PICO
Nature-based solutions (NBS), such as forest landscape restoration (FLR), provide vital opportunities to reverse these trends and restore ecological, social, climatic, and economic benefits. Major international commitments, including the Bonn Challenge and the UN Decade on Ecosystem Restoration, underscore the urgency of scaling restoration. At the regional level, the EU has launched research and innovation programs, such as Interreg CE-RENFORCE and H2020-SUPERB, to address the societal, economic, and policy dimensions of forest degradation and restoration.
Despite such efforts, forest degradation remains insufficiently understood due to inconsistent definitions, transboundary impacts, and limited monitoring tools. This session aims to advance knowledge by gathering insights into monitoring approaches, stakeholder perspectives, and policy dimensions of NBS and FLR under climate change. We welcome contributions on:
Modelling and predicting forest degradation drivers.
Impacts of degradation on ecosystem services.
Stakeholder perspectives and policy initiatives for NBS in FLR.
Innovative, cross-scale restoration strategies, including co-benefits and resilience under climate change.
IUCN (2021) Deforestation And Forest Degradation. IUCN Issues Brief. February 2021. Available at: https://iucn.org/sites/default/files/2022-04/deforestation-forest_degradation_issues_brief_2021.pdf
Qin Y, Xiao X, Wigneron JP, et al (2021) Carbon loss from forest degradation exceeds that from deforestation in the Brazilian Amazon. Nature Climate Change 2021 11:5 11:442–448.
Seidl R, Schelhaas MJ, Rammer W, Verkerk PJ (2014) Increasing forest disturbances in Europe and their impact on carbon storage. Nat Clim Chang 4:806–810.
PICO: Wed, 6 May, 10:45–12:30 | PICO spot 4
Escalating natural disturbances in Central Europe necessitate restoration strategies that prioritize ecological integrity and adaptive capacity. Over the last decade, Slovenian forests—traditionally managed via close-to-nature silviculture—faced historic damage from a catastrophic 2014 ice storm, followed by extraordinary windthrows (2017, 2018, 2023) and subsequent bark beetle outbreaks. These events have rendered natural regeneration alone insufficient to preserve forest functions within acceptable timeframes.
Analyzing Slovenia Forest Service data (2007–2020), this study evaluates the economics of artificial forest restoration across 14 forest management regions. Based on an extensive data analysis conducted by the author (Bozic et al. 2025), we found that €33.6 million was invested to restore 5,353 ha via planting and 457 ha via sowing. Costs were dominated by planting (53%) and protection against game animals (42%). Crucially, natural disasters shifted management dynamics, with disaster-related restoration (planting) rising from 42% pre-2014 to 76% by 2020.
These findings advocate for a shift from reactive forest restoration toward proactive forest structures based on two pillars. First, we see the synergy between genetic adaptation of seed sources and nursery production as vital for seedling survival in extreme environments. To mitigate economic burdens, we propose: (1) differentiated co-financing for resilient mixtures; (2) increased use of sowing; (3) systematic investments in forest stability; and (4) fiscal incentives for quality containerized seedlings and protection against wildlife.
Second, forest restoration could be operationalized through a systematic five-step framework for future forests, co-developed by the authors (Kovac et al. 2024). By integrating site-specific actions into broader landscape goals, this holistic approach ensures consistent decision-making and equitable promotion of all sustainability components—ecological, social, and economic—by treating stands as building blocks of functional habitats. Adhering to the precautionary principle, the framework integrates: (1) environmental zoning via structured forest planning situation analysis; (2) climate-optimal species selection based on desired future portrayals and specific stand-level goals, such as species mingling; (3) the identification of climate-resilient seed sources and provenances to ensure that seedlings possess the genetic plasticity required for optimal growth and long-term adaptation to specific site conditions over several decades; (4) specialized silvicultural models executed via site-specific planting blueprints; and (5) adaptive monitoring. This path, supported by the author's extensive data analysis (Bozic et al. 2025) and personal field leadership, provides a foundation for a scientifically grounded transition from disaster-related restorations toward resilient, high-value forest ecosystems.
How to cite: Bozic, G., Ferreira, A., Kusar, G., Pintar, A. M., Minic, M., and Mali, B.: Economic Insights and a Systematic Framework for Creating Resilient Forests: Transitioning from Reactive to Proactive Restoration in Slovenia, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3450, https://doi.org/10.5194/egusphere-egu26-3450, 2026.
Mediterranean agroforestry represents a diverse set of socio-ecological systems that provide a variety of agri-food products while preserving key ecosystem services, and linking local value chains to international consumers. However, increasing pressures from intensive production practices and environmental change threaten its long-term sustainability. In response, the PRIMA section 2 SHARE (Shared Innovations for Mediterranean Agroforestry Systems) project focuses on the resilience of tree-based agroforestry systems through Living Lab approaches, promoting the co-creation, stakeholder engagement, and collaborative innovation within public-private partnership. This study uses an interdisciplinary approach to assess the present status of agroforestry products and their interactions with consumers across the Mediterranean region. The analysis combines a review of academic literature, policy documents, and project reports with qualitative value-chain assessments conducted in selected living labs, using a “follow-the-thing” method to monitor products from production to consumption. The analysis is based on the first step in the argan-based agro-sylvo-pastoral system of Ait Souab-Ait Mansour, registered under the Globally Important Agricultural Heritage System (GIAHS) Programme and located within the Arganeraie Biosphere Reserve in Souss Massa region of Morocco. This case study is compared with other typical agroforestry systems, including olive groves in Central Italy, tree-trained vineyards in Occitanie (France), the Montado system in southern Portugal, olive groves with livestock grazing in Cyprus and in south-eastern Tunisia. The outcomes of the comparative study highlight challenges and system-specific synergies, as well as consumer preferences that can support the development of more sustainable agroforestry value chains.
Keywords: Agroforestry, Value chains, Ecosystem Services, Mediterranean region, argan system.
How to cite: Ait lahssaine, I., El Hafyani, M., Hssaisoune, M., D’Ottavio, P., Chaaou, A., Ait-Ichou, H., Faouzi, E., Tadoumant, S., Meskour, B., Ijlil, S., and Bouchaou, L.: Enhancing Sustainability in Mediterranean Agroforestry Systems: A Living Lab ‘Follow-the-Thing’ Assessment of Products and Value Chains, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3998, https://doi.org/10.5194/egusphere-egu26-3998, 2026.
We evaluated the long-term development, ecological performance, and carbon dynamics of reclaimed and unreclaimed post-mining forest sites on coal spoil heaps in northwestern Czech Republic. Using historical aerial photographs, field inventories, and repeated surveys spanning 12–90 years, we characterized spontaneous forest succession and compared it with alder-reclaimed sites. Early successional stages on unreclaimed sites were dominated by pioneer species, primarily silver birch (Betula pendula), goat willow (Salix caprea), and aspen (Populus tremula), with Norway spruce (Picea abies) establishing naturally in intermediate stages. A 90-year-old site approached climax forest, hosting 21 woody species dominated by pedunculate oak (Quercus robur) and European beech (Fagus sylvatica).
Tree density and biomass were initially higher on reclaimed sites however in intermediate stages of sucession tree biomas in unreclaimed sites exceed reclaimed ones. Ecosystem measurements using eddy covariance showed that unreclaimed sites functioned as stronger carbon sinks (−256 g C m⁻² yr⁻¹) than alder-reclaimed sites (−166 g C m⁻² yr⁻¹). Unreclaimed sites supported more favorable conditions for the establishment, growth, and mycorrhizal colonization of climax species namely Oak, beach and spruce, linked to lower soil pH, higher organic matter, and richer soil biota. Repeated surveys revealed sustained natural recruitment and relatively low mortality rates of climax species which ensure succesful establishment despite being several kilometers from seed sources.
Overall, spontaneous succession produced structurally and functionally diverse forests with comparable or superior long-term performance and carbon sequestration relative to conventional reclamation, highlighting the ecological value of unassisted forest recovery while suggesting cautious use of nitrogen-fixing plantations.
How to cite: Frouzova, J. and Frouz, J.: Long term comparison of post mining site restoration with unassisted forest recovery, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6923, https://doi.org/10.5194/egusphere-egu26-6923, 2026.
Post-disturbance active forest restoration is common in Europe, but climate change, new socioeconomic conditions, and scientific knowledge acquired in the last years are highlighting the inefficiencies of some business-as-usual practices. Especially after forest fires, the frailty of the burnt ecosystem calls for the use of low-impact interventions focused on nature-based solutions (NBS), taking advantage of biological legacies on the site, instead of site preparation and regular-scheme planting. This study presents an ongoing experiment set in one of the largest burnt areas on record in the Dolomites (Taibon Agordino, Italy). Although the forest is already recovering, the presence of invasive species, major changes in forest species composition, and the presence of cascade disturbances in nearby stands triggered the interest in local managers to test novel restoration interventions. Propagules (seeds, seedlings) of Quercus pubescens Mill. have been deployed near biological legacies (shrubs, branches, logs) used as NBS, along with sensors for air temperature and light intensity. We hypothesise that the selected biological legacies enhance the local microclimate and protect propagules from limiting factors such as deer browsing. The tree species selected is not present in the area yet, but it thrives in similar conditions in the Western Alps, and it is expected to adapt to the drier and warmer conditions anticipated with climate change. This intervention represents one of the first examples of assisted migration in the region, paving the way for further trials in the Eastern Alps. Survival and growth of the plants will be monitored periodically over the first two growing seasons, together with microclimate variations near the biological legacies. Preliminary results already show some differences between the experimental treatments. Local stakeholders shared great interest in the outcomes of this study, which can provide new solutions for post-fire forest restoration under a changing climate, in a region where forests provide multiple and highly valued ecosystem services.
How to cite: Taccaliti, F., Sforza, F., Baggio, T., Atzeni, F., Marangon, D., and Lingua, E.: Testing NBS and assisted migration to restore a burnt forest in the Dolomites, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7741, https://doi.org/10.5194/egusphere-egu26-7741, 2026.
The Guidelines for Climate Adaptive Forest Restoration and Reforestation Projects address key questions for climate adaptive forest restoration and reforestation success. Forestry professionals often encounter complex issues related to climate change and the need to adapt forest management practices while preserving biodiversity and maintaining sustainable ecosystems. This book is a compendium of practices based on robust and up-to-date knowledge. The 11 chapters of this guideline focus on the main research questions: how to set the goals of reforestation; how to select the best forest reproductive material; how to determine the appropriate attributes and methods to produce Forest Reproductive Material; and how to apply the best forest establishment techniques and develop post-planting protection and silviculture? Although this work mainly refers to the context of European forestry, practitioners, scientists, environmentalists and decision-makers worldwide will find guidance on how to address the challenges of climate-resilient forest management. Thanks to the joint efforts of 10 editors and 130 authors, scientists, and experts in climate-smart forestry, members of PEN-CAFoRR (Pan-European Network for Climate Adaptive Forest Restoration and Reforestation) COST Action (CA19128), a unique publication has been developed to meet the growing demand for practical knowledge. We are now entrusting this book to people who are deeply committed to the idea of maintaining and shaping future forests. The guideline is available in open access formula.
How to cite: Stanturf, J., Villar-Salvador, P., Mariotti, B., Ivetić, V., Madsen, P., Montagnoli, A., Andivia, E., Bebre, I., Dimitrova, A., and Klisz, M.: Guidelines for Climate Adaptive Forest Restoration and Reforestation Projects, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8314, https://doi.org/10.5194/egusphere-egu26-8314, 2026.
Fire is an important disturbance in European forests, particularly in the Mediterranean region. However, the effects of climate change on fuel availability and fire weather, combined with the widespread dominance of conifer monocultures, high population density, and the significance of human-caused ignition, support predictions of increasing fire risk in temperate Central Europe – a phenomenon likely to necessitate expanded post-fire forest restoration. The non-intervention approach based on ecological succession is often not favoured over active restoration due to economic considerations or legal requirements. Nevertheless, natural ecosystem recovery has been shown to enable successful tree establishment, support biodiversity, and provide microclimatic benefits. Here, we present data on early (2–5 years) natural tree regeneration following non-stand-replacing wildfires in lowland coniferous forests of Białowieża, northeastern Poland, in relation to burn depth and selected microsite characteristics, collected from sample plots along parallel transects within burnt and unburnt forest sections. Our results demonstrate that fire promoted the establishment of diverse tree taxa, including Pinus, Picea, Quercus, Betula, Populus, and Salix. A higher number of saplings was recorded in burnt plots across all sites, with Pinus and Betula benefiting most from both fire disturbance and burn depth. Furthermore, our findings confirm the importance of fire disturbance for the natural regeneration of Scots pine, which is currently nearly absent in the Białowieża Forest otherwise. Our study contributes to the discussion on fire regimes, post-fire ecosystem recovery, and forest restoration in Central Europe, highlighting the great potential for a non-intervention approach after fire. It also provides baseline information to inform conservation and management strategies in the region.
How to cite: Zin, E., Churski, M., Bielak, M., Granström, A., Pilch, K., Kuberski, Ł., Elfverson, E., Morawski, K., Verhoeven, B., and Niklasson, M.: Can we leave it to nature? – post-fire tree regeneration in Białowieża Forest, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13793, https://doi.org/10.5194/egusphere-egu26-13793, 2026.
Drawing from the Millennium Ecosystem Services, planted forests have been increasingly important for provisioning services of wood fiber and commodity production, and have emerged as a unique regulating Nature-based solution (NBS) for climate change adaptation and mitigation. Forest plantations account now for at least 30% of global industrial roundwood production and their contribution can be further increased, while reducing pressures on natural forests. Planted forests have been proposed as one of the most efficient and cost-effective means to store more atmospheric carbon and reduce adverse impacts of climate change in the short- to medium-term, along with improved forest management and reduced emissions from forest area loss.
Increasing the amount and productivity of planted forests is a crucial method to meet increasing timber and climate demands by capturing carbon in forests and subsequent wood products and providing short-run terrestrial energy. They also can help adapt to forest species migration by purposeful introduction of forest species adapted to new climate in a warmer planet, and provide additional forest biodiversity, soil health, and water quality and quantity benefits.
Increases in planted forests to achieve their promise for economic provisioning and climate regulating services mandate that a host of technical, research, policy issues must be resolved quickly. These include technical questions such as (1) the trends and magnitude of planted forests extent needed to increase production and climate roles; (2) the relative benefits of plantations versus natural forest restoration or retention for carbon storage; (3) questions of where such plantings can occur and how to deploy well-performing species to new regions; (4) the technical capacity required to produce seedlings; (5) the rapid development of forest products research and development of engineered forest and mass timber products, and (6) the environmental benefits and impacts of planted forests.
Massive expansion of planted forests must also resolve issues such as (7) rural land tenure status and rights in developed and developing countries, (8) regulations promoting or limiting intensive public forest land management, (9) infrastructure requirements and development; (10) cooperation, partnerships, and policy implementation, (11) investment opportunities, costs, returns, and incentives required to attract private landowners and outgrowers to plant forests, and (12) the effects on local and global timber markets.
These substantial questions must be resolved or planted forests will not achieve their potential to produce desirable wood fiber and products supplies, realize bioenergy opportunities, or store and offset vast amounts of global carbon emissions. This research tackles these questions while assessing historical trends and current status of planted forests worldwide and identifying the best practices for the development of planted forests for landscape restoration, climate change mitigation, and range of environmental, social, and economic co-benefits.
How to cite: Siry, J., Chudy, R., and Cubbage, F.: Planted Forests: A Key Nature Based Solution for Restoring Forest Landscapes and Mitigating Climate Change, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14516, https://doi.org/10.5194/egusphere-egu26-14516, 2026.
Large-scale bark beetle outbreaks can compromise multiple forest ecosystem services, including timber yield, carbon sequestration capacity, and the protective and cultural values of forests. In Central Europe, recent Ips typographus outbreaks have highlighted the increasing vulnerability of spruce-dominated forests under changing climatic conditions.
Historically, major bark beetle outbreaks were usually initiated by windthrow or snow damage, with fallen trees providing suitable host material and enabling rapid beetle population growth. Recently, drought is increasingly recognised as an additional amplifying or even triggering factor. Heat and water limitation impair spruce defence mechanisms, while warmer temperatures benefit beetles by extending their flight periods and accelerating development, potentially allowing additional generations per year. Together, these processes increase the likelihood that both beetle population growth and host susceptibility coincide over multiple consecutive years.
The aim of this work is to develop a predictive model of bark beetle disturbance vulnerability at the European scale. The modelling framework covers the period 1981–2021 and integrates a range of spatially explicit covariates, including climatic variables (temperature, precipitation, drought metrics), stand properties, and topographic characteristics. Model calibration relied on forest management records and remote sensing–based disturbance maps identifying historical bark beetle outbreaks. These disturbance layers provided spatially explicit binary response data and formed the core reference for model training and validation. The performance of a suite of statistical and machine-learning models was evaluated using both spatial and temporal cross-validation.
Such trained models were subsequently applied to projected future climate conditions under a high-emission scenario (SSP5-8.5), with inter-annual climatic variability explicitly incorporated. Ensemble predictions across different models and iterated climate simulations were aggregated to derive spatially explicit estimates of future bark beetle disturbance risk.
The results emphasize the importance of considering disturbance risk at spatial scales relevant for regeneration planning, highlighting species composition, spatial dispersion, and bet-hedging strategies under increasing ecological uncertainty. The outcomes will contribute to a decision-support system currently developed within the RE-ENFORCE project.
How to cite: Čepl, J., Chuchlík, J., and Korecký, J.: Forecasting Bark Beetle Disturbance Risk for Forest Regeneration Planning, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15186, https://doi.org/10.5194/egusphere-egu26-15186, 2026.
When large and severe disturbances affect mountain forests, their ability to provide fundamental ecosystem services may be impaired for a long time. Indeed, in the Alps, forested slopes exert a crucial protective function and rapidly restoring the forest cover after a stand-replacing event is key to prevent the occurrence and mitigate the impact of subsequent natural hazards. Post-disturbance intervention can make or break forest recovery and should thus be tailored to meet management requirements and ecological needs. Widespread salvage logging removing all deadwood and other biological legacies in harsh environments where natural regeneration relies on facilitation mechanisms is a classical example of human intervention leading to undesired consequences. Quite often, when time is not a constraint, passive restoration can be the best option. Whenever active restoration is deemed necessary, particularly when large areas are affected, several challenges and limitations have to be addressed. Lack of saplings supply from tree nurseries, specialized workers and funding availability can hamper restoration activities.
Some lessons learnt from mountain forests of the Italian Alps will be presented, considering restoration interventions after forest fires, windthrows and bark beetle outbreaks. Taking advantage of biological legacies, assisted regeneration and applied nucleation provided encouraging results, with nature-based solutions proving to be effective in promptly restoring the ecosystem services provided by forests, especially in protective stands.
How to cite: Lingua, E., Varotto, M., Taccaliti, F., Barbarick, E., Marangon, D., Richter, P., Baggio, T., Garbarino, M., Anselmetto, N., Berger, F., and Marzano, R.: Recovering protective forests after a disturbance. Lessons from active and passive restoration approaches in mountain forests., EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17190, https://doi.org/10.5194/egusphere-egu26-17190, 2026.
The Interreg Central Europe project RE-ENFORCE policy brief advocates accelerating forest restoration in Central Europe through the harmonization of definitions, policies, action plans and monitoring. It further calls for the development of a common EU-wide framework for assessing forest restoration success, based on ecosystem-specific indicators that capture biodiversity, structural complexity, and regeneration outcomes. In this context, we propose an adapted approach that explicitly considers local biological diversity, including genetic diversity, in forest restoration and the establishment of close-to-nature forests. To increase future adaptability, naturally occurring local regeneration should be enhanced with enrichment planting using forest reproductive material (FRM) from tree species and provenances that are potentially adapted to future climates.
This approach should be supported by field testing, modern monitoring techniques and decision support methods and should include long-term monitoring of forest restoration projects, enrichment plantings and provenance or common garden trials. In Slovenia, we are developing systems for georeferenced planting and monitoring of local and regional FRM, combined with climate and soil data to evaluate tree species and provenance suitability and resilience when using different restoration techniques.
In our contribution, we present a system for georeferenced planting using highly accurate GNSS antennas and QGIS software, as well as a system design for nationwide forest restoration and FRM suitability monitoring and evaluation in Slovenia. The system also helps address the requirements of the new Regulation on the production and marketing of FRM in the EU regarding the preparation and regular updating of national contingency plans to ensure proactive and effective action against risks arising from climate change and the spread of pests and diseases.
How to cite: Rantaša, B., Kavčič Sonnenschein, K., Dovč, N., Ogorevc, S., Westergren, M., and Kraigher, H.: The potential of georeferenced planting and large dataset analysis for close-to-nature forest restoration, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17414, https://doi.org/10.5194/egusphere-egu26-17414, 2026.
Post-fire regeneration in Mediterranean pine forests is increasingly constrained by recurrent high-severity fires and post-disturbance interventions. We assessed the drivers of early natural regeneration in a coastal Pinus halepensis Mill. forest in Spotorno (NW Italy) affected by two recent high-severity wildfires (September 2006 and July 2015) followed by salvage logging. Pine seedlings were mapped in spring 2025 with an RTK GNSS antenna, while high-resolution UAV images and LiDAR products were used to derive terrain- and forest structure-based predictors. Topographically mediated constraints on regeneration were quantified using the Topographic Wetness Index (TWI) and the Heat Load Index (HLI), which capture spatial variation in soil moisture accumulation and heat exposure. Seed availability was represented by the distance to remnant adult pines, identified from the canopy height model using a local-maximum filtering approach. Spatial point pattern analysis (inhomogeneous Ripley’s K and pair correlation) was used to test whether empirically evident regeneration clusters reflected plant–plant interactions, or environmentally-driven density variation. Drivers of regeneration were modelled using GLMs, GAMs and Random Forests (RF), and two pseudo-absence strategies in the RF were explicitly compared by training models with (i) ecologically informed, spatially homogeneous pseudo-absences and (ii) randomly sampled pseudo-absences. The informed pseudo-absence Random Forest achieved substantially higher discrimination (AUC = 0.895; ACC = 0.821; SEN = 0.785; SPE = 0.864) than the random-absence model (AUC = 0.653; ACC = 0.607; SEN = 0.648; SPE = 0.571). The best model was applied to generate a 5 x 5 m ecological suitability map identifying regeneration “hotspots”, i.e., near seed sources under warm, well-drained microsite conditions, and persistent “coldspots” in convergent terrain and seed-limited areas. This workflow provides an operational, transferable basis for precision-oriented post-fire restoration planning in Mediterranean landscapes where passive recovery is uncertain.
How to cite: Atzeni, F., Taccaliti, F., Marangon, D., and Lingua, E.: Fine-scale environmental filtering and seed limitation shape early post-fire regeneration patterns in Mediterranean Pinus halepensis Mill. forests, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17839, https://doi.org/10.5194/egusphere-egu26-17839, 2026.
Rejuvenation of forests is one of the most important ecological and economic challenges in central Europe. In an existing large-scale experiment in southern German forests, c. 500 thousand c. 2 years old tree seedlings of Beech, Douglas fir, Silver, Oak have been planted in rows. However, our knowledge of how potential small-scale factors like tree stumps and tree mixture mechanistically enhance tree establishment after planting is limited.
We focused on 6 plots (c. 2500 seedlings) of Douglas fir, planted on a comparably dry site without mature trees. We observed that those trees differed in height, 3 years after planting. Moreover, trees of comparably greater height cluster together on a small spatial scale of 3 m radius. However, conventional tree planting methods (in rows) neglect those beneficial small-scale sites for tree establishment.
Using an app we programmed (Shiny package in R) for quickly finding trees clustered by e.g. height, clusters of 3 m radius of well- and poorly-established trees were identified. A combination of multispectral drone-derived optical parameters, morphological analyses of twigs and 13C analyses of tree needles was then used to provide insight into the factors driving the trees’ height differences.
First results showing the positive effects on the establishment of young trees are presented, i.e. incorporating spatial proximity to tree stumps and using a tree mixture in the planting method. Further steps to gain a better understanding of the mechanisms driving tree seedling establishment are discussed.
How to cite: Busse, T., Krieger, F., Weikl, F., Hafner, B. D., Toraño Caicoya, A., Peters, R. L., and Grams, T. E. E.: Towards a better understanding of tree seedling establishment and its use for forest rejuvenation in Central European forests, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19077, https://doi.org/10.5194/egusphere-egu26-19077, 2026.
Climate change is expected to profoundly alter the climatic suitability of tree species across Europe, necessitating large-scale reforestation and assisted migration to maintain forest ecosystem services. Here, we present a pan-European projection of potential seedling requirements under assisted migration across three reforestation strategies: conifer-preferred, broadleaf-preferred, and promotion of natural regeneration. Our simulations show that under the moderate-emission scenario (RCP4.5), total seedling requirements range from ~92 billion under the natural-regeneration-oriented strategy to ~144 billion when broadleaves are prioritized. Under the high-emission scenario (RCP8.5), demand rises substantially, reaching up to ~192 billion seedlings across the landscape.
Temporal patterns differ between scenarios. Under RCP4.5, seedling requirements are highest early in the century, with 2035 totals of ~69–72 billion for replacement-focused strategies and ~47 billion for the natural regeneration scenario, declining steadily toward 2095. In contrast, RCP8.5 projections peak at the end of the century, reaching ~76–82 billion seedlings for replacement-focused strategies and ~50 billion under natural regeneration.
Species composition of projected demand varies with reforestation strategy. In the conifer replacement strategy, silver fir, Scots pine, and black pine dominate, together requiring roughly 50–60 billion seedlings, with higher totals under strong warming. In the broadleaf-focused scenario, pedunculate oak, European beech, and sessile oak account for over 40 billion seedlings under moderate warming and exceed 55 billion under RCP8.5. Prioritizing natural regeneration reduces overall demand, though these broadleaf species remain dominant, requiring ~30–35 billion seedlings even under strong climate change.
Spatially, Central-East Europe represents the largest potential market, driven primarily by Poland, Belarus, Ukraine, Romania, and Czechia. Under RCP8.5 with broadleaf expansion, these countries collectively require over 72 billion seedlings, with Poland and Belarus alone accounting for ~23 and ~21 billion seedlings, respectively. Central-West Europe forms the second-largest market, led by Germany (~28 billion seedlings), while Northern, South-Eastern, and South-West Europe show moderate to low demand, rarely exceeding 15 billion seedlings per region.
Our results highlight the scale of effort required to implement assisted migration in Europe and emphasize the critical need for strategic planning in seedling production and distribution. Central and Central-Western Europe, in particular, will likely require substantial increases in nursery capacity and cross-border coordination to meet projected needs. These findings provide actionable insights for policymakers and the nursery sector, supporting the development of climate-adapted reforestation strategies capable of sustaining Europe’s forests under future climate conditions.
How to cite: Ciceu, A., Chauvin, T., Konrad, H., Chakraborty, D., and Schueler, S.: Assisted Migration and Large-Scale Restoration in Europe Would Require Over 100 Billion Seedlings, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-22570, https://doi.org/10.5194/egusphere-egu26-22570, 2026.
