Mechanistic-statistical model for the expansion of ash dieback.

Ash ( Fraxinus excelsior ) is one of the most dominant species in UK broadleaved woodlands, contributing up to 10 million tonnes of national carbon stock. However, it is currently threatened by ash dieback disease ( Hymenoscyphus fraxineus ). Despite the pervasiveness of this pathogen, its impact on forests’ capacity to mitigate global change and the factors influencing symptom severity and mortality of infected trees are poorly understood. Analysing 40 years of data on ash dynamics, we assess impacts of ash dieback on the demography and carbon stocks of five natural populations. We further investigate risk factors for developing severe ash dieback symptoms or mortality. We observed an 8.7 % reduction in ash population numbers since previous surveys and a significant increase in mortality rates of small trees. There has been no significant increase in carbon stocks within ash populations since the conformation of ash dieback in the UK in 2012. Large trees have a decreased risk of mortality from ash dieback, while number of ash neighbours increased the risk. The severity of dieback symptoms decreased with increasing neighbourhood basal area and light availability. Trees with severe dieback symptoms hold 27.4 % of total carbon stored by ash trees, constituting a committed carbon loss or debt within these forests. Together, our results highlight the importance of stand density and light competition in modulating symptom severity and mortality of infected ash trees. We also suggest that the carbon debt within living, but fatally infected ash, requires consideration when calculating carbon mitigation capacities of effected forests. • Total ash population mortality rates haven't significantly increased since the first case of ash dieback in the UK in 2012. • Nearly a third of carbon stocks in ash constitute a committed debt of carbon, slowly lost as severely infected trees die. • Ash dieback symptom severity increased with decreasing light availability and neighbourhood basal area. • Likelihood of ash mortality increased for smaller trees and with number of ash neighbours.

ABSTRACTAsh dieback disease, caused by the pathogenic fungus Hymenoscyphus fraxineus, is now widespread in the UK. The pathogen has caused substantial loss of European ash over recent decades, the long‐term consequence of which is complex to assess. While no higher plant species are exclusively associated with ash, widespread ash mortality is predicted to affect woodland floral biodiversity because of the functional traits uniquely associated with this species: namely the greater light penetration through the canopy, rapid foliar decomposition and nutrient cycling abilities. In woodlands where ash is frequent, vascular plant communities may undergo considerable compositional changes after loss of ash trees. At present little is known regarding how ash trees contribute to plant community and functional diversity at a fine scale across different woodland types. Using data from 1274 survey plots characterized in the Woodland Survey of Great Britain alongside plant functional trait data, we examined the local relationship between ash trees and plant community diversity and functional trait distribution. We show that ash trees are significantly associated with key plant functional traits and diversity indices and that this functional association is not typical of other dominant canopy species in the UK. Specific leaf area, nutrient and pH requirements and community diversity show significant correlations with ash basal area across various woodland types. Additionally, effects of ash appear to interact with soil pH resulting in a greater structural effect of ash upon plant community composition in lower pH soils. These findings support previous suggestions that ash functions as a keystone species with respect to nutrient cycling and plant community composition with potentially stronger influence on lower pH soils. Consideration should be given to these ecological roles when monitoring and addressing the impacts of widespread ash mortality from dieback disease across Europe.

Olive (Olea europaea) is one of the most important crop trees, with olive oil being a key ingredient of the Mediterranean diet. Oleuropein, an oleoside-type secoiridoid, is the major determinant of olive oil flavor and quality. Iridoid biosynthesis has been elucidated in Catharanthus roseus, which produces secologanin-type secoiridoids, but iridoid biosynthesis in other species remains unresolved. In this work, we sequenced RNA from the fruit mesocarp of six commercial olive cultivars with various oleuropein contents during maturation and ripening. Using these data, we discovered three polyphenol oxidases with oleuropein synthase (OS) activity, a novel oleoside-11-methyl ester glucosyltransferase (OMEGT) that synthesizes a potential intermediate in the pathway, and a 7-epi-loganic acid O-methyltransferase (7eLAMT). Interestingly, the use of transcriptome assemblies for 15 plant species from three iridoid-producing plant orders (Lamiales, Gentianales, and Cornales) for orthogroup inference, and integration of two tissue expression panels from Jasminum sambac and Fraxinus excelsior, enabled the discovery of two 2-oxoglutarate-dependent dioxygenases (named 7eLAS) that synthesize 7-epi-loganic acid; by contrast, C. roseus 7-deoxy-loganic acid hydroxylase (7DLH), a known bottleneck in MIA production, is a cytochrome P450. This comparative co-expression method, which combines guilt-by-association and comparative transcriptomics approaches, can successfully leverage large datasets for untargeted discovery of enzymes. Given the increasing availability of expression data from species across the plant kingdom, the methods for gene discovery used in the present work can be readily applied to other untraced pathways.

In the Central Forest-Steppe of the European part of the Russian Federation, characterized by high plowed area and progressing degradation processes, protective forest plantations perform a key environment-forming and resource-saving functions. The aim of the study is to assess the forest reclamation potential of shelterbelts of different conditions and to substantiate the prospects for their use in agroforestry systems. The objects of study were 46 shelterbelts located on black soils in the Kamennaya Steppe, Semiluksky and Khokholsky districts of the Voronezh Region. The work was carried out using reconnaissance and instrumental survey methods, laying temporary test areas, taxation descriptions, and forestry reclamation assessment according to the E.S. Pavlovsky scale and the Forests Sanitary Safety Regulations. It was found that the studied plantations are in the age range of 20-126 years, differing in their species composition, structure, and sanitary condition. Based on the analysis of quantitative and qualitative forestry factors, three models of forest belts have been identified: those that have completely lost their intended purpose (subject to replacement), those that have partially lost their functions (require reconstruction), and those that have retained high efficiency (need systematic care). This made it possible to classify land areas according to the level of agroreclamation potential. The first group includes plantations with high forest reclamation efficiency (Forest reclamation assessment class 5a–4b) that do not require operational measures; the second group includes plantations with low potential (Forest reclamation assessment class 3a–3b) that are viable under reconstruction; the third group includes dead or poorly preserved plantations (Forest reclamation assessment class 2–0) that need complete replacement. The fourth group consists of low productivity agricultural lands suitable for implementing forest-climatic projects with a zero baseline. It has been shown that the most stable and productive plantings are those with the participation of Quercus robur and Acer platanoides and timely forest management. High reclamation potential is also demonstrated by mono species poplar and birch forest belts aged 20-30 years with tracery windswept structure. It has been found that practically 100% mortality of Fraxinus excelsior and Fraxinus pubescens due to the damage caused by the Agrilus planipennis, which requires excluding these species from the composition of the created protective plantations. The obtained results allow for a differentiated approach to planning measures for preservation, reconstruction, and new afforestation, as well as serve as a basis for integrating protective forest plantations into regional sustainable development strategies and forest-climatic projects.

Accurate characterization of stomatal morphology and surrounding epidermal traits is essential for understanding stomatal function. A comparative protocol is presented using two complementary techniques-epidermal peels and leaf clearing-to assess stomatal and epidermal cell size, shape, and density in two ecologically distinct dicot species, Fraxinus excelsior and Taraxacum officinale. The protocol includes detailed steps for sample preparation, imaging, and trait quantification using cost- and labor-effective manual measurements (tissue clearing and peeling), and AI-assisted image analysis with the potential to facilitate high throughput applications. Three segmentation tools-a YOLOv8-based stomatal detection model, a generalist deep learning tool for cell segmentation, and a pixel-based classifier-were evaluated for their accuracy and suitability across methods. Significant differences in stomatal and epidermal traits are consistently observed between peeling and clearing techniques in both manual and AI analyses. AI tools enabled reproducible quantification, with YOLOv8-based stomatal detection model (StoManager1) performing best for stomatal traits and a generalist deep learning tool for cell segmentation (Cellpose) for epidermal segmentation. AI-based trait detection was highly consistent in T. officinale but limited in F. excelsior, results still diverged from manual measurements, illustrating how species-specific anatomy and image quality impact method suitability. These findings suggest that while AI-assisted analysis provides a useful framework for stomatal and epidermal trait quantification, expert validation and pilot testing remain essential before broader or high-throughput application.

ABSTRACT Water potential gradients govern water fluxes, and plants respond with species‐specific hydraulic traits that influence ecosystem function. While understanding these traits is key to predicting vegetation responses to climate change, traditional methods like the pressure chamber limit temporal resolution and continuity. Additionally, suitable methods for continuous monitoring remain limited. We addressed this gap by evaluating the potential of microtensiometers for continuous stem water potential ( ψ stem ) monitoring in mature forest trees across three temperate sites. We collected ψ stem data over the 2023–2024 vegetation periods from 21 microtensiometers installed in Fagus sylvatica , Fraxinus excelsior and Carpinus betulus , alongside high‐frequency soil matric potential ( ψ soil ) measurements and meteorological data. Microtensiometers provided realistic daily cycles and good agreement with pressure chamber‐derived leaf water potential ( ψ leaf ). Crucially, our results show that ψ soil , next to species identity, is one dominant driver of stem water potential across sites. Diurnal patterns showed that ψ stem is driven by shallow soil layers during the day, when strong transpirational pull creates more negative ψ stem , enabling access to these drier upper soils. At night, when transpiration ceases and ψ stem becomes less negative, deeper, wetter soil layers predominantly supply water, reflecting the physical constraints of water flow within the root zone. This soil control was consistent across all species and sites under moderately dry to normal conditions. We further show that ψ stem data can support broader physiological analyses, including refining tree water deficit–water potential relations and highlighting spatial variability in root water uptake. Our findings indicate that horizontal and vertical ψ soil heterogeneity must be accounted for to avoid oversimplified interpretations of plant water use. This study demonstrates that microtensiometers can provide continuous, nondestructive measurements of plant water status and, when carefully installed and continuously monitored, can reveal meaningful ecological patterns while also requiring attention to methodological constraints. Most notably, we show that species identity and soil moisture regulate stem water potential, underscoring the central role of soil–plant interactions in shaping forest water dynamics under changing climatic conditions.

Ash dieback, caused by the fungus Hymenoscyphus fraxineus, continues to threaten European ash (Fraxinus excelsior), yet the contribution of the leaf microbiome to disease severity remains poorly understood. We surveyed 133 ash trees across nine sites in Northern Ireland, using canopy cover as a proxy for health, and characterised leaf-associated microbial communities using Pacific Biosciences (PacBio) long-read amplicon sequencing (full-length 16S and ITS) and QIIME2-based workflows. Many trees exhibited partial tolerance to ash dieback, with most maintaining stable canopy cover year-on-year, while fewer trees show a decline and a smaller portion showing improvement. Microbial communities were largely stable irrespective of ash health with little difference in alpha diversity (Shannon) or beta diversity (Bray–Curtis PERMANOVA) for either bacteria or fungi. Differential abundance and correlation analyses showed that H. fraxineus was, as expected, negatively associated with canopy cover. Only one fungal species, Papiliotrema flavescens, demonstrated a strong positive association with healthier trees, consistent with previous findings. These results indicate that Northern Ireland hosts a reservoir of ash trees displaying tolerance to ash dieback. While the leaf microbiome does not appear to drive this tolerance at the community level, one fungus, P. flavescens, was correlated with healthier ash.

Ash dieback is an often-fatal disease caused by the fungus Hymenoscyphus fraxineus (T. Kowalski) Baral, Queloz & Hosoya. It emerged in Europe during the 1990s and poses a substantial threat to ash populations. In Hungary, symptoms were first detected on common ash (Fraxinus excelsior L.) in 2008. The disease also severely impacts another native species, the narrow-leaved ash (Fraxinus angustifolia Vahl). An effective strategy for counteracting ash decline is to identify and utilize sources of tolerance. We are monitoring the health status of the selected trees that demonstrate low susceptibility (plus trees) and conducting molecular genetic studies to enable their genetic characterization and individual identification using 16 nuclear microsatellite (nSSR) markers. The PCoA (Principal Coordinates Analysis) separated the eight assessed groups into two distinct clusters based on the taxonomic traits. Based on the Structure analysis results, K = 2 was the most probable cluster number. Hybridization was also indicated in the case of several individuals across various groups. We intend to incorporate the results in the establishment of seed orchards using the selected plus trees, considering the taxonomical, geographical, and genetic distinctiveness of the different groups.

Heavy metal pollution poses significant risks to ecosystems and human health, necessitating effective monitoring and mitigation strategies. This study focused on the priority pollutant selenium (Se) content, evaluating five tree species (Tilia tomentosa, Robinia pseudoacacia, Cedrus atlantica, Pseudotsuga menziesii, and Fraxinus excelsior) to assess their capacity to biomonitor and mitigate Se in urban parks of Düzce (Türkiye). We quantified Se accumulation in the outer bark, inner bark, and wood across the four cardinal directions of the stem. Results showed striking inter-species variation: R. pseudoacacia and C. atlantica woods accumulated exceptionally high Se concentrations (91.9 and 77.4 mg·kg⁻¹, respectively), while P. menziesii and F. excelsior showed non-detectable levels. Strong directional effects were pronounced, e.g., with the north aspect in C. atlantica accumulating 2.7× higher Se than the east aspect (77.40 vs. 28.09 mg·kg⁻¹). Se was generally higher in bark than wood. C. atlantica is recommended for phytoremediation due to constrained inter-tissue translocation (e.g., north-south differential: 45.39 vs. 36.10 mg·kg⁻¹). In comparison, R. pseudoacacia showed high bioavailability but high variability by cardinal direction (66.40–91.92 mg·kg⁻¹). These findings reveal species-specific Se accumulation patterns influenced by microenvironmental factors, emphasizing the targeted use of R. pseudoacacia and C. atlantica for pollution monitoring and Se mitigation in urban areas.

In the current article the revised molecular data of the taxonomic status, as well as eco-geographical distribution and hostpreferences of white rot medicinal fungus Fomes fomentarius sensu lato (Polyporaceae, Agaricomycetes) in Armeniawidely distributed in the Northern Hemisphere was discussed. We carried out phylogenetic analysis of InternalTranscribed Spacers (ITS1 and ITS2) of nuclear rDNA and 5.8S rRNA obtained from 30 samples, including 18 mycelialcollections of genetically heterogeneous medicinal fungus Fomes fomentarius s.l. collected in three floristic regions ofArmenia (Ijevan, Aparan and Yerevan). Analysis showed that this species complex is comprises in two sympatric crypticsublineages, corresponding to taxonomic species Fomes fomentarius sensu stricto and Fomes inzengae. The ratio ofnucleotide divergence (Dxy) between ITS1-5.8S-ITS2 sequences and their nucleotide diversity (π) according to the Hudsonfixation coefficient (FST =0.98) indicates a high genetic differentiation of F. fomentarius s.s. and F. inzengae, confirmingthat these two Fomes species are taxonomically distinct. In Armenia they were only found on deciduous trees: F.fomentarius s.s. on Fagus orientalis and Carpinus betulus, whereas F. inzengae on Acer platanoides, C. betulus, F.orientalis, Fraxinus excelsior, Juglans regia, Populus nigra, Salix alba, and Ulmus laevis. The altitudinal distribution ofhighland F. fomentarius s.s. in north-eastern part of Armenia (Aparan and Ijevan floristic regions) is about 680–1750 ma.s.l., while of lowland species F. inzengae is 680–1650 m a.s.l. (Yerevan, Ijevan and Aparan floristic regions). Thecontact (sympatry) zone where the studied populations of both cryptic species overlap is Ijevan floristic region on C.betulus at about 680–750 m a.s.l. Further studies of geographically different collections of Fomes species using morphoecological,physiological, biochemical and molecular methods are in progress.

ABSTRACT The ash dieback pathogen (Hymenoscyphus fraxineus) is a major threat to ash populations across Europe. This study examined how strain handling can affect in vitro growth and in planta virulence of H. fraxineus, with implications for maintaining culture collections for laboratory and greenhouse studies. Ten H. fraxineus strains were selected: seven from a strain collection and three newly isolated individuals. Growth characteristics of the strains were evaluated in vitro on malt extract agar (MEA) and ash-amended malt extract agar (AMEA). Virulence was also investigated in planta following artificial inoculations into Fraxinus excelsior saplings. In vitro growth rate did not correlate with virulence in planta. The strains were subsequently reisolated to investigate changes in in vitro growth and in planta virulence due to reintroduction to the host. Reintroduction to the host led to increased virulence of strains in planta, including a significant increase in necrosis growth rate following two reintroductions. There was a significant increase in necrosis growth rate following two reintroductions to the host. These observations were more distinct in newly isolated strains previously cultured on AMEA. Moreover, more strains were virulent when previously cultured on AMEA, compared with MEA. These results indicate not only that strains of H. fraxineus from collections can be rejuvenated, but also that the virulence of newly isolated strains can be increased. Overall, these results provide insights into the impacts of laboratory protocols on in vitro growth characteristics and in planta virulence of H. fraxineus strains. Furthermore, these results provide methodological opportunities for maintaining growth characteristics in strains intended for long-term use and storage in collections, as well as a possible method for rejuvenating strain virulence.

Priority habitat 91E0* (alluvial forests with Alnus glutinosa and Fraxinus excelsior) constitutes a key riparian biodiversity hotspot, yet it is increasingly threatened by woody invasions that alter the community composition and reduce the habitat’s heterogeneity. Ten permanent plots (15 m radius) were surveyed in the Nestos River delta (NE Greece) in 2019 and 2023, following a manual control campaign conducted in 2021, targeting Amorpha fruticosa and Acer negundo. Because systematic plot-level vegetation data were collected only in 2019 and 2023, the study evaluates before–after changes rather than continuous annual dynamics. Woody species composition and diversity, community turnover (Bray–Curtis dissimilarites/PCoA; PERMANOVA), invasive dynamics (negative binomial GLMs), and community-weighted Ellenberg-type indicator values and their relationships with the soil properties (0–30 cm) were assessed. Across the surveys, 18 woody taxa were recorded, dominated by native riparian trees and shrubs, together with four established alien species. The total alien abundance declined from 943 to 385 individuals between 2019 and 2023, driven by A. negundo (−68%) and A. fruticosa (−39%). The woody community composition differed significantly between years (R2 = 0.12; p = 0.013) and river banks, whereas plot-scale diversity indices changed modestly and evenness increased. The mean community-weighted moisture affinity increased (CWM_F: 6.28 → 7.07), nutrient affinity remained high, and reaction values declined slightly. The soil’s properties did not differ between the treated and control plots; nevertheless, Shannon diversity was positively correlated with organic C, total N, exchangeable Ca and K, and clay content. Permanent plot resurveys thatintegrate soil properties and indicator-based community metrics provide robust baselines to support Article 17 reporting under the EU Habitats Directive and to guide spatially targeted invasive-species management in Mediterranean alluvial forests (habitat 91E0) undergoing restoration actions.

Urban forests serve as representations of nature within city landscapes. Green Forest, spanning 5,198,412 square meters, has been incorporated into the Municipality of Timișoara's public domain and designated as a forest park. This fact increased green space per capita and enriched biodiversity within Timișoara's landscape architecture. This study explores the diversity of Green Forest trees and highlights their contribution to the urban landscape. Statistical methods, including comparative and linear relationships analyses, were employed to assess significant variations in the dendrometric parameters of the analyzed tree species: mean tree height, mean trunk diameter at breast height (DBH), tree age, and stand density. Principal Component Analysis (PCA) and cluster analysis were applied to uncover underlying patterns in the data. Using ArchiCAD and Lumion, high-quality 3D visual representations were developed for an ecological education area, an active recreation region, and a passive recreation area within Green Forest. Due to their morphological characteristics and phenotypic traits, the predominant tree species include Quercus robur, Quercus cerris, Quercus rubra, Fraxinus excelsior, Acer platanoides, Acer pseudoplatanus, Ulmus campestris, and Robinia pseudoacacia, which contribute to Timișoara's urban aesthetic. Moreover, the results of the dendrometric analysis provide a foundation for further research in urban ecology. A key practical application of this study is landscape design renderings, which provide detailed and realistic visualizations to effectively communicate the design and functionality of Green Forest's spaces. If implemented, these developments will encourage public engagement with nature, promoting mental and physical well-being within the community.

ABSTRACT The ash dieback epidemic spreading across Europe has created an urgent need to propagate ash (Fraxinus excelsior) trees with demonstrable resistance to the disease, both to support restoration of ash populations in the landscape and to advance research. Seed propagation remains the most effective approach to preserve the high genetic diversity of F. excelsior populations. It ensures the retention of genetic variation critical for long-term adaptability to environmental change. We employed an embryo extraction technique originally developed by Raquin et al. ([2002]. Rapid seedling obtaining from European ash species Fraxinus excelsior (L.) and Fraxinus angustifolia (Vahl.). Ann For Sci. 59:219–224. https://doi.org/10.1051/forest:2002009), which we adapted to retain high germination rates using a simplified protocol. Our findings are primarily observational, aimed at demonstrating the practicality and effectiveness of the adapted method. We compare our experience with the original protocol and highlight the improvements in efficiency. Additionally, we propose that this simplified technique could be adopted by conservation volunteers and other non-specialists to support local efforts in growing genetically diverse ash populations for restoration projects.

Hymenoscyphus fraxineus is the causal agent of ash dieback, a devastating disease of European ash (Fraxinus excelsior). Although the pathogen is believed to have originated in East Asia and has been confirmed in Japan, European ash trees cultivated in the Sapporo Experimental Forest of Hokkaido University remain asymptomatic despite the presence of H. fraxineus. In this study, we investigated the early infection behavior of H. fraxineus and associated host defense responses by comparing asymptomatic F. excelsior with the susceptible control species F. angustifolia. Leaflets were inoculated with ascospores, and fungal development as well as host responses were examined microscopically during early infection stages. In addition, we analyzed the accumulation of selected coumarins, which have been proposed as candidate compounds associated with ash dieback tolerance, and assessed their effects on ascospore germination. We found that fungal growth was consistently restricted on F. excelsior at 7 days post inoculation, particularly at the stage of invasion into adjacent epidermal cells. Fraxetin was detected in F. excelsior leaflets but not in F. angustifolia, and fraxetin treatment significantly reduced ascospore germination in vitro. While typical markers of induced resistance were not clearly detected at the examined time points, these results indicate that constitutive chemical traits, including fraxetin accumulation, may contribute to early-stage suppression of H. fraxineus growth in F. excelsior. Together, our findings provide insight into early host-pathogen interactions associated with ash dieback tolerance and highlight the potential role of constitutive defenses during initial infection.

Early afforestation influences on soil fungal communities but bacterial and oomycetes are slower to respond

In the current work, the analysis covered 70 isolates of fungi belonging to Botryosphaeriaceae obtained in the years 2007–2017 during research on the mycobiota of F. excelsior trees with dieback symptoms in various regions of Poland. Five botryosphaeriaceous species were identified: Diplodia fraxini, D. seriata, D. sapinea, Dothiorella omnivora, and Do. sarmentorum, supported by morphological characteristics and nucleotide sequence data from three genes. The effect of temperature on the in vitro growth of colonies of five identified botryosphaeriaceous species was assessed. Dothiorella omnivora achieved optimal growth at 19.0 °C, while the other four species have shown optimal growth between 22.8 °C (Do. sarmentorum) and 25.7 °C (D. seriata). The pathogenicity test was performed in field conditions on nine-year-old F. excelsior seedlings. In total, wound inoculation was performed on 176 shoots, using 22 isolates of five identified fungal species. Each isolate was inoculated onto eight F. excelsior shoots. The symptoms on shoots were examined at 12 weeks after the inoculation. Among the tested fungal species, necrotic lesion was caused by D. fraxini, D. seriata, and Do. sarmentorum. The extent of damage they caused showed statistically significant differences. The highest pathogenic properties were demonstrated by D. fraxini, which caused necrotic lesion with a length of 34.25–50.50 mm (mean 40.13 mm) on inoculated trees. D. seriata showed the lowest degree of virulence. Half of its strains caused necrotic lesions, which did not differ significantly from the control. Diplodia sapinea and Do. omnivora did not cause any visible lesions. None of the control shoots developed necrosis. The role of Botryosphaeriaceae species in intensifying disease symptoms in ash trees in the context of Hymenoscyphus fraxineus invasion and climate changes was discussed.

The Potocki family of the Pilawa coat of arms was among the most powerful noble lineages of the former Polish–Lithuanian Commonwealth, and its history is closely intertwined with that of Poland, Lithuania, Belarus, and Ukraine. In the late seventeenth century, Feliks Kazimierz Potocki (1630–1702) founded the town of Krystynopol (now Chervonohrad), named in honor of his wife, Krystyna Lubomirska. The residence, passed down through successive generations of the Potocki family, was transformed in the mid-eighteenth century into an impressive Baroque palace-and-garden complex designed by Pierre Ricaudde Tirregaille, becoming a model example of the magnate cultural landscape on the border of present-day Poland and Ukraine. In the centuries that followed, the estate changed owners multiple times, suffered devastation during the world wars, and in the Soviet period housed the Museum of Atheism. Today, the partially restored palace accommodates a small regional museum. Although in the eighteenth century the palace was surrounded by an extensive Italian-French style garden with water canals, ponds, and fountains, the area has since been built over with public-utility buildings. This study presents a concept for the development of the surviving elements of the historical palace park. The project is based on historical analyses, field research, site inspections, interviews with museum staff and town residents, as well as a detailed dendrological inventory including an assessment of tree health. The study area covers 4.71 ha, and the current tree stand is composed mainly of Salix alba, Populus nigra, Populus alba, Betula pendula, Quercus robur, Fraxinus excelsior, Ulmus laevis, Acer negundo, and Acer pseudoplatanus. Archival sources allowed for the reconstruction of the original layout of the palace-park complex. The aim of the project is therefore to introduce new representative, educational, recreational, social, ecological, and touristic functions to the currently neglected area while respecting its historical heritage.

Abstract Climate change has altered the global temperature regimes leading to warmer temperatures occurring earlier in spring in many temperate regions. This has induced an earlier budbreak making trees susceptible to late spring-frost events, however, information on species-specific late spring-frost tolerance is only available from observational studies. Here, we implemented a quantitative study on late spring-frost tolerance determined by in vitro leaf-level measurements of three temperate broad-leaved tree species via the assessment of the maximum quantum yield efficiency of the photosystem II ( F v /F m ). We investigated to what extent in vitro measurements conducted one day before a late spring-frost event can predict the in vivo damage caused by a cold snap. Fraxinus excelsior showed the lowest in vitro tested tolerance to late spring-frost, and the leaves lost 50% of F v /F m (LT50) at + 0.60 ± 0.26 °C. The damage induced by the cold snap the following day (minimum temperature of − 3.28 °C) was a fatal decline of F v /F m to 5.8% of the maximum. The other two species, namely Fagus sylvatica and Quercus robur, were characterized by LT50 of − 0.17 ± 9.99 °C and − 2.29 ± 1.11 °C, respectively. The cold snap induced less damage, F v /F m values declined to 46.9% and 53.5% of the maximum in the two species, respectively. The in vitro measurements precisely predicted the damage caused by the late spring-frost event. We suggest that in vitro estimated LT50 values can be used as a comparative leaf trait as it has high predictive power for tree species performance after late spring-frost.