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The use of agroforestry biomass provides several advantages, both from an environmental point of view, in terms of the mitigation of global warming, and in terms of a circular economy for agricultural or agroforestry companies that reuse pruning residues as a source of energy. However, even if the use of energy pellets resulting from the pruning residues of various agroforestry species has excellent potential for the valorization of agricultural by-products, the physicochemical characteristics of these pellets have been scarcely studied by the scientific community. In this context, this study aims to assess the valorization potential of various lignocellulosic material residues produced during agroforestry activities. The objectives of the study include evaluating the chemical and physical characteristics of pellets produced with different mixtures of agroforestry biomass (olive, citrus, black locust, poplar, paulownia, etc.) in order to determine the optimal pellet blend from an energy and physicochemical perspective. The results of this study demonstrate that this comprehensive analysis provides valuable information on the optimization of biomass mixtures for better energy valorization, addressing both compositional and combustion-related challenges. In fact, it is observed that the addition of citrus and olive biomass to the various mixtures increases their energy potential. Furthermore, all of the pellets analyzed are found to possess an adequate and useful durability index (PDI) for their handling during storage and transport operations. This study demonstrates that olive and citrus pruning residues can be used to improve biomasses that have poor suitability in energetic, physical, and chemical terms. Further studies could be useful to understand which specific interaction mechanisms have an influence on emissions in order to optimize mixtures using different biomass sources for sustainable energy production. [ABSTRACT FROM AUTHOR]

The importance of seed and vegetative propagation for the spontaneous expansion of black locust on abandoned agricultural land was evaluated in the present study. The dynamics of expansion was reconstructed on the basis of spatial distribution data on the age of individuals of this species. A non-homogeneous Poisson process with a linear trend and a Widom-Rowlinson model were the most appropriate in explaining the spatial distribution of R. pseudoacacia individuals. The negative linear trend was statistically significant for the vast majority of polygons in the area of spontaneous expansion of R. pseudoacacia, but insignificant in the artificial plantation. The model parameter η indicates the aggregated spatial distribution of R. pseudoacacia in the zone of spontaneous spread due to the vegetative mechanism of spread. The distribution of R. pseudoacacia in the artificial tree plantation was close to regular, or either random or aggregated. In the early stages, the seed reproduction is the most likely process of R. pseudoacacia spreading. The seed mechanism of spreading follows a spatial pattern, which is explained by a linear trend. The next stage is a combination of both seed and vegetative mechanisms of spread, which also lasts about 4–5 years. At the last stage, the spread occurs mainly through the vegetative mechanism, and the rate of spread of the community slows down significantly. The trigger for the spread is anthropogenic impact. [ABSTRACT FROM AUTHOR]

Kunitz trypsin inhibitor genes play important roles in stress resistance. In this study, we investigated RpKTI2 cloned from Robinia pseudoacacia and its effect on tobacco. RpKTI2 was introduced into the tobacco cultivar NC89 using Agrobacterium-mediated transformation. Six RpKTI2-overexpressing lines were obtained. Transgenic and wild-type tobacco plants were then compared for photosynthetic characteristics and endogenous hormone levels. Transgenic tobacco showed minor changes in chlorophyll content, fluorescence, and photosynthetic functions. However, the maximum photochemical efficiency (Fv/Fm) increased significantly while intercellular CO2 concentration (Ci) decreased significantly. Stomatal size and hormone content (indole-3-acetic acid, zeatin riboside, gibberellin, and indole-3-propionic acid) were reduced, while brassinosteroid content increased. Random forest regression revealed that RpKTI2 overexpression had the biggest impact on carotenoid content, initial fluorescence, Ci, stomatal area, and indole-3-acetic acid. Overall, RpKTI2 overexpression minimally affected chlorophyll synthesis and photosynthetic system characteristics but influenced stomatal development and likely enhanced the antioxidant capacity of tobacco. These findings provide a basis for future in-depth research on RpKTI2. [ABSTRACT FROM AUTHOR]

At the end of the last century, European Union (EU) energy policies encouraged the use of dedicated short rotation forestry (SRF) plantations in member countries in which fast-growing woody species are grown for energy purposes. Recently, in Italy some SRF plantations developed in the 90s have been abandoned or managed more extensively for economic and environmental reasons. However, these abandoned plantations can play a key role in biodiversity conservation and carbon storage. The present study is aimed to estimate carbon stock (C-stock) in living biomass and deadwood in three abandoned SRF plantations in Central Italy. The C-stock was estimated in three different 20-years SRF plantations (hybrid poplar, willow, black locust) located on the same site and unmanaged for 15 years. The results show a C-stock considering three of five C pools equal to: 47.30 MgC ha−1 for hybrid poplar (65.3% in biomass and 34.7% in deadwood respectively), 23.02 MgC ha−1 for willow (77.6% and 22.4% respectively), and 80.41 MgC ha−1 for black locust (95.9% and 4.1% respectively). Outcomes of this research offer support for the forest restoration practices of similar abandoned SRF plantations. The application of extensive management techniques and the development of the naturalization process will ensure the role of biodiversity reservoir of these plantations, helping their evolution toward semi-natural systems mainly oriented to biodiversity conservation and climate change mitigation. [ABSTRACT FROM AUTHOR]

Climate change has had a widespread and profound impact on global temperature and precipitation patterns, especially in semi-arid areas. Plant δ13C and iWUE indicate the trade-off between carbon uptake and water loss, which is pivotal for understanding plant responses to climate change. Information about the long-term responses of the physiological and ecological processes of different tree species to climate change is also required. To investigate the impact of different forest stand structures and site conditions on long-term growth and physiological processes of coniferous and broad-leaved trees in the mountainous area of Beijing, we analyzed the tree-ring δ13C variation of four tree species (Platycladus orientalis, Pinus tabuliformis, Quercus variabilis, Robinia pseudoacacia) sampled from 64 plots with varying site and stand conditions. We found that the tree-ring δ13C of the four tree species varied from each other and was mainly affected by density and slope aspect, followed by slope and age. Both tree-ring δ13C and iWUE of the four tree species showed increasing trends over time, mechanistically linked to long-term changes in global CO2 concentration. This indicates the four native tree species have adapted well to climate change, and the risk of decline is relatively low. The increased iWUE translated into different growth patterns which varied with tree species, site, and stand condition. Different tree species have varying sensitivities to environmental factors. The iWUE of coniferous tree species is more sensitive to climate change than that of broad-leaved tree species, especially to temperature (T), the Standardized Precipitation Evapotranspiration Index (SPEI), and vapor pressure deficit (VPD). [ABSTRACT FROM AUTHOR]

Forests make an important contribution to the global carbon cycle and climate regulation. Caijiachuan watershed false acacia (Robinia pseudoacacia Linn.) plantation forests have been created for 30 years, but a series of problems have arisen due to the irrationality of the density involved at that time. To precisely assess the contribution of R. pseudoacacia plantations with different densities to this cycle, we measured the diameter at breast height (DBH), tree height (H), biomass, and carbon stocks in trees, shrubs, herbs, litter, and soil across different density ranges, denoted as D1 = 900–1400, D2 = 1401–1900, D3 = 1901–2400, D4 = 2401–2900, and D5 = 2901–3400 trees ha−1. In order to achieve the purpose of accurately estimating the biomass, carbon stocks and the contribution rate of each part in different densities of R. pseudoacacia plantations were measured. The results are as follows: (1) Both DBH and H decreased with increasing density, and field surveys were much more difficult and less accurate for H than DBH. Based on the two allometric growth models, it was found that the determination coefficient of the biomass model that incorporated both H and DBH (0.90) closely resembled that of the model using only DBH (0.89), with an error margin of only 0.04%. (2) At the sample scale, stand density significantly affected R. pseudoacacia stem biomass and total biomass. At the individual plant scale, stand density significantly affected R. pseudoacacia organ biomass. Increasing stand densities promoted the accumulation of vegetation biomass within the sample plot but did not improve the growth of individual R. pseudoacacia trees. The stem biomass constituted the majority of the total R. pseudoacacia biomass (58.25%–60.62%); the total R. pseudoacacia biomass represented a significant portion of the vegetation biomass (93.02%–97.37%). (3) The total carbon stock in the sample plots tended to increase with increasing stand density, indicating a positive correlation between density and the carbon stock of the whole plantation forest ecosystem. Hence, in future R. pseudoacacia plantations, appropriate densities should be selected based on specific objectives. For wood utilization, a planting density of 900–1400 trees ha−1 should be controlled. For carbon fixation, an initial planting density of 2900–3400 trees ha−1 should be selected for R. pseudoacacia. This study provides theoretical support for local forest management and how to better sequester carbon. [ABSTRACT FROM AUTHOR]

Clanis bilineata Walker (Lepidoptera: Sphingidae), a burgeoning edible insect, is experiencing rising demand in China and other regions. Despite this interest, larval production is currently constrained by the limitations of artificial production technologies, particularly the selection of optimal host plants. This study rigorously evaluated the performance of C. bilineatha larvae on four main host plants: round-leaf soybean, pointed-leaf soybean, black locust, and kudzu. Preference tests demonstrated that the larvae were most attracted to black locust (34.76 ± 4.65%), with subsequent preferences for kudzu (25.00 ± 6.12%), round-leaf soybean (23.17 ± 2.79%), and pointed-leaf soybean (14.02 ± 4.74%). No significant preference differences were noted between round-leaf soybean and either black locust or kudzu. In feeding assays, the larvae exhibited a marked preference for round-leaf soybean (37.36 ± 0.81 g, total feeding amount for larvae), followed by kudzu (37.26 ± 0.82 g), pointed-leaf soybean (35.38 ± 1.31 g), and black locust (28.53 ± 0.81 g). When the larvae were fed on round-leaf soybean, they exhibited significantly higher survival rate (39.33 ± 0.90%), body weight (9.75 ± 0.07 g), total biomass (383.43 ± 7.35 g), pupation rate (87.78 ± 1.73%), and egg production (189.80 ± 1.06 eggs/female) compared to other hosts. These findings uncovered that round-leaf soybean significantly enhances larval performance, suggesting its potential for improving C. bilineata larval production and sustainability in cultivation systems. [ABSTRACT FROM AUTHOR]

The role of diverse soil microbiota in restoring erosion‐induced degraded lands is well recognized. Yet, the facilitative interactions among symbiotic arbuscular mycorrhizal (AM) fungi, rhizobia, and heterotrophic bacteria, which underpin multiple functions in eroded ecosystems, remain unclear. Here, we utilized quantitative microbiota profiling and ecological network analyses to explore the interplay between the diversity and biotic associations of root‐associated microbiota and multifunctionality across an eroded slope of a Robinia pseudoacacia plantation on the Loess Plateau. We found explicit variations in slope multifunctionality across different slope positions, associated with shifts in limiting resources, including soil phosphorus (P) and moisture. To cope with P limitation, AM fungi were recruited by R. pseudoacacia, assuming pivotal roles as keystones and connectors within cross‐kingdom networks. Furthermore, AM fungi facilitated the assembly and composition of bacterial and rhizobial communities, collectively driving slope multifunctionality. The symbiotic association among R. pseudoacacia, AM fungi, and rhizobia promoted slope multifunctionality through enhanced decomposition of recalcitrant compounds, improved P mineralization potential, and optimized microbial metabolism. Overall, our findings highlight the crucial role of AM fungal‐centered microbiota associated with R. pseudoacacia in functional delivery within eroded landscapes, providing valuable insights for the sustainable restoration of degraded ecosystems in erosion‐prone regions. Highlights: Robinia pseudoacacia strategically recruited AM fungi to cope with phosphorus limitation.AM fungi interacted with the assembly and composition of bacteria and rhizobia.AM fungal‐centered underground network supported slope multifunctionality.The R. pseudoacacia–AM fungi–rhizobia association restores eroded ecosystems. [ABSTRACT FROM AUTHOR]

Urban forests are an important element of nature in highly urbanised areas. Due to their specificity (e.g. fragmentation, disturbances, alien propagule pressure), they are particularly susceptible to the penetration of alien species. The aim of this study was to determine the share of alien species in the tree stand structure of urban forests in the city of Katowice (Upper Silesian Industrial Region). A total of 50 woody species were recorded in the analysed stands, including 31 native species and 19 of alien origin. The share of alien species in the stands of individual forests was significant, as they constituted from 15% to 44% of the total number. Among the 20 trees most frequently included in the stand, as many as six are species of alien origin (Robinia pseudoacacia L., Padus serotina (Ehrh.) Borkh., Acer negundo L., Quercus rubra L., Juglans regia L. and Fraxinus pennsylvanica Marshall). The most abundant species were Robinia pseudoacacia, Quercus rubra and Padus serotina. The local potential of alien woody species was determined using the index of their abundance in the understory; the highest value of the average abundance index was obtained by Padus serotina, Robinia pseudoacacia, Acer negundo and Quercus rubra. Most alien tree species were more likely to inhabit forest edges (ecotone zone). [ABSTRACT FROM AUTHOR]

In the paper, we present the results carried out in central-southern Italy during the years 2022 and 2023 of a field survey conducted on the leaf-miners of the tree Robinia pseudoacacia. Three invasive alien species pests, Chrysaster ostensackenella, Parectopa robiniella and Macrosaccus robiniella (Lepidoptera Gracillariidae), were collected. Some ecological aspects and an illustration of their characteristics, supplemented with photographs of the three leaf-miners, emphasizing life history and diagnostic characteristics enabling their differentiation, are also provided. [ABSTRACT FROM AUTHOR]

Natural regeneration is deemed essential for maintaining biodiversity and ecosystem stability. Previous studies, however, have primarily concentrated on regions exhibiting limited environmental and climatic variability, overlooking the classification of natural regeneration based on age and source. Research conducted at the mesoscale, characterized by increased environmental variability and the incorporation of neighborhood competition and understory-associated vegetation, enhances our comprehension of the multifaceted influences on natural regeneration. To comprehend this issue, this study implemented 60 plots, each measuring 20 m × 20 m, across five distinct areas of Chongqing, China. Twenty explanatory variables were chosen from five diverse categories: understory vegetation, neighborhood competition, stand structure, climatic factors, and environmental factors. And the naturally regenerated species were classified into seedlings and saplings, as well as endogenous and exogenous species, based on their age and origin. We examined the response of the different categories of natural regeneration to various factors and constructed a structural equation model (SEM) for significant factors to investigate their direct and indirect effects on natural regeneration. A total of 61 regenerated tree species belonging to 29 families and 42 genera were found in the study area, and the naturally regenerating species with high importance values were Quercus fabri, Robinia pseudoacacia, Alangium chinense, Cunninghamia lanceolata, and Ligustrum lucidum. It was found that neighborhood competition and understory-associated vegetation explained the largest proportion (more than 50%) of the variation in the different categories of natural regeneration, and forests with clumped distribution (W), a high mingling index (M) and strong competition (H) had a reduced natural regeneration capacity. Understory-associated herbs significantly reduced natural regeneration and the crowdedness index (C) significantly inhibited the understory-associated herbs, thus indirectly promoting natural regeneration. The shrub cover is significantly and positively correlated with the number of naturally regenerated plants and can be used as an indicator of a forest community's regeneration potential. Understanding the differences in the importance of various factors at the mesoscale, as well as their direct and indirect impacts, can help us further comprehend the mechanisms of natural regeneration and provide a foundation for the sustainable development of forests. [ABSTRACT FROM AUTHOR]

Soil bacterial communities play a remarkable role in nutrient cycling, significantly affecting soil organic material content, soil fertility, and, in an indirect way, plant succession processes. Conversely, vegetation type influences microbial soil life. The present study compared the bacterial microbiome composition, diversity and catabolic activity profile of topsoil samples collected under three different forest types (a twice-coppiced black locust stand, a young, naturally reforested, and a middle-aged mixed pedunculate oak stand) planted on former arable land in the early 20th century. Diversity indices determined during 16S ribosomal RNA sequencing-based metagenome analysis indicated that the black locust stand had the highest soil bacterial community diversity. At the phylum level, Acidobacteriota, Actinobacteriota, Proteobacteria, Verrucomicrobiota, Bacteroidota, and Gemmatimonadota were the most abundant taxa in the forest soils. Concerning soil parameters, redundancy analysis revealed that pH had the highest impact on bacterial community structure and pH, and soil organic carbon content on the samples' respiration patterns. As for catabolic activity, the recently clearcut oak forest showed the lowest substrate-induced respiration, and citrate was the main driver for the inter-stand variability of microbial activity. Our results confirm that soil parameters and forest type influence the composition and functioning of the soil bacterial microbiome. [ABSTRACT FROM AUTHOR]

An assessment was made on the main growth and productivity indicators in half-sibs progeny planta-tions of 18 Robinia pseudoacacia L. clones in the region of Ruse, on (М-I-2 D1 (13)) site, on rich, dry and compacted (Haplic luvisols) grey forest soil, at planting scheme 3.0х1,5 m. The differences in the main inventory indicators, defining the growth and productivity of the progenies of 18 black locust clones, confirm good qualities of the progenies of the Bulgarian clones Pordim-10, Pordim-13, Obretenik-1, Obretenik-6 and Ryahovo-1 and of the Hungarian clones Szajki and Nyirségi. This should be taken into account in the selection of material for establishment of industrial plantations and plantations for bio-mass production, as well as in the choice and performance of tending activities.

Abstract Species composition of forests is a very important component from the point of view of nature conservation and forestry. We aimed to identify 10 tree species in a hilly forest stand using a hyperspectral aerial image with a particular focus on two invasive species, namely Ailanthus tree and black locust. Deep learning‐based training data augmentation (TDA) and post‐classification techniques were tested with Random Forest and Support Vector Machine (SVM) classifiers. SVM had better performance with 81.6% overall accuracy (OA). TDA increased the OA to 82.5% and post‐classification with segmentation improved the total accuracy to 86.2%. The class‐level performance was more convincing: the invasive Ailanthus trees were identified with 40% higher producer's and user's accuracies (PA and UA) to 70% related to the common technique (using a training dataset and classifying the trees). The PA and UA did not change in the case of the other invasive species, black locust. Accordingly, this new method identifies well Ailanthus, a sparsely distributed species in the area; while it was less efficient with black locust that dominates larger patches in the stand. The combination of the two ancillary steps of hyperspectral image classification proved to be reasonable and can support forest management planning and nature conservation in the future.

In this study, we introduce a novel application of wood as the construction material for Microbial Fuel Cell (MFC) containers, developing what we term the Wooden Membrane-less Microbial Fuel Cell (WML-MFC). This innovative approach leverages the natural properties of wood to enhance the sustainability and cost-effectiveness of MFCs. Employing three different types of wood—pine, oak, and black locust—the WML-MFC design incorporates a carbon felt anode inside the wooden container and a carbon cloth cathode wrapped externally. This configuration not only protects the cathode from biofouling but also utilizes the inherent moisture management capabilities of wood to maintain operational stability. The performance of these wooden MFCs was assessed in terms of electricity generation and water treatment efficacy. Pine and oak containers achieved maximum power densities (MPD) of 35 mW/m^2 and 4 mW/m^2, respectively, with corresponding maximum open-circuit voltages of 551 mV and 269 mV. Black locust showed the least effective bioelectricity generation. COD removal efficiency was observed between 18 and 48% for pine and 3% to 39% for oak over hydraulic retention times of 24–48 h. Notable water loss due to moisture diffusion was recorded at 20%/day in pine and 6%/day in oak. Durability assessments through DMA and SEM analyses confirmed the suitability of wood as a container material, emphasizing the dual environmental and economic benefits of this WML-MFC design. [ABSTRACT FROM AUTHOR]

The increase in atmospheric CO2 concentration is a significant factor in triggering global warming. CO2 is essential for plant photosynthesis, but excessive CO2 can negatively impact photosynthesis and its associated physiological and biochemical processes. The tetraploid Robinia pseudoacacia L., a superior and improved variety, exhibits high tolerance to abiotic stress. In this study, we investigated the physiological and proteomic response mechanisms of the tetraploid R. pseudoacacia under high CO2 treatment. The results of our physiological and biochemical analyses revealed that a 5% high concentration of CO2 hindered the growth and development of the tetraploid R. pseudoacacia and caused severe damage to the leaves. Additionally, it significantly reduced photosynthetic parameters such as Pn, Gs, Tr, and Ci, as well as respiration. The levels of chlorophyll (Chl a and b) and the fluorescent parameters of chlorophyll (Fm, Fv/Fm, qP, and ETR) also significantly decreased. Conversely, the levels of ROS (H2O2 and O2·−) were significantly increased, while the activities of antioxidant enzymes (SOD, CAT, GR, and APX) were significantly decreased. Furthermore, high CO2 induced stomatal closure by promoting the accumulation of ROS and NO in guard cells. Through a proteomic analysis, we identified a total of 1652 DAPs after high CO2 treatment. GO functional annotation revealed that these DAPs were mainly associated with redox activity, catalytic activity, and ion binding. KEGG analysis showed an enrichment of DAPs in metabolic pathways, secondary metabolite biosynthesis, amino acid biosynthesis, and photosynthetic pathways. Overall, our study provides valuable insights into the adaptation mechanisms of the tetraploid R. pseudoacacia to high CO2. [ABSTRACT FROM AUTHOR]

Scientifically adjusting forest stand structure emerges as a vital approach to addressing soil degradation in plantation forests within urban green areas. In order to provide a theoretical basis for the rational operation of urban green space, in this study, artificial pure forests of Pinus tabulaeformis, Ulmus pumila, and Robinia pseudoacacia in the forest park of Taiyuan city, Shanxi province were selected. The 20 m×20 m sample plots were established, and soil samples were collected evenly at 5-meter intervals. The stand structure parameters including the number of trees and the average DBH(Diameter at Breast Height) of adjacent trees at various radii from the soil sampling point were calculated based on the positioning of standing trees and the inspection of each tree's base. Pearson's correlation and partial least squares regression analysis were employed to explore the effects of stand structure factors on soil physical properties. The results showed that disparities existed in soil physical properties among different stands. The soil bulk density under Ulmus pumila forests was significantly lower than that under Pinus tabulaeformis and Robinia pseudoacacia forests, while soil water content, capillary water holding capacity, capillary porosity, and saturated water holding capacity in the soil were higher than those under Pinus tabulaeformis and Robinia pseudoacacia forests. Correlation coefficients between stand structure factors and soil physical properties peaked at scales approximating the mean size of standing tree crowns. By double verification of the the Pearson correlation analysis and partial least squares regression analysis, Ulmus pumila forest height had a very high positive correlation with soil saturated water holding capacity, capillary water holding capacity, and water content, so Ulmus pumila forest had superior performance in improving soil physical properties compared to the other two species. [ABSTRACT FROM AUTHOR]

Forest plantations most likely promote exotic plant invasion. Using an in situ monitoring method, this study investigated the traits correlated with growth and reproduction of an understory invader, Phytolacca americana L., and ecological factors including understory irradiance, soil stoichiometry and microbial patterns associated with these traits in different exotic plantations of Robinia pseudoacacia L. and Pinus thunbergii Parl. at Mount Lao, Qingdao, China. We found that the traits of P. americana underneath the R. pseudoacacia stand might be situated at the fast side of the trait economic spectrum. The R. pseudoacacia stand appeared to "nurse" P. americana. Furthermore, we intended to explain the nurse effects of R. pseudoacacia stands by examining their ecological factors. First, the R. pseudoacacia stand created understory light attenuation, which matched the sciophilous feature of P. americana. Second, the soil beneath the R. pseudoacacia stand might benefit P. americana more since the soil has greater resource availability. Third, a higher microbial diversity was found in the soil derived from P. americana underneath the R. pseudoacacia stand. A greater abundance of plant pathogens was detected in the soil derived from P. americana in the R. pseudoacacia stand, while more abundant mycorrhizal fungi were detected in the P. thunbergii stand. We speculate that plant pathogens can defend P. americana from aggression from other understory competitors. The mycorrhizal fungi in the P. thunbergii stand might benefit P. americana while simultaneously benefiting other understory plants. Intensive competition from other plants might interfere with P. americana. The potential relationships between plant performance and ecological factors may explain the invasion mechanism of P. americana. The present study provides a novel insight on the facilitative effects of exotic tree plantation on an exotic herb through the modification of soil biota, with implications for the biocontrol of invasive species and forest management and conservation. [ABSTRACT FROM AUTHOR]

The task of tree species classification through deep learning has been challenging for the forestry community, and the lack of standardized datasets has hindered further progress. Our work presents a solution in the form of a large bark image dataset called CentralBark, which enhances the deep learning-based tree species classification. Additionally, we have laid out an efficient and repeatable data collection protocol to assist future works in an organized manner. The dataset contains images of 25 central hardwood and Appalachian region tree species, with over 19,000 images of varying diameters, light, and moisture conditions. We tested 25 species: elm, oak, American basswood, American beech, American elm, American sycamore, bitternut hickory, black cherry, black locust, black oak, black walnut, eastern cottonwood, hackberry, honey locust, northern red oak, Ohio buckeye, Osage-orange, pignut hickory, sassafras, shagbark hickory silver maple, slippery elm, sugar maple, sweetgum, white ash, white oak, and yellow poplar. Our experiment involved testing three different models to assess the feasibility of species classification using unaltered and uncropped images during the species-classification training process. We achieved an overall accuracy of 83.21% using the EfficientNet-b3 model, which was the best of the three models (EfficientNet-b3, ResNet-50, and MobileNet-V3-small), and an average accuracy of 80.23%. [ABSTRACT FROM AUTHOR]

There is a long history of humans either intentionally or accidentally moving plant species to areas outside of their native ranges. In novel environments, populations of many of these plant species exhibit explosive population growth and spread, in part due to the absence of coevolved enemies such as herbivorous insects. However, over time such enemies can 'catch up' with their host and re‐establish host–herbivore relationships. Though this phenomenon has been documented in several systems, little evidence exists on how this re‐assembly of enemies results in increased levels of herbivory. In this study we focus on the case of black locust Robinia pseudoacacia, a sparsely populated tree species when growing on undisturbed sites in its limited native range in the eastern USA but a highly invasive species, especially in disturbed environments, in most temperate world regions. We recorded folivore damage on invasive populations in five continents, including both native and invaded portions of North America. Here, we investigated 1) how total foliage damage and damage caused by different groups of folivores differs among regions; 2) how seasonal development of folivore damage differs among regions; 3) how folivory varies with distance from the native range within North America; and 4) how the number of recorded specialist folivores correlates with the amount of folivory. We observed strong differences among regions in the amount and type of folivore damage, with the native range experiencing the highest damage, especially that caused by the native chrysomelid beetle Odontota dorsalis, which is limited to the native and invaded North American range of R. pseudoacacia. Among world regions, total folivory is negatively associated with the distance from the native range and positively associated with the number of established R. pseudoacacia specialist folivore species, supporting the hypothesis that global patterns of herbivore invasions are associated with diminished enemy release. [ABSTRACT FROM AUTHOR]

Black locust (Robinia pseudoacacia L.) plantations on the Loess Plateau have become multigenerational sprouting forests with an obvious trend toward degradation. The species composition and vertical distribution pattern of understory woody plants were investigated in mature stands located at the top (T_GS) and bottom (B_GS) of a slope in the gully region to explore whether there may be replacement species for black locust. The species composition of T_GS and B_GS clearly differed, and species diversity indices in B_GS were significantly greater than those in T_GS. These differences in species composition were mainly attributed to elevation, leaf area index, and basal area of total canopy trees. In T_GS, Rubus corchorifolius and Rosa xanthina had an absolute advantage in terms of the number of individuals in the vertical space of (0, 100] cm and (100, 300] cm, respectively. In B_GS, Acanthopanax senticosus was dominant at (0, 200] cm, and Broussonetia papyrifera and Celtis sinensis began to dominate at >200 cm. These results suggest that shrub species (Rubus corchorifolius and Rosa xanthina) and tree species (Broussonetia papyrifera and Celtis sinensis) should be prioritized when mixed with black locust in T_GS and B_GS, respectively, to gradually replace black locust on the Loess Plateau. [ABSTRACT FROM AUTHOR]

The seed provenance, the type of substrate and its properties, as well as the watering regime in the first years after sowing are among the most important characteristics affecting the production of containerized seedlings. The objective of this study was to analyse the growth of black locust (Robinia pseudacacia L.) seedlings on different types of substrate (six mineral and two organic) with different textures and pHs under three different regimes of available water content (no-limiting, medium drought, severe drought) over a period of five months (May–October 2023), using seeds from three sources located in the southeast, south, and west of Romania. The highest seedling emergence rate (73.7%) was obtained for the medium seeds with 18.492 g weight (1000 seed weighs) (Bucharest provenance). Direct sowing in the field and containerized seedlings both showed a trend of growing in height during unlimited water and of growing in diameter during low watering. The lowest survival rate of seedlings (86.7%) occurred in the mineral substrate in the case of rendzina with additional sand (pH 8.70), and for the organic substrate, the lowest survival rate (87.0%) occurred for the peat MKS 3 substrate (pH 4.54). [ABSTRACT FROM AUTHOR]

This article describes an effective approach for selecting suitable plant species for afforestation in post-mining rehabilitation. The research was conducted in the Western Black Sea region of Turkey. The aim of the research is to perform accurate criteria weighting and species prioritization for afforestation in post-mining degraded areas. This helps to ensure consistent conditions for the future use of the site as a forest, sustainability of nature, and selection of appropriate species adapted to the difficult post-mining conditions. In this study, which is a multi-criteria decision-making problem (MCDM), the weights of the criteria were determined by stepwise weight assessment ratio analysis (SWARA), and the priority ranking of the species was determined by the analytic hierarchy process (AHP). Analyses were carried out with 10 afforestation criteria and five tree species. According to the analysis, the top three ranked criteria are Economic Efficiency > Carbon Stock and Credit > Reducing Afforestation Cost. The five species' priority ranking is Robinia pseudoacacia L. (0.456) > Alnus glutinosa subsp. glutinosa (0.248) > Populus nigra subsp. nigra (0.146) > Salix alba L. (0.103) > Quercus robur subs. robur (0.048). The hybrid approach is expected to increase the effectiveness of post-mining rehabilitation works. [ABSTRACT FROM AUTHOR]

In Romania, huge quantities of gangue material from the mining activity practiced in the past were improperly stored and led to the pollution of the environment. Thus, this work is framed to manage the sterile dump of the "Radeș" mine (Alba, Romania) through a 12-week phytoremediation process. The efficient use of Robinia pseudoacacia was studied through the implementation, at the laboratory level, of a phytoremediation experiment based on various variants prepared by mixtures of gangue material, uncontaminated soil, and dehydrated sludge. The prepared variants, all planted with R. pseudoacacia, were watered with tap water, potassium monobasic phosphate, and enzyme solution. The bioconcentration and translocation factors for lead showed values ˂ 1, which indicates a potential presence of an exclusion system for Pb or a reduced Pb bioavailability since the R. pseudoacacia accumulates high concentrations of metals absorbed on and inside the roots. For copper, both factors had values > 1 indicating the suitability of R. pseudoacacia to readily translocate copper into the epigean organs. In the investigated experimental conditions, the highest efficiency in the removal of copper (93.0%) and lead (66.4%) by plants was obtained when gangue material was not mixed with other materials and wetted with enzymatic solution. [ABSTRACT FROM AUTHOR]

Soil heterotrophic microorganisms play crucial roles in soil biogeochemical cycles by secreting extracellular enzymes, but their metabolism is often limited by resource availability. Identifying major resources that limit soil microbial metabolism could help to create reasonable management practices for the maintenance of ecosystem function. Robinia pseudoacacia plantations perform crucial functions in reconstituting the ecological integrity of disturbed ecosystems; however, soil microbial metabolic limitations in R. pseudoacacia plantations remain poorly understood. Herein, R. pseudoacacia plantations of four age classes (10, 22, 37, and 47 years old) were sampled in the loess hilly‐gully region of northern Shaanxi Province in China. This study analyzed the effects of stand age on soil extracellular enzyme activities and soil microbial metabolic limitation. It also determined the main factor driving soil microbial metabolic limitation and extracellular enzyme activities. The results of ecoenzymatic stoichiometry showed that nitrogen (N) limited soil microbial metabolism in R. pseudoacacia plantations. Soil microbial metabolism at 10 and 22 years old were more carbon (C)‐ and N‐limited than that at 37 and 47 years old. Except for N‐ and phosphorus (P)‐acquiring enzyme activities at 10–20 cm, soil C‐, N‐, and P‐acquiring enzyme activities (in 0–10 and 10–20 cm of soil) at 10 and 22 years old were significantly higher than those at 37 and 47 years old. The enzymatic ratio of C:N:phosphorus(P) acquisition in all R. pseudoacacia plantations, regardless of stand age and soil depth, deviated from 1:1:1. Soil nutrients explained most of the variation (90.80%) in soil extracellular enzyme activities based on variation‐partitioning analysis. The partial least squares path model showed that soil nutrients had the highest total negative effect on microbial C limitation and microbial N/P limitation. Our results confirmed that microbial metabolic limitation was induced by soil resource deficits. The findings provide another visual that increases our understanding of soil microbial metabolic limitation in R. pseudoacacia plantations. [ABSTRACT FROM AUTHOR]

Afforestation is considered to be an important means to improve the ecological environment and mitigate climate change. However, inappropriate vegetation restoration can result in severe soil desiccation and ecosystem degradation in water‐limited regions. Here, we evaluated the effects of six different afforestation patterns on soil moisture content, soil organic carbon (SOC) sequestration, and especially the conversion efficiency of the two on the Loess Plateau, taking abandoned land (Al) as a control sample, and attempting to recognize a suitable afforestation pattern based on these parameters. The six afforestation patterns considered were two single‐species shrub plantations (Caragana korshinskii, Ck and Hippophae rhamnoides, Hr), two single‐species tree plantations (Robinia pseudoacacia, Rp and Platycladus orientalis, Po), and two mixed‐species plantations (Rp, Po, Pinus tabuliformis, Pt, and Ulmus pumila, Up mixed plantations (MP); Po and Pt with terracing [MP + T]). We found that mixed‐species plantations (MP + T and MP) have less soil moisture depletion than single‐species plantations, Ck had the highest SOC sequestration but also had a significant deep soil moisture deficit. MP + T had less deep soil moisture deficit but also had lower SOC sequestration than MP. MP show a better comprehensive effect when considering both soil organic carbon sequestration and soil water‐carbon conversion efficiency. Therefore, multispecies MP represent a potentially valuable approach to sustainable afforestation patterns for soil carbon sequestration on the Loess Plateau. This afforestation pattern has the potential to be applied in other similar semi‐arid and semihumid regions. Our results provide insight into vegetation restoration in areas with degraded land. In future afforestation activities, planners must alleviate regional water pressure, increase soil carbon sequestration by increasing species richness, and select the best combination of species to optimize the stability and sustainability of the plantation ecosystem. [ABSTRACT FROM AUTHOR]

In water-limited areas, planted trees can extract substantial amounts of soil water from deep layers (> 200 cm) to meet their high water demand, resulting in deep soil desiccation, which influences not only regional water cycling but also the sustainability of trees per se in drylands. However, the specific dimensions of deep soil desiccation in relation to both the soil moisture limitation and the maximum root water uptake (RWU) depth are still not well determined. Whether the dimensions depend on tree species and how they will affect trees' xylem hydraulic conductivity are also unclear, restricting our ability to predict the fate of dryland tree plantations. Therefore, we studied the spatiotemporal distribution of deep soil moisture deficit (DSMD) for two typical planted trees, apple (Malus pumila Mill.) and black locust (Robinia pseudoacacia L.), based on published data and multiple field samplings on China's Loess Plateau. The results indicated that the lowest deep soil moisture (DSM; units of gravimetric percent, i.e., grav-%) occurred under the planted trees aged 24–28 years at all sites. The lowest DSMD varied around - 0.6, which was close to the DSMD at the permanent wilting point (PWP, grav-%), regardless of tree species and site, although shallow (< 200 cm) soil moisture was not reduced to the point of limitation. This suggests that PWP is a reliable indicator of the moisture limitation of deep-layer soil desiccation for the tree species examined. The corresponding depth of soil moisture use reached 18.0–22.0 m for these old planted trees at different sites, while it was more than 25 m for R. pseudoacacia in the drier site of Mizhi. Furthermore, the mean values of native percentage loss of hydraulic conductivity of planted trees' branches xylem reached 74.9 %–96.5 % in the plantations sampled in this study, indicating that tree mortality may occur. The findings help predict the sustainability of planted trees in semi-arid regions with a thick vadose zone. [ABSTRACT FROM AUTHOR]

Solid biomass can be used for energy generation and the production of various renewable bioproducts. The aim of this study was to determine the yield and characteristics of wood obtained as debarking residue from 14 genotypes of short-rotation woody crops (SRWCs). These included five Populus genotypes, one Robinia genotype, and eight Salix genotypes, harvested in both annual and quadrennial cycles. The results showed that the highest dry wood yield (12.42 Mg ha−1 y−1 DM) and yield energy value (244.34 GJ ha−1 y−1) were obtained from willow (cultivar Żubr) harvested in a quadrennial cycle. The best effect among the poplar genotypes was achieved for the Hybryda275, and it was particularly marked in the quadrennial harvest cycle. The poorest results were determined for black locust. The Robinia characteristics included the significantly lowest moisture content (31.6%), which was a positive attribute from the energy point of view, but, on the other hand, it had some adverse characteristics—the highest levels of sulfur (0.033% DM), nitrogen (0.38% DM), and ash (0.69% DM). More beneficial properties in this respect were determined for willow and poplar wood. Moreover, willow and poplar wood contained more cellulose—51.8 and 50.0% DM, respectively—compared with black locust. Extending the SRWC shoot harvest cycle from annual to quadrennial resulted in an increase in cellulose, lignin, and carbon, higher heating value, and a decrease in nitrogen, sulfur, ash, and moisture content. Therefore, extending the harvest cycle improved the parameters of SRWC wood as an energy feedstock. [ABSTRACT FROM AUTHOR]

In the agroforestry system, the organic matter in the farmland and natural ecosystem enters the farmland soil in a mixed form to improve soil fertility and carbon pool quality. However, it is unclear how soil microbial carbon-degrading enzyme activity responds to carbon dynamics in this process. Therefore, we took farmland in the Loess Plateau as the research object, combining the application of corn straw and Robinia pseudoacacia leaves in a mass ratio of 4:0, 3:1, 2:2, 1:3, and 0:4 for returning to the field. We measured corn grain yield, carbon emission, organic carbon pool component content, and carbon-degrading enzyme activity of the farmland. The results showed that combining corn straw and Robinia pseudoacacia leaves had a significant impact on soil organic carbon components (readily oxidizable organic carbon and recalcitrant organic carbon), carbon-degrading enzymes (polyphenol oxidase, peroxidase, and cellobiohydrolase), and cumulative carbon emissions. The trend of different indicators in different treatments during the corn growth period was similar. We found that soil carbon emissions were closely related to ROC and soil oxidase activity, while soil carbon content was closely related to soil hydrolase activity. Compared to not returning straw to the field, the corn straw and Robinia pseudoacacia leaves returned to the field in a mass ratio of 1:3(Y1C3) can increase corn grain yield by 32.04%. The Y1C3 treatment has the highest soil carbon content and the lowest crop carbon emission efficiency. Soil water content plays a crucial role in the process of carbon pool transformation driven by soil carbon-degrading enzymes. In conclusion, soil carbon dynamics are closely related to the activity of soil carbon-degrading enzymes. Combining the application of corn straw and Robinia pseudoacacia leaves may be a more suitable farming measure for fragile habitats in the Loess Plateau than other solutions. [ABSTRACT FROM AUTHOR]

Aims: In Morocco, the Zaida abandoned mine is a major source of metallic trace elements that are harmful to the environment and human health. With the aim to use the heavy metal tolerant legume tree Robinia pseudoacacia in the phytostabilization of this mine's tailings, we isolated and characterized its indigenous microsymbionts, and tested their effects on the plant growth under high Pb-acetate concentrations. Methods: Thus, 27 bacteria were isolated from nodules of the plant grown in the Zaida abandoned mine tailings, and we examined their tolerance to high concentrations of Pb-acetate in-vitro. Four strains were then selected for symbiotic, molecular, and phenotypic analyses, and we analyzed the effect of inoculation on the plant growth parameters under increasing Pb-acetate concentrations (in-vivo). Results: The isolated strains tolerate high lead concentrations. The Phylogenetic analyses of 16 S rRNA, five housekeeping genes (MLSA), and three symbiotic genes showed the affiliation of the strains with Ensifer meliloti sv. rigiduloides and E. kummerowiae sv. meliloti. Representative strains of both symbiovars tolerate 1100 µg ml− 1 Pb-acetate in-vitro and nodulate R. pseudoacacia even under 1200 µg ml− 1 of Pb-acetate. In all tests, the plant proline content increased as a response mechanism to increasing concentrations of Pb-acetate. Inoculation experiments under high concentrations of Pb-acetate showed that both strains improved the plant growth parameters and chlorophyll content compared to controls. Conclusion: Our results show that E. meliloti sv. rigiduloides strain RPZ12 improves plant growth under Pb stress conditions more than E. kummerowiae sv. meliloti strain RPZ17. Strain RPZ12 would be an excellent inoculum to use for the phytostabilization of Zaida mine tailings. This is the first description of symbiovar meliloti in E. kummerowiae. [ABSTRACT FROM AUTHOR]

Species composition of forests is a very important component from the point of view of nature conservation and forestry. We aimed to identify 10 tree species in a hilly forest stand using a hyperspectral aerial image with a particular focus on two invasive species, namely Ailanthus tree and black locust. Deep learning‐based training data augmentation (TDA) and post‐classification techniques were tested with Random Forest and Support Vector Machine (SVM) classifiers. SVM had better performance with 81.6% overall accuracy (OA). TDA increased the OA to 82.5% and post‐classification with segmentation improved the total accuracy to 86.2%. The class‐level performance was more convincing: the invasive Ailanthus trees were identified with 40% higher producer's and user's accuracies (PA and UA) to 70% related to the common technique (using a training dataset and classifying the trees). The PA and UA did not change in the case of the other invasive species, black locust. Accordingly, this new method identifies well Ailanthus, a sparsely distributed species in the area; while it was less efficient with black locust that dominates larger patches in the stand. The combination of the two ancillary steps of hyperspectral image classification proved to be reasonable and can support forest management planning and nature conservation in the future. [ABSTRACT FROM AUTHOR]

Assimilation (A) and photosystem II (PSII) efficiency value light response curves [A/PPFD and PSII/PPFD curves (PPFD - photosynthetic photon flux density)] of promising black locust clones (NK2 and PL251) and the registered Üllői clone were analysed to study the net assimilation rates and PSII efficiency within the function of PPFD levels. The natural logarithmic regression functions fitted well to the measured data points for A/PPFD, R2 values varied between 0.9515-0.9884. For PSII/PPFD values, we used the exponential regression function with R2 ranging from 0.9948 to 0.9989. Except for PL251, the A/PPFD curves of the tested clones increased steadily with increasing illumination levels but flattened at the 600 µmol·m-2·s-1 PPFD level due to the effect of photorespiration on the assimilation rate. For PL251, the A/PPFD curve decreased at the 1 200 µmol·m-2·s-1 PPFD level. Unlike A/PPFD results, the PSII/PPFD exponential curve decreased as the PPFD level increased. Europe is forecast to experience significant negative climate change factors, including increased drought, heat, and irregular precipitation. Under such conditions, relatively drought-tolerant tree species such as black locust will play a vital role in new afforestation and uninterrupted wood supply. Consequently, growing and improving newly bred black locust clones, including the ecophysiological studies of relatively drought-tolerant clones, is increasingly vital. [ABSTRACT FROM AUTHOR]

Determining the productive potential of flowering vegetation is crucial in obtaining bee products. The application of a remote sensing approach of terrestrial objects can provide accurate information for the preparation of maps of the potential bee pasture in a given region. The study is aimed at the creation of a novel algorithm to identify and distinguish white flowering honey plants, such as black locust (Robinia pseudo-acacia) and to determine the areas occupied by this forest species in mixed forest ecosystems using UAV-based RGB imaging. In our study, to determine the plant cover of black locust in mixed forest ecosystems we used a DJI (Da-Jiang Innovations, Shenzhen, China) Phantom 4 Multispectral drone with 6 multispectral cameras with 1600 × 1300 image resolution. The monitoring was conducted in the May 2023 growing season in the village of Yuper, Northeast Bulgaria. The geographical location of the experimental region is 43°32′4.02″ N and 25°45′14.10″ E at an altitude of 223 m. The UAV was used to make RGB and multispectral images of the investigated forest massifs, which were thereafter analyzed with the software product QGIS 3.0. The spectral images of the observed plants were evaluated using the newly created criteria for distinguishing white from non-white colors. The results obtained for the scanned area showed that approximately 14–15% of the area is categorized as white-flowered trees, and the remaining 86–85%—as non-white-flowered. The comparison of the developed algorithm with the Enhanced Bloom Index (EBI) approach and with supervised Support Vector Machine (SVM) classification showed that the suggested criterion is easy to understand for users with little technical experience, very accurate in identifying white blooming trees, and reduces the number of false positives and false negatives. The proposed approach of detecting and mapping the areas occupied by white flowering honey plants, such as black locust (Robinia pseudo-acacia) in mixed forest ecosystems is of great importance for beekeepers in determining the productive potential of the region and choosing a place for an apiary. [ABSTRACT FROM AUTHOR]

Rhizobia and arbuscular mycorrhizal fungi (AMF) are symbiotic microorganisms important for plants grown in nutrient-deficient and heavy metal-contaminated soils. However, it remains unclear how plants respond to the coupled stress by heavy metal and nitrogen (N) deficiency under co-inoculation. Here, we investigated the synergistic effect of Mesorhizobium huakuii QD9 and Funneliformis mosseae on the response of black locust (Robinia pseudoacacia L.) grown in sand culture to cadmium (Cd) under N deficiency conditions. The results showed that single inoculation of AMF improved the growth and Cd resistance of black locust, co-inoculation improved the most. Compared to non-inoculated controls, co-inoculation mediated higher biomass and antioxidant enzyme activity, reduced oxidative stress, and promoted nodulation, mycorrhizal colonization, photosynthetic capacity, and N, P, Fe and Mg acquisition when exposed to Cd. This increase was significantly higher under N deficiency compared to N sufficiency. In addition, the uptake of Cd by co-inoculated black locust roots increased, but Cd translocation to the above-ground decreased under both N deficiency and sufficiency. Thus, in the tripartite symbiotic system, not merely metabolic processes but also Cd uptake increased under N deficiency. However, enhanced Cd detoxification in the roots and reduced allocation to the shoot likely prevent Cd toxicity and rather stimulated growth under these conditions. [ABSTRACT FROM AUTHOR]

N2-fixing legumes can strongly affect ecosystem functions by supplying nitrogen (N) and improving the carbon-fixing capacity of vegetation. Still, the question of how their leaf-level N status and carbon metabolism are coordinated along leaf ageing remains unexplored. Leaf tissue carbon isotopic composition (δ13C) provides a useful indicator of time-integrated intrinsic water use efficiency (WUEi). Here, we quantified the seasonal changes of leaf δ13C, N content on a mass and area basis (Nmass, Narea, respectively), Δ18O (leaf 18O enrichment above source water, a proxy of time-integrated stomatal conductance) and morphological traits in an emblematic N2-fixing legume tree, the black locust (Robinia pseudoacacia L.), at a subtropical site in Southwest China. We also measured xylem, soil and rainwater isotopes (δ18O, δ²H) to characterize tree water uptake patterns. Xylem water isotopic data reveal that black locust primarily used shallow soil water in this humid habitat. Black locust exhibited a decreasing δ13C along leaf ageing, which was largely driven by decreasing leaf Nmass, despite roughly constant Narea. In contrast, the decreasing δ13C along leaf ageing was largely uncoupled from parallel increases in Δ18O and leaf thickness. Leaf N content is used as a proxy of leaf photosynthetic capacity; thus, it plays a key role in determining the seasonality in δ13C, whereas the roles of stomatal conductance and leaf morphology are minor. Black locust leaves can effectively adjust to changing environmental conditions along leaf ageing through LMA increases and moderate stomatal conductance reduction while maintaining constant Narea to optimize photosynthesis and carbon assimilation, despite declining leaf Nmass and δ13C. [ABSTRACT FROM AUTHOR]

Global climate change is increasing the frequency and intensity of drought and salt stress worldwide, with profound impacts on tree growth and survival. However, the response of plant hydraulic transport and carbon balance to combined drought and salt stress remains unclear. This study investigated the leaf physiological traits, stem xylem hydraulic traits, and nonstructural carbohydrate concentration of Robinia pseudoacacia seedlings under normal irrigation treatment (CK, freshwater at 80–100% FC); salt stress treatment (SS, 0.3% soil salinity with freshwater); drought stress treatment (DS, withholding irrigation); and combined drought and salt treatments (SDS, 0.3% soil salinity withholding irrigation). Our results showed that the leaf physiological traits responded differently to different treatments. DS and SDS treatment significantly decreased leaf water potential and stomatal conductance, while SS treatment did not. DS treatment increased stomatal density but decreased stomatal area to adapt to water deficit, while SS and SDS treatment decreased stomatal length or width. In terms of xylem hydraulic traits, SS, DS and SDS significantly decreased xylem specific hydraulic conductivity by 47%, 42% and 49%, while percent loss of conductivity (PLC) significantly increased by 81% and 62% in DS and SDS, but the PLC of SS was not increased significantly. Additionally, net photosynthetic rate and transpiration rate significantly decreased in SS, DS and SDS, while leaf water use efficiency significantly increased. The chlorophyll content index and maximum light quantum efficiency of photosystem II were also decreased. For nonstructural carbohydrate, the soluble sugars, starch and total non-structural carbohydrate were significantly decreased in DS in specific tissues, showing reductions of 42%, 68%, and 56% in leaves, 69%, 61%, and 62% in stem, and 30%, 59%, and 57% in root. Our findings provide evidence that salt addition alleviated drought stress by improving hydraulic traits and carbohydrate reserves, which is expected to contribute to predicting future vegetation dynamics under climate change. [ABSTRACT FROM AUTHOR]

Background: Mixed plantations utilize resources through specific strategies. However, the impact mechanism of mixed plantations on the water and nutrient use efficiency of different tree species remains unclear. Methods: Robinia pseudoacacia mixed (R. pseudoacacia and Amygdalus davidiana, RPAD; R. pseudoacacia and Armeniaca sibirica, RPAS) and monoculture stands (R. pseudoacacia, RP; A. davidiana, AD; and A. sibirica, AS) were used to determine mixing species relative to monoculture effects on leaf water (WUE), nitrogen (NUE), and phosphorus (PUE) use efficiencies and their potential drivers in the Loess Hilly Region. Results: Mixing R. pseudoacacia and A. sibirica is a good strategy to maximize soil nutrient resources. Compared to monocultures of all species, R. pseudoacacia and A. davidiana in RPAD and A. sibirica in RPAS had higher WUE and lower NUE and PUE; P limitation of R. pseudoacacia in mixed stands was lower than that in RP. Furthermore, R. pseudoacacia WUE was positively correlated with stand density and crown area, A. davidiana and A. sibirica were the opposite. Regarding all tree species, WUE was influenced by leaf dry matter content, leaf tissue density, and soil available P, while NUE, PUE, and N:P ratio were by average tree height and specific leaf area. Notably, irrespective of tree species, WUE exhibited a negative correlation with NUE and PUE, but a positive correlation with N:P ratio. Conclusions: Mixed plantations affect water and nutrient use efficiency by altering the above- and below-ground niche through tree structure, and there is a degree of trade-off between WUE, and NUE, PUE. [ABSTRACT FROM AUTHOR]

Black locust flower extract contains various polyphenols and their glucosides contribute to the potential health benefits. After intake of these bioactive compounds and passage through the gastrointestinal tract, their degradation can occur and lead to a loss of biological activity. To overcome this problem, the bioactive compounds should be protected from environmental conditions. This study aimed to encapsulate the black flower extract in the microparticles based on biodegradable polysaccharides, alginate, and chitosan. In the extract, the total antioxidant content was found to be 3.18 ± 0.01 g gallic acid equivalent per 100 g of dry weight. Also, the presence of lipids (16), phenolics (27), organic acids (4), L-aspartic acid derivative, questinol, gibberellic acid, sterol, and saponins (2) was confirmed using the UHPLC–ESI–MS analysis. In vitro assays showed that the extract has weak anti-α-glucosidase activity and moderate antioxidant and cytotoxic activity against the HeLa cell line. The extrusion method with secondary air flow enabled the preparation of microparticles (about 270 μm) encapsulated with extract. An encapsulation efficiency of over 92% was achieved in the alginate and alginate–chitosan microparticles. The swelling study confirmed a lower permeability of alginate–chitosan microparticles compared with alginate microparticles. For both types of microparticles, the release profile of antioxidants in the simulated gastrointestinal fluids at 37 °C followed the Korsmeyer–Peppas model. A lower diffusion coefficient than 0.5 indicated the simple Fick diffusion of antioxidants. The alginate–chitosan microparticles enabled a more sustained release of antioxidants from extract compared to the alginate microparticles. The obtained results indicated an improvement in the antioxidant activity of bioactive compounds from the extract and their protection from degradation in the simulated gastric conditions via encapsulation in the polymer matrixes. Alginate–chitosan showed slightly slower cumulative antioxidant release from microparticles and better antioxidant activity of the extract compared to the alginate system. According to these results, alginate–chitosan microparticles are more suitable for further application in the encapsulation of black locust flower extract. Also, the proposed polymer matrix as a drug delivery system is safe for human use due to its biodegradability and non-toxicity. [ABSTRACT FROM AUTHOR]

This study aimed to determine the suitable reclamation ways of post‐mining magnesite. It was hypothesized that adding amendments and planting would decrease pH, increasing the nutrient availability and enhancing the soil microbial activity. Treatments included 200 g gypsum, 2 kg goat manure, and 200 g sulfur per square meter. Cedar (Cedrus libani A. Rich.), black locust (Robinia pseudoacacia L.), black pine (Pinus nigra J.F. Arnold), and sainfoin (Onobrychis sativa L.) were planted. Before and after the treatments, samples were taken from each experimental unit and analyzed. Analysis of the data indicated that the pH had decreased by 0.6 and 0.5 units on the gypsum + sulfur‐ and gypsum + manure‐treated experimental units, respectively, compared to the other treated plots. In addition, using manure significantly increased the organic matter N, P, and K content, by 3‐fold, 2.5‐fold, 7.5‐fold, and 2.5‐fold, respectively, and enhanced microorganism activity. The sulfur + manure treatment increased microbial C and N approximately twofold. Because the manure, sulfur, and gypsum treatments improved the tailings conditions for plant growth, the use of these amendments for mine tailing reclamation was strongly recommended. Across all treatments, cedar and black pine demonstrated 83 and 77% survival rates for the first 3 years of afforestation, respectively. For the same period, the black locust survival rate was 35% lower than that of the other species. The gypsum + manure application increased seedling height growth by about 20% for all three species compared to the other treatments. [ABSTRACT FROM AUTHOR]

Forest stock volume (FSV) stands as an important indicator in evaluating the potential for carbon sequestration. It is crucial for forest resource management at local, regional, and national scales. In order to achieve an accurate estimation of FSV, this article takes Mengyin County, Shandong Province, China as the research area, builds a random forest (RF) model for four tree species based on airborne Lidar data, and forms a monitoring system of "individual tree - grid - county" granularities. The results demonstrated that all four models exhibited excellent generalization capabilities, with no signs of overfitting. In the test phase, the R2 of the poplar and pine models exceeded 0.9, while the R2 of the cypress model was 0.81, and the rRMSE was controlled within 20%, indicating that the fitting effect of the three tree species models was better; the accuracy of the robinia pseudoacacia model was relatively poor, with R2 of 0.60 and rRMSE of 20.60%. This study provides a feasible method for estimating forest stock volume within the county, which provides strong technical support for forest resource management and planning, and helps promote sustainable forestry development. [ABSTRACT FROM AUTHOR]

The mesic-origin species Robinia pseudoacacia L. (black locust) is widely planted in the semiarid and sub-humid areas of the Loess Plateau for the reforestation of vegetation-degraded land. Under the scenario of changing precipitation patterns, exploring the response of photosynthesis to drought allows us to assess the risk to sustainable development of these plantations. In this study, paired plots were established including the control and a treatment of 30% exclusion of throughfall (since 2018). The photosynthetic characteristics were investigated using a portable photosynthesis system for four periods in the full-leaf growing season of 2021–2022, the fourth and fifth years, on both treated and controlled sampling trees. Leaf gas exchange parameters derived from diurnal changing patterns, light response curves, and CO2 response curves showed significant differences except for period II (9–11 September 2021) between the two plots. The photosynthetic midday depression was observed in 2022 in the treated plot. Meanwhile, the decline of net photosynthetic rate in the treated plot was converted from stomatal limitation to non-stomatal limitation. Furthermore, we observed that black locust adapted to long-term water deficiency by reducing stomatal conductance, increasing water use efficiency and intrinsic water use efficiency. The results demonstrate that reduction in precipitation would cause photosynthesis decrease, weaken the response sensitivity to light and CO2, and potentially impair photosynthetic resilience of the plantations. They also provide insights into the changes in photosynthetic functions under global climate change and a reference for management of plantations. [ABSTRACT FROM AUTHOR]

Robinia pseudoacacia is widely planted in the Loess Plateau as a major soil and water conservation tree species because of its dense canopy, complex structure, and strong soil and water conservation ability. The precise measurement of small-scale locust forest biomass is crucial to monitoring and evaluating the carbon sequestration functions of soil and water conservation vegetation. This study focuses on an artificial locust forest planted in the early 1990s in Caijiachuan Basin, Jixian County, Shanxi Province. A drone equipped with LiDAR was used to obtain point cloud data and generate a canopy height model. A watershed segmentation algorithm was used to identify tree vertices and extract individual trees. A relationship model between tree height, diameter at breast height, and biomass, combined with sample survey data, was established to explore the spatial distribution of biomass in the artificial locust forest at the level of the entire basin. The results show the following: (1) the structural parameters of locust extracted using UAV point cloud data have a good degree of fit and accuracy, and the recall rate is 72.7%; (2) the average error rate of the extracted maximum tree height value of locust is 7%, that of the minimum tree height value is 14%, and that of the average tree height value is 18%; (3) the average error rate of the extracted maximum diameter at breast height of locust is 15%, that of the minimum diameter at breast height is 37%, and that of the average diameter at breast height is 36%; and (4) the average error rate of the biomass estimation of locust calculated using point cloud data is 16.0%. [ABSTRACT FROM AUTHOR]

The forest canopy affects the water entering the forest ecosystem by intercepting rainfall. This is especially pertinent in forests that depend on rainfall for their ecological water needs, quantifying and simulating interception losses provide critical insights into their ecological hydrological processes. In the semi‐arid areas of the Loess Plateau, afforestation has become an effective ecological restoration measure. However, the rainfall interception process of these plantations is still unclear. To quantify and model the canopy interception of these plantations, we conducted a two‐year rainfall redistribution measurement experiment in three typical plantations, including a deciduous broadleaf plantation (Robinia pseudoacacia) and two evergreen coniferous plantations (Platycladus orientalis and Pinus tabuliformis). Based on this, the revised Gash model was used to simulate their interception losses, and the model applicability across varying rainfall types was further compared and verified. The experiment clarified the rainfall redistribution in the three plantations, and the proportions of throughfall to gross rainfall in Robinia pseudoacacia, Platycladus orientalis, and Pinus tabuliformis were 84.8%, 70.4%, and 75.6%; corresponding, the stemflow proportions were 2.0%, 2.2%, and 1.8%; the interception losses were 13.2%, 27.4%, and 22.6%, respectively. The dominant rainfall pattern during the experiment was characterized by low‐amounts, moderate‐intensity, and short‐duration, during which the highest interception proportions across the three plantations were observed. We used the Penman‐Monteith equation and the regression method, respectively, to estimate the canopy average evaporation rate of the revised Gash model, finding that the latter provides a closer match to the measured cumulative interception (NSE >0.7). When simulating interception under the three rainfall patterns, the model with the regression method better simulated the cumulative interception and event‐scale interception for Platycladus orientalis and Pinus tabuliformis plantations under the dominant rainfall pattern. The results contribute valuable information to assess the impact of forest rainfall interception on regional hydrologic processes. [ABSTRACT FROM AUTHOR]

Black locust is the only host of Robinia-specialist insects in Europe. However, no study to date has examined future range shifts of specialist insects, and the relative effects of host plant availability and other factors on their range shifts. Here, we characterized the future range shifts in the host and its four specialist insects and the factors contributing to changes in their ranges. We detected substantial range expansions in all target species. Climate predictors and host plant availability were expected to have the strongest effects on the range shifts in the host and its specialist insects, respectively, suggesting that the specialist insects will track the ranges of their host. Parectopa robiniella showed the largest potential and expanding ranges and should be made a priority species for controlling invasions of Robinia-specialist insects in Europe. The expanding ranges of all specialist species were largely identified in the United Kingdom, Germany, and France, suggesting that these should be priority regions for mitigating their effects on ecosystems. Reducing future climate change is essential for preventing the spreading of specialist insects in Europe since specialist insects track their specialist host plants, and host range expansions are mainly driven by future climate changes.

This article is an editorial that highlights the ecological links between aboveground and underground ecosystems. It emphasizes the importance of studying the interactions between these systems in the context of global environmental changes. The editorial presents a compilation of six articles that cover various topics, including the effects of radiation on soil microbial communities, the relationship between leaf dry mass and leaf age, the impact of non-native species on native ecosystems, the phenotypic plasticity of trees in response to climate change, the nesting behaviors of birds in urban greenspaces, and the influence of plant diversity on root biomass. The article concludes by emphasizing the complexity and interconnectedness of aboveground and underground ecosystems and the need for multidisciplinary research and conservation strategies to address environmental challenges. [Extracted from the article]

Physical model experiments are increasingly applied in the study of the water infiltration law in loess with roots. In the past, due to differences in study objects and the limitations of measuring techniques, the infiltration law in loess with roots is rarely evaluated by using appropriate indoor physical model experimental data. In order to investigate the law of water infiltration in loess with roots, we designed a new soil column experimental device that can automatically collect data and images. By comparing the soil column experiment data of loess, we analyzed variables in root contents (the ratio of root mass to dry soil mass) and root types. Roots with diameters of 0–2 mm, 2–5 mm, and 5–10 mm are defined as type I, type II, and type III, respectively. It was found that the water infiltration rate, water-holding capacity, and saturated permeability coefficient increase with the increase in root content. In loess containing different root types, the root types were found to improve the rate of water infiltration, water-holding capacity, and saturated permeability coefficient in the soil. The root types were ranked in descending order in terms of their impact: root type II had the highest improvement, followed by root type III, and then root type I. The phenomenon of circumferential flow existed when water infiltrated loess with roots. Root content and root type would affect the radius of circumferential flow, infiltration path, and cross-section. When calculating the saturated permeability coefficient of loess with roots, ignoring the effect of circumferential flow would lead to a higher result. [ABSTRACT FROM AUTHOR]

[Objective] This study evaluated diversity characteristics of Robinia pseudoacacia plantations with different stand densities and analyzed their differences to provide theoretical basis for determining reasonable stand density of Robinia pseudoacacia plantations and their healthy and sustainable management. [Method] Robinia pseudoacacia plantations with densities of 675, 1 025, 1 575, 2 175 and 2 500 plants/hm² in loess areas of Western Shanxi were investigated. Species, number and cover of understory shrubs and herbs plants, and plant diversity indices were analyzed, 10 evaluation indicators were identified, and plant diversity was evaluated using principal component analysis. [Result] (1) The plants of Robinia pseudoacacia forests were mainly from Asteraceae, Rosaceae and Gramineae, and plants with high importance values included Rosa xanthina, Periploca sepium, Rubus parvifolius and Artemisia argyi. (2) With he increase of the density of Robinia pseudoacacia plantations, the plant diversity index of stands tended o increase first and then decrease, with the greatest diversity index at moderate densities of 1 575 and 2 175 plants/hm². There were significant differences between Shannon-Wiener index and Pielou index of hrub layer of 1 575 plants/hm² Robinia pseudoacacia plantations and 675 and 2 500 plants/hm² (P < 0.05). The Simpson index and Shannon-Wiener index of 1 575 plants/hm² were significantly different from hose of 675 and 2 500 plants/hm² (P<0.05). (3) The evaluation of plant diversity in different stand densities showed that the density of 1 575 plants/hm² had the highest overall plant diversity assessment value. [Conclusion] The density of 1 185-1 785 plants/hm² with high diversity of understory plants was suggested for Robinia pseudoacacia plantations in the loess area of Western Shanxi. [ABSTRACT FROM AUTHOR]