Publications de l'IFN

• Bührle L.J., Kalt T., Bebi P., Teich M., Hobi M.L., Bast A., … Bottero A. (2026) Regional disturbance predisposition assessment to support management in Norway spruce-dominated mountain forests. For. Ecol. Manag. 611, 123636 (17 pp.). https://doi.org/10.1016/j.foreco.2026.123636

  Mountain forests provide essential ecosystem services, including protection against natural hazards. However, climate change and the predominance of structurally homogeneous Norway spruce stands increase their predisposition to disturbances such as windthrow, bark beetle infestation, and snow breakage. Given limited resources for proactive and reactive forest management, prioritizing silvicultural interventions is crucial. We present a framework for the spatially explicit assessment of forest predisposition to snow breakage, windthrow, and bark beetle infestation at 10 m resolution across regional scales. The approach integrates high-resolution forest structural and site factor attributes primarily derived from nationally available airborne laser scanning (ALS) data. These attributes are weighted using an expert-based model according to their influence on disturbance predisposition. Weighted values are aggregated and classified into four predisposition classes, from low (< 50th) to extreme (> 95th percentile). Validation of local foresters at 142 reference sites showed significant correlations between forester-rated and modeled predisposition for windthrow and bark beetle, but not for snow breakage. New bark beetle infestations were strongly associated with increasing predisposition classes. Forest structural parameters such as forest mixture and spruce share, development stage, and canopy layering were key predictors and could be determined with high accuracy, enabling detailed and accurate predisposition mapping even in steep terrain. Assessing predisposition to snow breakage remains challenging due to the high stochastic variability in the location, characteristics, and amount of snow fall. As the main predictors are derived from nationwide ALS data, the methodology is transferable to other mountain regions. Developed in close collaboration with practitioners, the framework supports operational forest management by improving prioritization of interventions.

  DOI: 10.1016/j.foreco.2026.123636

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• Clerc‐Schwarzenbach F., Astagneau P.C., Muñoz Castro E., van Meerveld I., Seibert J., Andréassian V. (2026) Cheeky cheating or a sensible strategy? 'Sweep parameters' in bucket‐type hydrological models. Hydrol. Process. 40(1), e70375 (7 pp.). https://doi.org/10.1002/hyp.70375

  The model performance of bucket-type hydrological models is often improved by including an additional path for water to enter or leave the catchment, aside from precipitation, evaporation, and streamflow. We refer to parameters allowing for such an additional path as 'sweep parameters'. Far from being an exception, sweep parameters are rather ubiquitous. In this commentary, we discuss the relevance and justifiability of sweep parameters. We argue that although the use of sweep parameters can be considered cheating, as it is a way to fix the water balance, it is a transparent way to do so. Furthermore, in some cases they may represent actual processes. We also present some results on the effects of a sweep parameter on the performance and robustness of two bucket-type hydrological models. We find that sweep parameters do not necessarily reduce model robustness towards variations in the meteorological inputs and often improve streamflow simulations. Therefore, sweep parameters should not per se be frowned upon, as long as they are clearly described and not hidden under the rug.

  DOI: 10.1002/hyp.70375

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• Huo J., Stadelmann G., Burg V., Subal L., Jakobs A., Thürig E., Hellweg S. (2026) Prospective climate change impacts of Swiss forest management and wood utilization strategies by integrating biogenic carbon dynamics. Resour. Conserv. Recycl. 226, 108692 (12 pp.). https://doi.org/10.1016/j.resconrec.2025.108692

  Forests and wood products play crucial roles in climate change mitigation, yet their climate impacts remain poorly understood. We couple empirical Swiss forest development models with dynamic life cycle assessment to evaluate climate impacts of two forest management scenarios (reference and increased harvest) and four wood utilization scenarios (business-as-usual, increased material use, extended lifetime, and chemical substitution) in Switzerland from 2014 to 2113. Results reveal that increased harvest leads to higher climate impacts compared to the reference management practices under empirical modeling, contradicting simplified regrowth model conclusions favoring increased harvest. The contrasting results underscore uncertainty in forest carbon projections, warning against simplified carbon-neutrality assumptions of biogenic CO₂ emissions. Increased wood use for construction applications and extended product lifetimes demonstrate climate benefits, while diverting wood from energy to chemical production increases emissions. We emphasize the necessity of improved forest carbon modeling for informed climate mitigation strategies and recommend prioritizing long-lived wood construction applications.

  DOI: 10.1016/j.resconrec.2025.108692

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• Li B., Pang Y., Kükenbrink D., Wang L., Kong D., Marty M. (2026) ITS-Net: a platform and sensor agnostic 3D deep learning model for individual tree segmentation using aerial LiDAR data. ISPRS J. Photogramm. Remote Sens. 231, 719-744. https://doi.org/10.1016/j.isprsjprs.2025.11.019

  Recent advances in aerial Light Detection and Ranging (LiDAR) technologies have revolutionized the capability to characterize individual tree structure, enabling detailed ecological analyses at the tree level. A critical prerequisite for such analysis is an accurate individual tree segmentation. However, this task remains challenging due to the complexity of forest environments and varying quality of point clouds collected by diverse aerial sensors and platforms. Existing methods are mostly designed for a single aerial platform or sensor and struggle with complex forest environments. To address these limitations, we propose ITS-Net, an aerial platform and sensor-agnostic deep learning model for individual tree segmentation, which integrates three modules designed to enhance its learning capability under complex forest environments. To facilitate and evaluate its platform and sensor-agnostic capabilities, we constructed AerialTrees, a comprehensive individual tree segmentation dataset that included aerial LiDAR data collected with point densities ranging from 50 to 10,000 pts/m² using different sensors from ALS and ULS platforms over four climate zones. This dataset also included 2,903 individual trees that had been labeled manually. ITS-Net outperformed state-of-the-art individual tree segmentation methods on AerialTrees, achieving the highest average performance with a detection rate of 94.8 % and an F1-score of 90.9 %. It achieved an F1-score of 88.1 % when tested on the publicly available FOR-instance dataset. ITS-Net also performed better than the state-of-the-art ForAINet method for multi-layered canopy segmentation, outperforming the latter by 12.3 % in detecting understory vegetation. When directly transferred to the five study sites of the FOR-instance dataset as well as the study sites in Switzerland and Russia, ITS-Net produced accuracies that were reasonably close to those produced by several other algorithms trained over those study sites. These results were achieved without requiring efforts to address differences in LiDAR data characteristics through explicit data preprocessing or to fine tune the parameters of the deep learning model, demonstrating ITS-Net's robustness for segmenting various aerial LiDAR point clouds acquired using different sensors from different aerial platforms. As a sensor and platform agnostic method, ITS-Net may provide an end-to-end solution needed to facilitate the use of rapidly evolving aerial LiDAR technology in various forestry applications. The AerialTrees dataset developed through this study is a significant contribution to the very few publicly available labeled LiDAR datasets that are crucial for calibrating, testing, and benchmarking individual tree segmentation algorithms. Our code and data are available at: Global warming has shifted the timing of leaf senescence, influencing water and carbon cycles in terrestrial ecosystems. Climate conditions preceding leaf senescence play a critical role in regulating senescence timing, yet the temporal variation in the effect of temperature on leaf senescence remain unclear, hindering accurate predictions of growing season length. Based on 321,639 in situ phenological records of four dominant European tree species (Aesculus hippocastanum, Betula pendula, Fagus sylvatica, and Quercus robur) collected from 1950 to 2021, we found that leaf senescence has significantly delayed by 5.7 days over the past seven decades, primarily driven by preseason temperature and the timing of spring leaf-out. Rising preseason temperatures delayed leaf senescence (β = 0.37, P < 0.05), whereas earlier leaf-out timing advanced it (β = 0.32, P < 0.05). More importantly, the effects of temperature on leaf senescence have shifted significantly, with the delaying effect of temperature becoming stronger, especially in cold regions. This variation could be explained by the divergent effects of early- and late-season temperature on leaf senescence, as well as by the shortened optimal preseason length of temperature (−2.3 days per decade). Our study highlights the importance of the optimal preseason length of temperature in regulating leaf senescence and emphasizes the need to incorporate its variation into senescence models to improve predictions of growing season length and carbon-cycle dynamics..

  DOI: 10.1016/j.isprsjprs.2025.11.019

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• Lu Y., Eisenhauer N., Patoine G., Chen Y., Heintz-Buschart A., Küsel K., … Guerra C.A. (2026) Landscape effects on global soil pathogenic fungal diversity across spatial scales. Nat. Commun. 17, 1164 (15 pp.). https://doi.org/10.1038/s41467-025-67929-5

  Growing evidence has shown that, apart from local environmental factors, changes in landscape-level factors by accelerated land-use change can also shape soil pathogenic fungal diversity. However, the global representativeness of such patterns remains unclear. Here, we assess how pathogenic fungal diversity in 511 soil samples worldwide responds to landscape factors, including landscape complexity index based on eight landscape metrics and quantity of different land cover types across six spatial scales (i.e., surrounding landscape, 250 m to 10,000 m radii from the sampling coordinate). We find that while soil variables explain over half of the variance, pathogenic fungal alpha diversity increases with landscape complexity and crop cover proportion, but decreases with grass and tree cover proportion, together explaining 23.4% of the total variance. Landscape factors have weaker impacts on beta diversity, explaining 13.0% of the variance. Across spatial scales, grassland ecosystems exhibit increasingly stronger responses to landscape variables compared to forest ecosystems. Landscape factors have a higher relative contribution to root-associated fungi than leaf/fruit/seed-associated fungi. Our results emphasize the importance of local factors and the complementary role of landscape patterns in shaping global soil pathogenic fungal distributions, highlighting scale-dependent effects across ecosystems and fungal functional groups.

  DOI: 10.1038/s41467-025-67929-5

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• Manzanedo R.D., Visakorpi K., Bieger A., Temperli C., Portier J., Goetsch S., Hille Ris Lambers J. (2026) High climatic niche stability across life stages in Swiss forest tree species. J. Ecol. 114(5), e70338 (17 pp.). https://doi.org/10.1111/1365-2745.70338

  1. Ontogenetic niche dynamics, that is the change in environmental requirements throughout an individual's development, remains an underexplored aspect in ecological research with potentially major implications for predicting species responses to climate change. Despite a growing body of research in tree regeneration dynamics, multispecies assessments to establish the expectations for niche ontogeny are still lacking.
  2. Here, we used country-wide repeated inventory data from the Swiss National Forest Inventory to: (i) compare juvenile and adult climate niches across 43 tree species, (ii) investigate the direction and magnitude of ontogenetic niche shifts across species, and (iii) investigate the temporal consistency of these niche estimates over inventories. Additionally, for the five best replicated species, we investigate niche overlaps and shifts in further detail over seven size classes, spanning from juveniles under 10 cm in height to large adult trees.
  3. Ontogenetic niche conservatism, that is large niche overlap between size classes, was the prevailing pattern across species. Non-overlapping fractions of the niche were small and tended to be suitable to juveniles only, suggesting slightly larger juvenile than adult niches. In-detail analyses of size class transitions also suggested high niche overlap between consecutive sizes classes (>93% in average). Niche estimations were temporally consistent over inventories for both adults and juveniles, though lower for juveniles. Finally, juvenile niche shifts did not align with climate change expectations, being highly variable across species. Consecutive size class transitions similarly indicated niche shifts that were not consistent within- nor across species.
  4. Synthesis. Our results strongly suggest niche conservatism as the expected patterns across ontogeny over Swiss tree species. This imply that approaches relying exclusively on adult presence are still likely to be representative of all life stages, at least for temperate trees at mesic conditions, which are those best represented across Swiss forests. At the same time, the lack of clear climate change responses in juveniles (or across size classes) for most species emphasizes the importance of species-specific and non-climatic factors in predicting climate change range shifts. How these shifts in potential niches translate to in situ responses or tolerance to extremes of seedlings living under the canopy remain to be tested.

  DOI: 10.1111/1365-2745.70338

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• Moreno-Fernández D., Adame P., Breidenbach J., Cañellas I., Fischer C., Korhonen K.T., … Alberdi I. (2026) Cross-country patterns of compositional and structural forest diversity across European regions. Eur. J. For. Res. 145(4), 74 (15 pp.). https://doi.org/10.1007/s10342-026-01909-2

  Forest diversity is a multidimensional concept comprising different components such as species diversity, functional diversity, structural diversity and genetic diversity. These diverse elements are recognised as being connected to the health and functioning of forest ecosystems and human well-being. However, information on forest diversity at broad spatial scales is scarce. Thus, the primary goal of this study is to quantify compositional diversity (i.e., tree species heterogeneity) and structural diversity (i.e., tree size heterogeneity) across a wide climatic gradient in European forest ecosystems, while also examining the influence of forest attributes and climatic variables on these two key components of forest diversity. Using harmonised data from eight European National Forest Inventories (n = 146,235 plots), we calculated Shannon's Diversity Index as a measure of compositional and structural diversity. Finally, we estimated measures of forest diversity at three spatial scales (α, β and γ-diversity) for each country. Basal area was positively related to compositional and structural diversity. In contrast, the quadratic mean diameter of the trees in each plot presented both positive and negative relationships with compositional and structural diversity, respectively. Climatic variables played a minor role, with precipitation and temperature showing a positive association with forest compositional and structural diversity. Furthermore, our findings revealed a positive link between compositional and structural diversity. Finally, the compound analyses of α, β, and γ-diversity emerged as key elements in interpreting compositional patterns at landscape scale. Results revealed strong scale dependence (from local to landscape level) in diversity metrics across countries, thereby highlighting the importance of reporting national forest information at multiple spatial scales.

  DOI: 10.1007/s10342-026-01909-2

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• Nabuurs G.J., Maximo Y.I., Starcevic A., Patacca M., Filipek S., Schulte M., … Schelhaas M.J. (2026) Contemporary high resolution European forest structure assessed using tree-level National Forest Inventory data. PLoS One. 21(6 June), e0346611 (20 pp.). https://doi.org/10.1371/journal.pone.0346611

  This exploratory study presents an objective and consistent approach for assessing forest structure across multiple European countries, focusing on the distributions of tree species and tree diameter at breast height (DBH) as assessed by European National Forest Inventories (NFIs) and one landscape inventory. We distinguish six structural classes, ranging from mono-specific plots with a narrow (regular) DBH distribution to multi-species plots with a wide (irregular) DBH distribution. We used tree level data on basal area, species, and diameter, from 18 countries, and harmonised the data as much as possible by adopting a common diameter measurement threshold and by scaling the different plot radii to one ha. Data from 255,418 inventory plots indicate that roughly half of the forests are dominated by a single-species, while the other half consists of multiple-species. According to our approach, the predominant structural type in the surveyed countries is characterized by single-species dominance (56%) and a narrow DBH distribution. The relatively small plot radii across inventories and the diameter threshold of 10 cm also contribute to dominance of this structural type. The single-species regular class was the most prevalent ranging from 35.8% in Switzerland to 79.7% in Spain. The second most important was the multiple-species regular class, present on 37.7% of the forest area. Although the plots are not weighed to the full forest area, these results indicate a regular forest structure on 94% of Europe’s forests. The distribution of forest area per country over the categories varied only moderately. A shortcoming of a groundbased study is the challenge of harmonisation due to the different plot design of NFIs, showing a range in the plot radii from 9 to 25 meters hampering the comparison between countries. The results as presented at 0.2 degrees resolution (approximately 20 x 20 km) provide insight into forest structure in a consistent manner and can be updated in the future based on new releases of forest inventories. Although we did not study the effect of forest management on the current structure, these results are a basis to report temporal and spatial effects of management changes at this semi-high resolution, highly relevant to the EU Nature Restoration Law. We see this spatially explicit result as very promising, with advantages compared to the alternative of highly aggregated international statistics..

  DOI: 10.1371/journal.pone.0346611

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• Rüetschi M., Marty M., Waser L.T., Ginzler C. (2026) Das Trio der Vegetationshöhenmodelle des LFI – Evaluation und Empfehlungen für forstliche Anwendungen. Schweiz. Z. Forstwes. 177(2), 123-126. https://doi.org/10.3188/szf.2025.0123

  Das Schweizerische Landesforstinventar stellt neu drei flächendeckende Vegetationshöhenmodelle basierend auf unterschiedlichen Fernerkundungsdaten (LiDAR-Daten, Luft- und Satellitenbildern) auf map.geo.admin.ch zur Verfügung. Im folgenden Artikel werden die Unterschiede aufgezeigt und konkrete Nutzungsempfehlungen für verschiedene forstliche Anwendungsbereiche abgegeben.

  DOI: 10.3188/szf.2025.0123

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• Salak B., Trummer J., Hegetschweiler K.T., Fraefel M., Wunderlich A.C., Bauer N., … Hunziker M. (2026) Integrating physical and social variables to enhance understanding of urban forestry key-indicators: insights from a socio-cultural forest monitoring. Urban For. Urban Green. 118, 129311 (14 pp.). https://doi.org/10.1016/j.ufug.2026.129311

  Urban forests are vital for enhancing urban life, as they provide environmental benefits and support human well-being. They contribute to cleaner air, cooler cities, and mental and physical health. Yet, despite their importance, little is known about how physical forest features and social perceptions interact to shape the attractiveness of these forests for recreation and well-being. This study addresses this gap by integrating ecological and social perspectives in the context of Switzerland. A nationwide survey (n = 3116) was conducted where respondents were asked to map the forest they visited most frequently and to evaluate their recreation experiences. These spatially explicit participatory GIS data were linked with detailed forest inventory information. Distinct statistical models were developed to explain five indicators of forest use and perception: Reported "Visit frequency", "General visit satisfaction", "Perceived visual attractiveness", satisfaction with "Forest care and management", and "Self-perceived well-being". The results show that social and cultural variables explain outcomes far better than physical forest characteristics. The explanatory power of the models ranged from 13 to 40 %, with forest meanings, especially personal connection to forests, emerging as the most important factor. Spatial patterns revealed distinct clusters of high and low values across Switzerland. In particular, differences corresponded with well-known language regions, highlighting the influence of cultural context. Physical access factors, e.g., distance to bus stops, were of little relevance. These findings highlight the decisive role of people's perceptions, meanings, and cultural background in shaping forest-related experiences. They demonstrate that physical features alone cannot explain how forests are valued and used. By combining social and ecological data, this study offers a model for understanding urban forests that can be applied in other regions. It provides evidence that policy and planning must integrate cultural and social dimensions to improve management, enhance recreational value, and strengthen the role of urban forests in supporting well-being.

  DOI: 10.1016/j.ufug.2026.129311

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• Schweier J., Holm S. (2026) JuWaPfl (V.1.3): das WSL-Tool zur Schätzung von Produktivität und Kosten der Jungwaldpflege. Infoblatt Arbeitsgr. Waldplan. manag. 2026(1), 1-4.

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• Temperli C., Schweier J., Bont L. (2026) Arbeitsverfahren und Kosten der Holzernte in der Schweiz – eine Betrachtung über die letzten 30 Jahre. Schweiz. Z. Forstwes. 177(3), 156-164. https://doi.org/10.3188/szf.2026.0156

  Diese Studie untersuchte Entwicklungen bei Holzernteverfahren, Mechanisierungsgrad und Holzerntekosten in der Schweiz über die letzten drei Jahrzehnte. Die Daten dazu lieferte das schweizerische Landesforstinventar (LFI). Als Grundlage dienten Felddaten und Daten aus der Befragung der Forstdienste. Das Produktivitätsmodell HeProMo ermöglichte eine Berechnung auf einheitlicher Basis. Die Holzerntekosten auf allen LFI-Probeflächen mit waldbaulichen Eingriffen wurden so für 17 definierte Holzernteverfahren ermittelt. Die Ergebnisse zeigten, dass die häufigsten Eingriffe im Mittelland und im Jura stattfanden, wobei Sturmereignisse, Trockenheit, Bor kenkäfer und Eschentriebsterben oft die Auslöser waren. Das teilmechanisierte Verfahren «Motormanuelle Holz hauerei mit Bringung (Rückung) durch Schlepper» war am weitesten verbreitet, hat aber zugunsten vollmecha nisierter Verfahren deutlich an Bedeutung verloren – insbesondere im Mittelland und im Jura. In den Alpen nahm hingegen der Einsatz seilgestützter Verfahren zu, mit einem Trend hin zu mobilen Seilkränen. Die modellierten Holzerntekosten blieben über alle Inventuren und während der Berichtsperiode relativ stabil. Klare Unterschiede zeigten sich jedoch innerhalb der einzelnen Verfahren, wobei bodengestützte vollmechanisierte Verfahren die geringsten Kosten verursachten. Insgesamt zeigte sich ein langfristiger Trend zu höherer Mechanisierung und kostengünstigerer Holzernte in gut erschlossenen Tieflagen, während Bergwälder weiterhin auf kostenintensi vere, seil- und luftgestützte Verfahren angewiesen waren. Zukünftige Produktivitätsmodelle sollten Zwangsnut zungen expliziter berücksichtigen, da deren Bedeutung im Zuge des Klimawandels voraussichtlich zunehmen wird.
  
  Timber harvesting methods and costs in Switzerland – a review of the last 30 years
  This study examined trends in timber harvesting methods, the degree of mechanisation and timber harvesting costs in Switzerland over the last three decades. The data were pro vided by the Swiss National Forest Inventory (NFI). The ana lysis was based on field data and data from a survey of fo restry services. The HeProMo productivity model enabled calculations on a consistent basis. Timber harvesting costs were thus determined for 17 defined harvesting methods across all LFI sample plots where silvicultural interventions had taken place. The results show that the most frequent in terventions occurred in the Swiss Plateau and the Jura, with storm events, drought, bark beetles, and ash dieback often being the triggers. The semi-mechanised method “motor- manual felling with skidding by tractor” was the most wide spread but has lost significant ground to fully mechanised methods – particularly in the Swiss Plateau and the Jura. In the Alps, by contrast, the use of cable-based methods in creased, with a trend towards tower yarders. The modelled timber harvesting costs remained relatively stable across all inventories and during the reporting period. Clear differences were evident within the individual methods, however, with ground-based fully mechanised methods incurring the lowest costs. Overall, there was a long-term trend towards a higher degree of mechanisation and more cost-effective timber har vesting in easily accessible lowland areas, whilst mountain fo rests continued to rely on more cost-intensive, cable- and air based methods. Future productivity models should take salvage logging into account more explicitly, as its signifi cance is likely to increase in the wake of climate change.

  DOI: 10.3188/szf.2026.0156

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• Trummer J., Wunderli J.M., Schäffer B., Hunziker M., Tobias S., Heusser A., … Hegetschweiler T. (2026) The role of visual and acoustical characteristics on forest attractiveness. Urban For. Urban Green. 118, 129306 (15 pp.). https://doi.org/10.1016/j.ufug.2026.129306

  Recreational forests play a vital role for human well-being and recreation. Yet, the role of and interplay between visual and auditory environmental characteristics in forest recreation remain underexplored. This study investigates how multisensory characteristics, particularly visual forest characteristics and the local soundscape, influence perceived forest attractiveness, perceived restfulness, and visit frequency aiming to gain a holistic understanding of forest visitors' multisensory perceptions of recreational environments. Employing a mixed-method approach, we conducted quantitative surveys with a total of 482 participants and recordings of the local soundscape at 20 study sites across Switzerland's lowlands with high recreational demand, which represent Swiss National Forest Inventory sample plots. Multilevel regression models combining physical forest data, acoustic, psychoacoustic and sound categories (e.g., birdsong, road traffic etc.) obtained from recordings, and survey data revealed that personal characteristics and individual soundscape perceptions accounted for the majority of variance for the three investigated variables. Notably, natural auditory stimuli such as birdsong enhanced perceived visual attractiveness, while anthropogenic sounds (e.g., helicopters, road traffic) significantly diminished restfulness and reduced visit frequency. Ground vegetation features, such as moss and ferns, also positively influenced perceptions, while dense understory and deadwood had negative impacts. The results highlight the importance of subjective, multisensory experience (e.g., perceived soundscape quality) over environmental characteristics and external sounds in shaping forest preferences. The study’s findings further emphasize the importance of integrating soundscape considerations into forest planning to maintain and enhance restorative qualities, as well as the need for holistic, multisensory strategies in recreational forest management.

  DOI: 10.1016/j.ufug.2026.129306

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• Weixelbaumer M., Abegg M., Wilkes-Allemann J. (2026) A dataset of inventory plots and biomass estimates from the Chaco dry forest. Ann. For. Sci. 83, 14. https://doi.org/10.1186/s13595-026-01327-9

  In the study area around Yacuiba, Bolivia, four field inventory plots were established. The associated plots cover a total of 16 ares of Chaco forest, distributed across zones of high and low photosynthetic activity. This dataset supports the assessment of climate impacts and provides field-based data for biomass analysis.

  DOI: 10.1186/s13595-026-01327-9

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• Wohlgemuth T., Abegg M., Kupferschmid A.D., Molteni U., Moser B., Nikolova P., Scherrer D. (2026) Stammzahlen zur Verjüngung in Schweizer Wäldern nach Region und Höhenstufe 1995–2022. Schweiz. Z. Forstwes. 177(2), 81-91. https://doi.org/10.3188/szf.2026.0081

  Angesichts der sich rasch ändernden klimatischen Bedingungen stellt sich die Frage, wie sich der Schweizer Jungwald verändert und ob die aufgrund der aktuellen Verjüngung absehbare Menge und die Zusammensetzung der Baumarten den zukünftigen Ansprüchen an den Wald genügen werden. In der vorliegenden Studie werden die repräsentativen Verjüngungserhebungen bezüglich Stammzahlen, die im Rahmen des Schweizerischen Landesforstinventars (LFI) für die Zeiträume 1993–1995 (LFI2), 2009–2017 (LFI4) und 2019–2024 (LFI5; Daten von 56% der Stichproben verfügbar) gemacht wurden, für biogeografischen Regionen und Höhenstufen sowie für zwei wichtige Standorttypen vergleichend analysiert und visualisiert. Hierfür verwenden wir die erfassten Stammzahlen pro Grössenklasse G1 10–39 cm (Anwuchs), G2 40–129 cm (Aufwuchs) und G3 ≥130 cm mit <12 cm BHD (Dickung). Landesweit stiegen die mittleren Stammzahlen im Anwuchs signifikant von 11 540 Stück/ha (LFI2) auf 14 400 Stück/ha (LFI4) und verringerten sich danach (LFI5) deutlich auf 11 900 Stück/ha. Im Aufwuchs stiegen die Stammzahlen zwischen LFI2 und LFI4 von 2900 auf 3770 Stück/ha und in der Dickung von 1660 auf 1970 Stück/ha deutlich an und verblieben danach (LFI5) auf diesem Niveau. Während die Stammzahlen im Jura und im Mittelland rund doppelt so hoch sind wie im landesweiten Mittel, erreichen sie in den Zentralalpen und auf der Alpensüdflanke die tiefsten Werte. Generell hat der Laubholzanteil zugenommen, wobei massgeblich die Buche zahlreicher wurde. Dagegen nahm die Esche von LFI4 zu LFI5 in allen Grössenklassen deutlich ab. Als Gründe für die Zunahme der Laubbäume kommen vor allem Zwangsnutzungen infolge zunehmender Extremereignisse und der Klimawandel infrage. Die Verjüngung in den Waldöffnungen ist eine Chance für die natürliche Anpassung an veränderte Umweltbedingungen. 

  DOI: 10.3188/szf.2026.0081

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• Wunderlich A.C., Hunziker M., Hegetschweiler K.T., Bauer N., Palm T., Weinbrenner H., … Salak B. (2026) Exploring forest visits: comparing experiences across Switzerland, Baden-Württemberg, and Bayern in Germany. Urban For. Urban Green. 117, 129228 (24 pp.). https://doi.org/10.1016/j.ufug.2025.129228

  Urban and peri-urban forests play an increasingly important role in public health and recreation, particularly in the context of urbanization and demographic change. This study compares forest visit patterns across Switzerland, Baden-Württemberg, and Bavaria based on harmonized, large-scale survey data. We analyze visit frequency, motives, satisfaction, and perceived forest health through multilevel and Bayesian models. Results show that individual factors strongly shape satisfaction and visit frequency, while regional effects are minimal. Our findings highlight the need for user-centered forest management that considers diverse motives and especially the needs of younger and more frequent users in urbanizing contexts.

  DOI: 10.1016/j.ufug.2025.129228

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• Wöhlbrandt A., Onay A., Bachmann-Gigl U., Falk W., Temperli C., Aspalter S., … Thurm E.A. (2026) Dual modeling approach reveals: Need for assisted migration to mitigate loss of forest productivity in Europe. J. Environ. Manag. 404, 129142 (11 pp.). https://doi.org/10.1016/j.jenvman.2026.129142

  Tree species selection is a critical forest management decision, raising fundamental questions: which species will survive and thrive under future climates, where, and to what extent? To address these questions, we applied a dual-model approach that combines 23 site index models with species distribution models. Drawing on a pan-European dataset of six million individual trees, the models project top height (site index) and climatic suitability (species distribution) for a reference period (1981–2010) and two future periods (2041–2070 and 2071–2100) under RCP4.5 and RCP8.5 scenarios. By integrating site index predictions with low-risk species distribution classifications, we restricted growth projections to climatically suitable ranges derived from Species distribution models (SDMs). Our analysis examined four key aspects: (1) overall changes in forest productivity, (2) regional gains and losses for each species across five major European regions, (3) the most productive species by region, and (4) species with the greatest productivity gains (“winners”). Results reveal contrasting trends: productivity is projected to increase in northern Europe but decline in southern and central regions. Beneficiary species include Douglas-fir, Norway spruce, and European larch in the north, and downy oak and black locust in the south. These findings point to potential management-relevant patterns, suggesting that non-native species may become increasingly suitable in northern regions, while southern forests may require a broader portfolio of adaptation and mitigation strategies to cope with projected productivity declines.

  DOI: 10.1016/j.jenvman.2026.129142

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