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Here we report on the detection and surveillance response to two Rugonectria species found in Sydney, Australia, in 2015. Both Rugonectria castaneicola and R. wingfieldii sp. nov. were found in association with cankers on Quercus robur (English oak). The fungi were initially found to be localised on amenity trees in northern Sydney, New South Wales, and as they were new detections for Australia, eradication was considered. Ongoing surveillance across the Sydney basin, regional New South Wales, and the Australian Capital Territory, however, indicated that they were already well established. Species identities were confirmed through morphological examination and molecular barcoding, with the subsequent analysis undertaken to classify R. wingfieldii sp. nov. This study provides the first records of Rugonectria found in association with canker on Oak trees in Australia. [ABSTRACT FROM AUTHOR]

Most urban tree inventories depend on resource-intensive, field-based assessments, which are unevenly distributed in space and time. Recently, these inventories have been conducted using field inventories combined with airborne multispectral, hyperspectral, LiDAR, and spaceborne multispectral remote sensing. Significant advances have been made in urban tree GIS databases and remote sensing methods, which include delineating individual tree crowns, extracting tree species metrics, and employing classification techniques. Generally, remote sensing methods distinguish individual urban trees using either pixel-based or object-based methods, while image classification procedures are typically divided into parametric (e.g., regression-based classification, Bayesian, and principal component analysis) and non-parametric approaches such as machine learning (e.g., random forests support vector machines) and deep learning (e.g., convolutional neural networks). Our synthesis of the current state of science suggests sensors with the highest spatial (m), spectral (bands), and temporal (repeat time) resolutions result in the most accurate tree species identification. Combining airborne LiDAR/hyperspectral or airborne LiDAR/spaceborne high-resolution multispectral sensors yields the highest accuracy for the most diverse urban forests. An object-based non-parametric approach, like a fully convolutional neural network, scores higher in accuracy assessments than pixel-based parametric approaches. Future studies can leverage global/regional GIS field inventory databases to expand the scope of studies within and across multiple cities, utilizing LiDAR and spaceborne sensors. [ABSTRACT FROM AUTHOR]

Brief introduction: What are microclimates and why are they important? Microclimate science has developed into a global discipline. Microclimate science is increasingly used to understand and mitigate climate and biodiversity shifts. Here, we provide an overview of the current status of microclimate ecology and biogeography in terrestrial ecosystems, and where this field is heading next. Microclimate investigations in ecology and biogeography: We highlight the latest research on interactions between microclimates and organisms, including how microclimates influence individuals, and through them populations, communities and entire ecosystems and their processes. We also briefly discuss recent research on how organisms shape microclimates from the tropics to the poles. Microclimate applications in ecosystem management: Microclimates are also important in ecosystem management under climate change. We showcase new research in microclimate management with examples from biodiversity conservation, forestry and urban ecology. We discuss the importance of microrefugia in conservation and how to promote microclimate heterogeneity. Methods for microclimate science: We showcase the recent advances in data acquisition, such as novel field sensors and remote sensing methods. We discuss microclimate modelling, mapping and data processing, including accessibility of modelling tools, advantages of mechanistic and statistical modelling and solutions for computational challenges that have pushed the state‐of‐the‐art of the field. What's next?: We identify major knowledge gaps that need to be filled for further advancing microclimate investigations, applications and methods. These gaps include spatiotemporal scaling of microclimate data, mismatches between macroclimate and microclimate in predicting responses of organisms to climate change, and the need for more evidence on the outcomes of microclimate management. [ABSTRACT FROM AUTHOR]

Urban development in South America has experienced significant growth and transformation over the past few decades. South America's urban development and trees are closely interconnected, and tree cover within cities plays a vital role in shaping sustainable and resilient urban landscapes. However, knowledge of urban tree canopy (UTC) coverage in the South American continent remains limited. In this study, we used high-resolution satellite images and developed a semi-supervised deep learning method to create UTC data for 888 South American cities. The proposed semi-supervised method can leverage both labeled and unlabeled data during training. By incorporating labeled data for guidance and utilizing unlabeled data to explore underlying patterns, the algorithm enhances model robustness and generalization for urban tree canopy detection across South America, with an average overall accuracy of 94.88% for the tested cities. Based on the created UTC products, we successfully assessed the UTC coverage for each city. Statistical results showed that the UTC coverage in South America is between 0.76% and 69.53%, and the average UTC coverage is approximately 19.99%. Among the 888 cities, only 357 cities that accommodate approximately 48.25% of the total population have UTC coverage greater than 20%, while the remaining 531 cities that accommodate approximately 51.75% of the total population have UTC coverage less than 20%. Natural factors (climatic and geographical) play a very important role in determining UTC coverage, followed by human activity factors (economy and urbanization level). We expect that the findings of this study and the created UTC dataset will help formulate policies and strategies to promote sustainable urban forestry, thus further improving the quality of life of residents in South America. [ABSTRACT FROM AUTHOR]

This paper explores the significance of ecosystem functions in maintaining the health and balance of ecological systems, particularly in the context of planning, managing, and maintaining trees in landscape settings. It emphasises the multifaceted relationship between humans and trees, encompassing cultural, ecological, economic, and emotional connections, and underscores the value of traditional ecological knowledge alongside empirical science. By combining these two ways of knowing, along with social science insights into human health and well-being, future landscapes can be crafted to be sustainable, diverse, and functional. As urbanisation continues to shape landscapes globally, urban planners face the challenge of managing rapidly changing environments. Urban forestry and arboriculture have emerged to address these challenges, aiming to enhance environmental quality and human well-being. The concept of Nature-based Solutions (NbS) has gained traction, recognising the importance of integrating natural systems into urban planning to address environmental challenges while preserving functional ecosystems. This paper advocates for an enhanced understanding of tree and human ecology to navigate the complex relations between trees, people, and their environments. It calls for interdisciplinary collaboration, research, and education to inform policy, assess environmental impacts, and widen approaches to ecosystem management. By monitoring ecosystem health and collaborating across disciplines, arboriculturists and urban foresters can shape resilient practices for tree conservation and sustainable urban development. In conclusion, integrating tree ecology into urban planning and management practices is essential for ensuring the health, resilience, and sustainability of tree populations and the ecosystems they inhabit. By embracing a holistic understanding of trees and their environments, professionals can contribute to shaping future landscapes that support both human well-being and biodiversity. [ABSTRACT FROM AUTHOR]

Tree bounties were a historical mechanism to facilitate afforestation. This study investigates how citizens participated in historical tree bounty programmes in North Dakota, South Dakota, and Minnesota during the late nineteenth and early twentieth centuries. Although tree bounties in the United States have been around for centuries, there has been very little published literature on how participants used them. Six hundred and one tree bounty claims from North Dakota, South Dakota, and Minnesota were examined and statistically analysed with t-tests. For example, it was found that for Ward County, North Dakota, box elder trees, cottonwood, willow, and poplar trees were more commonly planted; an average of 909 trees were planted per acre, the majority of applicants had homesteaded the land, and the average number of trees planted covered two acres. A statistically significant difference occurred where more claimants planted trees in northeast and northwest directions. The types of trees planted; the number of trees planted per acre; the number of times tree bounty claims were submitted; and incentives are discussed. Ideas for future research include expanding the research study and further understanding the breakdown of tree bounties for future improvement. [ABSTRACT FROM AUTHOR]

Rapid population growth and a high urbanisation rate have led to significant forest and tree losses in Lagos State, which is the smallest of the 36 States in Nigeria. Located on West Africa's Atlantic Ocean littoral, Lagos State is low-lying and crisscrossed by wetlands and numerous water bodies. These topographical and geographical characteristics render the State highly vulnerable to the sea level rises and flooding that are predicted with a changing climate. In response, the State government has introduced legislation to institutionalise tree planting. This tree mandate is amplified by the Lagos climate action plan and coexists with the State government's long-standing forestry mandate. It is accepted that urban forestry can improve climate resilience and deliver multifaceted economic, social, and environmental benefits. This article analyses the forestry and tree mandates that are in force in Lagos State and their implications for urban forestry. It identifies the lack of a synergistic approach by the Lagos State government as a major obstacle to successful urban forestry outcomes. [ABSTRACT FROM AUTHOR]

Access and exposure to urban green space—the combination of parks and vegetative cover in cities—are associated with various health benefits. As urban green space is often unequally distributed throughout cities, understanding how it is allocated across socio-demographic populations can help city planners and policy makers identify and address urban environmental justice and health equity issues. To our knowledge, no studies have yet combined assessments of park quality, park availability, and green cover to inform equitable urban green space planning. To this end, we developed a comprehensive methodology to identify urban green space inequities at the city scale and applied it in Portland, OR, USA. After auditing all public parks in Portland and gathering green cover data from publicly accessible repositories, we used a suite of statistical tests to evaluate distribution of parks and green cover across Census block groups, comprising race, ethnicity, income, and educational attainment characteristics. Right-of-way tree canopy cover was the most significant urban green space inequity identified in bivariate analysis (rs = −0.73). Spatial autoregressive models identified that right-of-way, private, and overall tree canopy cover (Nagelkerke pseudo-R2 = 0.66, 0.77, and 0.67, respectively) significantly decreased with the proportion of minoritized racial population and increased with median income. The results were then used to identify priority locations for specific urban green space investments. This research establishes a process to assess intra-urban green space inequities, as well as identify data-informed and spatially explicit planning priorities to promote health equity and environmental justice. [ABSTRACT FROM AUTHOR]

To preserve biodiversity and maintain ecosystem services provided by trees in the course of climate change, it is essential to consider challenging tree species, which are less studied primarily due to a lack of investment compared to commercial species. Species of the genus Quercus present an interesting case because of their economic and ecological importance, and their syngameon biology. As a model for exploring ecological diversification, and with recent advances in forest genomics, knowledge, data, and genomic resources for oak have accumulated and are summarized in this review to foster oaks as potential candidate species for future reforestation programs in Canadian natural, peri-urban, and urban ecosystems. We summarize the state of current genomic research in oak and the accompanying opportunities genomics can provide to achieve the potential of oak silviculture in Canada. Further, we highlight the socio-economic benefits of planting oaks and genomic tools for the development of a traceability system along the value chain. Finally, we discuss some of the remaining challenges to successfully integrate oaks into different forest management programs. In light of their increased drought resistance, oak species exhibit a strong potential as viable choices for future forests, resilient agricultural landscapes, and urban areas. By leveraging the progress made in oak genomics and the new applications that have been developed for commercial species, we can foster the successful management of oak genetic resources for the production of suitable seedlings, thereby aiding Canada in its ambitious pursuit of planting two billion trees to combat climate change. [ABSTRACT FROM AUTHOR]

Several researchers recognize the importance of plants as effective tools for environmental biomonitoring. The black poplar (Populus nigra L.) often emerges as a useful bioindicator of air quality in urban environments, where this tree species is widely employed for urban areas. Here, we used ICP-MS analysis to assess the presence and concentration of trace elements, with a special focus on heavy metals (HMs), in black poplar leaves and soil samples from three urbanized sites showing varying degrees of environmental quality. Specifically, the foliar concentrations of Zn (173.3 ppm), Cd (0.7 ppm), Co (1.1 ppm) and As (0.2 ppm) exceeded reference values for unpolluted sites, indicating potential environmental hazards. Additionally, we correlated the foliar concentrations of HMs with those quantified in soil and with air quality data provided by the regional air quality-monitoring network. Subsequently, we estimated the values of foliar fluctuating asymmetry, and evaluated their relationships with HM concentrations in both leaves and soil. Our results suggest that element concentrations in black poplar leaves are related to soil contamination and atmospheric quality, and the extent depends on the proximity to relevant pollution sources. Furthermore, the study species showed a pronounced accumulation capacity for some HMs (i.e., Zn, Cd) commonly found in particulate matter. The extent of foliar fluctuating asymmetry is related to atmospheric quality and HM soil concentration, possibly because of the growth anomalies induced by this kind of environmental contamination. Overall, our data indicate the study species can supply an effective biomonitoring service in urbanized contexts, offering valuable insights into the occurrence and biological implications of heavy metal contamination. [ABSTRACT FROM AUTHOR]

Trees growing in urban environments are often impacted by maintenance or construction work involving the cutting of roots. Tree protection zones have been proposed to avoid critical damage to the tree. However, despite incorporating quantitative information, they heavily rely on expert judgement that remains to be validated. In a study conducted across six parks in Quebec City, Canada, two commonly found tree species, Acer platanoides L. and Tilia cordata Mill., presumed to be different in terms of vulnerability to root damage, were subjected to a range of trenching treatments. The trees were between 23 and 40 cm diameter at breast height (DBH). A safety factor was calculated relating the turning moment the tree can withstand to the turning moment imposed by high winds likely to occur. The safety factor against uprooting was assessed for each tree before and after root trenching using a non-destructive pulling approach. The effects of tree species, distance to the trench, and their combined interaction were tested on tree stability. The relationship between tree stability and soil texture, tree characteristics, and the number of damaged roots were also tested. Safety factors were initially variable, ranging from 0.5 to 4.5. T. cordata safety factors were lower than those of A. platanoides and influenced by soil texture. Trenching treatments had no effect on the safety factor, even when two perpendicular trenches were dug at 1 m from the stem. No index of the amount of root damaged was significantly related to the safety factor. Root trenching treatments that encroached closer to the tree trunk than the recommended tree protection zones did not affect the stability of both species. Nevertheless, it is essential to recognize that other ecophysiological processes might still be influenced, and long-term monitoring is crucial. Both should be taken into account when determining these zones. [ABSTRACT FROM AUTHOR]

Green infrastructures (e.g., forests, parks, and other types of green spaces) in urban areas provide people with a huge volume of ecosystem benefits. However, the quality of urban green infrastructure varies among cities in different countries/regions, and key ecological processes, maintaining mechanisms, and policy decision routes remain unclear. Here, we recognize four themes that link studies from the Asia-Pacific and European regions presented in this Editorial: (1) indicators and services of urban green spaces; (2) assembly of and changes in diverse plant communities; (3) utilization and evaluation of urban forest landscape; and (4) patterns and drivers of urban agro-forestry systems. These investigations enlarge our understanding on the theoretical exploration and methodological innovation of urban forestry studies in response to the changing environment, and shed some light on routes to achieve sustainable development goals in the context of rapid urbanization. [ABSTRACT FROM AUTHOR]

Accurate and rapid localization and identification of tree leaves are of significant importance for urban forest planning and environmental protection. Existing object detection neural networks are complex and often large, which hinders their deployment on mobile devices and compromises their efficiency in detecting plant leaves, especially against complex backgrounds. To address this issue, we collected eight common types of tree leaves against complex urban backgrounds to create a single-species leaf dataset. Each image in this dataset contains only one type of tree but may include multiple leaves. These leaves share similar shapes and textures and resemble various real-world background colors, making them difficult to distinguish and accurately identify, thereby posing challenges to model precision in localization and recognition. We propose a lightweight single-species leaf detection model, SinL-YOLOv5, which is only 15.7 MB. First, we integrated an SE module into the backbone to adaptively adjust the channel weights of feature maps, enhancing the expression of critical features such as the contours and textures of the leaves. Then, we developed an adaptive weighted bi-directional feature pyramid network, SE-BiFPN, utilizing the SE module within the backbone. This approach enhances the information transfer capabilities between the deep semantic features and shallow contour texture features of the network, thereby accelerating detection speed and improving detection accuracy. Finally, to enhance model stability during learning, we introduced an angle cost-based bounding box regression loss function (SIoU), which integrates directional information between ground-truth boxes and predicted boxes. This allows for more effective learning of the positioning and size of leaf edges and enhances the model's accuracy in detecting leaf locations. We validated the improved model on the single-species leaf dataset. The results showed that compared to YOLOv5s, SinL-YOLOv5 exhibited a notable performance improvement. Specifically, SinL-YOLOv5 achieved an increase of nearly 4.7 percentage points in the mAP@0.5 and processed an additional 20 frames per second. These enhancements significantly enhanced both the accuracy and speed of localization and recognition. With this improved model, we achieved accurate and rapid detection of eight common types of single-species tree leaves against complex urban backgrounds, providing technical support for urban forest surveys, urban forestry planning, and urban environmental conservation. [ABSTRACT FROM AUTHOR]

Background: Toumeyella parvicornis is an alien pest of recent introduction in Italy that infests stone pines (Pinus pinea L.), its main host plant in Europe. Infestations are currently controlled through endotherapic treatments, but the high costs and the long‐term inefficacy highlight the need for alternative control strategies applicable in natural systems as well. An analysis of the effectiveness of autochthonous and naturalized predators is the first step to achieve this goal. This work focused on two candidate predators, Exochomus quadripustulatus and Cryptolaemus montrouzieri (Coleoptera: Coccinellidae), that may potentially control T. parvicornis. The analysis was carried out under laboratory‐controlled and semi‐field conditions. Results: Laboratory tests were carried out to assess: (i) the predation rate of the ladybugs over different densities of pest preimaginal stages, and (ii) the effect of the presence of heterospecific and conspecific predators on the attractiveness of prey colonies. Semi‐field experimentations were carried out by wrapping infested stone pine twigs with net sleeves and applying one of three treatments: (i) Exochomus quadripustulatus, (ii) Cryptolaemus montrouzieri, and (iii) control containing only the pest population. Both the ladybugs were attracted by T. parvicornis, offered as prey. Exochomus quadripustulatus was more attracted to conspecific and heterospecific ladybugs than Cryptolaemus montrouzieri and responded to prey more quickly. Conclusions: The results obtained could be useful for planning further experimentations to explore the potential use of these predators in biological control programs that may be applied in infested areas. Besides the use in an urban context, where pesticide use is strongly limited, the release of natural enemies may help safeguard stone pine forests. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

AbstractUrban tree planting initiatives (TPIs) have become a prominent form of public work that has the potential to increase the livability and sustainability of cities. However, if not sufficiently resourced and thoughtfully planned and implemented, these high-profile programs may fail to achieve intended goals. To promote successful implementation of TPIs, we offer recommendations for the pre-planting, installation, and post-planting phases. During each of these phases we present five cross-cutting themes: ensuring adequate funding for all project phases; cultivating place-based landscape design; engaging and investing in communities; implementing sound planting practices; and evaluating performance and adapting over time. [ABSTRACT FROM AUTHOR]

Background: Public engagement is needed to make sure urban forestry management efforts align with the values of the public being served. Noting this, we determined current and desired urban forest access of Florida (United States) residents using the criteria from the 3-30-300 rule (i.e., 3 trees visible from home, 30% urban tree canopy in neighborhood, and a green space within 300 meters of home). Methods: A survey of 1,716 Florida residents was conducted to assess canopy coverage and green space access. Respondents were then asked if this level of urban forest access was sufficient. We also asked their perceptions of the benefits and drawbacks of urban trees and whether they had any negative interactions with trees in the past. Results: We found that 37.3% of Florida residents met all 3 criteria of the 3-30-300 rule. Despite this, half the respondents would prefer more trees in their neighborhoods. When asked to name the top benefits provided by trees, the most common responses were shade, beauty, and attracting wildlife. The most common drawbacks to urban trees included the risk of damage to property, leaves/debris, and fears regarding storms and hurricanes. Conclusions: Florida residents largely value their urban forest and would like to see it maintained or enhanced. Improving access to greenspaces for recreation is the most pressing concern for urban forest managers in Florida looking to meet the requirements of the 3-30-300 rule. Results from this study can inform urban forest management efforts in Florida and beyond. [ABSTRACT FROM AUTHOR]

Background: Trees in towns and cities provide many benefits, but also disservices such as risk and conflicts. Structural pruning of young trees can reduce future conflicts and risk as trees grow larger; it also can reduce future maintenance costs. Volunteers can perform important urban forestry tasks such as planting, watering, and conducting inventories. It was hypothesized that, with training, they could also learn to structurally prune young street trees. Methods: Forty-seven volunteers in three cities in Massachusetts were trained to structurally prune trees. Twenty volunteers trained in a classroom lecture; twenty-seven trained with a hands-on approach. The volunteers' performance was evaluated with a written exam and in situ assessments of their ability to specify and explain pruning recommendations and make pruning cuts. Training type and covariates (e.g., volunteers' familiarity with trees, number of branches) influence on volunteers' performance were investigated. Results: On the assessment of volunteers' ability to explain pruning recommendations, volunteers who received hands-on training achieved higher mean scores (79%) than volunteers who received classroom training (74%). All volunteers who received hands-on training did not leave a stub when making a reduction cut, but only 70% of volunteers who received classroom training did not leave a stub. Volunteers who received classroom training achieved higher scores on the exam (93%) than volunteers who received hands-on training (85%). Conclusions: Results suggest that with minimal training volunteers successfully learned structural pruning. This is an encouraging finding that may help municipal arborists accomplish more with limited urban forestry budgets. [ABSTRACT FROM AUTHOR]

Accurately estimating vegetation biomass in urban forested areas is of great interest to researchers as it is a key indicator of the carbon sequestration capacity necessary for cities to achieve carbon neutrality. The emerging vegetation biomass estimation methods that use AI technologies with remote sensing images often suffer from arge estimating errors due to the diversity of vegetation and the complex three-dimensional terrain environment in urban ares. However, the high resolution of Light Detection and Ranging (i.e., LiDAR) data provides an opportunity to accurately describe the complex 3D scenes of urban forests, thereby improving estimation accuracy. Additionally, deep earning foundation models have widely succeeded in the industry, and show great potential promise to estimate vegetation biomass through processing complex and arge amounts of urban LiDAR data efficiently and accurately. In this study, we propose an efficient and accurate method called 3D-CiLBE (3DCity Long-term Biomass Estimation) to estimate urban vegetation biomass by utilizing advanced deep earning foundation models. In the 3D-CiLBE method, the Segment Anything Model (i.e., SAM) was used to segment single wood information from a arge amount of complex urban LiDAR data. Then, we modified the Contrastive Language–Image Pre-training (i.e., CLIP) model to identify the species of the wood so that the classic anisotropic growth equation can be used to estimate biomass. Finally, we utilized the Informer model to predict the biomass in the ong term. We evaluate it in eight urban areas across the United States. In the task of identifying urban greening areas, the 3D-CiLBE achieves optimal performance with a mean Intersection over Union (i.e., mIoU) of 0.94. Additionally, for vegetation classification, 3D-CiLBE achieves an optimal recognition accuracy of 92.72%. The estimation of urban vegetation biomass using 3D-CiLBE achieves a Mean Square Error of 0.045 kg/m2, reducing the error by up to 8.2% compared to 2D methods. The MSE for biomass prediction by 3D-CiLBE was 0.06kg/m2 smaller on average than the inear regression model. Therefore, the experimental results indicate that the 3D-CiLBE method can accurately estimate urban vegetation biomass and has potential for practical application. [ABSTRACT FROM AUTHOR]

Urban forests have long been understudied, resulting in a scarcity of long-term data to guide future management. The New York Botanical Garden in New York City has been stewarding the 20 ha Thain Family Forest since 1895. Using inventory data between 1937 and 2021, we document how structure, diversity, and composition of the forest have changed over the past century. Our results show an increase in the proportion and diversity of hardwood species, including oaks, hickories, red maple, black cherry, and American beech, following the loss of a dominant species, eastern hemlock. Despite changes in composition, we find no significant differences in the mean basal area, density, and tree diameter of canopy trees (diameter at breast height [DBH] ≥ 15 cm) from 1937 to 2021. Assessments of small diameter stems (DBH ≥ 2.54 cm) show increasing density, decreasing diameter, and increasing richness from 1985 to 2021, suggesting a period of understory recruitment/regeneration. During this time, native species have been dominant in both overstory and understory strata. These observations mirror trends recorded in hemlock–hardwood and oak–hickory forests region-wide, indicating that, with continued conservation and active management, urban and rural forests may develop in similar patterns and encouraging regional approaches to forest management. Study Implications: Urban forests have long been understudied, resulting in a scarcity of long-term data to guide future management. Over the past century, the 20 ha Thain Family Forest in New York City has experienced a significant change in species composition, with an increase in the proportion and diversity of hardwood species following the loss of eastern hemlock. Despite these changes, forest canopy structure has remained stable. These observations mirror those observed in hemlock–hardwood and oak–hickory forests regionwide, suggesting that with continued conservation and active management, urban and rural forests may develop in similar patterns. The results of this study support continued investment in the research and management of urban forests as a comprehensive part of regional forest management efforts. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbon (PAH) concentrations in the leaves and 1-year-old branches of three common tree species growing in a middle-sized city located in a moderate climate zone were estimated. For this purpose, PAH phytoaccumulation in Platanus × acerifolia, Celtis australis, and Tilia grandifolia species from highly urbanized, traffic congested, and highly PAH-contaminated streets was compared with trees from non-contaminated parks in the same urban core. The gathered data was used to define 17 PAH profiles, identify the main PAH pollution emission sources, and determine the organ and species specificity of PAHs accumulation. Due to the direct absorption of polluted air via stomata, the leaves accumulated up to 30% more PAHs compared to the 1-year-old branches. As expected, PAH concentrations were much higher in street trees, while heavy weight PAHs (with five and six rings) were accumulated in the highest concentrations. The highest foliar Σ17 PAH concentrations were detected in street-grown C. australis, followed by P. acerifolia and T. grandifolia (502.68, 488.45, and 339.47 ng g−1 dry weight (DW), respectively). The same pattern was noted for Σ17 PAHs in branches (414.89, 327.58, and 342.99 ng g−1 DW, respectively). Thus, T. grandifolia emerged as the least effective PAH sink as it accumulated up to ~ 40% less PAHs than P. acerifolia and C. australis leaves/branches. Among the 17 tracked PAHs, benzo[a]anthracene, benzo[a]pyrene, dibenzo[a,h]anthracene, and pyrene were found to have accumulated in the highest concentrations in all analyzed species irrespective of the site, and accounted for more than 50% of the total detected PAHs. Finally, a "black box" about species and organ specificity, as well as specific drivers that limit PAHs uptake capacity by trees, was opened, while this work provides insights into further PAH phytoremediation strategies. [ABSTRACT FROM AUTHOR]

Monitoring atmospheric concentrations of greenhouse gases (GHGs) like carbon dioxide and methane in near real time and with good spatial resolution is crucial for enhancing our understanding of the sources and sinks of these gases. A novel approach can be proposed using a constellation of small satellites equipped with miniaturized spectrometers having a spectral resolution of a few nanometers. The objective of this study is to describe expected results that can be obtained with a single satellite named Uvsq-Sat NG. The SolAtmos end-to-end simulator and its three tools (IRIS, OptiSpectra, and GHGRetrieval) were developed to evaluate the performance of the spectrometer of the Uvsq-Sat NG mission, which focuses on measuring the main GHGs. The IRIS tool was implemented to provide Top-Of-Atmosphere (TOA) spectral radiances. Four scenes were analyzed (pine forest, deciduous forest, ocean, snow) combined with different aerosol types (continental, desert, maritime, urban). Simulated radiance spectra were calculated based on the wavelength ranges of the Uvsq-Sat NG, which spans from 1200 to 2000 nm. The OptiSpectra tool was used to determine optimal observational settings for the spectrometer, including Signal-to-Noise Ratio (SNR) and integration time. Data derived from IRIS and OptiSpectra served as input for our GHGRetrieval simulation tool, developed to provide greenhouse gas concentrations. The Levenberg–Marquardt algorithm was applied iteratively to fine-tune gas concentrations and model inputs, aligning observed transmittance functions with simulated ones under given environmental conditions. To estimate gas concentrations (CO2, CH4, O2, H2O) and their uncertainties, the Monte Carlo method was used. Based on this analysis, this study demonstrates that a miniaturized spectrometer onboard Uvsq-Sat NG is capable of observing different scenes by adjusting its integration time according to the wavelength. The expected precision for each measurement is of the order of a few ppm for carbon dioxide and less than 25 ppb for methane. [ABSTRACT FROM AUTHOR]

Gender-based violence (GBV) poses a significant concern in the construction and natural resources industries, where women, due to lower social status and integration, are at heightened risk. This systematic review aimed to identify the prevalence and experience of GBV in the construction and natural resources industries. A systematic search across databases including PubMed, OVID, Scopus, Web of Science, and CINAHL was conducted. The Risk of Bias Instrument for Cross-sectional Surveys of Attitudes and Practices by McMaster University and the Critical Appraisal of Qualitative Studies by the Center for Evidence Based Medicine at the University of Oxford were used to assess the studies included in the review. Six articles were included after full-text analysis. GBV was reported in the construction, mining, urban forestry, and arboriculture sectors. Workplace GBV was measured differently across the studies, and all studies examined more than one form of GBV. The main forms of GBV discussed in these studies were discrimination, sexual harassment, and sexism. The studies provided some insight for demographic factors that may or may not be associated with GBV, such as age, region of work, and number of years working in the industry. The review also suggests that workplace GBV has a negative impact on mental health and well-being outcomes, such as higher levels of stress and lower job satisfaction. The current research has not established the effectiveness of interventions, tools, or policies in these workplaces. Thus, additional research should include intervention studies that aim to minimize or prevent GBV in male-dominated workplaces. The current study can bring awareness and acknowledgement towards GBV in the workplace and highlight the importance of addressing it as this review outlines the negative consequences of GBV on mental health and well-being in these male-dominated industries. [ABSTRACT FROM AUTHOR]

Though the impact of urban vegetation on air quality and the microclimate has attracted increasing attention, there have been few studies quantitatively assessing this impact in North China, where air pollution is severe. In this study, we investigated the impact of urban forests and urban parks on air quality and the microclimate in Jinan, northern China. Six sites were chosen to represent urban forest, urban park, and downtown areas, respectively. The results indicate that urban forest can effectively reduce PM2.5 and ozone (O3) concentrations in the warm season, when temperatures are higher and plants are lush. The PM2.5 and O3 concentrations in the urban forest areas were 6.3–6.5 μg m−3 and 21–23 μg m−3 lower than those in downtown areas during the period of 10:00–15:00. In contrast, urban park areas can reduce PM2.5 concentrations but have little impact on gaseous pollutants such as nitrogen dioxide and O3. Furthermore, both urban forest and urban park areas reduced temperatures, by approximately 4.1–6.8 °C and 1.36 °C, respectively, and increased relative humidity, by about 13.4–12.9% and 0.9%, promoting a more comfortable thermal environment for residents. Therefore, this study highlights the crucial role of urban vegetation in improving air quality and creating a comfortable environment for residents. [ABSTRACT FROM AUTHOR]

Byblos, designated as a UNESCO World Heritage site, stands as one of Lebanon's most ancient urban centers, known for its expansive green spaces. However, ongoing urbanization threatens these valuable areas. This study uses a multi-faceted approach to evaluate the structure and landscape attributes of Byblos' urban and peri-urban forests (UPFs). Landscape canopy cover, diversity indices, forest structure, and a silhouette perceptual test were assessed across 24 streets in the city center, residential zones, and areas with heavy vehicular traffic. Findings reveal that 28% of Byblos' canopy cover is concentrated mostly in the northeastern region. Native tree species account for 30% of the total, and a notable variation in tree diversity exists among different land-use types (Shannon diversity index (H) was 1.02 for the city center, 1.35 for residential streets, and 0.64 for vehicular areas). Additionally, a normal J-shaped distribution of tree diameters was identified across all street types. This study highlights a correlation between tree silhouettes and visual preferences, with densely spreading canopies being favored. Residential trees demonstrate the highest structural diversity and varied blossoming seasons. This research represents the first investigation into the current state of urban forestry in Byblos and offers recommendations for sustainable management and planning strategies. [ABSTRACT FROM AUTHOR]

This research presents a classification methodology for the detection of new or emerging stress in trees using indices derived from hyperspectral data and tests whether existing hyperspectral indices are effective when used as the classification features for this problem. We tested six existing indices—Water Band Index (WBI), Gitelson–Merzlyak B Index (GMb), Normalized Phaeophytization Index (NPQI), Combined Carotenoid/Chlorophyll Ratio Index (CCRI), Photochemical Reflectance Index (PRI), and Red-Edge Chlorophyll Index (CIre)—along with a seventh Test Index—generated as a composite of PRI and Cire—as classification features. Analysis was conducted using data collected from trees with and without emerald ash borer (EAB) infestation to develop a methodology that could be adapted to measure emerging stress from other pathogens or invasive pests in other tree species. Previous work has focused specifically on the identification of damage or stress symptoms caused by a specific pathogen. In this study, we adapted that work to develop a system of classification that can be applied to the identification of stress symptoms from a range of sources, measurable in trees based on spectral response and, in some cases, detectable prior to the onset of visible symptoms that can be measured through human observation. Our data indicate that existing indices derived from hyperspectral data are effective as classification features when measuring spectral responses indicative of emerging stress in trees. [ABSTRACT FROM AUTHOR]

Changes in tree cover and impervious surfaces have been observed across many cities in the United States over the past 70 years. Many municipalities are implementing tree planting programs in efforts to increase tree cover. A detailed understanding of historical changes in land cover can inform urban forest management. I applied a convolutional neural network image segmentation approach to historical aerial imagery to delineate changes in land cover in 1957, 1974, and 2017 in Utica, New York, a small, postindustrial city. The model predicted tree, pavement, and building land cover in each year with overall accuracies ranging from 82–87%. From 1957 to 2017, tree cover declined in many areas and impervious surface cover (buildings and pavement) increased. Tree cover gains largely occurred in uninhabited, natural areas; whereas, the greatest declines in tree coverage occurred in many residential areas following the start of the urban renewal efforts in 1957. Current tree planting efforts targeted at homeowners could drive disparities in future tree cover since several areas of Utica with low tree have a high proportion of renter occupied homes and a low median household income. Convolutional Neural Network approaches for image segmentation of aerial imagery are a helpful tool in understanding patterns in changes in tree and impervious surfaces. A better understanding of the legacies of historical policies and neighborhood-scale changes in land cover can assist in highlighting priorities for urban forest management and justice-oriented urban forestry approaches to urban tree planting. [ABSTRACT FROM AUTHOR]

Campuses of Nigerian universities, especially the older ones, are home to aged trees that were originally planted for environmental beautification and aesthetics. However, due to the current global climate change and increased vulnerability to abiotic and biotic stressors, the old trees could pose threats to pedestrians, structures, and roads within the university campus environments. Therefore, the objective of this paper is to develop a geodatabase and evaluate the health risk assessment of avenue trees on selected roads in a tertiary institution in Ibadan, Oyo State, Nigeria using appropriate standard methods. Results obtained reported a total of 121 individual avenue trees belonging to 14 species along the study roads. The geospatial distribution analysis revealed that Emotan road had a lower density of avenue trees compared to Benue and Oduduwa roads. Furthermore, the health risk assessment indicated that 17.35% of the individual avenue trees had defects, posing potential hazards and risks of tree failure, and potential damage to pedestrians, vehicles, and neighboring utilities. The developed geodatabase is user-friendly and allows for easy data storage and quick information retrieval on the avenue trees, enhancing their maintenance and risk management. Furthermore, this study shows that systematic replacement, replanting, and management of avenue tree species could be a proactive initiative for the expansion of the geodatabase and to reduce negative health impacts.

Urban tree cover plays a pivotal role in bolstering the sustainability, livability, and resilience of cities. However, the changes in urban tree cover and exposure under the backdrop of urbanization in China remain unclear. This study investigates the spatial distribution and temporal trends of urban tree cover expansion and exposure change from 1985 to 2023. Our findings highlight significant progress in enhancing urban tree cover, with the average tree cover in Chinese urban areas reaching 11.9% in 2023, representing a remarkable 116% increase from 5.5% in 1985. However, this positive trend contrasts with persistent deficiencies in forest resources, as reflected by the fact that urban forest cover in Chinese cities was only 4.1% in 2023, compared with 0.1% in 1985. Furthermore, our study revealed substantial heterogeneity in the spatiotemporal variations of urban tree cover. Only five cities exhibited a decreasing trend in tree cover during the study period, with coastal cities demonstrating significantly higher tree cover compared with inland cities. Additionally, we observed that urban tree cover and expansion rates decreased significantly with increasing latitude. Moreover, nationwide, there has been a sustained and accelerated improvement in urban tree exposure levels, with average tree exposure increasing from 0.66% in 1985 to 7.45% in 2020. The 69% of cities experienced positive changes in tree exposure levels, while only 1% exhibited negative changes. These findings offer valuable insights for policymakers, planners, and stakeholders to foster greener, more resilient, and sustainable urban environments in China.

Urban vegetation plays a crucial role in reducing atmospheric particulate matter (PM), modifying microclimates, and improving air quality. This study investigates the impact of a laurel hedge (Laurus nobilis L.) on airborne PM, specifically total suspended particulate (TSP) and respirable particles (PM4) generated by a Diesel tractor engine. Conducted in a wind tunnel of approximately 20 m, the research provides insights into dust deposition under near-real-world conditions, marking, to our knowledge, the first exploration in a wind tunnel of this scale. Potted laurel plants, standing around 2.5 m tall, were arranged to create barriers of three different densities, and air dust concentrations were detected at 1, 4, 9, and 14 m from the plants. The study aimed both to develop an experimental system and to assess the laurel hedge’s ability to reduce atmospheric PM. Results show an overall reduction in air PM concentrations (up to 39%) due to the presence of the hedge. The highest value of dust reduction on respirable particles was caused by the thickest hedge (three rows of plants). However, the data exhibit varying correlations with hedge density. This study provides empirical findings regarding the interaction between dust and vegetation, offering insights for designing effective hedge combinations in terms of size and porosity to mitigate airborne particulate matter.

This study examines the spatio-temporal dynamics of Acacia auriculiformis in Lubumbashi city, southeastern Democratic Republic of Congo, in the context of rapid urbanization following the liberalization of the mining sector. The city has experienced significant demographic growth and unplanned spatial expansion, resulting in a decrease in vegetation cover. The introduction and proliferation of A. auriculiformis, an exotic tree species, have occurred without strategic planning or monitoring. Utilizing digitized remote sensing imagery from 2006, 2014, and 2021, we quantified the expansion of A. auriculiformis along the urban–rural gradient. Additionally, a floristic inventory conducted in 2021 provided insights into tree diversity within A. auriculiformis plantations. Our findings indicate a substantial increase in the number and area of A. auriculiformis patches, predominantly in urban zones. However, the patch values, highest in 2006, were shown to decline by 2021, especially in urban areas. The floristic inventory identified 39 tree species within A. auriculiformis plantations, including predominant species such as Albizia lebbeck, Albizia alba, and Leucaena leucocephala. Notably, 20 of these species are exotic, with half being invasive. In contrast, the 19 indigenous species were primarily found in peri-urban areas. While a greater number of tree species were observed in urban zones, larger average diameters were recorded in peri-urban zones. The persistence and expansion of A. auriculiformis in a landscape characterized by declining tree cover suggest its potential sustainability in this setting. However, A. auriculiformis plantations have facilitated the establishment of predominantly exotic and potentially invasive species. These findings highlight the need for the strategic management of A. auriculiformis and associated exotic flora to mitigate their spread and to consider their role in the restoration of degraded lands.

Urban vegetation plays a crucial role in reducing atmospheric particulate matter (PM), modifying microclimates, and improving air quality. This study investigates the impact of a laurel hedge (Laurus nobilis L.) on airborne PM, specifically total suspended particulate (TSP) and respirable particles (PM4) generated by a Diesel tractor engine. Conducted in a wind tunnel of approximately 20 m, the research provides insights into dust deposition under near-real-world conditions, marking, to our knowledge, the first exploration in a wind tunnel of this scale. Potted laurel plants, standing around 2.5 m tall, were arranged to create barriers of three different densities, and air dust concentrations were detected at 1, 4, 9, and 14 m from the plants. The study aimed both to develop an experimental system and to assess the laurel hedge's ability to reduce atmospheric PM. Results show an overall reduction in air PM concentrations (up to 39%) due to the presence of the hedge. The highest value of dust reduction on respirable particles was caused by the thickest hedge (three rows of plants). However, the data exhibit varying correlations with hedge density. This study provides empirical findings regarding the interaction between dust and vegetation, offering insights for designing effective hedge combinations in terms of size and porosity to mitigate airborne particulate matter. [ABSTRACT FROM AUTHOR]

Recent rapid economic and infrastructure growth in India has led to degraded environmental conditions. Congested and densely populated urban areas have seen increased pollution, water pollution, and habitat and biodiversity loss. Urban green spaces (UGSs) are vital for improving such environmental qualities and coping with environmental challenges within cities. UGSs provide numerous tangible and intangible environmental, recreational/social, and economic benefits, also acknowledged as ecosystem services. This study assessed residents' perceptions of UGSs ecosystem services in Delhi, India. The main objectives were to (1) understand residents' visiting patterns of UGSs and corresponding socio-economic correlations (2) assess residents' knowledge and perceptions of ecosystem services and disservices, and (3) ranking of ecosystem services provided by UGSs based on significance to the residents. This study is based on a survey of 620 randomly selected respondents in UGSs throughout the city. Most respondents knew about ecosystem services in UGSs and believed the ecosystem services outweighed any ecosystem disservices. The results also showed the importance of improving urban microclimate and environmental quality was emphasized. Interestingly, ecosystem services like improve mental health and aesthetic beauty rated high. The improvement of wildlife habitat, fresh water, water flow regulation & runoff mitigation and the collection of fuelwood, fruits, honey and medicine were not seen as important by the respondents. Residents more readily recognized UGSs' direct benefits over the indirect benefits. Awareness of economic benefit was relatively high. Results from this research could help urban planners and developers to consider residents' perceptions and expectations when designing UGSs. [ABSTRACT FROM AUTHOR]

The information related to the species of terrestrial mammals that can be detected along the nature trails established in the lowland tropical forests of Western Sabah remains scarce at this moment. The camera trapping surveys were commenced at the Tenghilan Community Forest (TCF), Kawang Forest Reserve (KFR), and the urban forest of Universiti Malaysia Sabah (UMS) to investigate the terrestrial mammal species that could be observed along the local trails. A total of 20 terrestrial mammal species belonging to 13 different families were observed in 2,077 trap nights, where most of them were validated to be non-threatened (n = 16 or 80.0%) and omnivorous (n = 13 or 65.0%) species. Twelve species were found along the nature trails in TCF (H’ = 2.223; 1-D = 0.8650) and KFR (H’ = 1.730; 1-D = 0.7078), whereas seven species were detected along the trails in the urban forest of UMS (H’ = 1.217; 1-D = 0.5567). The differences in the mammalian composition, diversity richness, and distribution evenness between these three study sites were validated as significant (p<0.05). The present findings emphasize that these three study sites are favorable habitats for four threatened species. Hence, conservation efforts are needed to protect these terrestrial mammal species from facing extinction risks in future. [ABSTRACT FROM AUTHOR]

Wasmannia auropunctata, the little fire ant, is an invasive pest threatening native biodiversity, agricultural and forestry production, and public health. In January 2022, wild populations of W. auropunctata were reported for the first time on the Chinese mainland. However, the stage and degree of W. auropunctata invasion in China are unclear. Therefore, assessing the risk of establishment and the potential impacts associated with this pest is crucial for preventing further spread. This study used the Bayesian additive regression trees (BARTs) model and global occurrence records to assess the potential distribution of W. auropunctata in southern China and the associated risk of invading urban, rural, agricultural, and forest lands. The results from our models indicate that: (1) coastal areas, southwest, and central areas are particularly suitable for W. auropunctata establishment; (2) temperature, clay content, mean normalized differential vegetation index (NDVI), and urban area are important factors in the distribution of W. auropunctata; (3) the agricultural lands in the coastal areas and the Yunnan–Guangxi border, the urban and rural lands in the coastal areas, and grasslands in the southwest should prepare for possible W. auropunctata invasion; and (4) forest lands have the highest area at risk of W. auropunctata invasion in southern China. These results provide valuable information for planning and implementing the monitoring and control strategies against W. auropunctata invasion in China. [ABSTRACT FROM AUTHOR]

Trees outside forests (TOF) are woody plants found on land which is less than 0.5 ha. These are important for biodiversity conservation and carbon storage. This study was conducted in Kathmandu Valley, central Nepal to determine tree species diversity and phytomass carbon stock patterns along the urban to rural spatial gradient of TOF. A detailed inventory was conducted across a total of 209 randomly selected points generated by MS Excel using circular plots of 20 m radius each. A total of 6,210 trees from 150 species belonging to 111 genera and 57 families were recorded under three strata (urban, suburban and rural). Out of 150 species, 53.33% were native and 46.67% were exotic. The average tree density was found to be higher in the suburban stratum (248.44 ha−1) compared to the urban (232.58 ha−1) and the rural (224.88 ha−1) strata. Species richness was found to be higher in the rural stratum (14.09 ha−1) compared to the urban (9.85 ha−1) and the suburban (9.70 ha−1) strata. But average species richness was found to be highest in the urban stratum (55.95 ha−1) followed by the suburban (46.31 ha−1) and the rural (45.74 ha−1) strata, respectively. Similarly, the average phytomass carbon stock recorded was highest in the urban stratum (39.41 t ha−1) compared to the rural (29.19 t ha−1) and the suburban (26.06 t ha−1) strata. The average phytomass carbon stock varied significantly between the native and the exotic species only in the urban stratum but not in the suburban and the rural strata. This study provides baseline data useful for green urban planning and development as well as carbon sink management. [ABSTRACT FROM AUTHOR]

Urban lakes serve an indispensable role in maintaining the ecological balance of cities, ensuring flood safety, and providing recreational spaces for tourism. With the development of human activities and economic, the extent of urban lakes are inevitably influenced. Currently, the ability to detect detailed temporal changes in urban lake areas using high resolution data still has limitations. This study proposed a novel method by combining time series Gaofen-1 (GF-1) remote sensing data and random forest machine learning algorithm to explore the urban lakes change Zhushan Lake located in Wuhan. The research conducted the extraction of surface water for Zhushan Lake and its surrounding pit-ponds from 2013 to 2020. And then, a quantitative analysis of the characteristics and driving factors of lake changes is conducted. We find that (1) the accuracy of surface water extraction using the random forest classification method consistently exceeded 96%. The Kappa coefficient ranges from a minimum of 0.86 to a maximum of 0.99. (2) A noticeable decline was observed in the water areas of Zhushan Lake and its surrounding pit-ponds, predominantly along the northwestern shoreline and in the eastern pond regions. This decline is primarily attributed to pressures from building construction. The methodology proposed in this study is suitable for the area management of lakes in urban areas. [ABSTRACT FROM AUTHOR]

The study assessed the problems and prospects of tree planting in Kano metropolis, employing a mixed-methods approach utilizing both primary and secondary data sources. Simple random sampling was used in selecting LGAs, 180 questionnaires were administered and retrieved using proportional allocation. Data screening, organization, and analysis, including descriptive statistics and Chi-square test were conducted using SPSS version 23. The result revealed demographic characteristics of the respondents, indicating that the age group between 20-30 years had the highest response rate, with 64% of respondents being male and 36% female. Additionally, singles constituted the majority of respondents (64.91%), while urban dwellers accounted for 76.61%. The occupational distribution showed that 39% were business people, with farming and civil service having the lowest representation at 15%. In terms of educational qualifications, HND/BSc holders comprised 38% of the respondents, while FSCL had the lowest representation at 4.7%. The research also identified challenges in tree planting among urban dwellers, including inadequate land, tendering to maturity, lack of public enlightenment, low private involvement, poor government policy, poverty, and insufficient funding and planting materials. These challenges were emphasized with a Likert mean score of 3.025. Solutions include initiatives such as tax breaks, subsidies, and green space regulations can incentivize tree planting, while collaborative efforts involving public-private partnerships and community-based education campaigns are vital for widespread awareness and active involvement. Adequate funding remains a linchpin, and its securement through diverse channels ensures the long-term success of tree planting programs. Effective land use planning, incorporating zoning regulations and strategic establishment of nurseries, further contributes to a resilient and green urban environment. By addressing these facets comprehensively, cities can navigate challenges and cultivate thriving urban forests that benefit both the environment and the well-being of their residents. [ABSTRACT FROM AUTHOR]

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The Society of American Foresters (SAF) Committee on Accreditation (COA) recently met to review forestry degree programs at various colleges and universities. Michigan State University and the University of British Columbia were granted initial candidacy for their forestry programs, while Iowa State University, Texas A&M University, and the University of Vermont had their accreditation renewed. Progress reports were required for Alabama A&M University, Duke University, and Michigan Technological University. The COA also reviewed and took action on other degree programs in forest technology, natural resources and ecosystem management, and urban forestry. This document provides a list of universities and colleges across the United States that offer forestry programs, including information on degree options, establishment dates, and accreditation years. [Extracted from the article]

In cities nature is taking on a new role as infrastructure, providing essential services in terms of temperature regulation and water management, as well as the provision of habitat for biodiversity conservation. With this turn to green infrastructure have come new challenges to maintenance. Plants are lively things and if they are to perform their infrastructural roles they must be routinely tended to in particular ways. In the context of neoliberal governance, much of this labor falls to volunteer humans. Framed as stewardship, this volunteerism for plant-city thriving is posited as a way to meet maintenance needs while promoting human health and well-being and creating support for nature-based solutions through a sense of ownership and responsibility. While it is thus possible to read stewardship as an enrollment of people and plants into the reproduction of neoliberal urban political ecologies, in this paper I argue that such an analysis overlooks the involution of plants and people that occurs during acts of stewardship. Drawing on ethnographic research with street tree stewards in New York City I explore how vegetal agency draws people into affective, embodied relations. During acts of stewardship, trees act on people and reconfigure their relations in ways that potentially exceed the strictures of stewardship. Rather than allowing stewardship discourses and critiques thereof to be our sole frame for understanding these people-plant relations, we should also consider them from the perspective of vegetal agency and what human-tree involutions do within, around, and to human practices of stewardship. [ABSTRACT FROM AUTHOR]

This study examines the spatio-temporal dynamics of Acacia auriculiformis in Lubumbashi city, southeastern Democratic Republic of Congo, in the context of rapid urbanization following the liberalization of the mining sector. The city has experienced significant demographic growth and unplanned spatial expansion, resulting in a decrease in vegetation cover. The introduction and proliferation of A. auriculiformis, an exotic tree species, have occurred without strategic planning or monitoring. Utilizing digitized remote sensing imagery from 2006, 2014, and 2021, we quantified the expansion of A. auriculiformis along the urban–rural gradient. Additionally, a floristic inventory conducted in 2021 provided insights into tree diversity within A. auriculiformis plantations. Our findings indicate a substantial increase in the number and area of A. auriculiformis patches, predominantly in urban zones. However, the patch values, highest in 2006, were shown to decline by 2021, especially in urban areas. The floristic inventory identified 39 tree species within A. auriculiformis plantations, including predominant species such as Albizia lebbeck, Albizia alba, and Leucaena leucocephala. Notably, 20 of these species are exotic, with half being invasive. In contrast, the 19 indigenous species were primarily found in peri-urban areas. While a greater number of tree species were observed in urban zones, larger average diameters were recorded in peri-urban zones. The persistence and expansion of A. auriculiformis in a landscape characterized by declining tree cover suggest its potential sustainability in this setting. However, A. auriculiformis plantations have facilitated the establishment of predominantly exotic and potentially invasive species. These findings highlight the need for the strategic management of A. auriculiformis and associated exotic flora to mitigate their spread and to consider their role in the restoration of degraded lands. [ABSTRACT FROM AUTHOR]

The benefits of the urban tree and tree canopy (UTC) are increasingly crucial in addressing urban sustainability. Yet, increasingly evident from earlier research is the distributional inequities of UTC and active efforts to expand tree plantings. Less is known about the dynamics of UTC loss over time and location. This study aims to understand the dynamics of UTC change, especially canopy loss, and to investigate the drivers of the loss. This study draws on a high–resolution dataset of an urban canopy in Portland, Oregon, USA, assessing changes in UTC from 2014 to 2020. By integrating demographic, biophysical, and policy data with UTC information, we use a spatial autoregressive model to identify the drivers of UTC loss. The results reveal an unexpected spatial distribution of UTC change: less gain in the neighborhoods with the least UTC, and greater loss in the neighborhoods with moderate UTC. This study identifies four primary drivers of UTC loss: socioeconomic characteristics, urban form, activities on trees, and residential status. Factors such as population density, race, and income have an impact on canopy loss, as well as the building footprint and the number of multifamily housing units; residential statuses, such as the proportion of owner-occupied housing and residential stability, impact canopy loss. [ABSTRACT FROM AUTHOR]

Background: The importance of urban trees and their benefits to society are increasingly recognized. However, cities are a challenging environment for trees to grow and thrive. Current knowledge on tree vulnerabilities to existing urban stressors remains scarce and available only for a limited number of species and specific stressors. Methods: Using the Delphi method with urban forestry experts familiar with the studied area and a closed-ended questionnaire, we sought to elucidate the tolerance of commonly planted urban tree species in northeastern North America to multiple urban stressors—air pollution, soil compaction, de-icing salts, insects and diseases, strong winds, ice storms, snow, drought, and extreme temperatures—as well as to assess which characteristics may capture a species’ ability to cope with these stressors. Results: Ginkgo biloba, Gleditsia triacanthos, Quercus spp., and Ulmus spp. were rated by urban forestry professionals as the most tolerant species in northeastern North America to the studied stressors. No species was listed as tolerant to all stressors. Furthermore, respondents disagreed on how a given species was likely to be affected by or respond to a given stressor. Conclusions: Our study provides a powerful approach to gaining difficult-to-obtain information on trees’ vulnerabilities to environmental stressors and identifying the gaps that remain unaddressed. Our findings fill some of the gaps in our knowledge of city trees’ vulnerabilities, which makes the approach useful in practice to inform the choice of tree species that could be planted across our cities to build more resilient urban forests. [ABSTRACT FROM AUTHOR]