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Urban street trees offer cities critical environmental and social benefits. In New York City (NYC), a decadal census of every street tree is conducted to help understand and manage the urban forest. However, it has previously been impossible to analyze growth of an individual tree because of uncertainty in tree location. This study overcomes this limitation using a three-step alignment process for identifying individual trees with ZIP Codes, address, and species instead of map coordinates. We estimated individual growth rates for 126,362 street trees (59 species and 19% of 2015 trees) using the difference between diameter at breast height (DBH) from the 2005 and 2015 tree censuses. The tree identification method was verified by locating and measuring the DBH of select trees and measuring a set of trees annually for over 5 years. We examined determinants of tree growth rates and explored their spatial distribution. In our newly created NYC tree growth database, fourteen species have over 1000 unique trees. The three most abundant tree species vary in growth rates; London Planetree (n = 32,056, 0.163 in/yr) grew the slowest compared to Honeylocust (n = 15,967, 0.356 in/yr), and Callery Pear (n = 15,902, 0.334 in/yr). Overall, Silver Linden was the fastest growing species (n = 1,149, 0.510 in/yr). Ordinary least squares regression that incorporated biological factors including size and the local urban form indicated that species was the major factor controlling growth rates, and tree stewardship had only a small effect. Furthermore, tree measurements by volunteer community scientists were as accurate as those made by NYC staff. Examining city wide patterns of tree growth indicates that areas with a higher Social Vulnerability Index have higher than expected growth rates. Continued efforts in street tree planting should utilize known growth rates while incorporating community voices to better provide long-term ecosystem services across NYC. [ABSTRACT FROM AUTHOR]

Tree growth is a key mechanism driving carbon sequestration in forest ecosystems. Environmental conditions are important regulators of tree growth that can vary considerably between nearby urban and rural forests. For example, trees growing in cities often experience hotter and drier conditions than their rural counterparts while also being exposed to higher levels of light, pollution, and nutrient inputs. However, the extent to which these intrinsic differences in the growing conditions of trees in urban versus rural forests influence tree growth response to climate is not well known. In this study, we tested for differences in the climate sensitivity of tree growth between urban and rural forests along a latitudinal transect in the eastern United States that included Boston, Massachusetts, New York City, New York, and Baltimore, Maryland. Using dendrochronology analyses of tree cores from 55 white oak trees (Quercus alba), 55 red maple trees (Acer rubrum), and 41 red oak trees (Quercus rubra) we investigated the impacts of heat stress and water stress on the radial growth of individual trees. Across our three‐city study, we found that tree growth was more closely correlated with climate stress in the cooler climate cities of Boston and New York than in Baltimore. Furthermore, heat stress was a significant hindrance to tree growth in higher latitudes while the impacts of water stress appeared to be more evenly distributed across latitudes. We also found that the growth of oak trees, but not red maple trees, in the urban sites of Boston and New York City was more adversely impacted by heat stress than their rural counterparts, but we did not see these urban–rural differences in Maryland. Trees provide a wide range of important ecosystem services and increasing tree canopy cover was typically an important component of urban sustainability strategies. In light of our findings that urbanization can influence how tree growth responds to a warming climate, we suggest that municipalities consider these interactions when developing their tree‐planting palettes and when estimating the capacity of urban forests to contribute to broader sustainability goals in the future. [ABSTRACT FROM AUTHOR]

Urban forests in coastal regions are vulnerable to changing climate conditions, especially sea level rise (SLR). Such climate change impacts add complexity for urban forest managers as they make decisions related to tree species selection. The New York City (NYC) Parks Department manages over 660,000 street trees, many of which occupy sites that are susceptible to saltwater flooding. In order to build a resilient urban tree canopy in these flood-prone zones, we ranked tree species based on their overall tolerance to coastal vulnerability factors such as high winds, salt spray, and soil salinity. Our results revealed that 16 of the 44 species ranked high in overall tolerance to these factors. We also developed a GIS-based tool, specific to NYC, which delineates three coastal tiers based on their susceptibility to coastal vulnerability factors using SLR projections for the 2100s. The species list combined with the GIS tool provides urban forest managers a method to assign tree species to different coastal tiers based on their ability to withstand coastal climate change impacts into the future. We provide details on how this tool was developed for NYC so other coastal cities can replicate this approach to creating a more resilient future coastal urban forest. [ABSTRACT FROM AUTHOR]

Soils in urban natural areas can be highly variable due to legacies of land use change that include excavation of existing soils and dumping of construction debris or other anthropogenic materials. As cities undertake large‐scale tree planting efforts to sustain and increase forest cover, understanding how urban soil quality influences native tree seedling survival and performance is important. In a greenhouse setting we examined growth and physiology of native silver maple (Acer saccharinum), black birch (Betula lenta), red oak (Quercus rubra), and Canadian serviceberry (Amalanchier canadensis) seedlings planted in soils collected from locations across New York, NY, U.S.A. The soils were collected from areas currently undergoing forest restoration, representing a range of soil nutrient quality and anthropogenic disturbance. We measured seedling survival, height growth, leaf chlorosis, and chlorophyll fluorescence for two growing seasons, after which seedlings were harvested to assess biomass allocation and foliar chemistry. Selected variables were standardized and combined to create a seedling stress index. Overall, seedlings performed best in the least disturbed urban soils and had the poorest performance in the more highly disturbed, nutrient‐poor urban soil types and a greenhouse mix. Species × soil type interactions on physiological responses indicate that tree species may not respond to urban soil conditions consistently. Consequently, matching native tree species to soil type could help optimize establishment and growth of urban forest restoration projects. Seedling stress scores from the first growing season were correlated with second year height growth for three of four species, illustrating their utility for managers. [ABSTRACT FROM AUTHOR]

Constructed soils are soils that are created with a mixture of various materials. An innovative soil exchange program - the Clean Soil Bank (CSB) in New York City allows recycling of clean glacial outwash sediments excavated from depth at construction sites. One previous study showed that soils constructed from CSB sediment and compost can effectively support crop growth in community gardens, but no research has been conducted on its potential usage as a medium for tree growth. Moreover, biochar has been used to improve soil quality, but its efficacy for street trees incorporated into constructed soils has largely not been quantified in the field. The objective of this project was to evaluate the feasibility of using soils constructed from the CSB and compost for tree planting and to investigate the impact of biochar on tree performance. Thirty-six trees of two species (Maackia amurensis and Zelkova serrata) were planted in 2019, on the sidewalks of a residential-business neighborhood in Bronx, New York. Each tree pit contains one of three soil types: type A - existing and purchased topsoil mixed with 33% compost and biochar, type B - CSB sediment mixed with 33% compost, and type C - CSB sediment mixed with 33% compost and biochar. Soil samples were collected in 2019 (before planting) and in 2021. Tree health assessments were conducted in September 2020 and July 2021 using a protocol developed by the USDA Forest Service. Other tree health parameters collected include diameter at breast height (DBH), crown diameter, tree height, photosynthetic capacity, and foliar chemistry. Significant differences in bulk density, water holding capacity, and K, Fe, and Zn concentrations were found among the three soil types. However, comparison of tree performance and foliar chemistry showed no systematic differences among the three soil types. The results indicate that CSB sediment mixed with compost can be an effective replacement for purchased topsoil for tree growth. No evidence was found that biochar provides additional benefits to street tree performance. Considering the abundant availability of glacial outwash sediment at low cost to the city, as well as access to locally produced compost, constructed soils can be a reliable source of material for urban forestry programs. • Cities are experiencing increased demand for new clean soil but soil transportation from rural areas is not sustainable. • This project aimed to study the feasibility of using constructed soil from NYC's Clean Soil Bank (CSB) for tree planting. • Thirty-six trees of two species were planted in existing and purchased topsoil or constructed soil in 2019. • Soil properties and tree health were measured in 2020 and/or 2021 and compared. • The results shows that CSB sediment mixed with compost can be an effective replacement for purchased topsoil for tree growth. [ABSTRACT FROM AUTHOR]

Background: Real-time monitoring of tree growth can provide novel information about trees in urban/suburban areas and the myriad ecosystem services they provide. By monitoring irrigated specimen trees, we tested the hypothesis that in trees with sufficient water, growth is governed by environmental factors regulating energy gain rather than by factors related to water use. Methods: Internet-enabled, high-resolution dendrometers were installed on 3 trees in Southampton, NY, USA. The instruments, along with a weather station, streamed data to a project web page that was updated once an hour. Growing periods were determined using a Hidden Markov Model based on a zero-growth model. Linear models and conditional inference trees correlated environmental variables to growth magnitude and rate of growth. Results: Growth was governed by the interacting environmental variables of air temperature, soil moisture, and vapor pressure deficit (VPD), and took place primarily at night. Radial growth of spruce began April 14 after the accumulation of 69.7 °C growing degree days and ended September 7. Cedar growth began later (April 26) after the accumulation of 160.6 °C and ended later (November 3). During the observation period, these 3 modest suburban trees sequestered 115.1 kg of CO2. Conclusions: Though irrigated, residential tree growth in our experiment was affected by environmental factors relating to both water use and energy gain through photosynthesis. Linking tree growth to fluctuations in environmental conditions facilitates the development of a predictive understanding useful for ecosystem management and growth forecasting across future altering climates. [ABSTRACT FROM AUTHOR]

Even highly urban environments are settings for outdoor learning of local biodiversity, for they contain easily accessible street tree diversity that students walk pass daily. This study uses pre/post assessments and a tree observation curriculum grounded in scientific observation practice to understand the everyday and scientific tree observation practice of urban middle school students of mixed socioeconomic status (SES). Specifically, it examined students' abilities to name trees, the specific features of trees students noticed, and the botanical vocabulary they used to describe the trees they pass daily. Participants included 308 intervention students and 265 comparison students (11–14 years old) in six public New York City middle schools. Findings show that without the intervention students could not identify common street trees (oak, maple, honey locust), that they did not notice key tree features like leaf arrangement and shape and that they lacked the botanical vocabulary to accurately describe the features of the trees they see daily. Instead, students mostly differentiated trees by obvious uninformative gross features like overall tree size. Generalised multilevel statistical models of pre/post test results show that the ability to name, notice, and describe trees with botanical terminology improved with the study intervention. Students from medium SES schools had more prior knowledge and showed greater growth in learning than students from low SES schools. [ABSTRACT FROM AUTHOR]

The provisioning of critical ecosystem services to cities of the eastern USA depends on the health and physiological function of trees in urban areas. Although we know that the urban environment may be stressful for trees planted in highly developed areas, it is not clear that trees in urban forest patches experience the same stressful environmental impacts. In this study, we examine chlorophyll fluorescence parameters, leaf traits, foliar nutrients and stable isotope signatures of urban forest patch trees compared with trees growing at reference forest sites, in order to characterize physiological response of these native tree species to the urban environment of three major cities arranged along a latitudinal gradient (New York, NY; Philadelphia, PA; Baltimore, MD). Overall, white oaks (Quercus alba L.) show more differences in chlorophyll fluorescence parameters and leaf traits by city and site type (urban vs reference) than red maples (Acer rubrum L.). The exceptions were δ13C and δ15N, which did not vary in white oak foliage but were significantly depleted (δ13C) and enriched (δ15N) in urban red maple foliage. Across all sites, red maples had higher thermal tolerance of photosynthesis (T crit) than white oaks, suggesting a greater ability to withstand temperature stress from the urban heat island effect and climate change. However, the highest average values of T crit were found in the Baltimore urban white oaks, suggesting that species suitability and response to the urban environment varies across a latitudinal gradient. Stomatal pore index (SPI) showed inter-specific differences, with red maple SPI being higher in urban trees, whereas white oak SPI was lower in urban trees. These results demonstrate that differences in native tree physiology occur between urban and reference forest patches, but they are site- and species-specific. Data on local site characteristics and tree species performance over time remain necessary to gain insight about urban woodland ecosystem function. [ABSTRACT FROM AUTHOR]

Municipally managed urban trees provide environmental, social, and economic benefits. Continued provision of these benefits depends on the health and sustainability of these trees, which depends in turn on tree managers having the type of information usually found in a tree inventory. The city of Ithaca, New York, USA possesses 7 inventories of its street and park trees dating back to 1902. This paper uses the data contained in these inventories to assess the health and sustainability of the city's street and park tree populations. Attention is given to the structure of these populations with emphasis placed on species and genera diversity and DBH size class distributions. Prior to 1987, the city's municipal tree population was dominated by a few species, such as Norway maple (Acer platanoides), and genera such as maples (Acer) and elms (Ulmus), and the DBH size class distribution was skewed unsustainably towards older trees. From 1987 onwards, new plantings have significantly increased species and genera diversity, and the DBH size class distribution suggests sufficient younger trees to account for tree mortality and removals. These changes did not occur quickly due to the persistent legacy effect of past planting preferences and practices, but required a consistent effort by municipal tree managers over many years. As a result, based on an analysis of the most recent tree inventory conducted in 2019, the city's street and park trees and the benefits they provide look to be on a more sustainable footing, although challenges still remain. [ABSTRACT FROM AUTHOR]

Planting low-pollen trees could reduce aeroallergen exposure in cities, but the effects of historical tree planting on contemporary airborne pollen exposure remains largely unexplored. Whether tree selection decisions can effectively reduce airborne pollen will depend in part on which taxa are the most important sources of allergenic pollen and the extent to which they are intentionally planted vs. unplanted (i.e., recruiting naturally). Here, we use airborne pollen measurements to examine which taxa are of allergenic importance in New York City (NYC), and then combine two tree surveys with allometric equations to determine pollen production for several taxa. Future changes in pollen production as a function of growth, mortality, and recruitment are then simulated using i-Tree Eco Forecast. The most important producers of allergenic pollen in NYC are Quercus, Platanus, Morus, and Betula ; they comprise 71% of airborne pollen measured and 93% of estimated pollen production (107 quadrillion pollen grains; however, pollen production was not estimated for all taxa). Previous municipal planting decisions have resulted in the high abundance of Platanus × acerifolia ; it accounts for 34% of total street tree basal area and has an estimated annual pollen production of 27.7 ± 6.4 quadrillion grains. In contrast, Morus and Betula are generally unplanted, indicating that tree planting decisions will have smaller effects on their future pollen production rates in NYC. Quercus trees produced an estimated 68.2 ± 12.3 quadrillion pollen grains and accounted for almost 25% of airborne pollen collected, but were very abundant in parks and were mostly unplanted, suggesting that planting has not and will not have a major effect on city-wide pollen production. Overall, this study demonstrates that tree planting decisions can have important and long-lasting consequences for city-wide pollen production but only for species that are both primarily planted and large producers of allergenic pollen. [ABSTRACT FROM AUTHOR]

Street trees are abundant in the urban landscape and provide many ecosystem services including stormwater management. For trees housed within tree pits, the ability to mitigate stormwater runoff can be modulated by the permeability of the soil within the tree pit itself. Thus, developing a better understanding of how tree pit design and management impact soil permeability can be important to quantifying, and potentially improving, the stormwater benefits of street trees. To this end, water infiltration rate was measured at forty tree pits representing the variety of physical conditions commonly seen in New York City, including the presence or absence of a tree pit guard, the size of the tree pit, the size of the tree, the presence or absence of ground cover planting, the presence or absence of mulch, and the elevation of the pit’s soil surface relative to the sidewalk. An initial analysis of results first tested the impact of each physical condition on infiltration rate individually. Genetic programming was then used to investigate interactive effects between the physical conditions, and to develop a statistical model that captured 66% of the variability in the observed infiltration rate using simple physical features of a tree pit. Results showed that the most significant factor influencing the infiltration rate was the presence of a guard around a tree pit, with guarded tree pits having higher infiltration rates. Additionally, higher infiltration rates in guarded pits were associated with larger pit areas, built-up surface elevations (binary) and the combined presence of ground cover planting (binary) and mulch (binary). Tree size, as measured by circumference at breast height, was found to be a less significant indicator of the infiltration rate. The statistical model, together with the study measurements, can be used to estimate the stormwater benefits of different tree pit management strategies, inform designs for improved stormwater management, and help identify useful observations or measurements for a street tree census. [ABSTRACT FROM AUTHOR]

Scholarship on the ecosystem services provided by urban forests has focused on regulating and supporting services, with a growing body of research examining provisioning and cultural ecosystem services from farms and gardens in metropolitan areas. Using the case of New York, New York, USA, we propose a method to assess the supply of potential provisioning ecosystem services from species and spaces other than those explicitly designated for food production. We analyze the abundance and spatial distribution of trees and shrubs with known uses for food, medicine, craft, and other purposes across urban greenspace types. To do so, we created a database of all woody species known to occur in New York City, joining a citywide assessment of trees and shrubs with additional data from a metropolitan flora and a guide to native plants in the city. A second database of useful, or forageable, species was created by compiling information from a New York City-focused online foraging application and ten field guides chosen for the likelihood that prospective foragers would find and consult them. The City’s street tree inventory and associated GIS shapefile provided the basis for more detailed analyses of forageable woody species in this land use type. Our results show a substantial supply of potential provisioning ecosystem services from woody species in New York City. Coupled with growing literature on actual foraging in cities worldwide, these findings suggest implications for accountings of ecosystem services from urban forests as well as policy and management initiatives to enhance social-ecological resilience. [ABSTRACT FROM AUTHOR]

The author discusses the history of street trees in Boston, Massachusetts and New York City. She mentions the early use of trees as landmarks on the streets, the growing appreciation of urban beautification, and the incorporation of tree planting in urban planning efforts in both cities.

Urban trees offer extensive environmental benefits. However, the distribution of trees in urban areas often disproportionately favors higher-income neighborhoods. Implementing tree-planting programs in lower-income neighborhoods may provide environmental amenity values but may also lead to unintended consequences, such as gentrification. This paper focuses on one of the largest tree-planting programs in the U.S., the MillionTreesNYC Program, and estimates the impact of an increased supply of urban street trees on housing values and neighborhood compositions. The results demonstrate that the additional urban street trees did serve as an environmental amenity, resulting in higher housing values and attracting more white, educated, and young households to areas with new trees. However, the gentrification effects of this tree-planting program were relatively small, with minimal change in community composition. These findings suggest that it is possible to provide public goods without significant displacement of the existing population while also reaping the numerous benefits trees offer to urban areas. [ABSTRACT FROM AUTHOR]

Urban green spaces are important for urban insects, providing both habitat space as well as stopover locations within the urban landscape. Street tree pits in cities are small, heterogeneous, and understudied green spaces that may be important for supporting urban insect communities. The purpose of this study was to investigate the composition of insect communities within tree pits in New York City, New York, USA (NYC) and compare tree pit insect communities across NYC neighborhoods. Tree pits in NYC are part of the New York City Parks system but are primarily managed by residents of each street. We postulated that insect assemblages within tree pits would contain both permanent (habitat) and transient (stopover) members and those communities would vary among neighborhoods. Insects were collected from understory plants in tree pits in four NYC neighborhoods during the summer of 2019. We found that the tree pits provided habitat for nine orders and 51 families of insects, the majority of which were herbivores and their associated predators or parasitoids, which were likely utilizing the tree pits as habitat space. Few clearly transient species (e.g. pollinators) were collected. Furthermore, insect communities were similar both within neighborhoods and among neighborhoods, suggesting that while tree pits management is not strictly regulated in NYC, tree pits in all neighborhoods provided habitat to sustain similar insect assemblages. At the neighborhood level, urban tree pits can harbor a diverse insect community and that capability is similar throughout the urban landscape. [ABSTRACT FROM AUTHOR]

Urban trees store and sequester large amounts of carbon and are a vital component of natural climate solutions. Despite the well-recognized carbon benefits of urban trees, there is limited effort to examine how spatial distribution of carbon density varies across distinctive social, demographic, and built dimensions of urban landscapes. Moreover, it is unclear whether specific aspects of landscape structure and design could help increase carbon densities in urban trees. Here, we produced a fine-resolution carbon density map of urban trees in New York City (NYC) by integrating high-resolution land cover map, LiDAR-derived tree metrics, i-Tree Eco, and field survey data. We then explored spatial variations of carbon density across the gradients of urban development intensity, social deprivation index, and neighborhood age, and we examined the relationships between carbon density, and fragmentation, aggregation, size, and shape of tree canopy cover. We find that carbon stored in urban trees in NYC is estimated as 1078 Gg, with an average density of 13.8 Mg/ha. This large amount of carbon is unevenly distributed, with carbon densities being highest in Bronx and in open parks and street trees. Furthermore, carbon densities are negatively associated with urban development intensity and the social gradient of deprivation. Regarding the impacts of tree morphology on carbon density, our results show that while the amount of tree cover is the most influential factor in determining carbon density, small-sized forest patches and moderate levels of forest edges are also conductive to increasing carbon densities of urban trees. To incorporate urban forestry into developing innovative, effective, and equitable climate mitigation strategies, planners and decision makers need to identify the optimal spatial configuration of urban forests and invest in tree planting programs in marginalized communities. • Carbon density in urban trees in New York City is estimated as 13.8 Mg/ha. • Socially deprived areas are associated with lower carbon densities. • Small-sized forest patches and moderate levels of forest edges are beneficial to increase carbon densities of urban trees. • The findings provide implications to incorporate urban forestry to develop effective and equitable climate mitigation strategies. [ABSTRACT FROM AUTHOR]

The article discusses a study aimed at testing a frame for analyzing the state and use of urban tree inventories in major cities to obtain insight into their status and identify directions for future, more comprehensive research on inventories. Semi-structured expert interviews were conducted with urban foresters in Toronto, Canada, New York City and Oslo, Norway. The study showed that none of the investigated cities had a complete and regularly updated inventory of their urban forest.

The article discusses a study that sampled the arborescent vegetation located at three sites within Inwood Park in Manhattan, New York, by the quadrant method in October 2004 and May 2005. The vegetation was compared with the trees present in the same quadrants on a map of trees at Inwood Park, prepared by the federal Works Program Administration in 1935. It cites the dominant trees at each site in 1935 and 2005, as well as the increased mean tree diameter over the past 70 years.

• The associations between street trees and crime were examined using spatial Durbin regressions. • Tree canopy cover, streetscape greenery, and species diversity were negatively associated with crime rates. • Proportion of small-sized trees was conductive to increase crime rates. • Tree canopy cover and streetscape greenery were beneficial to a reduction in crime severity. The extent to which street trees affect crime is moderated by many characteristics of tree structure, streetscapes, and tree management. To effectively utilize urban greening interventions as crime preventing programs, it is necessary to distinguish tree-related characteristics that increase crime from those that cause crime to decline. This study derived a complete set of tree-related characteristics and crime attributes from a variety of sources. We then applied ordinary least squares and spatial Durbin regressions to reveal the associations between street trees and crime in New York City. Our results showed that street tree characteristics that were negatively associated with crime rates included tree canopy cover, species diversity, and streetscape greenery, while the opposite was observed for the proportion of small-sized trees. The characteristics of street trees that displayed a dual-feature with crime rates included tree health, proportion of harmful tree guards, and proportion of trees with trunk problems, while tree stewardship was not significantly associated with crime. In addition, our findings demonstrated that tree canopy cover and streetscape greenery were conducive to reduce crime severity. The mixed associations between street tree characteristics and crime could be potentially explained by the "broken window theory", trees' view-obstructing effect, the "eyes on the street", and trees' therapeutic effect. The revealed findings have important implications for the implementation of tree-planting programs in tackling the dual tasks of improving urban greening and reducing crime, and could help translate crime reduction into specific actions of streetscape design and tree management that can be taken by government and local stakeholders. [ABSTRACT FROM AUTHOR]

Describes the transformation of New York city from an area of rich and diverse natural landscapes into a metropolis of skyscrapers in the late 1800s and early 1900s and examines the efforts of a group of social reformers to resist this transformation. New York citizens' 1889 crusade against the removal of street trees; Significance of trees for New Yorkers; Arguments for and against street trees.

3-year field study of the water relations of street trees in New York City was undertaken with the following objectives; (i) to ascertain whether there was empirical evidence for water deficits; (ii) if water deficits occur, to correlate these events with prevailing weather conditions; (iii) to determine whether tree water relations varied systematically with street exposure; (iv) to compare street microclimate with that of a nearby park; (v) to compare water relations of two common street tree species; (vi) to evaluate the effectiveness of a minimum irrigation programme. Water deficits in trees, as evidenced by midday stomatal closure, occurred but with lower frequency than is commonly expected. Average predicted frequency during the summer was 13% over a 21-year period. When deficits occurred, they were demand driven rather than supply limited. Deficit periods were characterized by maximum air temperatures on the street >41°C and a maximum atmospheric vapour pressure deficit of 7.5kPa. Official weather station data collected in a nearby park indicated far milder conditions, with a maximum air temperature and vapour pressure deficit of 32°C and 2.5 kPa, respectively. Over the midday period, the mixing ratio, a conservative measure of atmospheric water content, was 8.4gkg-1 lower on Columbus Avenue than in the park, indicating that the street microclimate was far drier. The west side of the street received more solar radiation than the east and was usually slightly hotter than either the east or the park. Yet, trees on the west side of the street were not more water stressed. Though Fraxinus pennsylvanica transpired at higher rates and sustained more negative water potentials than Tilia cordata these differences were variable and could not be separated statistically. Similarly, Fraxinus pennsylvanica showed small but statistically non-significant responses to minimal weekly irrigation while Tilia cordata was unresponsive. [ABSTRACT FROM AUTHOR]

Most street tree inequality studies focus on examining tree abundance at single time point, while overlooking inequality dynamics measured based on a complete set of tree measures. Whether the severities of street tree inequalities vary with different tree structure measures, whether street tree inequalities are diminishing or growing over time, and how the inequality dynamics are affected by tree-planting programs remain largely unexplored. To fill these gaps, this study applied binned regression and cluster analyses to street tree census data of 1995–2015 in New York City. We investigated different structural measures of street tree inequalities pertaining to various aggregations of people, compared street tree inequalities over time, and revealed the inequity remediation role of the MillionTreesNYC initiative. We found that the underprivileged populations, characterized by higher percentages of the poor, racial minorities, young people, and less-educated people, are more likely to have lower tree abundance, less desired tree structure, poorer tree health condition, and more sidewalk damages. When disaggregating inequalities across various aggregations of people, income-based and education-based inequalities were the most severe, but the inequalities diminished over time. The race-based and age-based inequalities show mixed results that disfavor Hispanics, Blacks, and young people. The equity outcome of the MillionTreesNYC initiative is not ideal as the inequalities decrease when measured using tree count and species diversity, whereas they increase when measured using tree health and average diameter at breast height. The findings have important implications for more effective decision-making to balance resources between planting trees and protecting existing trees, and between increasing tree abundance and improving tree structure. • Street tree inequalities in New York City during 1995–2015 were examined. • The underprivileged subpopulations are associated with lower tree abundance and poorer tree structure. • The equity outcome of the MillionTreesNYC program is not ideal, as both diminishing and growing inequalities were observed. [ABSTRACT FROM AUTHOR]

• Street tree measures of abundance, species diversity, and size structure are derived from multiple data sources. • GWR is employed to examine street tree inequalities among different socioeconomic groups. • Inequalities are prevalent based on tree abundance and species diversity. • Race- and education-based inequalities are more severe than age-, income-, and household characteristic-based inequalities. • Equitably allocate limited public resources to underprivileged populations and socially vulnerable areas is needed. Street trees are often unequally distributed in urban areas, and their physical and structural attributes, such as extent of canopy cover, species composition, and size distribution, are also spatially heterogeneous. Some studies report that inequalities are more prevalent in streetscapes than in private landscapes. Considering the existing inequality issues and public nature of street trees, street tree inequality studies warrant greater attention. However, most existing studies in this field focus heavily on the unequal distribution of tree canopy cover, while disregarding other tree attributes. In this study, seven street tree measures covering tree abundance, species diversity, and size structure were derived from high-resolution satellite images, Google Street View, and street tree census. We then applied the geographically weighted regression to these seven tree measures in New York City, United States, compared street tree inequalities among different socioeconomic groups, and identified inequality hotspots. Our results show that street tree inequalities are greatest with respect to tree abundance and species diversity. Furthermore, race-based and education-based inequalities are most notable, and age-, income-, and household characteristic-based inequalities were also detected based on tree abundance or species diversity. Socially vulnerable areas that suffer the most severe inequalities are clustered in Brooklyn and Queens. Disaggregated street tree inequalities, with explicit recognition of the differentiated distribution of limited tree resources among different social groups and across geographical areas, are critical for effective decision-making to alleviate environmental inequities. [ABSTRACT FROM AUTHOR]

Reports on the plan of New York City-based Dreyfus Service Corp. Vice President Norma Niehoff to plant trees on both sides of the entire block from the New York Stock Exchange at Broad Street to William Street. Amount needed to finance the project; Reason for the support given by the Financial Women's Association of New York.