Dexter H Locke

US Forest Service | FS · Northern Research Station

Urban parks provide vital social, environmental and health benefits to residents. However, the spatial distribution of parks, and the amenities they provide, may not be equitably distributed within cities. We examine the accessibility of urban parks with different social, environmental and health amenities by race and ethnicity. We identified 122,9...

Reducing nitrogen delivery to coastal waters is a “wicked problem” involving tradeoffs in environmental, economic and equity domains. Because these tradeoffs arise from spatial and temporal complexities in sources and sinks of this element, we hypothesized that a transdisciplinary focus on disproportionality could allow for the identification of “h...

Urban tree canopy (UTC) cover is rarely distributed equitably across social groups, space, and time. Over the past 20 years, research on the social, spatial, and temporal dynamics of UTC has grown considerably as municipalities adopt ambitious tree canopy cover goals. Yet less is known about how these three dimensions of tree canopy intersect. This...

Urban forests provide ecosystem services important for regulating climate, conserving biodiversity, and maintaining human well‐being. However, these forests vary in composition and physiological traits due to their unique biophysical and social contexts. This variation complicates assessing the functions and services of different urban forests. To...

Public parks are critical urban infrastructures offering health, environmental, social, and cultural benefits to people. However, the idea of park quality has lacked a clear operational definition and normative standard for measurement. We provide critical insights into existing park quality instruments and advocate for an alternative approach. Fir...

Urbanization alters species ranges and nature’s contributions to people, motivating urban conservation. Residential segregation policies have left an indelible impact on urban environments, greenspaces, and wildlife communities, creating socioeconomic heterogeneity and altering biota. However, the extent to which data sufficiently capture urban bio...

Mitigating heat is a vital ecosystem service of trees, particularly with climate change. Land surface temperature measures captured at a single time of day (in the morning) dominate the urban heat island literature. Less is known about how local tree canopy and impervious surface regulate air temperature throughout the day, and/or across many days...

Neighborhoods are one of the key determinants of health disparities among young people in the United States. While neighborhood deprivation can exacerbate health disparities, amenities such as quality parks and greenspace can support adolescent health. Existing conceptual frameworks of greening‐health largely focus on greenspace exposures, rather t...

Residential landscapes are essential to the sustainability of large areas of the United States. However, spatial and temporal variation across multiple domains complicates developing policies to balance these systems’ environmental, economic, and equity dimensions. We conducted multidisciplinary studies in the Baltimore, MD, USA, metropolitan area...

The 3-30-300 rule offers benchmarks for cities to promote equitable nature access. It dictates that individuals should see three trees from their dwelling, have 30 % tree canopy in their neighborhood, and live within 300 m of a high-quality green space. Implementing this demands thorough measurement, monitoring, and evaluation methods, yet little g...

There are growing concerns about increases in the size, frequency, and destructiveness of wildfire events. One commonly used mitigation strategy is the creation and maintenance of defensible space, a zone around buildings where vegetation is managed to increase potential for structures to survive during wildfires. Despite widespread acceptance and...

Urbanization is simultaneously one of the most creative and destructive processes our planet has ever experienced. Developing rural areas into cities and suburbs results in dramatic habitat transformation, leading to significant biodiversity loss and modification. Yet, urban areas also have tremendous conservation value. Biodiversity is in crisis a...

Historic segregation and inequality are critical to understanding modern environmental conditions. Race-based zoning policies, such as redlining in the United States during the 1930s, are associated with racial inequity and adverse multigenerational socioeconomic levels in income and education, and disparate environmental characteristics including...

Vacant and abandoned buildings are common features in many post-industrial US cities, and are consistent predictors of violence. Demolition programs are regularly employed as an urban land use policy to stabilize housing markets and mitigate public health problems including violence. The objective of this research was to examine the effect of vacan...

The 3-30-300 rule offers benchmarks for cities to promote equitable nature access. It dictates that individuals should see three trees from their dwelling, have 30% tree canopy in their neighborhood, and live within 300 meters of a high-quality green space. Implementing this demands thorough measurement, monitoring, and evaluation methods. Seven da...

Identifying locations prone to exporting nitrogen (N), also called export control points, within residential landscapes, is key to determining N mitigation strategies. Within residential landscapes, lawns have the potential to act as either a sink of N via uptake and denitrification, or a source of N via additions such as fertilizer. Lawns draining...

Diverse workforce representation helps organizations achieve their goals and is important for government agencies that seek to gain public trust. Prior research has examined patterns of representation in the USDA Forest Service and found an overall lack of representation despite advances at leadership levels. Federal agencies are required to report...

Given ambitious tree canopy goals, land cover change analyses in cities are imperative. Urban tree canopy change analyses have been hindered by data with low categorical resolution (e.g., canopy vs. not canopy), over relatively short time horizons (5–10 years), representing only two points in time, and scarce linkages to other temporal datasets (e....

A diverse, representative workforce is both beneficial and legally mandated for U.S. federal agencies. While previous research documents overall diversity within public agencies, like the USDA Forest Service, little is known about career outcomes and trajectories within these agencies. In this work, we look at individual-level career met-rics which...

Street-facing trees have been cited as providing a vast range of environmental benefits and also a contributing factor to community livability and quality of life. One measure of well-being that speaks directly to the livability of a city is residential satisfaction, which is represented by the social and physical environments of the particular pla...

Tree canopy cover is a critical component of the urban environment that supports ecosystem services at multiple spatial and temporal scales. Increasing tree canopy across a matrix of public and private land is challenging. As such, municipalities often plant trees along streets in public rights‐of‐way where there are fewer barriers to establishment...

The relationship between (a) the structure and composition of the landscape around an individual's home and (b) environmental perceptions and health outcomes has been well demonstrated (eg the value of vegetation cover to well‐being). Few studies, however, have examined how multiple landscape features (eg vegetation and water cover) relate to perce...

Humans promote and inhibit other species on the urban landscape, shaping biodiversity patterns. Institutional racism may underlie the distribution of urban species by creating disproportionate resources in space and time. Here, we examine whether present‐day street tree occupancy, diversity, and composition in Baltimore, MD, USA, neighborhoods refl...

Attributes of property parcel owners are hypothesized to impact land management outcomes, because different types of owners are likely to have different capacities and motivations for land stewardship. We used emerging data resources to examine how owner type relates to the prevalence of overgrown vegetation in Toledo, Ohio, and Trenton, New Jersey...

Women and Black, Indigenous, and People of Color (BIPOC) employees are underrepresented in science and natural resource management institutions. Student and recent graduate trainee and internship programs have been used to try to address this in United States federal agencies over the last few decades. Our study evaluates how effective such program...

The conversion of native ecosystems to residential ecosystems dominated by lawns has been a prevailing land-use change in the United States over the past 70 years. Similar development patterns and management of residential ecosys- tems cause many characteristics of residential ecosystems to be more similar to each other across broad continental gra...

Urban forests are important components of societal interactions with nature. We focused on urban forest patches, a distinct and underexplored subset of the urban forest that spans land uses and ownerships, and requires silvicultural practices to address their unique biophysical characteristics and management regimes. Our goal was to elucidate multi...

Understanding the heterogeneity of biomass accumulation in second‐growth tropical forests following land use abandonment is important for informing ecosystem carbon models and forest restoration efforts. There is an urgent need for a broad sample of second‐growth forests to enhance our knowledge of carbon accumulation in human‐dominated landscapes,...

The now-published, peer reviewed version containing additional analyses, can be found here: https://www.nature.com/articles/s41562-023-01688-5 The paper was retitled "Bird biodiversity sampling shows increasing geographical disparities associated with historical redlining in the United States" Citizen science data has rapidly gained influence in u...

Urban green spaces have previously been linked to reduction in crime and improvements in neighborhood environments. This study considered if the Care-A-Lot (CAL) program in Baltimore City, which incentivizes local community groups to maintain and green vacant lots, reduces violent and property crime. Compared to a 2016-2017 baseline, city block gro...

We analyzed USDA Forest Service (Forest Service) employment data from 1995 to 2017, by race and ethnicity, gender, as well as race/ethnicity and gender, to assess progress towards the Forest Service’s goal of achieving a multicultural workforce that reflects the US population. We look at the trends by an employee’s level in the Forest Service and b...

Green infrastructure increasingly is used to ameliorate water quality and quantity problems caused by runoff in cities. Studies show how the spatial distribution of these Green Stormwater Infrastructure (GSI) sites are unevenly distributed relative to socioeconomic and demographic groups. Often this is described as an indicator of perpetuated envir...

Redlining was a racially discriminatory housing policy established by the federal government’s Home Owners’ Loan Corporation (HOLC) during the 1930s. For decades, redlining limited access to homeownership and wealth creation among racial minorities, contributing to a host of adverse social outcomes, including high unemployment, poverty, and residen...

Urbanization has a homogenizing effect on biodiversity and leads to communities with fewer native species and lower conservation value. However, few studies have explored whether or how land management by urban residents can ameliorate the deleterious effects of this homogenization on species composition. We tested the effects of local (land manage...

Residential yards are a significant component of urban socio‐ecological systems; residential land covers 11% of the United States and is often the dominant land use within urban areas. Residential yards also play an important role in the sustainability of urban socio‐ecological systems, affecting biogeochemical cycles, water and the climate via ind...

We introduce a conceptual model of the urban forest patch as a complex social-ecological system, incorporating cross-scale interactions. We developed this model through an interdisciplinary process engaging social and ecological scientists and urban land management decision makers, with a focus on temperate forest social-ecological systems. In this...

Previous research has shown that trees and other roadside vegetation can mitigate adverse environmental conditions on urban street corridors, and, in turn, positively contribute to pedestrian perceptions of safety and walkability. In this study, pedestrian surveys (n = 181) were collected from three Massachusetts post-industrial cities to understan...

Despite the social and ecological importance of residential spaces across the country, scant research examines urban yard management policies in the U.S. Governance scholarship points to the implementation challenges of navigating policy language. Our research provides an exploration of yard ordinance language, with implications for communities acr...

Understanding the distribution of urban tree canopy cover and its relationship with socioeconomic characteristics is critical for informing urban planning and ecological research. However, most knowledge on this topic comes from studies in high-income countries (e.g., North America), and thus, little is known for other cultural, ecological, and pol...

Ecological research increasingly considers integrative relationships among phenomena at broad spatial and temporal domains. However, such large‐scale inferences are commonly confounded by changing properties in the processes that govern phenomena (termed nonstationarity), which can violate assumptions underlying standard analytical methods. Changin...

Lawns are a common ecosystem type in human-dominated landscapes which can have negative impacts on water quality due to fertilizer applications, but also host a range of ecosystem services. While many studies have addressed water and nitrogen (N) dynamics in lawns, few have considered how topography interacts with human behaviors to control these d...

Local regulations on residential landscapes (yards and gardens) can facilitate or constrain ecosystem services and disservices in cities. To our knowledge, no studies have undertaken a comprehensive look at how municipalities regulate residential landscapes to achieve particular goals and to control management practices. Across six U.S. cities, we...

Urban vegetation can generate social and ecological benefits, so vegetation abundance is commonly treated as a proxy for greater benefits. A repeated finding in environmental justice research related to urban vegetation is that commonly marginalized populations live in neighborhoods with less vegetation. However, urban vegetation can function as am...

The provision of ecosystem services is a prominent rationale for urban greening, and there is a prevailing mantra that 'trees are good'. However, understanding how urban trees contribute to sustainability must also consider disservices. In this perspective article, we discuss recent research on ecosystem disservices of urban trees, including infras...

Although the yard is a hybrid social and material landscape, much social science research emphasizes the socio-cultural factors and has mostly neglected the potentially important influence of plants, animals, and the nonliving material world on homeowners’ decision-making. Using interviews across six metropolitan areas in the United States, we inve...

Plant biodiversity is affected by limiting resources such as water, nutrients, and sunlight. In urban settings, such as residential yards, however, limiting resources may also include the social factors of time and money spent on yard care. To examine the role that these precious human resources play in determining plant community structure and div...

Background Cities across the world are undertaking ambitious projects to expand tree canopy by increasing the number of trees planted throughout public and private spaces. In epidemiological studies, greenspaces in urban environments have been associated with physical and mental health benefits for city dwellers. Greenworks Philadelphia is a plan t...

Greenspace is increasingly examined as a low-cost way to increase standardized test scores in public schools. However, the evidence for this intervention is mixed. One potential explanation is the variety of ways that greenspace is measured using remotely sensed data. For instance, aggregate measures can be captured from tree, grass, and shrub cove...

Redlining was a racially discriminatory housing policy established by the federal Home Owners’ Loan Corporation (HOLC) during the 1930s. For decades, redlining limited access to homeownership and wealth creation among racial minorities, contributing to a host of adverse social outcomes, including high unemployment, poverty, and residential vacancy,...

A city's treescape (or lack thereof) has a big impact on the quality of life. A unique government and academic partnership uses lidar and GIS technology to help communities map, assess, and monitor their urban tree canopy.

Civic environmental stewardship groups actively take care of their local environment and are known to work in urban contexts. Research on the geographies of this urban environmental stewardship is young. Understanding where stewardship groups work and the associated organizational and neighborhood contexts advances the understanding of the environm...

Context Tree canopy connectivity is important for supporting biodiversity. In urban landscapes, empirical examinations of habitat connectivity often overlook residential land, though yards and gardens often comprise a large portion of urban forests. Objectives We quantify structural composition (patches and paths), connectivity and fragmentation o...

Stormwater runoff is an important component of the hydrologic cycle of urban watersheds. There is increasing concern with the water quality of stormwater runoff , in addition to the effects of flooding. Changes in the structure of watersheds and in human behavior are important to improve stormwater quality. These changes often require support for g...

Residential land is expanding in the United States, and lawn now covers more area than the country’s leading irrigated crop by area. Given that lawns are widespread across diverse climatic regions and there is rising concern about the environmental impacts associated with their management, there is a clear need to understand the geographic variatio...

The air quality issues caused by extreme haze episodes in China have become increasingly serious in recent years. In particular, fine particulate matter (PM2.5) has become the major component of haze with many adverse impacts and has therefore become of great concern to scientists, government, and the general public in China. This study investigate...

Residents’ participation is key to the success of urban tree planting programs, yet a gap between resident intentions and participation actions may limit the benefits provided by such programs. Philadelphia Parks and Recreation (Pennsylvania, US) has conducted tree giveaway events for residents since 2012 with the goal of increasing tree canopy. Bu...

Residential development is one of the most intensive and widespread land uses in the United States, with substantial environmental impacts, including changes in forest cover. However, the relationships between forest cover and residential development are complex. Contemporary forest cover reflects multiple factors, including housing density, time s...

Residential yards comprise most land and green space across cities. Despite yards being ubiquitous, little comprehensive information exists on how vegetation varies between front and backyards. This hinders our ability to optimize greening interventions on private urban land. We devised an accurate GIS algorithm to locate and classify front and bac...

Many factors influence yard care in urban and suburban areas, but the explicit difference between front versus back yards is one factor that has not been fully examined. This paper introduces the Landscape Mullet concept. The two key components of this concept are: (1) social norms are an important driver of yard management; and (2) the influence o...

A landscape succession paradigm has shaped much of our understanding about the processes of forest emergence and transformation in the United States. Drawing heavily from theory and method in environmental history, this paradigm has focused attention on the role of landscape-scale shifts in land use and land cover in the production of forests. The...

Fine-scale information about urban vegetation and social-ecological relationships is crucial to inform both urban planning and ecological research, and high spatial resolution imagery is a valuable tool for assessing urban areas. However, urban ecology and remote sensing have largely focused on cities in temperate zones. Our goal was to characteriz...

Los Angeles, California is prone to extreme climate events-e.g. drought, wildfires, and floods-that are only expected to increase with climate change. The establishment of green infrastructure, including a stable urban forest, is a strategy to improve resilience not only to these events, but also to contribute to other environmental, social, and ec...