examines changes in dominance and composition from pure to mixed forests across bioclimatic gradients and forest types in Iberian forests over recent decades based on data from the Spanish National Forest Inventory from 1960 to 2020. Then, considering different environmental, anthropic, and disturbance variables we also identify some of the most important drivers associated with the shifts observed from 1986 to 2020. Our results confirm an ongoing increase in mixed forests involving the replacement of conifers by broadleaved species. These shifts are greater in the Atlantic biogeoregion and in pure broadleaved deciduous forests. Climate warming-associated disturbances such as drought severity together with land use legacies and forest types showed the strongest relationships with the observed changes in the studied forests. Our results support the premise put forward by palaeoecologists which states that the increase in tree mixtures is a natural process reversing the historical human-induced simplification of Iberian forests. The increasing importance of mixed forest in southern Europe makes decisive the revision of forest classifications as well as forest management and conservation plans in order to include these increasingly abundant novel stands in forest policies. [ABSTRACT FROM AUTHOR]

Predatory long-legged flies of the genus Medetera are important, but currently understudied, natural enemies of Scolytinae bark beetles such as Ips typographus. Medetera flies lay eggs on beetle-infested trees, where the developing larvae find their prey, but the chemical cues used by Medetera to locate infested trees are currently unknown. To identify odors attracting Medetera signaticornis, a species in Europe, headspace samples were collected at several time-points through different stages of I. typographus attacks on logs of Norway spruce (Picea abies). The headspace samples were analyzed using combined gas chromatography and mass spectrometry (GC–MS), and gas chromatography coupled with electroantennographic detection (GC-EAD) to determine compounds that stimulate M. signaticornis antennae. Antennae of M. signaticornis males and females were found to detect (–)-cis-verbenol, (+)-trans-verbenol and myrtenol, which are known to be produced by bark beetles. Antennal responses were also observed for verbenene, isoterpinolene, α-pinene oxide, camphor, pinocamphone, terpinene-4-ol, myrtenal, borneol, α-terpineol, geranyl acetone, and verbenone, which are primarily produced by microorganisms, and α-pinene, α-fenchene, β-pinene, camphene, 3-carene, limonene, γ-terpinene, and terpinolene, known spruce tree compounds. In field experiments testing two synthetic blends containing 18 antennal active and two additional compounds 2-methyl-3-buten-2-ol and ipsdienol we observed significant attraction of M. signaticornis within 24 h. These attractive blends can form the basis for development of Medetera monitoring lures for use in future forest and pest management. [ABSTRACT FROM AUTHOR]

Aim: The biogeography of European forests presents many interesting case studies, as inferred from phylogeography, contemporary population genetics, and distribution modelling of saproxylic species. Here, we pose four main hypotheses: (i) the phylogeographic paradigm known for temperate species in Europe is also applicable for saproxylic taxa; (ii) current expansion is occurring only in some genetic lineages; (iii) genetic diversity decreases from east to west, reflecting differences in forest naturalness and management; and (iv) climatic changes will force a northward range shift. Location: Europe. Taxon: The saproxylic beetle, Cucujus cinnaberinus (Scopoli, 1763). Methods: Beetles from 37 locations throughout the species range were genotyped using microsatellites and mtDNA (468 and 237 individuals, respectively). Molecular data were analysed to describe population diversity, structure, and demography. 200 records were used to model distribution based on climate data. Results: mtDNA analyses revealed three clades: the most divergent in Italy and two less distinct in north‐western and central‐to‐southeastern Europe. Microsatellites showed no clear geographic distribution pattern except for a distinct lineage in Italy. The highest genetic diversity was found in southern refugia, in natural forests of Central‐Eastern Europe, and in a mixing zone in Pannonia. During the Holocene, the Italian population declined, whereas populations in the rest of Europe showed no clear changes. Distribution models revealed the existence of glacial refugia along the coasts of the Adriatic and Black Seas, and northward dispersal in the Holocene continued in the XXI century. Conclusions: C. cinnaberinus has a complex historical biogeography, discordant with patterns known for temperate or boreal taxa. The current expansion occurs only in populations from mainland Europe, whereas southernmost populations are in decline. Current genetic diversity is shaped by recent forest management, which is the least intensive in Eastern Europe. Climate change will most likely enhance northward dispersal and threaten the survival of the southernmost populations. [ABSTRACT FROM AUTHOR]

Tar production was an important part of forest management until the beginning of the 20th century. Tar – used for many purposes – from glue, through boatbuilding, to a pharmacy – was widely produced throughout Europe. As early as in the 18th century, in some parts of Europe, tar production became massive. In the eastern part of Europe, however, that process was still carried out with simple methods known from the Middle Ages. With Airborne Laser Scanning, we have detected 53 traces of tar processing in the Polish part of the Białowieża Forest. In 2019, one of the features was archaeologically excavated to identify its preserved structure/architecture and collect samples for laboratory tests. The outcomes of the archaeological test trench did not provide answers to many research questions. Therefore, it was decided to apply an interdisciplinary approach to determine the utilised raw material, timing and the process of tar production. In result of the dendrochronological and anthracological analyses, it was found that diverse parts of Scots pine trees were used for tar production. Our tree ring analyses provided also the first information about the absolute chronology of the tar kiln activity. To obtain information on the tar production process, i.e. the burning temperature and the characteristics of the obtained tar, we performed chemical analyses of the tar samples (microscopic and Fourier Transform Infrared, FTIR). This multidisciplinary case study of one of the many sites from the Białowieża Forest provided basic information about the methods of tar production in modern times and their probable impact on the immediate vicinity of the forest. However, such an interdisciplinary approach is limited by both the quantity and quality of the preserved artefacts, found during archaeological excavations. [ABSTRACT FROM AUTHOR]

The tree flora of the Mediterranean Basin contains an outstanding taxonomic richness and a high proportion of endemic taxa. Contrary to other regions of the Mediterranean biome, a comprehensive phylogenetic analysis of the relationship between phylogenetic diversity, trait diversity and environmental factors in a spatial ecological context is lacking.We inferred the first calibrated phylogeny of 203 native tree species occurring in the European Mediterranean Basin based on 12 DNA regions. Using a set of four functional traits, we computed phylogenetic diversity for all 10,042 grid cells of 10 × 10 km spatial resolution to completely cover Mediterranean Europe. Then, we tested the spatial influence of environmental factors on tree diversity.Our results suggest that the nature of the relationship between traits and phylogeny varies among the different studied traits and according to the evolutionary distance considered. Phylogenetic diversity and functional diversity of European Mediterranean trees correlated strongly with species richness. High values of these diversity indices were located in the north of the study area, at high altitude, and minimum temperature of the coldest month. In contrast, the two phylogenetic indices that were not correlated with species richness (Mean Phylogenetic Distance, Phylogenetic Species Variability) were located in the south of the study area and were positively correlated with high altitude, soil organic carbon stock and sand soil texture.Our study provides support for the use of phylogenies in conservation biology to assess ecosystem functioning, and provides insights for the implementation of sustainable forest ecosystem management. [ABSTRACT FROM AUTHOR]

Emerging and invasive tree pests and pathogens in Europe are increasing in number and range, having impacts on biodiversity, forest services, ecosystems and human well-being. Stakeholders involved in tree and forest management contribute to the detection and management of new and emerging tree pests and pathogens (PnPs). We surveyed different groups of stakeholders in European countries. The stakeholders were mainly researchers, tree health surveyors and forest managers, as well as forest owners, nurseries, policy-makers, advisors, forestry authorities, NGOs and civil society. We investigated which tools they used to detect and manage PnPs, surveyed their current PnP awareness and knowledge and collated the new and emerging PnP species of concern to them. The 237 respondents were based in 15 European countries, with the majority from the United Kingdom, France and the Czech Republic. There was a strong participation of respondents with a work focus on research and surveying, whereas timber traders and plant importers were less represented. Respondents were surveyed on 18 new, emerging PnPs in Europe and listed an additional 37 pest species and 21 pathogen species as potential future threats. We found that species on EPPO's list of 'priority pests' were better known than those not listed. Stakeholders working in urban environments were more aware of PnPs compared to those working in rural areas. Stakeholders' awareness of PnPs was not related to the number of new, emerging PnP species present in a country. Stakeholders want access to more detection and management tools, including long-term citizen-science monitoring, maps showing spread and range of new PnPs, pest identification smartphone apps, handheld detection devices, drone monitoring and eDNA metabarcoding. To help facilitate better forest health across Europe, they called for mixed forest development, reduced nursery stock movement, biosecurity and data sharing amongst organisations. These results indicate that stakeholder knowledge of a few key PnP may be good, but given that the large diversity of threats is so large and future risks unknown, we conclude that multiple and varied methods for generic detection, mitigation and management methods, many in development, are needed in the hands of stakeholders surveying and managing trees and woodlands in Europe. [ABSTRACT FROM AUTHOR]

Standing deadwood is an important structural component of forest ecosystems. Its occurrence and dynamics influence both carbon fluxes and the availability of habitats for many species. However, deadwood is greatly reduced in managed, and even in many currently unmanaged temperate forests in Europe. To date, few studies have examined how environmental factors, forest management and changing climate affect the availability of standing deadwood and its dynamics.Data from five periods of the Austrian National Forest Inventory (1981–2009) were used to (I) analyse standing deadwood volume in relation to living volume stock, elevation, eco‐region, forest type, ownership and management intensity, (II) investigate the influence of forest ownership and management intensity on snag persistence and (III) define drivers of standing deadwood volume loss for seven tree genera (Abies, Alnus, Fagus, Larix, Picea, Pinus and Quercus) using tree‐related, site‐related and climate‐related variables, and predict volume loss under two climate change scenarios.Standing deadwood volume was mainly determined by living volume stock and elevation, resulting in different distributions between eco‐regions. While forest type and management intensity influenced standing deadwood volume only slightly, the latter exhibited a significant effect on persistence. Snag persistence was shorter in intensively managed forests than in extensively managed forests and shorter in private than in public forests.Standing deadwood volume loss was driven by a combination of diameter at breast height, elevation, as well as temperature, precipitation and relative humidity. Volume loss under climate change predictions revealed constant rates for moderate climate change (RCP2.6) by the end of the 21st century. Under severe climate change conditions (RCP8.5), volume loss increased for most tree genera, with Quercus, Alnus and Picea showing different predictions depending on the model used as the baseline scenario. We observed trends towards faster volume loss at higher temperatures and lower elevations and slower volume loss at high precipitation levels. The tree genera most susceptible to climate change were Pinus and Fagus, while Abies was least susceptible.Synthesis and applications. We recommend to protect standing dead trees from regular harvesting to ensure the full decomposition process. The consequences for decomposition‐dependent species must be taken into account to evaluate the influences of management and climate change on standing deadwood dynamics. [ABSTRACT FROM AUTHOR]

Spruce forests face many threats such as climate change and bark beetle outbreaks. Yet, bark beetle dynamics have a long co-evolutionary history strongly linked to spruce forest structural dynamics. Disturbed spruce forest sites resulting from bark beetle outbreaks therefore should not be regarded as degraded land, but as early successional stages following natural forest dynamics. Three post-bark-beetle disturbance sites and one closed-canopy site in the Bavarian Forest and Šumava National Parks were investigated with the focus on moth communities. The three disturbed sites had undergone different post-disturbance management regimes, with one being treated by salvage logging, while at the other two forest sites deadwood was kept in the forest. To avoid the spread of bark beetles, however, the bark of dead trees was either gouged or removed. The aim was to determine how many moths can be found at the undisturbed and disturbed forest sites and if differences in community composition can be explained by different management regimes. The results highlight that natural forest disturbance can increase moth diversity, especially by favouring species that are associated with open and shrub habitats. Many rare and endangered species benefit from bark beetle outbreaks, indicating that accepting natural forest dynamics is an important part of conservation management. Postbark beetle management seems to have a minor effect on moth communities. [ABSTRACT FROM AUTHOR]

Spruce forests face many threats such as climate change and bark beetle outbreaks. Yet, bark beetle dynamics have a long co-evolutionary history strongly linked to spruce forest structural dynamics. Disturbed spruce forest sites resulting from bark beetle outbreaks therefore should not be regarded as degraded land, but as early successional stages following natural forest dynamics. Three post-bark-beetle disturbance sites and one closed-canopy site in the Bavarian Forest and Šumava National Parks were investigated with the focus on moth communities. The three disturbed sites had undergone different post-disturbance management regimes, with one being treated by salvage logging, while at the other two forest sites deadwood was kept in the forest. To avoid the spread of bark beetles, however, the bark of dead trees was either gouged or removed. The aim was to determine how many moths can be found at the undisturbed and disturbed forest sites and if differences in community composition can be explained by different management regimes. The results highlight that natural forest disturbance can increase moth diversity, especially by favouring species that are associated with open and shrub habitats. Many rare and endangered species benefit from bark beetle outbreaks, indicating that accepting natural forest dynamics is an important part of conservation management. Postbark beetle management seems to have a minor effect on moth communities. [ABSTRACT FROM AUTHOR]

Over the last decades, the natural disturbance is increasingly putting pressure on European forests. Shifts in disturbance regimes may compromise forest functioning and the continuous provisioning of ecosystem services to society, including their climate change mitigation potential. Although forests are central to many European policies, we lack the long‐term empirical data needed for thoroughly understanding disturbance dynamics, modeling them, and developing adaptive management strategies. Here, we present a unique database of >170,000 records of ground‐based natural disturbance observations in European forests from 1950 to 2019. Reported data confirm a significant increase in forest disturbance in 34 European countries, causing on an average of 43.8 million m3 of disturbed timber volume per year over the 70‐year study period. This value is likely a conservative estimate due to under‐reporting, especially of small‐scale disturbances. We used machine learning techniques for assessing the magnitude of unreported disturbances, which are estimated to be between 8.6 and 18.3 million m3/year. In the last 20 years, disturbances on average accounted for 16% of the mean annual harvest in Europe. Wind was the most important disturbance agent over the study period (46% of total damage), followed by fire (24%) and bark beetles (17%). Bark beetle disturbance doubled its share of the total damage in the last 20 years. Forest disturbances can profoundly impact ecosystem services (e.g., climate change mitigation), affect regional forest resource provisioning and consequently disrupt long‐term management planning objectives and timber markets. We conclude that adaptation to changing disturbance regimes must be placed at the core of the European forest management and policy debate. Furthermore, a coherent and homogeneous monitoring system of natural disturbances is urgently needed in Europe, to better observe and respond to the ongoing changes in forest disturbance regimes. [ABSTRACT FROM AUTHOR]

Spruce forests face many threats such as climate change and bark beetle outbreaks. Yet, bark beetle dynamics have a long co-evolutionary history strongly linked to spruce forest structural dynamics. Disturbed spruce forest sites resulting from bark beetle outbreaks therefore should not be regarded as degraded land, but as early successional stages following natural forest dynamics. Three post-bark-beetle disturbance sites and one closed-canopy site in the Bavarian Forest and Šumava National Parks were investigated with the focus on moth communities. The three disturbed sites had undergone different post-disturbance management regimes, with one being treated by salvage logging, while at the other two forest sites deadwood was kept in the forest. To avoid the spread of bark beetles, however, the bark of dead trees was either gouged or removed. The aim was to determine how many moths can be found at the undisturbed and disturbed forest sites and if differences in community composition can be explained by different management regimes. The results highlight that natural forest disturbance can increase moth diversity, especially by favouring species that are associated with open and shrub habitats. Many rare and endangered species benefit from bark beetle outbreaks, indicating that accepting natural forest dynamics is an important part of conservation management. Postbark beetle management seems to have a minor effect on moth communities. [ABSTRACT FROM AUTHOR]

Spruce forests face many threats such as climate change and bark beetle outbreaks. Yet, bark beetle dynamics have a long co-evolutionary history strongly linked to spruce forest structural dynamics. Disturbed spruce forest sites resulting from bark beetle outbreaks therefore should not be regarded as degraded land, but as early successional stages following natural forest dynamics. Three post-bark-beetle disturbance sites and one closed-canopy site in the Bavarian Forest and Šumava National Parks were investigated with the focus on moth communities. The three disturbed sites had undergone different post-disturbance management regimes, with one being treated by salvage logging, while at the other two forest sites deadwood was kept in the forest. To avoid the spread of bark beetles, however, the bark of dead trees was either gouged or removed. The aim was to determine how many moths can be found at the undisturbed and disturbed forest sites and if differences in community composition can be explained by different management regimes. The results highlight that natural forest disturbance can increase moth diversity, especially by favouring species that are associated with open and shrub habitats. Many rare and endangered species benefi t from bark beetle outbreaks, indicating that accepting natural forest dynamics is an important part of conservation management. Postbark beetle management seems to have a minor effect on moth communities. [ABSTRACT FROM AUTHOR]

The upper regions of the Bohemian and Bavarian Forests are home to what appear to be some of the best-preserved natural ecosystems in Europe. Airborne laser scanning (LIDAR) methods have nonetheless revealed numerous surface relics of past human activity. Among the most recent discoveries is a series of quadrangular enclosures with various types of stone walls or stone earth banks that range from 20 m to 40 m wide. At altitudes of around 1100 m a.s.l., there are some 600 of these barely detectable and little-known features that have largely fallen out of the historical consciousness, partly as a result of the displacement of the German population after the Second World War, and partly because they are hardly recognizable in the terrain. Radiocarbon dating, an analysis of historical administrative, topographical and forestry maps, and observations regarding the present-day vegetation enable us to estimate the origin of the enclosures between the second half of the 17th century and the second half of the 19th century. Preliminary results suggest that some of them could have been forest nurseries and seedbeds, some of which could have been founded before the great forest disturbances of the 1860s and 1870s. They therefore represent a missing piece in the history of forest management in the Šumava region. [ABSTRACT FROM AUTHOR]

Societal Impact Statement: The planet faces a climate crisis with severe health, economic and environmental consequences. Political actions such as the European Green Deal aim to mitigate climate change by shifting production and consumption patterns, and the production of mycorrhizal sporocarps—the fruiting body of fungi—is no exception. The production of mycorrhizal sporocarps has a high economic, cultural and environmental impact in the Mediterranean region. With a key role in forest ecosystems, ectomycorrhizal fungi provide services and goods essential to maintain soil quality, ecosystem functions and food, contributing to the achievement of sustainable production and the European Green Deal goals—a climate‐neutral Europe. Summary: Ectomycorrhizal fungi (ECMF) cultivation is an important economic activity in the Mediterranean region. Sporocarps from ECMF species such as Terfezia claveryi, Tuber melanosporum, Tuber aestivum and Lactarius delicious have been successfully cultivated. Due to biotechnological advances, a considerable evolution in ECMF cultivation techniques was observed in the last decade. New technologies and intensified Research and Development allow for a better understanding of the physiology of the plant‐fungi symbioses and how climate change affects them. Studying forest management practices is also essential to optimise the natural production of ectomycorrhizal sporocarps and help develop sustainable production practices. This knowledge revealed the importance of ECMF and their role in the rural bioeconomy and highlighted the need to establish sustainable cultivation practices. A successful example of ECMF cultivation is the production of Terfezia species, namely, Terfezia claveryi and Terfezia boudieri. Terfezia truffles are traditional delicacies with high socioeconomic relevance and numerous biotechnological applications. Furthermore, these Mediterranean native species are an important tool to develop the bioeconomy in rural areas by creating new production strategies. Furthermore, exploiting these and other native Mediterranean species can promote sustainable practices in line with new European Green Deal strategies, such as the Farm to Fork strategy, the EU Biodiversity strategy for 2030 and the Climate Law. This work reviews ECMF cultivation practices and forest management studies, presenting the case of Terfezia cultivation and how the sustainable production of wild and planted ECMF may contribute to achieving the European Green Deal objectives and to a more resilient Europe. [ABSTRACT FROM AUTHOR]

Data from long-term experimental catchments are the foundation of hydrological sciences and are crucial to benchmark process understanding, observe trends and natural cycles, and are prerequisites for testing predictive models. Integrated data sets which capture all compartments of our landscapes are particularly important in times of land use and climate change. Here, we present ecohydrological data measured at multiple spatial scales which allow to characterise so called "blue" water fluxes (which supply groundwater recharge and support streamflow generation) and "green" water fluxes (which sustain vegetation growth). There are two particular unique aspects to this data set though: a) we measured water stable isotopes in the different landscape compartments (that is in precipitation, surface water, soil, ground- and plant water); and b) conducted this monitoring during the extreme drought of 2018 in Central Europe. Stable water isotopes are so useful in hydrology as they provide "fingerprints" of the pathways water took when moving through a catchment. Thus, isotopes allow to evaluate the dynamic relationships between water storage changes and fluxes, which is fundamental to understanding how catchments respond to hydroclimate perturbations or abrupt land use conversion. Second, as we provide the data until 2020 one can also investigate recovery of water stores and fluxes after extreme droughts. Last but not least: lowland headwaters are often understudied systems despite them providing important ecosystem services such as groundwater and drinking water provision and management for forestry and agriculture. [ABSTRACT FROM AUTHOR]

Although much is known about the ecology and functional importance of canopy arthropods in temperate forests, few studies have tried to assess the overall diversity and investigate the composition and dynamics of tree-specific communities. This has impeded a deeper understanding of the functioning of forests, and of how to maintain system services. Here, we present the first comprehensive data of whole arthropod communities, collected by insecticidal knockdown (fogging) from 1159 trees in 18 study areas in Central Europe during the last 25 years. The data includes 3,253,591 arthropods from 32 taxa (order, suborder, family) collected on 24 tree species from 18 genera. Fogging collects free-living, ectophytic arthropods in approximately the same number as they occur in the trees. To our knowledge, these are the most comprehensive data available today on the taxonomic composition of arboreal fauna. Assigning all arthropods to their feeding guild provided a proxy of their functional importance. The data showed that the canopy communities were regularly structured, with a clear dominance hierarchy comprised of eight 'major taxa' that represented 87% of all arthropods. Despite significant differences in the proportions of taxa on deciduous and coniferous trees, the composition of the guilds was very similar. The individual tree genera, on the other hand, showed significant differences in guild composition, especially when different study areas and years were compared, whereas tree-specific traits, such as tree height, girth in breast height or leaf cover, explained little of the overall variance. On the ordinal level, guild composition also differed significantly between managed and primary forests, with a simultaneous low within-group variability, indicating that management is a key factor determining the distribution of biodiversity and guild composition. [ABSTRACT FROM AUTHOR]

In the context of global change, the integration of non-native tree (NNT) species into European forestry is increasingly being discussed. The ecological consequences of increasing use or spread of NNTs in European forests are highly uncertain, as the scientific evidence is either constraint to results from case studies with limited spatial extent, or concerns global assessments that lack focus on European NNTs. For either case, generalisations on European NNTs are challenging to draw. Here we compile data on the impacts of seven important NNTs (Acacia dealbata, Ailanthus altissima, Eucalyptus globulus, Prunus serotina, Pseudotsuga menziesii, Quercus rubra, Robinia pseudoacacia) on physical and chemical soil properties and diversity attributes in Europe, and summarise commonalities and differences. From a total of 103 publications considered, studies on diversity attributes were overall more frequent than studies on soil properties. The effects on soil properties varied greatly among tree species and depended on the respective soil property. Overall, increasing (45%) and decreasing (45%) impacts on soil occurred with similar frequency. In contrast, decreasing impacts on biodiversity were much more frequent (66%) than increasing ones (24%). Species phylogenetically distant from European tree species, such as Acacia dealbata, Eucalyptus globulus and Ailanthus altissima, showed the strongest decreasing impacts on biodiversity. Our results suggest that forest managers should be cautious in using NNTs, as a majority of NNT stands host fewer species when compared with native tree species or ecosystems, likely reflected in changes in biotic interactions and ecosystem functions. The high variability of impacts suggests that individual NNTs should be assessed separately, but NNTs that lack European relatives should be used with particular caution. [ABSTRACT FROM AUTHOR]

Biochar (BC) is often proposed as a tool for climate change mitigation, due to the expected long lifetime in the environment. However, BC's stability can vary depending on feedstock type and the presence of labile carbon fractions. In this study, we verify the recent methods with new possible tools for biochar stability assessment on six different biochars derived from commonly available Europe biomass sources. Elemental composition (CHNO), dissolved organic carbon (DOC) and water-soluble carbonates content (WSC), volatile organic compounds (VOCs) composition, and mid-infrared spectra (MIR) were performed to estimate the persistence of biochars. Under similar conditions of pyrolysis, biochar properties can vary depending on a feedstock origin. Less aromatic structure and higher contents of labile carbon fractions (DOCs and WSC) in food waste biochars affected the lower stability, while biochars derived from high lignocellulose materials (straw, wood, and grass) were strongly carbonized, with persistent, aromatic structure. Labile carbon pool content (DOC, WSC) and spectral analysis can be useful tools for biochar stability assessment, giving similar information to the standard molar ratio method. Biochars obtained from agriculture and forestry management biomass should be considered as highly stable in soil and are appropriate for long-term carbon sequestration purposes. [ABSTRACT FROM AUTHOR]

Tree species maps derived from satellite imagery increasingly support forest administrations and nature conservation authorities with large-scale and up-to-date information. However, many species are often excluded or aggregated in classification tasks due to a limited knowledge of the most suitable predictors. Our study aims to gain a better understanding of optical and polarimetric traits for tree species mapping by examining Sentinel-1 and Sentinel-2 time series from 61 tree species in temperate Europe. For a selection of 32 optical, polarimetric and structural variables, the principal component analysis revealed that Sentinel-2 variables mainly explain the variance in the data by contributing to the "seasonality" and "foliage color" components. Sentinel-1 contribute most to the "texture" component. The Normalized Difference Vegetation Index (NDVI), Tasseled Cap Greenness (TCG) and Radar Vegetation Index (RVI) were chosen as key variables for further analysis. Seasonality was found to be the most dominant aspect in all vegetation indices. Furthermore, the TCG was found to be useful to distinguish between early and late budding species. The RVI showed a large potential to discriminate conifers, which is attributed to the crown volume effect of C-band SAR. Using exploratory data analysis, we further examined the influence of management, biogeographical and meteorological factors on the time series from Fagus sylvatica , Pinus sylvestris , and Picea abies. The NDVI and TCG are relatively robust to different conditions. For the two conifer species however, we found strong spatial variations of the RVI which are presumably caused by different crown conditions across the study area. Using Sentinel-1 data could therefore lead to uncertainties in tree species mapping across large biogeographical gradients. This study contributes to the improvement of tree species mapping based on optical and dual-polarimetric data and thus benefits forest authorities and other stakeholders in their monitoring tasks and decision-making. [Display omitted] • The spectral-temporal characteristics of 61 tree species are investigated. • S1 and S2 mainly depict "seasonality", "foliage color" and "texture" information. • Grouping species by their spectral-temporal traits is better than using the genus. • Volume scattering at C-band SAR has a great potential to discriminate conifers. • S1 backscatter at spruce and pine stands is strongly affected by biogeography. [ABSTRACT FROM AUTHOR]

• The nexus between forest-based climate mitigation and health is poorly researched. • This scoping review identified exposure pathways and health co-benefits from forests. • There is potential for synergies between forest management and health benefits. • Interdisciplinary efforts are required for advancement of research and understanding. Climate change is a pressing global challenge with profound implications for human health. Forest-based climate change mitigation strategies, such as afforestation, reforestation, and sustainable forest management, offer promising solutions to mitigate climate change and simultaneously yield substantial co-benefits for human health. The objective of this scoping review was to examine research trends related to the interdisciplinary nexus between forests as carbon sinks and human health co-benefits. We developed a conceptual framework model, supporting the inclusion of exposure pathways, such as recreational opportunities or aesthetic experiences, in the co-benefit context. We used a scoping review methodology to identify the proportion of European research on forest-based mitigation strategies that acknowledge the interconnection between mitigation strategies and human impacts. We also aimed to assess whether synergies and trade-offs between forest-based carbon sink capacity and human co-benefits has been analysed and quantified. From the initial 4,062 records retrieved, 349 reports analysed European forest management principles and factors related to climate change mitigation capacity. Of those, 97 studies acknowledged human co-benefits and 13 studies quantified the impacts on exposure pathways or health co-benefits and were included for full review. Our analysis demonstrates that there is potential for synergies related to optimising carbon sink capacity together with human co-benefits, but there is currently a lack of holistic research approaches assessing these interrelationships. We suggest enhanced interdisciplinary efforts, using for example multideterminant modelling approaches, to advance evidence and understanding of the forest and health nexus in the context of climate change mitigation. [ABSTRACT FROM AUTHOR]

Habitat loss, fragmentation and degradation are major causes of the ongoing decline of epiphytic and epixylic lichen species in temperate forests throughout Europe. We investigated how extant species richness and composition of epiphytic and epixylic lichen communities in ten hot-spots of lichen diversity in the Czech Republic reflected the occurrence and properties of potentially suitable microhabitats and habitats. At each hot-spot, we surveyed a pair of 1-ha square plots, one in (over-)mature managed and the second in unmanaged forest. In total, we recorded 513 epiphytic and epixylic lichen species which represent a substantial part of lichen biota in Central Europe. Species richness and composition of lichen communities were explained by microhabitat heterogeneity, and also by the area of near-natural forest habitats (habitat extent) at the landscape scale. In addition, lichen species richness and number of red-listed species were explained by a categorial variable distinguishing mature managed and unmanaged plots, used as a proxy of temporal continuity of natural succession. This finding illustrates that temporal continuity of natural succession in unmanaged forests likely had an extra stimulus for lichen communities that may not be reflected by observed aspects of forest habitats. Hence, we confirmed indispensable positive effects of (micro)habitat heterogeneity, and spatial and temporal continuity for preserved hot-spots of lichen diversity in Central Europe. Due to generally slow colonization-extinction dynamics of epiphytic and epixylic lichens we call for strengthening microhabitat heterogeneity, and the spatial and temporal continuity of European temperate forests at the landscape scale. • We recorded a major part of epiphytic and epixylic lichen species of central Europe. • Lichen species diversity was considerable higher in unmanaged than managed forests. • Species richness was supported by habitat quality and spatiotemporal continuity. • Differences in lichen species composition mirrored microhabitat heterogeneity. • Protection of over-mature managed forests is needed for lichen conservation. [ABSTRACT FROM AUTHOR]

Europe has been dominated by cultural landscape and rather intensively managed forests. It is thus no surprise that the ongoing global biodiversity crisis as well as the consequences of climate change have been apparent. In recent years, forestry in Central Europe has been going through a crisis caused by extensive disturbances primarily in commercial monocultures; this phenomenon is particularly striking in the Czech Republic. Given the significance of the situation, it is essential to review and optimise the current forest management practices in relation to biodiversity protection. Therefore, a survey among Czech biologists was conducted in an effort to provide specific feedback to foresters and other stakeholders based on scientific and empirical knowledge of the survey respondents. The survey assessed the forest habitat (in terms of light conditions and the structure of the forest environment), forest management tools and conceptual approaches regarding specific species and groups of organisms. The respondents negatively perceived the current forestry practices, especially in terms of creating homogeneity across the forest environment and eliminating important habitats. Structurally diverse old-growth forests as well as the open forests with the presence of old and habitat trees were emphasised by the survey respondents as essential environments. Largescale non-intervention within protected areas is necessary to support the presence of old-growth forests. On the other hand, there is an urgent need to restore open forests which requires (but not exclusively) the active efforts of man. These two basic appeals are essential in order to diversify the landscape through a combination of segregative and integrative forest management tools that aim to support biodiversity. [ABSTRACT FROM AUTHOR]

Global-scale canopy height mapping is an important tool for ecosystem monitoring and sustainable forest management. Various studies have demonstrated the ability to estimate canopy height from a single spaceborne multispectral image using end-to-end learning techniques. In addition to texture information of a single-shot image, our study exploits multitemporal information of image sequences to improve estimation accuracy. We adopt a convolutional variant of a long short-term memory (LSTM) model for canopy height estimation from multitemporal instances of Sentinel-2 products. Furthermore, we utilize the deep ensembles technique for meaningful uncertainty estimation on the predictions and postprocessing isotonic regression model for calibrating them. Our lightweight model (${\sim }320{\mathrm {k}}$ trainable parameters) achieves the mean absolute error (MAE) of $1.29 ~{\mathrm {m}}$ in a European test area of $79 ~{\mathrm {km}}^{2}$. It outperforms the state-of-the-art methods based on single-shot spaceborne images as well as costly airborne images while providing additional confidence maps that are shown to be well calibrated. Moreover, the trained model is shown to be transferable in a different country of Europe using a fine-tuning area of as low as ${\sim }2 ~{\mathrm {km}}^{2}$ with ${\mathrm {MAE}}=1.94 {\mathrm {m}}$. [ABSTRACT FROM AUTHOR]

Protection and appropriate management of forests is one of the key instruments for climate change adaptation. Soil amendments with biochar have shown to be promising in achieving this goal; however, the evaluation of its long-term effects on forest soils has largely been neglected. To assess the advantages and drawbacks of biochar in forest soils, data from relict charcoal hearths (RCH) can be a potent tool as they show changes in soil properties after up to several hundred years. RCHs can be found in places of former metallurgical hot spots and their presence leaves characteristic formations identifiable on a large scale using laser detection technologies. Forest soils with biochar amendment show an increase in base cations, shift towards more alkaline pH, smaller bulk density and seem to be especially beneficial to hostile environments. Sites with favourable conditions may show little to no improvement or may even be adversely affected. Still, with proper investigation, areas with affordable feedstock materials and poor forest soils—such as spruce monocultures of Central Europe—may benefit from biochar amendments and continue to do so in the long term. [ABSTRACT FROM AUTHOR]

Private forest owners are the main forest ownership group within Europe, and important conservation values have been found on their land. Yet, small plot sizes, societal heterogeneity, and structural changes impede developing and implementing effective conservation programs in private forests. We present a systematic literature review focusing on small-scale private forest owners and their perspectives on nature conservation by synthesizing research approaches, social-ecological drivers, and policy recommendations. Conservation perspectives were positively related to female gender, higher levels of education, formalized forest management, an active relation to the forest, and ecological values of the property. In contrast, high age, rural orientation, economic forest management factors, large parcel size, and economic and sentimental property values negatively influenced conservation perspectives. Applying a natural resource conflict management framework, we synthesized recommendations covering three dimensions: substance, procedure, relationship. Considering perspectives of small-scale private forest owners in current forestry decision-making has great potential to strengthen sustainable forest management that integrates nature conservation and resource use. [ABSTRACT FROM AUTHOR]

Microclimatic conditions in forests depend on canopy cover and thus differ between closed and open forests and similarly change along the vertical axis from the forest floor to the upper canopy. Yet, it is unknown whether this similarity in microclimatic conditions in forest gaps and the upper canopy provides equivalent habitats for wood-inhabiting species assemblages and thus, whether deadwood in the canopy is needed to maintain biodiversity. We tested this question for wood-inhabiting beetles, fungi and bacteria, using 150 branch bundles of Picea abies , Abies alba and Fagus sylvatica experimentally exposed along a vertical and horizontal gradient in microclimate: sun-exposed in the upper canopy and in gaps, half-shaded in the mid canopy and at the edge of forest gaps and shaded near ground under a closed canopy in a temperate forest in Central Europe. Variation partitioning showed that assemblage composition of all taxa was predominantly determined by tree species, followed by vertical stratum in beetles. Beetle assemblages at upper and mid-canopy formed a distinct community compared to those near ground. Fungal assemblages in the upper canopy were similar to those in gaps near the ground, while bacteria assemblages in the upper canopy were different only from those near ground under closed canopy. Our results indicate that the canopy stratum and sun-exposed deadwood enlarge the niche space for saproxylic organisms. Conservation strategies should thus aim at retaining habitat trees of different tree species with deadwood in the canopy as well as gaps with sun-exposed deadwood, e.g., after disturbances, to maintain biodiversity. [ABSTRACT FROM AUTHOR]

Deadwood is a key old-growth element in European forests and a cornerstone of biodiversity conservation practices in the region, recognized as an important indicator of sustainable forest management. Despite its importance as a legacy element for biodiversity, uncertainties remain on the drivers of deadwood potentials, its spatial distribution in European forests and how it may change in the future due to management and climate change. To fill this gap, we combined a comprehensive deadwood dataset to fit a machine learning and a Bayesian hurdle-lognormal model against multiple environmental and socio-economic predictors. We deployed the models on the gridded predictors to forecast changes in deadwood volumes in Europe under alternative climate (RCP4.5 and RCP8.5) and management scenarios (biodiversity-oriented and production-oriented strategies). Our results show deadwood hotspots in montane forests of central Europe and unmanaged forests in Scandinavia. Future climate conditions may reduce deadwood potentials up to 13% under a mid-century climate, with regional losses amounting to up to 22% in Southern Europe. Nevertheless, changes in management towards more biodiversity-oriented strategies, including an increase in the share of mixed forests and extended rotation lengths, may mitigate this loss to a 4% reduction in deadwood potentials. We conclude that adaptive management can promote deadwood under changing environmental conditions and thereby support habitat maintenance and forest multifunctionality. [Display omitted] • We combine remote sensing and field observations to fit deadwood potential models. • We assess the drivers of deadwood potentials and upscale deadwood estimates. • Climate effects will alter deadwood distribution in European forests. • Forest management may partially counterbalance habitat loss under climate change. [ABSTRACT FROM AUTHOR]

Wind power is one of the fastest growing renewable energy sectors and plays a focal role in the transition to a fossil fuel free society in Europe. Technological developments have enabled the construction of turbines within forested areas, which has raised concerns regarding the audio-visual impact on these landscapes. However, there is a paucity of research with regard to the role that forests may play in mitigating the negative impacts of wind farms. In this study, we created a simplified model for noise attenuation based on the ISO 9613-2 and Nord2000 noise models and a visibility model which both relates the audio-visual effect to forest stand structure and applied them in the GIS environment. Our findings suggest that forests can act as effective noise barriers, with the sound attenuation level dependent on the distance that sound travels through the forest, as well as the size and density of the trees. However, in the case of a high elevation sound source (such as wind turbines), the forest begins to act as a noise shield from a distance of between 500 and 1500 m, depending on the height of the forest and the land topography. While current noise models do not consider the impact of tree species, our visibility model accounts for tree size, density and species, as well as understorey and thinning. Our results indicate that spruce trees provide a better visual constraint whereas visibility distances within mature Calluna -type pine forests tend to be more extensive. Both models include variables that can be adjusted by forest management, thereby allowing integration with forest planning software. Overall, this study presents indicative methods for the evaluation of potential forest landscape shields, a concept that could have broad applications, including Landscape Value Trading. • Forest can potentially provide additional noise attenuation of up to 10 dB. • Forest stands can serve as landscape shields effectively reducing visual disturbances. • Integrating noise and visibility models into forest management planning is feasible. [ABSTRACT FROM AUTHOR]

Non‐native tree species (NNT) are used in European forestry for many purposes including their growth performance, valuable timber, and resistance to drought and pest or pathogen damage. Yet, cultivating NNT may pose risks to biodiversity, ecosystem functioning, and the provisioning of ecosystem services, and several NNT have been classified as invasive in Europe. Typically, such classifications are based on risk assessments, which do not adequately consider site‐specific variations in impacts of the NNT or the extent of affected areas. Here, we present a new methodological framework that facilitates both mitigating risks associated with NNT and taking advantage of their ecosystem services. The framework is based on a stratified assessment of risks posed by NNT which distinguishes between different sites and considers effectiveness of available management strategies to control negative effects. The method can be applied to NNT that already occur in a given area or those NNT that may establish in future. The framework consists of eight steps and is partly based on existing knowledge. If adequate site‐specific knowledge on NNT does not yet exist, new evidence on the risks should be obtained, for example, by collecting and analyzing monitoring data or modeling the potential distribution of NNT. However, limitations remain in the application of this method, and we propose several policy and management recommendations which are required to improve the responsible use of NNT. [ABSTRACT FROM AUTHOR]

Forests in Europe are currently not endangered by soil erosion. However, this can change with climate change or with intensified forest management practices. Using a newly established network of plots in beech forests across Europe, the aims of this study were to (i) distinguish soil properties and erodibility indices in relation to bedrock, (ii) determine geochemical properties and organic carbon (Corg) influencing erodibility, and (iii) assess the effect of soil depth on erodibility indices. Seventy-six soil samples from 20 beech forests were collected in 11 countries to quantify soil properties influencing erodibility indices: clay ratio, modified clay ratio, sodium adsorption ratio, and oxides ratio. The results indicate that the dominant soil properties, determined by bedrock, that correlate with forest soil erodibility indices are Corg, pH, electrical conductivity, calcium and sodium ions concentrations, total water-soluble cations, and the percentage of sand. According to the tested indices, soil susceptibility to erosion follows the order granite > andesite > sandstone > quartzite > limestone. Deeper soil horizons on granite are more susceptible to erosion than surface horizons are, but this is not the case for soils on limestones. In conclusion, forest management should consider the predisposition of different soil types to erosion. [ABSTRACT FROM AUTHOR]

The increasing demand for innovative forest management strategies to adapt to and mitigate climate change and benefit forest production, the so-called Climate-Smart Forestry, calls for a tool to monitor and evaluate their implementation and their effects on forest development over time. The pan-European set of criteria and indicators for sustainable forest management is considered one of the most important tools for assessing many aspects of forest management and sustainability. This study offers an analytical approach to selecting a subset of indicators to support the implementation of Climate-Smart Forestry. Based on a literature review and the analytical hierarchical approach, 10 indicators were selected to assess, in particular, mitigation and adaptation. These indicators were used to assess the state of the Climate-Smart Forestry trend in Europe from 1990 to 2015 using data from the reports on the State of Europe's Forests. Forest damage, tree species composition, and carbon stock were the most important indicators. Though the trend was overall positive with regard to adaptation and mitigation, its evaluation was partly hindered by the lack of data. We advocate for increased efforts to harmonize international reporting and for further integrating the goals of Climate-Smart Forestry into national- and European-level forest policy making. [ABSTRACT FROM AUTHOR]

The potential of forest nature reserves as refuges for biodiversity seems to be overlooked probably due to their small size. These, however, may constitute important safe havens for saproxylic organisms since forest reserves are relatively numerous in Europe. Saproxylic beetles are among the key groups for the assessment of biodiversity in forest habitats and longhorn beetles may play an important role in bioindication as they are ecologically associated with various microhabitats and considered a very heterogeneous family of insects. To study the role of forest reserves as important habitats for saproxylic beetles, we compared cerambycid assemblages in corresponding pairs of sites (nature reserves and managed stands) in a forest region under high anthropogenic pressure (Upper Silesia, Poland, Central Europe). Moreover, we also intended to assess the role played by these beetles as bioindicators in the different forest types from this area. According to the obtained diversity index values, the most valuable stands are located in nature reserves, whilst sites with the lowest value included managed forests together with two homogeneous and relatively recently established nature reserves. Our analyses demonstrated a positive correlation between deadwood volume and biodiversity, for both species richness and abundance. Our results indicate that the decisive factor is the type of a given habitat, whose characteristics can be mainly influenced/determined by forest management. The potential role of longhorn beetles as bioindicators is highlighted and the effectiveness of using traps in this family, as well as general issues regarding the use of non-selective lethal traps in the study of single invertebrate groups in protected areas are discussed. [ABSTRACT FROM AUTHOR]

Global forests are the main component of the land carbon sink, which acts as a partial buffer to CO 2 emissions into the atmosphere. Dynamic vegetation models offer an approach to projecting the development of forest carbon sink capacity in a future climate. Forest management capabilities are important to include in dynamic vegetation models to account for the effects of age and species structure and wood harvest on carbon stocks and carbon storage potential. This article describes the implementation of a forest management module containing even-age and clear-cut and uneven-age and continuous-cover management alternatives in the dynamic vegetation model LPJ-GUESS. Different age and species structure initialisation strategies and harvest alternatives are introduced. The model is applied at stand and European scales. Different management alternatives are applied in simulations of European beech (Fagus sylvaticus) and Norway spruce (Picea abies) even-aged monoculture stands in central Europe and evaluated against above-ground standing stem volume and harvested volume data from long-term experimental plots. At the European scale, an automated thinning and clear-cut strategy is applied. Modelled carbon stocks and fluxes are evaluated against reported data at the continent and country levels. Including wood harvest in regrowth forests increases the simulated total European carbon sink by 32 % in 1991–2015 and improves the fit to the reported European carbon sink, growing stock, and net annual increment (NAI). Growing stock (156 m 3 ha -1) and NAI (5.4 m 3 ha 1 yr 1) densities in 2010 are close to reported values, while the carbon sink density in 2000–2007 (0.085 kg C m -2 yr 1) equates to 63 % of reported values, most likely reflecting uncertainties in carbon fluxes from soil given the unaccounted for forest land-use history in the simulations. The fit of modelled and reported values for individual European countries varies, but NAI is generally closer to reported values when including wood harvest in simulations. [ABSTRACT FROM AUTHOR]

Since the end of the 18th century Scots pine (Pinus sylvestris) monocultures have been artificially introduced in extensive areas of rusty soils in Central Europe. Such forest management practice has involved, however, several serious problems, like e.g. soil degradation implying the decrease in productivity of forest sites, and the clear increase in the risk of disturbances (pest gradations, fi res, wind damages etc.) occurrence. Those troubles have involved the increasing discussion on rational forest management on sandy soils, which are predominant in lowland woodlands of Central Europe. Thus, in this paper we aimed to indicate selected problems of sustainable management of rusty soils in forestry with regard to lowland forests found in the region. The special focus was paid on controversies being related to conversion of pine stands overgrowing these soils, because of its especially high importance for forest management in Central Europe. We postulate that we should intensify the conversion of pure pine stands overgrowing rusty soils into mixed forests, which would reduce the risk of the assumed, and being involved with the ongoing climate changes, problems with the stability of pine forests in Central Europe. The study shows that the current methodology of forest site types diagnosis used in Poland may lead to underestimation of the types, and consequently it consolidates the focus of Polish forestry on breeding pine stands on rusty soils. Following the existing controversies regarding the diagnosis of a forest site type on rusty soils, we postulate that we should more broadly underplant pine stands overgrowing the soils with deciduous trees, regardless of the diagnosed forest site type in forest inventory works. In turn, in conversions executed in maturing conifer stands using a gap cutting, the emphasis should be put on plant diversity. Namely, we highlight in the paper that in the gaps, besides major deciduous species (usually oak and/or beech), the admixture of ameliorative trees should obligatory be introduced (e.g. European hornbeam, Carpinus betulus), which happens to be ignored in practice. We postulate also that logging residues removal, which is still executed in some forest districts in Poland, should be skipped. This practice is especially irrational when it is done in sites dedicated for stand conversion, because it highly increases the risk of mortality and/or of the distinct decrease in growth dynamics of young hardwoods introduced in post-pine sites. [ABSTRACT FROM AUTHOR]

The abandonment of historical land‐use forms within forests, such as grazing or coppicing, and atmospheric nitrogen deposition, has led to an increasing overgrowth of forest gaps and canopy closure in forest ecosystems of Central Europe. From 1945 to 2015, 81% of the forest gaps greater than 150 m2 within the study area transitioned into a closed forest.This study investigated how the overgrowth process affects flower supply, flower visitors, and reproduction of Campanula species. Six native Campanula species with different light requirements were used as phytometers.The forest gaps in the studied area are a feature of the historical European cultural landscape. We compared large gaps caused by human activities, small gaps caused by habitat conditions, and closed forests. In eight blocked replicates, each with the three habitat categories, we recorded the flower cover and number of indigenous flowering species in the immediate surroundings, and, of six Campanula species, flower visitors and seed production.Forest gaps and their size positively affected the number of flowering plant species in the surrounding area, the number of all flower visitor groups, and the number of seeds produced by all six Campanula species. Flower cover in the surrounding area was higher in large gaps, but there was no difference between small gaps and closed forests. Among flower visitors, small bees varied the most between the three habitat categories, and flies varied the least. The effect on the number of seeds produced was particularly strong for three light‐demanding Campanula species.The overgrowth of forest gaps negatively affected flower supply, flower‐visiting insects, and seed sets of six Campanula species. Forest gaps should be managed to maintain the reproduction of open forest plants and their pollinators. [ABSTRACT FROM AUTHOR]

Schall et al. (2020) assessed how a combination of different forest management systems in managed forest landscapes dominated by European beech may affect the biodiversity (alpha, beta and gamma) of 14 taxonomic groups. Current forest policy and nature conservation often demand for combining uneven‐aged managed and unmanaged, set‐aside for nature conservation, beech forests in order to promote biodiversity. In contrast to this, Schall et al. (2020) found even‐aged shelterwood forests, represented by different developmental phases, to support highest regional (gamma) diversity.By pointing out that unmanaged forests included in our study are not old‐growth forests, Bruun and Heilmann‐Clausen (2021) challenge our conclusion as not providing sound scientific advice to societies. It is true that the studied unmanaged forests are not representing old‐growth forests as defined in the literature. However, we demonstrate the representativeness of our unmanaged forests for current beech forest landscapes of Central Europe, where managed forests were more or less recently set‐aside in order to develop old‐growth structures. We also show that the managed and recently unmanaged forests in our study already differ distinctively in their forest structures.We use this response to stress the role of forest reserves for promoting certain species groups, and to emphasise their importance as valuable research sites today and in the future.Synthesis and applications. We see two main conclusions from our study. First, unmanaged forests still matter. We agree with Bruun and Heilmann‐Clausen (2021) on the general importance of unmanaged, old‐growth or long‐untouched forests, and we do not question the importance of set‐aside forests for biodiversity conservation. However, a complete complementarity to managed systems may only reveal after many decades of natural development. Second, safeguarding biodiversity in largely managed forest landscapes should focus on providing a landscape matrix of different developmental phases with varying environmental conditions rather than on maximising the vertical structure within stands. Such landscapes can partly compensate for structures that are still missing in vital, dense and closed forests recently set‐aside or for unsuitable phases that may occur due to a cyclic synchronisation of forest structures in unmanaged forests. [ABSTRACT FROM AUTHOR]

Questions: Primary forests fulfil important roles in preserving biodiversity, storing carbon and increasing ecological understanding. Yet, they have become very rare in Europe. An important policy goal is thus to increase the share of naturally developing forests by creating protected areas in formerly managed forests. Here, we investigated: (a) if and how such forests return to conditions similar to old-growth; and (b) whether recently observed stand-replacing natural disturbances in combination with climate change set them onto an alternative developmental pathway. Location: Dürrenstein Wilderness Area (IUCN Cat. Ib) in the Austrian Alps, containing the Rothwald, one of the last primary forest remnants of Central Europe. Methods: We built a chronosequence of 87 plots, spanning 220 years of forest development after the cessation of management, and compared them to old-growth forests. We analysed the recovery of nine attributes of forest composition, structure and functioning. To evaluate stand-level development of these attributes after recent natural disturbance and climate change, we additionally used a process-based simulation model. Results: Old-growth forests showed a wide range of variability across investigated attributes. Forests converged to old-growth conditions after management ceased, with seven out of the nine attributes falling within the range of old-growth at the end of our chronosequence. The variation in tree diameters and the downed amount of deadwood were, however, still significantly lower than in old-growth forests after 220 years of unmanaged stand development. Simulations did not indicate an alternative developmental pathway of recently disturbed stands. Conclusions: While a full return to old-growth conditions can take centuries, a number of important forest attributes recover quickly, indicating that protecting formerly managed forests is a valuable strategy to enrich forest landscapes. Our results indicate that the mountain forests of Central Europe have high ecological resilience, developing towards old-growth conditions after both past management and current natural disturbance. [ABSTRACT FROM AUTHOR]

Although native to Australia, Eucalyptus species are found throughout Europe. At present, they are located mainly in the Iberian Peninsula and Eucalyptus globulus is the most commonly planted species. Climate forecasts anticipate an expansion of Eucalyptus to other regions of Europe. The fast growth of E. globulus, together with its resprouting ability and wood properties, has promoted the use of this species in the Iberian Peninsula. The total volume of E. globulus harvested there was close to 14 million m3 in 2019. Eucalyptus species represent the main source of raw material for the pulp and paper industries and provide an important source of income to non-industrial owners. Being exotic fast-growing trees, their expansion has also been associated with negative environmental impacts. The species therefore poses a series of challenges, while also generating opportunities. The objectives of this review paper are: (1) to summarize the importance of Eucalyptus plantations in Europe; (2) to analyse the opportunities and challenges of this genus in present and future plantations in Europe; (3) to assess to what extent forest management, at both stand and landscape levels, can reduce negative impacts; (4) to make policy and management recommendations that may support the use of this genus in other European regions. These aims are accomplished based on a thorough literature review, particularly focused on research developed in the Iberian Peninsula. [ABSTRACT FROM AUTHOR]

Robinia pseudoacacia is one of the most frequent non‐native species in Europe. It is a fast‐growing tree of high economic and cultural importance. On the other hand, it is an invasive species, causing changes in soil chemistry and light regime, and consequently altering the plant communities. Previously published models developed for the potential distribution of R. pseudoacacia concerned 2070, and were based mainly on data from Western and Central Europe; here we extended these findings and included additional data from Eastern Europe. To fill the gap in current knowledge of R. pseudoacacia distribution and improve the reliability of forecasts, we aimed to (i) determine the extent to which the outcome of range modeling will be affected by complementing R. pseudoacacia occurrence data with sites from Central, Southeastern, and Eastern Europe, (ii) identify and quantify the changes in the availability of climate niches for 2050 and 2070, and discuss their impacts on forest management and nature conservation. We showed that the majority of the range changes expected in 2070 will occur as early as 2050. In comparison to previous studies, we demonstrated a greater eastward shift of potential niches of this species and a greater decline of potential niches in Southern Europe. Consequently, future climatic conditions will likely favor the occurrence of R. pseudoacacia in Central and Northeastern Europe where this species is still absent or relatively rare. There, controlling the spread of R. pseudoacacia will require monitoring sources of invasion in the landscape and reducing the occurrence of this species. The expected effects of climate change will likely be observed 20 years earlier than previously forecasted. Hence we highlighted the urgent need for acceleration of policies aimed at climate change mitigation in Europe. Also, our results showed the need for using more complete distribution data to analyze potential niche models. [ABSTRACT FROM AUTHOR]

Global forests are the main component of the land carbon sink, which acts as a partial buffer to CO2 emissions into the atmosphere. Dynamic vegetation models offer an approach to making projections of the development of forest carbon sink capacity in a future climate. Forest management capabilities in dynamic vegetation models are important to include the effects of age and species structure and wood harvest on carbon stocks and carbon storage potential. This article describes the introduction of a forest management module in the dynamic vegetation model LPJ-GUESS. Different age- and species-structure setup strategies and harvest alternatives are introduced. The model is used to represent current European forests and an automated harvest strategy is applied. Modelled carbon stocks and fluxes are evaluated against observed data at the continent and country levels. Including wood harvest in simulations increases the total European carbon sink by 32 % in 1991-2015 and improves the fit to the reported European carbon sink, growing stock and net annual increment (NAI). Growing stock (156 m³ha-1) and NAI (5.4 m³ ha-1 y-1) densities in 2010 are close to reported values, while the carbon sink density in 2000-2007 (0.085 kgC m-2 y-1) is 63 % of reported values. The fit of modelled values and observations for individual European countries vary, but NAI is generally closer to observations when including wood harvest in simulations. [ABSTRACT FROM AUTHOR]