Search Results (109)

Water availability is the primary environmental factor limiting plant establishment in arid and semi-arid ecosystems, and increasing drought-stress due to climate change is making forest restoration efforts in the Mediterranean basin increasingly critical. The Eastern Mediterranean region of Türkiye, particularly Kahramanmaraş Province, is characterized by increasingly severe drought stress resulting from low natural precipitation and rising temperatures under global warming. This study comparatively evaluates the ecophysiological responses of Ailanthus altissima (Mill.) Swingle and Crataegus orientalis Pall. ex M. Bieb., under adequate irrigation and drought-stress conditions. To determine plant water status, pre-dawn and midday leaf water potentials were measured, and leaf gas exchange was characterized by measuring net photosynthesis (A), stomatal conductance (gs), and transpiration rate (E); water-use efficiency (WUE) was then derived from these parameters as the ratio of net photosynthesis to transpiration (A/E). Both species sustained positive net photosynthesis under drought, although at rates significantly below those of the well-watered controls in the driest months, and both attained higher WUE than the controls in most months, with marked seasonal variation. However, significant differences in physiological adaptation strategies emerged between the species. Ailanthus altissima exhibited a water-saving strategy, restricting stomatal conductance to maintain a stable leaf water status, whereas Crataegus orientalis adopted a water-spending strategy, sustaining high leaf gas exchange while tolerating pronounced tissue dehydration. Modeling results, supported by spatial drought stress indices, have shown that both species have high adaptation potential in arid and semi-arid rehabilitation areas. The findings reveal that ecophysiological characteristics play a critical role in the selection of drought-tolerant woody species and provide a scientific basis for sustainable forest restoration under climate change. Full article

Seasonal forest phenology is commonly summarized as canopy greenness or phenophase timing, although leaf development also redistributes observed plant material through three-dimensional space. We evaluated whether repeated RGB-colorized handheld simultaneous localization and mapping (SLAM) can provide height-resolved trajectories of seasonal observed occupancy in adjacent Ailanthus altissima-dominated and native-dominated sectors of a young deciduous forest. We acquired 149 scans on 25 dates from March 2025 to March 2026 at six permanent locations. Point clouds were restricted to date-invariant common support, normalized to a March terrain model, and voxelized at 0.20 m. New occupancy was referenced to the union of two strict March leaf-off scans. A weakly supervised foliage likeness proxy combined geometry-first pseudo-labels with relative color, intensity, and local three-dimensional features; its outputs were interpreted as relative scores rather than leaf fraction, LAI, or biomass. The strongest and most persistent invaded positive signal was localized to 2–4 m. Continuous-time models supported the integrated 1–5 m contrast from late April through October, whereas formal support for the 5–12 m crown domain was limited to the late season invaded positive phase; the earlier native positive crown feature remained descriptive. Height-integrated SLAM showed broad seasonal concordance with intercepted PAR (r_rm = 0.881), GCP-linked Sentinel-2 EVI2 (r_rm = 0.670) and the five-date litterfall comparison (r_rm = 0.914). However, correlations of the invaded minus native trajectories were positive but imprecise. The independent observations therefore supported the broad seasonal cycle rather than the detailed sector-specific or height-specific pattern. The workflow provides a conservative means of localizing relative seasonal observed occupancy in three dimensions, but the resulting contrasts remain site-specific and hypothesis-generating. Full article

Urban green areas contain numerous non-native tree species that may escape from cultivation and potentially become invasive. Climate change is expected to exacerbate this risk by creating favourable conditions for species that are currently climatically restricted. Here, we provide a comprehensive risk screening of 34 non-native urban tree species in continental Europe under current and projected future climate scenarios using the Terrestrial Plant Species Invasiveness Screening Kit (TPS-ISK). Under current conditions, 10 species (29.4%) were categorized as high risk, 23 (67.6%) as medium risk, and one (2.9%) as low risk. Under the projected climate change, 11 species were classified as high risk, including seven categorized as very high risk. Ailanthus altissima, Diospyros virginiana, and Quercus rubra consistently ranked among the highest-risk species, while Acer tataricum subsp. ginnala, Koelreuteria paniculata, Magnolia kobus, Phellodendron amurense, Pseudotsuga menziesii, and Robinia pseudoacacia showed an increased invasion potential under future climate conditions. These findings indicate that climate change may facilitate the establishment and spread of several currently cultivated urban tree species. Our study provides the first comprehensive TPS-ISK screening of non-native urban trees for mainland Europe and identifies priority species for early detection, monitoring, and management. Full article

Rapid urbanisation and climate change intensify heat, drought, wind exposure, and salinity risks in arid coastal cities, while simultaneously increasing dependence on trees for microclimate regulation and public-space quality. However, integrated evidence linking taxonomic concentration, spatial structure, tree dimensions, and current vitality remains scarce for Central Asian cities on the Caspian coast. This study characterised 13,951 trees across 10 green spaces in Aktau, Kazakhstan, belonging to 10 species, 10 genera, and 7 families, using a comprehensive inventory and an integrated taxonomic, spatial, and vitality framework. Stand density ranged from 27.1 to 510.3 trees ha⁻¹. Ailanthus altissima and Platycladus orientalis accounted for 42.74% and 23.13% of all trees, respectively, and together formed 65.87% of the inventory. Two species, two genera, and one family exceeded the indicative 10/20/30 diversification thresholds. The Shannon index ranged from 1.19 to 2.00, Pielou evenness from 0.52 to 0.87, and the share of the dominant species from 24.2% to 63.2%. Of all trees, 12,205 (87.48%) were classified as in good condition, but three sites accounted for 83.0% of all satisfactory or unsatisfactory trees. Maclura pomifera and Gleditsia triacanthos had the highest proportions of trees in good condition (96.3% and 94.2%), whereas Catalpa speciosa had the lowest (66.0%). The inventory, therefore, reveals a favourable current condition, but limited taxonomic redundancy and localised management hotspots. The findings provide a baseline for climate-resilient urban landscape planning based on gradual diversification, site-specific irrigation and soil management, control of invasive recruitment, and repeated monitoring of condition, growth, and mortality. Full article

Deltas are highly susceptible to biological invasions because of strong hydrological connectivity, frequent disturbance, and intense human use. Here, we synthesise coordinated monitoring observations and literature evidence on invasive alien plant species (IAS) recorded in four Black Sea riparian protected areas located across five countries, surveyed under the IASON/IASON+ initiatives (Danube Delta, Nestos Delta and Lake Vistonida, Kızılırmak Delta, Chorokhi Delta and Kolkheti National Park). Across the study sites, 17 IAS were documented, mainly represented by taxa native to North America and characterised by high propagule production and/or strong vegetative regeneration. Woody riparian invaders (e.g., Amorpha fruticosa, Robinia pseudoacacia, Acer negundo, Gleditsia triacanthos and Ailanthus altissima) exploited nutrient-rich floodplain soils and disturbances. In contrast, annual weeds (e.g., Ambrosia artemisiifolia, Sicyos angulatus and Xanthium orientale) remained associated with disturbed habitat edges. Aquatic dominance was confined to the Danube Delta, where Elodea nuttallii and Elodea canadensis formed dense submerged stands. Species were assigned to broad range expansion categories (slowly, moderately and rapidly spreading species) based on project observations and supporting records. We discuss shared invasion syndromes linked to reproductive and dispersal traits and outline management implications for Black Sea deltas, emphasising pathway prevention, early detection and rapid response for localised taxa, and sustained control combined with restoration for dominant invaders. Full article

The reconstruction of the Stuttgart Hauptbahnhof railway junction, known as Stuttgart 21, is a very large and long-term infrastructure project. The gradual extension of the project implementation creates a specific time period during which atypical vegetation management in the trackbeds takes place. The vegetation of the trackbeds of the current station includes a total of 68 plant taxa, with Erigeron bonariensis L., Geum urbanum L. and Senecio inaequidens DC being significantly represented, for example. The limited level of disturbance within this “time window” creates favorable conditions in particular for the development of woody plants and lianas, such as Acer campestre L., Acer pseudoplatanus L., Ailanthus altissima (Mill.) Swingle, Clematis vitalba L., Ficus carica L., Hedera helix L. and Sambucus nigra L. The detected spectrum of plant taxa also indicates the formation of a diverse mosaic of microhabitats, which allows the coexistence of species with different ecological requirements. The assessed railway lines also provide space for the occurrence of non-native species, many of which are capable of effective wind dispersal and can subsequently colonize surrounding urban areas. Habitats with a time window of limited vegetation management may represent a poorly described factor influencing the spread of some taxa in the technosphere. The knowledge gained may contribute to a better understanding of the population dynamics of individual taxa and their potential for further spread. Full article

Diet plays a critical role in shaping the composition of gut microbiota in insects. Samia ricini, an economically important Lepidoptera insect, is a polyphagous herbivore that offers a useful model for studying dietary effects on the animal gut microbiome. Here, we fed S. ricini larvae with different food plants, Ricinus communis, Ailanthus altissima, and Manihot esculenta leaves to investigate how host plant species influence growth performance, digestive enzyme activities, and the gut microbial community. Our results showed that the Ricinus group exhibited better growth performance. Regarding digestive enzymes, the midgut lipase activity was significantly higher in the Ricinus group than in the Ailanthus group, while no significant differences were observed in α-amylase, cellulase, or trypsin activities among the three groups. Compared to the Manihot group, the Ricinus group showed increased bacterial richness, while the Ailanthus group showed increased bacterial diversity. β-diversity analysis further revealed distinct microbial community structures among all three dietary groups. Specifically, Acinetobacter, Mammaliicoccus, Roseateles, Methylobacterium, Agrobacterium, Faecalibacterium, and Segatella were the dominant bacterial genera. Functional prediction revealed that gut microbes enriched in the Ricinus group were associated with terpenoid/polyketide metabolism, xenobiotics biodegradation, and glycan biosynthesis, whereas those involved in carbohydrate metabolism and biosynthesis of other secondary metabolites were higher in the Manihot group. Spearman correlation analysis indicated that Methylobacterium, Methylorubrum, and Agrobacterium were significantly positively correlated with larval weight, while Staphylococcus and Cyanothece_PCC-7424 exhibited negative correlations. Collectively, these findings suggest a potential association between different plant-derived diets, gut microbiota composition, and host growth performance, highlighting the pivotal role of diet in shaping insect gut microbial communities. Full article

Invasive plant species are increasingly recognized not only as ecological threats but also as potential sources of bioactive compounds with agricultural applications. However, the combined allelopathic and insecticidal potential of Ailanthus altissima’s different plant parts remains insufficiently explored. This study evaluated the bioactivity of different plant part (leaf, bark, and branch) extracts of A. altissima. Secondary metabolites were characterized by HPLC–DAD–MS, while ethanol extracts (0.5–5%) were tested on wheat (Triticum aestivum) seed germination, seedling growth, oxidative status, and on the survival and repellency of the rice weevil (Sitophilus oryzae). Biological responses were strongly plant part and concentration-dependent. Leaf extracts contained the highest phenolic levels, dominated by caffeoylquinic acids and quercetin derivatives, whereas bark and branch extracts showed lower but compositionally distinct profiles. Despite this, bark and branch extracts produced the strongest biological effects, inhibiting germination energy and root growth at higher concentrations, while leaf extracts stimulated seedling performance, including increased vigor index, while in insect bioassays, bark and branch extracts caused higher mortality and stronger suppression of rice weevil populations. This study provides new evidence that biomass extracts of the invasive species A. altissima represent a promising source of biologically active compounds with both allelopathic and insecticidal properties, highlighting its potential valorization as a plant-based biopesticide for sustainable pest management. Full article

The protection of landscape and biological diversity on small Mediterranean islands represents a significant challenge in the context of intensive anthropogenic pressure and land-use change. The aim of this study was to determine the composition of ornamental flora in private gardens on the island of Koločep (IPA, Natura 2000 site), the smallest inhabited island in the Croatian part of the Adriatic, with special emphasis on invasive (IAS) and potentially invasive (PIAS) plant species, and to analyse their relationship with landscape changes and property types. A total of 161 private gardens were analysed, representing all private gardens on the island. In total, 2095 plant records corresponded to 255 unique horticultural taxa from 82 families. Allochthonous species dominate in the gardens (73%). Private gardens represent the primary pathway for the introduction of IAS and PIAS taxa on the island. The taxa with the highest invasion intensity were Ailanthus altissima and Carpobrotus edulis, while among PIAS species, high invasive potential was observed for Mirabilis jalapa and Diospyros virginiana. The study highlights the need for systematic monitoring of ornamental flora and landscape transformation, and the promotion of horticultural practices focused on autochthonous species in gardens, in order to preserve island biological and landscape diversity. Full article

This study evaluated activities of crude extracts from different parts of the tree of heaven (Ailanthus altissima (Mill.) Swingle) collected in Slovenia and Hungary, using effect-directed analyses based on hyphenation of high-performance thin-layer chromatography (HPTLC) and nine in vitro assays performed in situ on chromatographic plates after the separation. HPTLC separation combined with a set of four antibacterial assays, two antifungal assays, and three enzyme inhibitor assays to evaluate the extracts of 15 plant parts: young shoots, young leaves, mature leaves, yellow leaves, petioles of leaves, petioles of male inflorescences, petioles of fruits, female inflorescences, young fruits, male inflorescences, mature male inflorescences, bark of 1–2-year branches, bark of 2-year branches, bark of tree trunk, and bark of roots. Antibacterial activities against Gram-positive bacteria (Bacillus subtilis, Rhodococcus fascians) and Gram-negative bacteria (Aliivibrio fischeri, Pseudomonas syringae pv. maculicola (Psm)), as well as inhibition of enzymes α-glucosidase, lipase, and acetylcholinesterase, were observed for all extracts. Extracts differed in their antifungal activities. Extracts of young shoots, mature leaves, petioles of leaves, and bark of roots showed antifungal activity against plant pathogens Fusarium avenaceum and Bipolaris sorokiniana. Extracts of yellow leaves, male inflorescences, bark of 1–2-year branches, and bark of tree trunks were only active against F. avenaceum, whereas extracts of young leaves were only active against B. sorokiniana. This study is the first to report that A. altissima extracts exhibit (1) antifungal activity against F. avenaceum and B. sorokiniana; (2) antibacterial activity against A. fischeri, Psm, R. fascians, and B. subtilis (except leaves, bark of branches and bark of tree trunks); and (3) inhibitory activity toward lipase, α-glucosidase (except bark of tree trunks), and acetylcholinesterase (except bark of tree trunks). Full article

To investigate the effects of mixed forests on soil bacterial characteristics in the Yellow River Delta, pure forests of Ailanthus altissima, Ulmus pumila, Robinia pseudoacacia, and Fraxinus velutina (hereafter Aa, Up, Rp, and Fv, respectively) and mixed forests of Aa-Rp, Up-Rp, Fv-Rp, and Ma (Melia azedarach)-Fv were selected as the research objects. High-throughput sequencing technology was employed to analyze the structure, diversity, and function of bacterial communities in this region. The results showed that Acidobacteria, Proteobacteria, and Actinobacteria were the dominant microbial groups. The relative abundance of Acidobacteria was reduced by mixed patterns of Up-Rp, Fv-Rp and Ma-Fv, and the abundance of Proteobacteria was increased in Ma-Fv. The Chao1, ACE and Shannon indices of Aa-Rp and Fv-Rp were increased, while the Chao1 and ACE indices of Up-Rp and Ma-Fv were decreased. Functional prediction revealed that chemoheterotrophic and aerobic chemoheterotrophic bacteria had the highest abundance, with mixed forests exerting variable effects on different functional bacterial groups. In conclusion, mixed forest management exerts a significant influence on shaping bacterial community structure, regulating its diversity, and facilitating the directional enrichment of functional bacteria, which is conducive to enhancing the stability and sustainability of plantations. Full article

This study aims to develop and demonstrate a low-cost LiDAR-based 3D mapping approach for estimating tree carbon stock in university campuses. Unlike conventional field-based measurements, which are labor-intensive and error-prone, the proposed system integrates a 2D LiDAR sensor with a servo motor and odometry data to generate three-dimensional point clouds of trees. From these data, key biometric parameters such as diameter at breast height (DBH) and total height are automatically extracted and incorporated into species-specific and generalized allometric equations, in line with IPCC 2006/2019 guidelines, to estimate above-ground biomass, below-ground biomass, and total carbon storage. The experimental study is conducted over approximately 70,000 m² of green space at Gazi University, Ankara, where six dominant species have been identified, including Cedrus libani, Pinus nigra, Platanus orientalis, and Ailanthus altissima. Results revealed a total carbon stock of 16.82 t C, corresponding to 61.66 t CO₂eq. Among species, Cedrus libani (29,468.86 kg C) and Ailanthus altissima (13,544.83 kg C) showed the highest contributions, while Picea orientalis accounted for the lowest. The findings confirm that the proposed system offers a reliable, portable, cost-effective alternative to professional LiDAR scanners. This approach supports sustainable campus management and highlights the broader applicability of low-cost LiDAR technologies for urban carbon accounting and climate change mitigation strategies. Full article

Fast-growing invasive tree species management produces a significant amount of low-density and low-value biomass, which offers a chance for waste valorization in the environmentally friendly construction sector. This study examines the utilization potential of low-value natural waste materials of tree bark, obtained from invasive hardwood species, in the production of environmentally friendly building mortars. More specifically, this study focuses on mixing bark powder of black locust (Robinia pseudoacacia L.) and tree-of-heaven (Ailanthus altissima (Miller) Swingle), with two commercial commonly found lime-based mortar powders in five different ratios of bark content (0%, 5%, 10%, 20% and 30%) characterizing the produced composites, in terms of physical, hygroscopic and mechanical properties. Slightly lighter composites were created with the use of bark additives especially at the bark content of 20% and 30%. As regards the compressive strength, the bark shares of 10% and 20% exhibited the most beneficial performance among those studied, though only the weaker performance of mortar type (M1) benefited significantly from bark incorporation. For both mortars, the composites containing black locust bark presented higher resistance to compression strength and elasticity, demonstrating higher composite integration in general and milder, plastic fraction in relation to tree-of-heaven bark-based specimens, the properties of which are considered crucial for the durability of structural materials. However, black locust bark exhibited higher water absorption compared to tree-of-heaven-based specimens. Despite the drawback of higher hygroscopicity, the results show that black locust bark, especially at lower incorporation rates (10–20%), is a promising functional additive for generating lighter, more ductile mortars, supporting the creation of novel building materials and sustainable waste management. Full article

Vegetation in residential areas plays a crucial role in biodiverse and sustainable cities as it enhances biological diversity, environmental quality, and the human well-being of city residents. However, the distribution of vegetation among these areas is often unequal, leading to disparities in access to its benefits. To promote a more biodiverse and environmentally just city, we investigated how woody plants (trees, shrubs and vines) vary with socioeconomic level in residential streetscapes of Santiago de Chile. Across the city, we sampled woody plants in 120 plots (11 m radius) located in residential streetscapes of three socioeconomic levels: low, medium, and high. A total of 557 woody plants were identified and measured. Of these, only 9.7% corresponded to native species, whereas 90.3% were introduced species. Wealthier residential areas had higher species richness and abundance of woody plants, as well as plants with greater structural size (revealed by height and crown area). In addition, we found that the composition of woody plants differed among socioeconomic levels: Liquidambar styraciflua, Platanus x hispanica, and Pittosporum tobira were more abundant in high socioeconomic areas; Prunus cerasifera, Citrus limon, and Ailanthus altissima were more abundant in medium socioeconomic areas; Robinia pseudoacacia, Acer negundo, and Schinus areira were more abundant in low socioeconomic areas. Our research highlights that woody plant diversity, abundance, structure, and composition vary with socioeconomic level in residential streetscapes. Key insights for reducing these inequalities and achieve a more environmentally just city include: (a) governance and equity-based investment; (b) prioritizing local native species; (c) promoting the use of non-tree woody plants; and (d) empowering communities through capacity building and stewardship. Full article

Ailanthus altissima (tree of heaven) is among the most abundant and widespread neophytic plants in Austria. The pollen season of Ailanthus usually ranges from the beginning of June until the mid of July, showing one peak period around the mid of June in Vienna (Austria). Over a span of 48 years (1976–2023), pollen data of Ailanthus was gathered from aerobiological samples and assessed for a temporal trend. In addition, weather data from Vienna (temperature, precipitation, relative humidity and sun hours) was incorporated to find possible associations with Ailanthus pollen indices. The change in the pollen season for Ailanthus described in this study has already manifested and is ongoing. Temperature and sunshine hours have a direct impact on the flowering of urban trees, indicating that global climate change may be a major driver towards more intense pollen and allergy seasons. Full article