Forests deliver a wide array of ecosystem services. They can be sustainably provided across spatial and temporal scales through ecosystem-based multi-objective forest management planning. The growing complexity of ecological dynamics—driven by climate change, natural disturbances, and evolving societal demands—necessitates a shift from static to adaptive, data-driven planning. Such an approach can simultaneously ensure the provision of desired ecosystem services while safeguarding the ecological integrity of forest ecosystems. This paper examines the theoretical foundations and proposes a conceptual framework for forest management planning, integrating emerging technologies such as Digital Twin (DT) systems and recent scientific advancements in ecosystem based forest management planning. At the core of this approach lies the dynamic coupling of real-time, high-resolution data with clearly defined management objectives and conservation targets rooted in ecological reference conditions. The proposed DT-integrated Forest Management Planning (DT-eFMP) framework facilitates continuous monitoring, scenario testing, and participatory decision-making while maintaining alignment with policy frameworks and sustainability goals. Emphasis is placed on the intelligent design of silvicultural regimes that emulate natural disturbance patterns, enhance forest resilience, and optimize the provision of ecosystem services. By incorporating advanced simulation, forecasting, and learning mechanisms, the framework provides a restructured decision support system capable of managing uncertainty and improving long-term planning outcomes. This work contributes an operationally relevant framework for forest managers and policymakers, offering both a scientific foundation and a practical guide for advancing adaptive and resilient forest ecosystem management in the digital era.

Mixed mountain forests of Norway spruce (Picea abies (L.) Karst.), silver fir (Abies alba Mill.), and European beech (Fagus sylvatica L.) are ecologically important across Europe, providing ecosystem services, supporting biodiversity, and contributing to the bioeconomy as crucial timber sources. Understanding background mortality in these forests is essential to distinguish the effects of this relatively continuous endogenous process from those induced by exogenous disturbances, and to inform sustainable management under changing conditions. To assess how stand density, tree-size dominance, species competition and diversity, site geomorphology, and climate influence background mortality, expressed as the annualised basal area loss rate, we applied generalised linear mixed models. We used tree measurements from 78 plots located in Bulgaria, Bosnia and Herzegovina, Slovenia, Slovakia, Poland, Germany, and Switzerland, inventoried from 1912 to 2016, with most of them first surveyed between 1953 and 1964. At the stand level, mortality increased with stand basal area, greater species diversity, and the interaction between fir dominance and drought. Spruce mortality increased with stand density, species diversity, and fir dominance, indicating a higher probability of spruce mortality under fir dominance pressure. Fir mortality increased with species diversity and mean annual temperature, revealing fir as sensitive to rising temperatures, and with the interaction between fir dominance and drought, with moisture effects varying along the fir dominance gradient. Beech mortality increased with stand density and fir dominance, suggesting that beech suffers more when fir occupies a dominant canopy position. These findings suggest that sustainable management of mixed mountain forests requires targeted silvicultural interventions to regulate stand density, manage species diversity, and limit fir size dominance.

Identifying the potential and demand for forest ecosystem services (FES) in a spatially explicit manner is crucial for multi-objective forest management. We developed a robust and transparent procedure for i) selecting indicators for assessing the potential and demand for three FES (timber production, recreation and nature conservation) and ii) determining their relative importance (weights) as perceived by forest planning experts from four European countries (Estonia, Finland, Poland and Slovenia) with different forestry traditions. A total of 19 indicators of FES potential and 10 of FES demand, linked to each of the three FES, were selected based on established indicators that were updated and downscaled through iterative, multistep group communication. The selected indicators describe site and stand characteristics, accessibility, infrastructure and attractiveness, legal status and forest use. Indicators describing expert assessments of FES potential and demand were also included. We applied the fuzzy Best-Worst Method to derive weights for FES indicators incorporating experts' preferences. For FES potential, evidence-based indicators relying on empirical data received higher weights, whereas for FES demand, expert-based assessments were prioritized. Pairwise statistical comparisons of indicator weights revealed notable differences in the importance assigned by experts across countries. By considering both the potential and demand for FES and combining evidence-based indicators with expert preferences, we contribute to a comprehensive and context-sensitive framework for FES assessment. Our approach enables forest planners to identify priority areas for promoting desired FES and tailor management strategies that balance multiple FES, ensuring that decisions align with ecological potential and societal demand.

Forests produce timber, mitigate climate change and provide important habitats; yet their capacity to provide these services under rapid global change is uncertain. “Closer-to-nature” forest management (CNFM) has been proposed by the EU Forest Strategy as a way to reconcile competing demands on forests while enhancing their resilience, but experiences with its implementation remain limited. We synthesized expert knowledge about CNFM in Central Europe, a region with a history of diverse forest management practices that has recently experienced severe impacts of climate change. We used a two-stage Delphi approach (including a questionnaire and a workshop) with experts in forest ecology and management to find a consensus about the effects of specific CNFM tools, and to identify knowledge gaps, barriers, and good practice examples of CNFM. A wider implementation of CNFM is likely to benefit biodiversity and ecosystem services under climate change, with only one clear trade-off identified between setting areas aside and wood production. However, limited empirical evidence exists for many of the expected effects. Substantial obstacles hinder the implementation of CNFM, including administrative constraints, social barriers, and gaps in knowledge and education. Nonetheless, we identified numerous successful cases of CNFM implementation from local to national scales in Central Europe. CNFM is viewed as a potent strategy to navigate future social and ecological uncertainties, including large-scale disturbances. However, the implementation of CNFM should be adapted to the local context and ensure landscape-scale heterogeneity. Existing good practices could serve as examples for mainstreaming CNFM in Central Europe and beyond.

Understanding tree species’ vulnerability to various disturbance agents is crucial for climate-smart forest management. Using a dataset on salvage cutting in Slovenian forests from 1995 to 2022 (n = 48,124,386 trees), we examined (1) the main trends in forest vulnerability to seven natural disturbance agents (insects, fungi and diseases, windthrow, snow-break, ice-break, fire, and others); (2) the vulnerability of Norway spruce, Scots pine, European beech, and sessile oak to these agents; and (3) the impact of tree diameter on vulnerability. We assessed vulnerability using a vulnerability index (VI), defined as the ratio of salvage cut volume to total growing stock for a given year, agent, and species. During the observed period, overall vulnerability increased, with insects being the predominant agent. Tree vulnerability to insects, windthrow, and diseases and fungi showed a positive linear trend, while vulnerability to snow-break, ice-break, and fire fluctuated stochastically, with extreme climate events being more frequent in the second half of the study period. Norway spruce was found to be the most vulnerable species, being 6.5 times more susceptible to disturbance agents than Scots pine, and 6.8 times more susceptible than European beech and sessile oak. Significant differences in vulnerability across diameter classes were observed for all species pairs except European beech and sessile oak. Overall, tree vulnerability increased with diameter up to 30 cm and then decreased. Insect outbreaks mainly affected Norway spruce trees above 30 cm in dbh, while larger trees (especially over 30 cm in dbh) of all species were more susceptible to windthrow, and thinner trees were more vulnerable to ice-break.

Forest recovery following disturbances is essential for maintaining ecosystem services, especially after large-scale events where regeneration is limited by seed availability. Understanding how environmental and biotic factors influence regeneration across spatial scales is fundamental for landscape-scale management, yet the importance and spatial extent of landscape-scale effects on local recovery remains uncertain. We aimed to assess the relative influence of recovery drivers at plot, patch, and landscape scales on post-disturbance forest regeneration. Specifically, we investigated how local topography, disturbance characteristics, and the spatial arrangement of undisturbed forests affect tree regeneration after severe disturbances, namely windthrows, fires, and bark beetle outbreaks. Our study combines a comprehensive ground-based dataset of post-disturbance regeneration from temperate European forests with Landsat-derived maps of forest cover. We applied a distance-weighted regression approach to evaluate the effect of landscape (i.e., undisturbed forest in proximity of disturbance patches) on recovery, improving upon traditional buffer-based approaches. We found that ¾ of the landscape influence on forest regeneration occurred within 112 m from plot centers, with undisturbed forests nearby positively enhancing regeneration, likely due to increased seed availability. In contrast, plot-level factors, namely disturbance severity and elevation, negatively impacted regeneration, suggesting that regeneration success can be hindered by severe disturbances reducing living biological legacies, as well as harsher local climatic conditions, associated with higher elevations. Our findings underline the importance of integrating landscape-scale management with targeted local interventions to promote post-disturbance forest recovery. Management strategies should consider spatially explicit planning to enhance seed source availability and mitigate severe disturbance impacts.

Studies on the long-term growth dynamics of tree species under global warming have yielded varying or even contradictory results, including for European beech. We studied the response of the basal area growth of European beech to 30-year climate averages (mean temperature, annual precipitation sum and mean diurnal range) across an altitudinal range of 78-1629 m a.s.l. Our analysis was based on an extensive dataset of 331,965 beech trees from 54,403 plots under diverse site and stand conditions. We found a non-linear response of beech basal area growth to temperature, precipitation sum and elevation. Separate analyses conducted for 400 m elevation belts revealed significant differences in growth responses. A unimodal response to temperature was observed along the entire elevation gradient; however, in the lowest and the highest elevation belts, the relationship was linear, negative in the lowest, and positive in the highest. Across the entire elevation range, growth showed a plateaued unimodal relationship with annual precipitation, while at elevations <= 400 m a.s.l., a positive linear response was observed. Significant differences in growth responses between stand canopies were also observed, with dominant trees being more sensitive to most predictors. Our results suggest that changes in growth rate due to rising temperatures should be interpreted relative to the current mean temperature. The varying responses of stand canopies to climatic variables, and the predominant impact of tree and stand variables on growth rate, underscore the importance of considering forest stand dynamics in climate-growth studies.

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. As a result of global change, forest disturbances are becoming larger and more severe, which may put forest recovery at risk, especially under a warm and dry climate. Our study shows that European temperate forests have been able to recover after large and severe disturbances and concurrent climate conditions, although with more difficulty after fires compared with other disturbance agents. The main factors negatively influencing tree regeneration after wind disturbances were increasing elevation and the removal of damaged trees from the disturbed forests.image

Many cities worldwide have adopted management strategies for urban forests, typically focusing on forest parks, street trees and park trees. However, planning that concentrates on natural urban forest areas remains scarce. This study introduces an advanced planning framework for the integrative management of natural urban forests and applies it to Ljubljana's urban forests (2151 ha). The framework consists of an initiation phase and a six-step planning procedure. Through a comprehensive process lasting 20 months, with strong stakeholder involvement and political support, we developed a strategic plan for Ljubljana's entire urban forest area and an operational plan for a specific block within this area. The approach employs the integrative management of forest stands within or near the city, incorporating harmonised activities in silviculture, recreation, protection, harvesting and communication. This planning method aims to bridge the gap between traditional forest management planning and urban green infrastructure planning.

We studied the impacts of site, stand and tree variables on the diameter growth of beech trees ( Fagus sylvatica L.) on carbonate bedrock and examined to what extent the regional diameter growth model can be used at the forest type level. Based on 12,193 permanent sampling plots (500 m 2 each) with 94,770 beech trees, we first developed a linear mixed-effect model of the periodic diameter increment at the regional level (Dinaric region, Slovenia, 1.7 thousand km 2 ). Subsequently, we parametrized the model for five forest types within the region (submontane, thermophilous, montane, upper montane and subalpine) and used a homogeneity-of-slopes model to test whether the covariates have different effects in the five forest types. The regional model suggested the positive impact of tree diameter (nonlinear), tree diameter diversity, mean diurnal temperature range and mean annual temperature and the negative impact of basal area, proportion of beech, inclination, rockiness and annual amount of precipitation. Stand basal area and the proportion of beech contributed > 50% of the total explained diameter increment variability, followed by tree diameter (44%), topographic (3%) and climatic variables (< 2%). The regional model was well transferable to forest types; the only variable with a significantly different effect in forest types was tree diameter. However, models at the forest type level differed with respect to the slopes and significance of several predictors, wherein coefficients for some predictors were even of opposite sign. Not all predictors from the regional model were included in the forest type models if predictor selection and model parameterization were performed independently for each forest type. Our study suggests that some growth characteristics of beech can be detected at the regional level only, while analyses at the forest type level can reveal significant differences in beech growth response to tree, stand and environmental variables.

The self-thinning law describes the progressive mortality of growing trees in crowded even-aged stands because of competition. In uneven-aged stands, however, density-dependent mortality is relatively poorly known. We developed density-dependent self-thinning models for mono-species and multi-species uneven-aged stands. Three models for mono-species Picea abies, Abies alba and Fagus sylvatica stands, four models for mixed conifer/ broadleaf stands and a model for single tree selection stands as a specific type of uneven-aged forest were parametrized by Quantile Regression (QR) and Stochastic Frontier Analysis (SFA) using data from n = 31,612 forest inventory plots in Slovenia. The average slope of the self-thinning line in uneven-aged stands of-1.422 was statistically significantly lower than Reineke's slope. Maximum stand density was higher in mono-species stands than in multi-species stands. The higher the proportion of beech in a stand, the higher the intercept and slope of the maximum stand density line. In single tree selection stands, the intercept and the slope of the maximum stand density line were highest and statistically different from all other types of uneven-aged forests. Species mixture had an impact on the slope and intercept of the self-thinning line. The slopes of the self-thinning lines differed between the studied types by up to 36% and 69% in the SFA and QR models, respectively, while the intercepts differed by up to 13% and 24%, respectively. However, maximum stand densities differed significantly only between compositionally very dissimilar stand types, such as Fagus sylvatica-or Picea abies-dominated mixtures versus other broadleaf mixtures (e.g., Quercus petraea, Carpinus betulus). The SFA predictions of maximum stand densities were systematically lower and less varying than the QR predictions, but not statistically different. The models can be used to constrain individual tree growth models in uneven-aged forests and to estimate the onset of inter-tree competition in irregular stands.

Tree recruitment models are important for predicting the dynamics of uneven-aged forests. Previous studies of recruitment of European beech, Norway spruce and silver fir have shown different ecological amplitudes of these species. However, recruitment in uneven-aged stands and the values of environmental factors at which the greatest and poorest recruitment can be expected remain poorly explained. The main objectives of this study were to 1) explain how 39 stand, site and climatic factors and their interactions influence the number of recruited trees in uneven-aged forests; 2) determine the optimal and critical ranges of influential factors, including stand basal area, number of trees, proportion of tree species, shade casting, soil pH, site productivity, temperature and precipitation; and 3) estimate the maximum expected response of recruitment to changes in stand density while controlling for the effect of other limiting factors. A Tobit censored regression model was used to consider that the observed range of the number of recruited trees is censored at zero. The models were parametrized and validated using 30,963 forest inventory plots (200 m2 each) in uneven-aged forests in Slovenia. The models, which used 9 stand, 6 site and 3 climatic factors, explained 15 %, 10 % and 8 % of the total variation of the number of recruited spruce, fir and beech, respectively. Stand structure was the most important factor, with stand basal area (BA) and the proportion of the studied species having the greatest effect. Site factors including soil pH and rockiness were important for fir recruitment. The number of recruited beech and spruce was positively influenced by decadal precipitation. Higher temperatures decreased recruitment of spruce. Beech was the only species sensitive to shade casting. Recruitment of beech was higher if shade was imposed by tree species other than beech. The optimal and critical ranges of limiting factors differ between species. The model suggests that the optimal stand basal area for recruitment of beech is <= 19 m2/ha, which is higher than that for spruce (<= 16 m2/ha) but lower than that for fir (<= 28 m2/ha). The maximum predicted response of the studied species to changes in stand basal area shows that stand density control is efficient for regulating recruitment of spruce and beech, but not for fir. The suggested sensitivities and threshold values may be used in individual tree growth models or simulation-optimization studies in support of forest management decisions.