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• Primary production was estimated by using indices (EVI and NDWI) derived by MODIS. • We perform an ex-ante and ex-post analysis of a fire disturbance in a wetland. • EVI and NDWI time series show a similar trend before and after the fire. • After the fire EVI and NDWI are positive correlated. • There is no correlation between indices and climatic data (temperature and precipitation) Fire disturbance is an intrinsic component of the Mediterranean biome playing an important role in ecosystem dynamics and processes. However, frequent and severe anthropogenic wildfires can be detrimental to natural ecosystems, particularly in small natural protected areas, where they may hamper the flow of ecosystem services (ES). While post-fire dynamics of individual ES are heavily context-dependent, the primary productivity of the ecosystem can be regarded as a generic driver of several provisioning and regulating ES, as it represents the amount of energy available to plants for storage, growth, and reproduction, which drives future ecosystem structure and functions. The aim of this study was to evaluate the effect of anthropogenic wildfire on the primary productivity of a rare wetland ecosystem in the Natura 2000 site "Torre Guaceto" in Southern Europe. Productivity was estimated by calculating a 15-year time series of vegetation indices (EVI and NDWI) from remotely sensed MODIS imagery. Our results in terms of PP trends may be relevant to assess the change in ecosystems services provided by wetlands. Interactions between wildfire, ecosystem productivity and climate were then analyzed. During the selected period, climate did not play a significant effect on primary productivity, which was mainly driven by post-fire vegetation recovery. Findings of the present study demonstrate that the wildfire affecting the Natural Protected Area of Torre Guaceto in summer 2007 had a major effect on primary productivity, inducing the regeneration of Phragmites australis and the replacement of old individuals by structurally and functionally better ones. [ABSTRACT FROM AUTHOR]

Highlights • Cone production is synchronised between trees, but dominated by "super-producers". • Cone and seed production show no long-term temporal trend despite strong regional warming. • Radial growth is lower in mast years that coincide with unfavourable climate (cool summer temperature). • Growth reductions in mast years are restricted to "super-producers". Abstract Tree growth and reproduction are subject to trade-offs in resource allocation. At the same time, they are both influenced by climate. In this study, we combined long records of reproductive effort at the individual- (29 years), population- (41 years) and regional (up to 53 years) scale, and tree ring chronologies, to investigate the effects of climate and reproductive allocation on radial growth in an Alpine Norway spruce forest. Seed and cone production was highly variable between years (mean individual CV = 1.39, population CV = 1.19), but showed high reproductive synchrony between individuals (mean inter-tree correlation = 0.72). No long-term trend in reproductive effort was detected over four decades of observations. At the stand scale, cone production was dominated by a small number of individuals ("super-producers"), who remained dominant over three decades. Individual tree growth responded positively to summer temperature, but the response to cone production varied between individual trees. Consequently, we found some evidence that mast years were associated with a divergence in growth between high and low cone producing individuals, and a decline in within-population growth synchrony. At the population level we found limited evidence of a relationship between growth and reproduction. Radial growth was lower than average in some mast years, but not in others. This was partly explained by summer temperature during the year of growth, with growth reductions restricted to mast years that coincided with colder than average summers. Regional mast records and tree ring chronologies provided some support to indicate that our results were consistent in other spruce stands, although the effect of mast years on growth appeared to vary between sites. Tree ring variation at the individual and population level, and between-tree growth synchrony are influenced by masting, and consequently dendrochronologists should consider both the occurrence of masting and the individual differences in reproductive effort when interpreting tree ring datasets. Our results also indicate that tree ring chronologies contain information to facilitate reconstruction of mast events, which will help address outstanding questions regarding the future response of masting to climate change. [ABSTRACT FROM AUTHOR]

Masting is the highly variable and synchronous production of seeds by plants. Masting can have cascading effects on plant population dynamics and forest properties such as tree growth, carbon stocks, regeneration, nutrient cycling, or future species composition. However, masting has often been missing from forest models. Those few that simulate masting have done so using relatively simple empirical rules, and lack an implementation of process-based mechanisms that control such events. Here we review more than 200 published papers on mechanistic formulations of masting, and summarize how the main processes involved in masting and their related patterns can be incorporated in forest models at different degrees of complexity. Our review showed that, of all proximate causes of masting, resource acquisition, storage and allocation were the processes studied most often. Hormonal and genetic regulation of bud formation, floral induction, and anthesis were less frequently addressed. We outline the building blocks of a general process-based model of masting that can be used to improve the oversimplified functions in different types of forest models, and to implement them where missing. A complete implementation of masting in forest models should include functions for resource allocation and depletion, and for pollination, as regulated by both forest structure and weather in the years prior to seed production. When models operate at spatio-temporal scales mismatched with the main masting processes, or if calibration data are not available, simulation can be based on parameterizing masting patterns (variability, synchrony, or frequency). Also, observed masting patterns have the potential to be used as “reality checks” for more process-based forest models wishing to accurately reproduce masting as an emergent phenomenon. [ABSTRACT FROM AUTHOR]

Beech forests are important for biodiversity conservation in Europe and studies to identify sustainable forest management practices are therefore required. The ground beetle Carabus olympiae Sella, 1855, is a large steno-endemic endangered alpine species with very restricted ranges. Its known range is only delimited in two beech forests in the western Italian Alps where beech wood is still harvested. Forty individuals were collected and radio-tracked in 2014–2015 in order to assess the effects of forest management on microclimatic conditions, microhabitat use and movements. Regarding microhabitat selection deadwood and tree bases were preferred, and were used as refuges during the daytime. Bare ground was not used. The length of the path travelled by individual insects was more variable and the tortuosity was lower in managed than in unmanaged stands, suggesting that management induced more constrained trajectories and variable distances. We concluded that logging may exert short-term negative effects on C. olympiae ground beetles. However, the preference for tree bases and deadwood suggests that forest management, concurrently, may also be beneficial, on the condition that: i) the coppice, which provides more suitable microhabitats, prevails over conversion to high forest, and ii) deadwood originating from cutting (branches and treetops) is properly accumulated. [ABSTRACT FROM AUTHOR]

Interest in coppices is growing due to the need to replace fossil fuels with renewable energy sources. In Italy, beech covers one million hectares, half of which originated by coppicing. This study tested which factors drive the presence and growth of beech resprouts, with a focus on fertility, cutting intensity, age, and size at time of coppicing. We analyzed 509 stools in 24 stands coppiced between 1 and 26 years before sampling. We fitted Generalized Linear Mixed Models of the probability of sprouting and height of the tallest resprout for each stool as a function of elevation, slope, aspect, bedrock, precipitation, temperature, age at coppicing, time since coppicing, residual shoot density, the sum, average and coefficient of variation of the diameter of cut shoots, and type of stool treatment. Of all harvested stools, 249 (49%) had sprouted with an average of 7.6 resprouts per stool. Height of the tallest resprout on each stool ranged from 3 to 800 cm, mainly as a function of time since coppicing. Resprout mortality was on average 1.4% per plot. Sprouting decreased with decreasing site fertility, increasing precipitation, and increasing size of cut stems. Leaving one or more shoots on the stool after felling produced a high proportion of sprouting stools (82%). Although based on a limited sample, our quantitative analysis of the driving factors of sprouting in beech can be used to support silvicultural decisions in over-mature beech coppices, and to optimize trade-offs between ecosystem services such as biomass production, biodiversity, and hydro-geologic protection. [ABSTRACT FROM AUTHOR]

Biomass and leaf area equations are often required to assess or model forest productivity, carbon stocks and other ecosystem services. These factors are influenced by climate, age and stand structural attributes including stand density and tree species diversity or species composition. However, such covariates are rarely included in biomass and leaf area equations. We reviewed the literature and built a database of biomass and leaf area equations for 24 European tree species and 3 introduced species. The final dataset contained 973 equations. Most of the equations were site-specific and therefore restricted to the edaphic, climatic and stand structural conditions of the given site. To overcome this limitation, the database was used to develop regional species-specific equations that can be used in a wide range of stands and to quantify the effects of climate, age and stand structure on biomass or leaf area. The analysis showed considerable inter- and intra-specific variability in biomass relationships. The intra-specific variability was related to climate, age or stand characteristics, while the inter-specific variability was correlated with traits such as wood density, specific leaf area and shade tolerance. The analysis also showed that foliage mass is more variable than stem or total aboveground biomass, both within and between species, and these biomass components have contrasting responses to age and changes in stand structure. Despite the large number of published equations, many species are still not well represented. Therefore, generic equations were developed that include species-specific wood density instead of species identity. Further improvements may be possible if future studies quantify the stand structure of individual tree neighbourhoods instead of using the stand means for all trees sampled with the given stand. [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]

Mountain forests are among the most important ecosystems in Europe as they support numerous ecological, hydrological, climatic, social, and economic functions. They are unique relatively natural ecosystems consisting of long-lived species in an otherwise densely populated human landscape. Despite this, centuries of intensive forest management in many of these forests have eclipsed evidence of natural processes, especially the role of disturbances in long-term forest dynamics. Recent trends of land abandonment and establishment of protected forests have coincided with a growing interest in managing forests in more natural states. At the same time, the importance of past disturbances highlighted in an emerging body of literature, and recent increasing disturbances due to climate change are challenging long-held views of dynamics in these ecosystems. Here, we synthesize aspects of this Special Issue on the ecology of mountain forest ecosystems in Europe in the context of broader discussions in the field, to present a new perspective on these ecosystems and their natural disturbance regimes. Most mountain forests in Europe, for which long-term data are available, show a strong and long-term effect of not only human land use but also of natural disturbances that vary by orders of magnitude in size and frequency. Although these disturbances may kill many trees, the forests themselves have not been threatened. The relative importance of natural disturbances, land use, and climate change for ecosystem dynamics varies across space and time. Across the continent, changing climate and land use are altering forest cover, forest structure, tree demography, and natural disturbances, including fires, insect outbreaks, avalanches, and wind disturbances. Projected continued increases in forest area and biomass along with continued warming are likely to further promote forest disturbances. Episodic disturbances may foster ecosystem adaptation to the effects of ongoing and future climatic change. Increasing disturbances, along with trends of less intense land use, will promote further increases in coarse woody debris, with cascading positive effects on biodiversity, edaphic conditions, biogeochemical cycles, and increased heterogeneity across a range of spatial scales. Together, this may translate to disturbance-mediated resilience of forest landscapes and increased biodiversity, as long as climate and disturbance regimes remain within the tolerance of relevant species. Understanding ecological variability, even imperfectly, is integral to anticipating vulnerabilities and promoting ecological resilience, especially under growing uncertainty. Allowing some forests to be shaped by natural processes may be congruent with multiple goals of forest management, even in densely settled and developed countries. [ABSTRACT FROM AUTHOR]

Alluvial forests with black alder are a priority conservation habitat in Europe. In the Po plain, black alder is traditionally managed by coppicing with frequent rotations. This study aims to ascertain whether such management is compatible with habitat conservation, by measuring the effect of time since coppicing on forest structure and plant species composition across different layers. We compared the effects of three treatments, each thrice replicated: recent (10–20 years), medium (20–30 years) and old coppice (>40 years). In all nine stands we measured basal area, tree and regeneration density, mean tree diameter and height, dominance by alder, species richness, Shannon diversity, and the number of ruderal and non-native species. Significant differences in dendrometric variables, species richness, diversity, and percent cover by chorotype were assessed for treatment effects by two-way ANOVA. Frequently coppiced stands had a lower basal area, mean tree size, and volume, a more simplified vertical structure, a lower cover of the herbaceous layer and higher bare soil cover due to harvesting disturbance, a significantly lower cover by typical woodland Fraxinetalia species, and a significantly higher frequency and cover of non-native species. Our study showed that frequent coppicing worsened the conservation status of black alder forests in the study area, simplified stand structure, deteriorated species composition, and increased the spread of non-native and ruderal plant species. Such negative effects persisted even 20–30 years after cutting. We recommend amending the current legislation and introducing mandatory Implications Assessment procedures everywhere alder forests are susceptible to be impacted in a similarly negative way. [ABSTRACT FROM AUTHOR]

The fire ecology of European beech ( Fagus sylvatica L.) is poorly understood. We analyzed beech recruitment after a mast year in recently burnt and unburnt stands to answer to the questions: (i) Does post-fire mast seed production and recruitment in beech depend on fire severity, and (ii) which are the processes by which fire and the environment affect beech seed production, germination and seedling emergence and establishment in the first year after masting? We selected three beech stands in the Southwestern Alps, burnt in either the winter of 2012 or 2013 but before the 2013 beech mast year. In the summer of 2013, at each stand, we established 30 sampling plots stratified by fire severity based on the percent basal area loss of beech (low; intermediate; high). Another 10 plots per stand were assigned to a control (unburnt) group. In the spring of 2014, we counted cupules, seeds, germinated seeds, and emergent seedlings (i.e., rooted in mineral soil) in four squares (0.4 × 0.4 m) at each plot. In the summer of 2014, at each plot, we measured stand characteristics (i.e., a circular area of 12-m in a planar radius) and counted established seedlings in 12 squares (1 × 1 m). Control stands had 448 ± 38 cupules m −2 and 489 ± 44 seeds m −2 with a germination rate of 11%. In comparison to the control, production of cupules and seeds was significantly lower only under high fire severity (−75% and −63%, respectively). At intermediate and low severity sites, cupule and seed production were similar to unburnt sites, while seed germination and seedling emergence were higher. At intermediate severity sites established seedlings (86,000 ± 10,574 seedlings ha −1 ) were significantly more frequent than the control. Generalized linear and additive models demonstrated that intermediate disturbance of litter and canopy cover favored beech regeneration. Mixed severity fires are an important ecological factor for the natural regeneration of beech. Such insights in beech disturbance ecology can help improve silviculture and post-fire restoration of Alpine forests. The synergy between fire and masting raises new questions concerning the role of fire in temperate beech forests. [ABSTRACT FROM AUTHOR]

Mountain forests provide important ecosystem services, such as protection against natural hazards, carbon sequestration, and plant and animal biodiversity. Natural disturbances occurring in forests can alter the provision of ecosystem services to local and offsite communities, but their influence on multiple service tradeoffs has rarely been analyzed. Our aim is to analyze the effect of avalanche frequency on the provision of ecosystem services in a mountain forest in the Italian Alps. We sampled tree and understory vegetation, soil carbon, and intensity of the browsing damage at 10 plots at each of the following observation sites: (1) an active avalanche track (“recent disturbance”), (2) an area last disturbed in 1959 by avalanches (“old disturbance”), occupied now by a dense aspen forest, and (3) the regularly managed spruce–fir stand (“control”). We computed metrics of plant diversity (Shannon and evenness indices), aboveground and belowground carbon stocks, and a browsing index on regeneration and shrubs as a proxy for ungulate habitat. Finally, we assessed the ability of forests in each site to mitigate rockfall hazard. In our study, higher avalanche frequency was associated with lower carbon stock, higher species diversity, and lower protection against rockfall. Of all species found in the avalanche track, 54% were exclusive to that site. After 50 years, the post-disturbance stand provided a very high protection effect against rockfall, but was temporarily unsuitable for wild ungulate habitat, due to the high tree density and lack of open areas. Species richness and diversity were lower in older than in more recently disturbed sites, and not significantly different than the control stand. The control stand fulfilled the requirements for minimal protection against rockfall, but may lose its effectiveness in the near future due to senescence or disturbance-related mortality of canopy trees. Elucidating the tradeoffs between ecosystem services and disturbance frequency will support managers in planning management actions (e.g., avalanche protection measures), and assess tradeoffs between the need to mitigate risks in the most vulnerable areas and the opportunity to improve the provision of ecosystem services where some disturbance can be allowed to occur. [ABSTRACT FROM AUTHOR]

European beech forests are of particular importance for biodiversity, although relatively little is known about how beech forest management impacts on invertebrate communities. In this paper we investigated the influence of beech forest management history [i.e. over-mature coppices (OC) and coppices in conversion to high forests (CCHF)], climatic, topographic and microhabitat characteristics on ground beetle diversity (measured as total relative abundance, species richness, Shannon diversity and abundance of the endangered endemic species Carabus olympiae) in northern Italy. The diversity of forest specialist carabids was higher in OC and in forest stands characterized by a higher mean temperature and lower relative humidity. Moreover, we detected a positive response of several diversity variables to coarse wood debris cover or volume, herb cover, and the standard deviation of tree diameter. Currently, OC seems to be a more favorable habitat for forest carabids, including C.olympiae, although succession over time can lead to a progressive homogenization of the vegetation structure, with negative consequences for the conservation of the forest carabid assemblage. Based on our results, we suggest that the traditional management of beech coppice and its conversion to high forest be modified by including practices aimed at promoting structural and microhabitat diversity such as retention of large trees, creation of canopy gaps, retention of coarse wood debris and the preservation of 'islands' of older trees in the managed stands. [ABSTRACT FROM AUTHOR]

Abstract: Regeneration of non fire-adapted conifers following crown fires on the European Alps is often delayed or unsuccessful. Fire may limit establishment by eliminating seed trees, altering soil properties, or modifying microsite and soil conditions via disturbance legacies. However, the effect of soil legacies on post-fire establishment has rarely been discussed. We analyzed the abundance of Scots pine regeneration in a 257ha wildfire in an inner-alpine forest. Our aims were (1) to model fire intensity at the soil surface and topsoil heating along a gradient of increasing fire severities; (2) to assess the differences in soil properties along the fire severity gradient; (3) to model the effect of disturbance and soil legacies on the density of pine seedlings. We reconstructed fire behavior and soil heating with the First Order Fire Effects Model (FOFEM), tested the effect of fire severity on soils by nonparametric distributional tests, and modeled seedling density as a function of site, disturbance and soil legacies by fitting a GLM following a variable selection procedure. Topsoil heating differed markedly between the moderate and high severity fires, reaching temperatures high enough to strongly and permanently alter soil properties only in the latter. High fire severity resulted in decreased soil consistency and wet aggregate stability. Burned soils had lower organic matter and cations than those unburned. Pine seedlings favored low-fertility, eroded, and chemically poor sites. Establishment was facilitated by the presence of coarse woody debris, but hampered by increasing distance from the seed source. These results suggest that in dry, inner-alpine valleys, fire residuals and soil legacies interact in determining the success of Scots pine re-establishment. High severity fire can promote favorable soil conditions, but distance from the seed source and high evaporation rates of bare soils must be mitigated in order to ensure a successful restoration. [Copyright &y& Elsevier]

Abstract: Pattern analysis of tree stems in forests stands is commonly used to assess the type and intensity of tree-to-tree interactions. Crowns are directly involved in competition for light, and plastically react by growing asymmetrically. We tested the hypothesis that the spatial pattern of crown centers is different than that of stem bases, and specifically more regular due to optimal foraging. We also postulated that shift to regularity in crown spatial pattern was directly related to individual crown asymmetry and the intensity of competition in the stand. We computed point pattern statistics in four long-term forest monitoring plots, established in Scots pine forests of the Alps, and the intensity of spatial association of crown centroids versus stem locations. Crown asymmetry was significantly correlated to competitive status. Crowns were more regularly distributed than stems in mature stands, but not so in a young stand where competition was at a lower intensity. At the stand level, the shift towards regularity was related to relative density and mean crown asymmetry. We propose that studies of competition in mature forests routinely analyze spatial pattern of crowns in addition to that of stems, in order to collect stronger evidence of competitive processes. [Copyright &y& Elsevier]

Abstract: Density management diagrams (DMD) are graphical tools used in the design of silvicultural regimes in even-aged forests. They depict the relationship between stand density, average tree size, stand yield and dominant height, based upon relevant ecological and allometric relationships such as the self-thinning rule, the yield-density effect, and site index curves. DMD effectively summarize stand structural descriptors, and are therefore helpful in determining stand characteristics needed to achieve a range of management goals. We constructed a DMD for Scots pine (Pinus sylvestris L.) forests in the western Italian Alps. We used 210 sample plots from a region-wide forest inventory to determine the maximum density line and volume and top height isolines. Site index curves were used to assess the time taken by stands to progress along their development trajectories. The protection provided by Scots pine stands is most effective against rockfall, due to the frequent occurrence of such forests in active source or transition areas. We used the DMD to identify combinations of size and density representing optimal and sub-optimal protection from rockfall. An actual pine stand was used as a case study to illustrate how the diagram can be used to assess current functionality of the forest, forecast its likely development and compare alternative management strategies. [Copyright &y& Elsevier]

Abstract: As a consequence of the recent change in human land-use intensity in mountain territories in the Italian Alps, many Norway spruce (Picea abies (L.) Karst.) subalpine forests have recently developed without significant anthropogenic disturbance. Even so, their structure and dynamics are still influenced by past human activity. In order to analyze the interactions between past management and current stand dynamics, competition among trees was studied in two 1-ha permanent plots in the Valbona Forest Reserve, located within the Paneveggio-Pale di San Martino Natural Park (eastern Italian Alps). The plots were established in 1993 in two stands with similar age, density and structure but different management history. Tree measurement was repeated in 2005. We carried out the analysis both on the stand- and on the individual tree scale. We computed maximum Stand Density Index (SDI) for Norway spruce in Paneveggio Park (SDImax 1380) based on an ancillary sample plot network. The intensity of stand-level competition and its course through time was assessed in each study area computing percent relative SDI (SDI%) for the two inventory years. Competition at individual level was studied using known individual-based competition indices (CIs) as well as a new set of Crown Area Indices (CAI), all of them based on tree variables such as dbh, height, crown area and inter-tree distance. We assessed the performance of each index by evaluating its explanatory power in forecasting individual tree basal area growth (Δg) in a 10-year period. In the more recently thinned plot, competition did not induce mortality rates comparable to the second plot, that has been unmanaged for the last 60 years. We expect the intensity of competition-induced mortality of the two stands to increase its similarity in the next future. Individual CIs based solely on tree diameter produced the best performance in plot 1 (e.g., Daniels’ CI, ). In plot 2 different CIs, including tree height, crown area and inter-tree distance as base variables also, proved the most explanatory ones, including CAI6 (), which not consider dbh. We attributed the differential role of tree spatial location and dominance-related descriptors in predicting growth to the time when the stand experienced the last anthropogenic disturbance. The competition relationships still experience the effect of the artificial alteration of forest structure: after human disturbance, mature Norway spruce subalpine forests need several decades to approach more natural dynamics. [Copyright &y& Elsevier]

Root reinforcement is a mechanism through which forests contribute to the prevention and mitigation of shallow instabilities in soils, one of the main hazards in mountain areas. This study aims to assess how spatial tree distribution and whether thinning operations affect root reinforcement in the most common forest types of the European Southern Alps. We measured size and position of the trees of 119 stands, belonging to sweet chestnut, European beech, Norway spruce, and spruce-beech-silver fir forest types. We developed, calibrated and validated a model for estimating root reinforcement at the stand level, using the spatial distribution of tree diameter as the input variable. Finally, we simulated a thinning of 18% stand basal area, selecting removal trees from smaller diameter classes (low thinning) or from random clusters (random cluster thinning), and assessed its effect on root reinforcement. Root reinforcement statistically differed among forest types and the lowest values were found in the sweet chestnut forest type. Irrespective of the forest type, low thinning did not significantly modify root reinforcement, while random cluster thinning reduced it five-fold. [ABSTRACT FROM AUTHOR]

• Harmonised freely-available data is crucial to model forest impacts on climate change. • We summarise available datasets on forest functioning and underlying drivers. • Data for key demographic mechanisms are available at the short-term at EU level. • Lack of high-resolution harmonised EU data for genetic and physiological tree responses to climate change. • Need for Pan-European data integration effort. Climate change is expected to cause major changes in forest ecosystems during the 21st century and beyond. To assess forest impacts from climate change, the existing empirical information must be structured, harmonised and assimilated into a form suitable to develop and test state-of-the-art forest and ecosystem models. The combination of empirical data collected at large spatial and long temporal scales with suitable modelling approaches is key to understand forest dynamics under climate change. To facilitate data and model integration, we identified major climate change impacts observed on European forest functioning and summarised the data available for monitoring and predicting such impacts. Our analysis of c. 120 forest-related databases (including information from remote sensing, vegetation inventories, dendroecology, palaeoecology, eddy-flux sites, common garden experiments and genetic techniques) and 50 databases of environmental drivers highlights a substantial degree of data availability and accessibility. However, some critical variables relevant to predicting European forest responses to climate change are only available at relatively short time frames (up to 10-20 years), including intra-specific trait variability, defoliation patterns, tree mortality and recruitment. Moreover, we identified data gaps or lack of data integration particularly in variables related to local adaptation and phenotypic plasticity, dispersal capabilities and physiological responses. Overall, we conclude that forest data availability across Europe is improving, but further efforts are needed to integrate, harmonise and interpret this data (i.e. making data useable for non-experts). Continuation of existing monitoring and networks schemes together with the establishments of new networks to address data gaps is crucial to rigorously predict climate change impacts on European forests. [ABSTRACT FROM AUTHOR]

Projections of landscape dynamics are uncertain, partly due to uncertainties in model formulations. However, quantitative comparative analyses of forest landscape models are lacking. We conducted a systematic comparison of all forest landscape models currently applied in temperate European forests (LandClim, TreeMig, LANDIS-II, iLand). We examined the uncertainty of model projections under several future climate, disturbance, and dispersal scenarios, and quantified uncertainties by variance partitioning. While projections under past climate conditions were in good agreement with observations, uncertainty under future climate conditions was high, with between-model biomass differences of up to 200 t ha−1. Disturbances strongly influenced landscape dynamics and contributed substantially to uncertainty in model projections (~25–40% of observed variance). Overall, model differences were the main source of uncertainty, explaining at least 50% of observed variance. We advocate a more rigorous and systematic model evaluation and calibration, and a broader use of ensemble projections to quantify uncertainties in future landscape dynamics. • The first systematic comparison of forest landscape models is presented. • Variance of model projections under several future scenarios is substantial. • Model differences explain most of the simulated variance. [ABSTRACT FROM AUTHOR]