Soil health degradation is a major threat to European forests, with consequences for biodiversity and climate stability. Although spatially distributed soil data are available, a clear and quantifiable framework for soil health monitoring, management, and policy support is still lacking. In this study, we applied the recently proposed SHERPA framework (Soil Health Evaluation, Rating Protocol, and Assessment) to ICP Forests Level I data. SHERPA was published as a framework for discussion and provides the first quantitative soil health assessment at the European scale (Alewell et al., 2025).

Soil health scores were estimated by considering all major soil degradation processes, which were averaged to obtain Part 2 scores. This value was then subtracted from the intrinsic soil health score (Part 1), which is based on altitude, parent material, and humus horizon thickness (OL, OF, and OH), to calculate the final quantitative soil health score. Preliminary results indicate that soil health in forests across Europe is significantly reduced. This is mainly driven by nitrogen surplus, reflecting the widely documented forest decline caused by nutrient imbalances. Soil health is further affected by soil erosion and elevated concentrations of heavy metals, particularly nickel, which are predominantly observed in southern Europe. Overall, 45% of the samples show soil health scores below 1 on a scale from -8 to 10. These results are based on coarse-resolution spatial data due to the limited availability of measured soil data, especially of information on soil compaction and/or disturbance of a closed humus layer coverage of the soil. Therefore, the estimates can be further improved, but they already highlight major threats to forest soil health across Europe.

How to cite: Gupta, S. and Alewell, C.: Evaluating Forest Soil Health in Europe Using ICP Forests Data and the SHERPA Framework, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3798, https://doi.org/10.5194/egusphere-egu26-3798, 2026.

Forests are a cornerstone of nature-based climate mitigation, yet carbon stocks in managed Central European forests remain substantially below their full potential. Understanding this gap is essential for developing realistic mitigation strategies within the timeframe of national carbon neutrality targets.

We compare the current aboveground carbon stocks for Norway spruce (Picea abies), Scots pine (Pinus sylvestris), European beech (Fagus sylvatica), and oak (Quercus robur and Q. petraea) to their theoretical potential across Central European forests. Relying on a unique network of 593 long-term, unmanaged experimental plots throughout Europe that represent stand development under natural dynamics, we derive the carbon storage potential under maximum stocking density conditions. In contrast, realized carbon stocks are obtained from recent National Forest Inventory data (2024), which represent the current state of managed forests. Nonlinear growth models were fitted separately to experimental and inventory datasets, relating standing carbon stock to age and site productivity, while accounting for species-specific survival probabilities.

We reveal that Central European managed forests stay considerably below their full carbon storage potential compared to fully stocked and unmanaged forests of comparable age and site quality. Differences are highly species- and age-specific, with the largest gaps observed in middle-aged to maturing stands of European beech. Norway spruce stands also exhibited substantial potential, albeit with higher risks at older ages. Overall, we estimate that theoretically >500 *10⁶ t CO₂ equivalents could be stored by increasing C stock.

Using the most recent National Forest Inventory cycle, our estimates quantify the gap between potential and realized carbon storage across species and age classes. These findings provide a quantitative foundation for science-based decisions on forest mitigation capacity and for evaluating management scenarios that could help narrow this gap.

How to cite: Hilmers, T., Müller, J., Peters, R. L., Schmied, G., and Pretzsch, H.: Carbon stock in Central European forests: potential and reality , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10931, https://doi.org/10.5194/egusphere-egu26-10931, 2026.

Facing an uncertain future, european forests are expected to fulfill a range of forest ecosystem services (FES), including timber supply, carbon storage or biodiversity. Using criteria and indicators forest managers can evaluate alternative management options and decision support systems (DSS) help them make decisions considering multiple objectives. Such tools need input on forest development under various scenarios, to obtain robust decisions, such as provided by forest models. We use the simulation results from the project “OptFor-EU” generated by the hybrid forest model PICUS v1.5 for four case study areas in Austria, Italy, Germany and Romania. We utilize six different climate input (3 RCPs, 2 regional climate models) and up to nine management alternatives in simulations until year 2100. The initial stand structure was derived using forest inventory data. We aggregated forest stands (represented by forest types) assuming even distribution of age classes in a hypothetical landscape or region of interest.

We found positive tradeoffs between key forest ecosystem services, FES (carbon sink, biodiversity, harvested wood volume) for selected forest management alternatives. Under a “no active management” scenario, most of the simulated forest stands in the case study areas reached their potential carbon storage in the second half of the century and thus their carbon sink becomes neutral during that period. A surprising result was that selected biodiversity indicators were higher under management scenarios than no management, at least for certain time periods and age classes. Less extensive forest management alternatives may offer tradeoffs between FESs. Next steps are expanding the simulations to additional case study areas and refining and optimizing the forest management, considering more realistic age class distributions and/or varying management by age class.

References

• Irauschek, W. Rammer, M.J. Lexer, Evaluating multifunctionality and adaptive capacity of mountain forest management alternatives under climate change in the Eastern Alps, Eur. J. For. Res. 136 (2017) 1051–1069. https://doi.org/10.1007/s10342-017-1051-6.
• Lexer, M. J. and K. Hönninger. 2001. A modified 3D-patch model for spatially explicit simulation of vegetation composition in heterogeneous landscapes. Forest Ecology and Management 144:43–65.

How to cite: Erich, N. and Neumann, M.: Tradeoffs in ecosystem services of European forests using a case study approach and a climate-sensitive modelling tool, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11243, https://doi.org/10.5194/egusphere-egu26-11243, 2026.

Forest-based climate mitigation measures are central to achieving the EU’s climate neutrality target by 2050 and meeting the LULUCF goal of 310 Mt CO₂ net removals by 2030. Forest management strategies should balance carbon sequestration and biodiversity conservation with wood production, and build resilient flows of ecosystem services under changing climatic conditions. In this study, we apply an integrated modelling framework combining dynamic vegetation models (LPJ-GUESS), forest resource models (EFISCEN-Space), a global forest sector model (EFI-GTM) and a wood flow model (aiphoria) with dynamic life-cycle assessment modelling to assess the long-term carbon and biodiversity impacts of alternative forest management approaches across Europe. We include the downstream effects of changed wood provision to harvested wood products impacting the forest sector carbon balance and provide insights into potential substitution effects. By linking biophysical and economic modelling, we identify management strategies that enhance resilience and multifunctionality while supporting EU policy objectives for climate mitigation and biodiversity in the forest sector.

Our results suggest that management portfolios emphasizing extended rotation periods, reduced thinning intensities, and shifting to continuous cover harvesting—particularly when coupled with long-lived wood product deployment that replaces fossil-intensive other materials —can boost carbon sequestration and biodiversity outcomes across Europe. However, they also suggest reduced near-time harvesting levels—which appears to be the more important regulator of forest C sinks than the method of harvesting. Changing harvesting regimes and other management practices can help closing the gap towards the 310 Mt CO₂ target and contribute to the EU’s 2050 climate neutrality goal, but they also affect near-time harvest yields.

How to cite: Peltoniemi, M., Rautiainen, A., Repo, A., Pugh, T., Eckes-Shephard, A., Lindeskog, M., Suvanto, S., Raymond, J., Arneth, A., Filipek, S., Schelhaas, M.-J., Nabuurs, G.-J., Moiseyev, A., Orfanidou, T., Müller, A., Cardellini, G., van't Veen, H., and Verkerk, H.: Exploring climate and biodiversity smart forest management options for European forests, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13226, https://doi.org/10.5194/egusphere-egu26-13226, 2026.

Boreal forests play a vital role in the global carbon cycle, yet the stability of this sink is uncertain during a period of rapid global environmental change. Swedish forest biomass has increased in recent decades, yet it remains unclear whether primary and managed secondary forests have changed similarly, and to what extent changes are driven by stand-age or shifts in growth curves. This is because intensive forest management practices in Sweden such as thinning, draining and fertilisation may obscure the effect of environmental changes, while rotational clear-cutting reduces the stand age. Here, we combine extensive National Forest Inventory data from 1983 to 2022 with random forest models to disentangle potential drivers of biomass change across forest types by isolating growth-curve and stand-age distribution effects. Our results indicate that management suppresses potential growth curve enhancement at a given stand-age as well as reducing the stand-age itself, leading to little net biomass change in managed secondary forests but large increases in primary forests. With the continued logging of unprotected primary forests, as well as the projected increase in warming, this has significant implications for the future boreal forest carbon stock.

How to cite: Register, E., Smith, H., Lindström, J., and Ahlström, A.: Enhanced growth rate and stand age leads to stronger biomass increase in primary versus managed secondary forests, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14710, https://doi.org/10.5194/egusphere-egu26-14710, 2026.

European forests have been subject to increasingly severe disturbances over recent years, particularly with respect to bark beetle outbreaks and fires. The occurrence of such disturbances will likely increase with intensifying climate change, impacting the services that forests provide including climate change mitigation and wood production. Disturbances events are, however, challenging to simulate, which means that possible changes in disturbances rates have been generally excluded from future projections of European forest dynamics. Here we draw on recent developments in the LPJ-GUESS dynamic vegetation model, allowing to simulate bark beetle outbreak, windthrow and fire at the European scale. We initialise LPJ-GUESS with observations of forest stand age and species composition from field and remotely-sensed data. Then we make projections of European forest dynamics over the period 2025–2100 under both strong and moderate climate change scenarios. Consideration of disturbances had locally substantial effects on the carbon sink, biomass stock and harvest extractions, but the effect averaged over the whole continent was relatively modest. Adaptation actions related to modifications of harvest rates, such as shortening or lengthening rotation periods, tended to impact forest dynamics more through their direct effects on harvest than through their interactions with disturbance impacts. Overall, it is harvest actions, not disturbances, which appear to primarily govern the future of the European forest.

How to cite: Pugh, T., Eckes-Shephard, A. H., Lindeskog, M., Arneth, A., Jönsson, A.-M., Lagergren, F., Miller, P. A., Nieradzik, L., Olin, S., Peltoniemi, M., Rautiainen, A., Schelhaas, M.-J., Suvanto, S., Verkerk, P. J., Wittenbrink, M., and Zhong, H.: The impact of future forest disturbances on the European forest carbon sink, stock and wood production, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17236, https://doi.org/10.5194/egusphere-egu26-17236, 2026.

Changes in alpine land management have led to the abandonment of high-altitude pastures in the European Alps. At the same time, climate warming facilitates upward forest expansion, creating opportunities for carbon (C) sequestration by afforestation. However, the magnitude of this potential remains uncertain, as soil C responses and forest growth at high elevations are still poorly understood.

We quantified biomass and soil C stocks in forest stands planted on subalpine pastures (1,600–2,100 m a.s.l.) in the Austrian Alps and compared them with adjacent pastures. In addition, we assessed vascular plant diversity and analysed timberline dynamics surrounding the afforestation sites.

Afforested plots stored 121 ± 49 Mg C ha⁻¹ more organic C than pastures, corresponding to a sequestration potential of 441 ± 179 Mg CO₂ ha⁻¹ within ~55 years after planting. Carbon sequestration occurred predominantly in tree biomass, which grew remarkably well despite the high-elevation conditions, while soil C stocks remained largely unchanged. Vascular plant diversity declined significantly under closed forest canopies, although higher diversity in nearby mature forests indicates partial recovery at later stand stages. Despite regional warming, the upper forest boundary remained largely stable over the past two decades.

Our results suggest that afforestation can accelerate forest establishment around the current upper forest edges and create local carbon sinks, while biodiversity impacts are mixed and strongly context-dependent.

How to cite: Schindlbacher, A., Inselsbacher, E., Foldal, C., König, A., Giunta, A., Markart, G., Lapin, K., Steiner, H., Schumacher, B., Kopecky, K., Schueler, S., Kindermann, G., and Ledermann, T.: Carbon sequestration potential of high-altitude afforestations in the Eastern Alps, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17632, https://doi.org/10.5194/egusphere-egu26-17632, 2026.

In recent years, German forests have faced numerous stress episodes, such as droughts, heatwaves and insect outbreaks, leading to a significant rise in tree mortality. Consequently, deadwood production increased, partly outpacing extraction capacities. This trend coincides with a shift towards more selective forest management methods that partially retain deadwood on logged sites. As a result, the average amount of deadwood per hectare in Germany has substantially increased, climbing from 19.9 m³ ha^-1 yr^-1 in 2012 to 29.4 m³ ha^-1 yr^-1 in 2022.

Besides providing valuable species habitats and sequestering carbon, deadwood plays a significant role in the water cycle, by reducing surface runoff and acting as a water reservoir.

Despite its growing abundance and ecological relevance, deadwood is largely neglected in current land surface models such as in JSBACH (ICON-LAND main component), particularly with respect to its impact on hydrology and microclimates.

This omission is rooted in the historical removal of deadwood under conventional management and in limited understanding of deadwood's hydrological properties, which vary with factors such as soil characteristics, canopy closure, deadwood position and species.

Here, we present an approach to quantify and model the influence of deadwood on hydrology and microclimates, by combining experimental field measurements from Bavarian Nature Reserves and the data from the LabForest project in the University forest of the LMU in southern Germany with JSBACH outputs. We compare different methodological pathways for deriving observation-based parameterizations suitable to model integration. Preliminary results indicate that deadwood exerts measurable effects on near-surface microclimate and soil moisture dynamics, highlighting the need to explicitly represent deadwood in land surface modeling frameworks.

How to cite: Matthias, B., Wolfgang, O., Lukas, L., Julia, P., and Markus, B.: Modelling the impact of dead wood water retention in Central European Forests, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-18726, https://doi.org/10.5194/egusphere-egu26-18726, 2026.

Forests are central to climate change mitigation while simultaneously delivering co-benefits to biodiversity, bioeconomy, and climate adaptation. Yet scientific evidence on forest’s mitigation capacities is often fragmented across datasets, spatial scales, and scenario assumptions, consequently limiting accessibility, understandability, and transparency for decision-making. This contribution presents the ForestNavigator Portal, a science–policy interface designed to support the integrated exploration of forest carbon mitigation pathways and associated mitigation potentials in the European Union.

The platform combines spatially explicit forest monitoring data with emerging pathway outputs derived from alternative policy scenarios to enable a consistent assessment of both historical dynamics, present conditions, and future mitigation options under a range of policy assumptions. The first portal component, the Data Explorer, provides harmonised geospatial indicators, including forest cover, disturbance, and carbon stock change, visualised primarily through spatial maps to support examination of recent trends and disturbance regimes relevant for monitoring and assessment of changes in forest carbon stocks. The Pathways Explorer, the second component, enables comparative analysis of mitigation pathways at EU level, while also supporting exploration of pathways at country level, informed by national data and models, across alternative policy scenarios using aggregated indicators and comparative visual summaries reflecting alternative forest management, wood-use, biodiversity, and adaptation options. Policy scenarios will include an EU reference policy scenario as well as alternative policy pathways for EU forests, based on stakeholder’s input from scenario co-development exercises.

A core methodological contribution is the platform’s capacity to make forest mitigation pathways directly comparable across alternative policy scenarios, with a focus on improving the accessibility and understandability of pathway assessments while supporting the exploration of uncertainty through comparison across alternative policy scenarios and interactions across key dimensions. Interactive comparison functions, split-screen visualisations, and downloadable harmonised datasets reduce barriers between complex modelling outputs and policy-relevant interpretation. Particular attention is given to disturbance monitoring within the Data Explorer and to adaptation-oriented considerations in pathway exploration.

By integrating monitoring data and pathway results within a unified interface, the ForestNavigator Portal advances the practical use of forest science for climate mitigation planning. The approach supports evaluation of combined forest mitigation portfolios rather than isolated measures and contributes to improved science-based understanding of forests capacity to mitigate climate change under evolving environmental and socio-economic conditions.

How to cite: Singh, K. N., Schmidt, S., Ali, S., Singh, R., Derci Augustynczik, A. L., Lejeune, Q., and Di Fulvio, F.: Enhancing accessibility and understandability of forest mitigation pathways anddata through an integrated science-policy interface, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20799, https://doi.org/10.5194/egusphere-egu26-20799, 2026.