Professor emeritus at the University of Georgia, Michael Dirr, is widely acknowledged as one of the leading experts on trees and shrubs for landscapes and gardens. Dirr has introduced over 200 woody plants to cultivation and holds 29 patents with the UGA Research Foundation. It’s with this impressive background that he’s put together his most recent book The Tree Book: Superior Selections for Landscapes, Streetscapes, and Gardens. Featuring trees widely available in the nursery trade, some new and promising choices, and a selection of overlooked options that deserve renewed interest, Dirr will discuss this must-have resource for landscapes architects, city foresters, horticulturists, and enthusiastic home gardeners.

Michael Dirr | Professor emeritus, horticulture, University of Georgia

The George Washington University (GW) has three campuses in the DMV region, including the flagship Foggy Bottom campus located blocks from the White House. GW’s commitment to sustainability includes a robust focus on strengthening habitat and optimizing natural space at each of the three campuses. While people don’t often associate nature with urban campuses, the more urban a location becomes, the more important it is to establish and maintain natural spaces. Recognizing this, GW has set ambitious goals around natural space on campus, including increasing green space, enhancing biological richness/diversity, and enhancing the tree canopy. Over time, this has led to tangible progress on campus: planting over 264 trees on the Foggy Bottom and Mount Vernon campuses through a partnership with Casey Trees; creating and integrating the GW Sustainable Landscape Guidelines into the campus construction process; and increasing the amount of permeable space by 12% across all three campuses. This session will detail the progress on campus and the strategies used by the GW Office of Sustainability to shift the culture and practices within the institution towards sustainable landscape management. Office of Sustainability Director Meghan Chapple will also provide a look ahead to some of the upcoming projects at GW, including developing a baseline for biodiversity on campus and the creation of a pollinator park in the heart of campus. GW demonstrates what is possible in densely populated urban ecosystems by creating and transforming outdoor spaces using sustainable landscape management practices.

Urban forestry relies heavily on data and technology like any other industry. Whether your focus is engagement, management, or research-oriented, geospatial information, and web/mobile applications can play a key role in how you achieve and sustain your goals. Looking broadly across sectors, geographic scales, roles, and missions, the types of data involved in planting, studying, and caring for urban trees are truly diverse. Examples include inventories, pest & disease monitoring, risk assessment, staff or volunteers, planting events, nursery orders, costs and budgeting, citizen service requests, work orders, site/plan reviews, woodlands, ecosystem services (e.g., i-Tree), land use/land cover, and crowdsourcing. Whew! A series of brief case studies will demonstrate web/mobile mapping applications that span geographic scales as well as government, private, and nonprofit sectors. At the landscape scale, urban tree canopy has been incorporated into online mapping tools to analyze areas of need and identify partners, funding, and stewardship opportunities. This allows cities and nonprofits to meet planning, development, sustainability, equity, and environmental goals. At the scale of individual trees, smartphones and tablets allow us to map, assess, manage, track, share and monitor urban tree information. Multiple users can contribute to maps, interact with dashboards, and use QR codes or augmented reality to learn about tree species and age class diversity, tree health, ecosystem services, and maintenance/stewardship needs. Practitioners improve management efficiencies, researchers gather and analyze trends, and the public can share community forestry maps, photos, and other information through social media or custom interactive maps with a simple web link. The diverse examples will present a broad range of ways technology is being used to influence and improve operational, social, and other aspects of urban forestry today.

Redlining was a discriminatory housing policy established by the Federal Home Owners’ Loan Corporation (HOLC) in 1937. Because this policy limited access to homeownership and wealth creation among racial minorities, redlining played an important role in creating several current negative social outcomes such as high unemployment, poverty, and residential vacancy. Urban trees mitigate the urban heat island effect and are important for the quality of life in cities. Because trees grow slowly, we investigate how the HOLC policy administered 80 years ago may relate to present-day tree canopy in 37 metropolitan areas. Our hypothesis is prompted by research in Baltimore, MD, which found that the redlining policy influenced the location and allocation of trees and parks. When these 37 metropolitan study areas were redlined in the 1930s, their populations ranged from ~42,000 people (Lynchburg, VA) to ~7.2 million people (New York City). Our analysis shows that areas formerly graded D, which were mostly inhabited by racial and ethnic minorities, have on average ~23% tree canopy cover today. Areas formerly graded A, characterized by U.S.-born white populations living in newer housing stock, had nearly twice as much tree canopy (~43%). Results are consistent across small and large metropolitan regions. The ranking system used by Home Owners’ Loan Corporation to assess loan risk in the 1930s parallels the rank order of average percent tree canopy cover today. This disparity matters because trees can have important public health consequences, including the reduction of urban heat islands, which impact patterns of heat-related mortality.

Join the Pennsylvania Horticultural Society to learn effective strategies for developing community buy-in for tree planting and stewardship in priority Philadelphia neighborhoods - neighborhoods with low canopy, high population density, high crime, and low income. We will highlight and pull learnings from trainings and partnerships that engage tree champions across barriers of language and academic comfort.

Specifically, we will highlight successes and challenges in coordinating our Spanish Tree Tenders trainings, our Roots to Re-entry (R2R) training for previously incarcerated citizens and our PowerCorps training for at-risk young adults. Participants will leave with a toolbox of tried and true techniques for adjusting trainings to meet the needs of different populations, without losing valuable content.

PHS Tree Tenders offers affordable training in tree planting, care and advocacy in SE Pennsylvania. Currently, there are over 5000 Tree Tenders who organize their neighbors in planting over 1500 street trees each year. Tree Tenders group also organize neighbors to check on and provide the follow-up care that ensures their young trees' health. The Pennsylvania Horticultural Society (PHS) a nonprofit organization founded in 1827, is America's leading horticultural society. Today, PHS includes a diverse community of people who use horticulture to advance the greater good with a keen focus on creating healthier living environments, increasing access to fresh food, expanding economic opportunity, and building deep social connections among people.

Blue Water Baltimore uses a system of pro-active and community-supported maintenance for our street tree and bioretention stormwater management projects. Lack of maintenance is the largest contributing factor to the death of street trees and the failure of bioretention projects, as is a lack of community support for our restoration work. Grant-funded nonprofits such as Blue Water Baltimore are often forced to prioritize their limited resources towards the implementation of new projects to meet funding source goals. The neighborhood communities we work with are a vital part of the health of our trees and projects. Without community support, previously installed projects are neglected and become unsustainable over time.

In Baltimore, a city with a history of infrastructural decisions going from proposal to completion without the inclusion of directly impacted citizens, there is a pervasive amount of distrust for any improvement projects. Maintenance includes more than just the physical tasks of pruning, watering, weeding, or re-staking a new tree. Neighborhood relationship maintenance starts early and remains ongoing. We attend or host planning and proposal meetings with community groups and partner organizations, go door-to-door to speak with neighborhood residents and lead volunteer-powered project installations. Maintenance during the establishment years is also necessary, but it is the time between these two steps that is most vital.

As residents see us invest our time and effort in keeping a project vital and healthy over time, they are more likely to view our efforts as worthwhile and, therefore, more likely to help maintain the project after the establishment period. When the expectation is that green infrastructure projects are predatory pave stones for future gentrification, organizations like ours must continue to prove that our efforts are genuine and yield tangible results that will benefit the project and, in turn, the surrounding community.

Food forests are a great way to incorporate food production, education, and canopy cover in all urban areas. Planting them where it matters is key.

This presentation delves into the 21st Century streetscape and how streets function as the biggest extension of the public realm in urban environments. The streetscapes of the future will be different than they are today, because of the transportation paradigm shift that is on the horizon from automated vehicles and micromobility. The race to fill the leftover spaces on streetscapes needs to be focused on green infrastructure and street trees.

This presentation will walk through case studies of successful LID solutions, street tree infrastructure, and how trees can be the catalyst to re-imagining the public realm in cities. We will look at project examples and innovations that allow street trees to be successful in the urban environment. The technologies presented will be a brief progression of structural soils, Silva and Strata Cell products, and innovations in the future. The presentation will conclude with the economic and placemaking justification for bigger and better street trees in urban streetscapes.

Parks and green spaces are treasured community assets that offer significant benefits. They can improve the health and wellbeing of users, provide public safety for the community, and mitigate environmental challenges by building resiliency. Parks have been used innovatively for stormwater management, alleviating urban heat island effect, among other core greening activities. Yet, not everyone has equal access to parks. The benefits of parks and green spaces are maximized – particularly for low-income neighborhoods and communities of color – when the surrounding community is actively engaged.

The challenge for policymakers and planners is how to make public investments in communities in ways that build wealth and position those investments as assets for existing residents while minimizing displacement pressures that may arise. Hence, fostering strong community-level participation is critical for tackling this and encouraging equitable and inclusive development. If parks are not designed and activated with the residents' interests in mind, they can go underutilized. But when the community is involved in planning and decisionmaking processes, park amenities can better mirror the community's priorities.

Access to green space has been a continual concern and priority for city planners, policymakers, and advocates. Organizations tout the number of urban trees they have planted. With satellite imagery, researchers easily count, measure, and categorize urban tree canopies. Yet, some of the best-designed and most sustainable streets have no trees. Access to quality green space is often less considered than street-level tree canopies. It is important for decision-makers to conceive of neighborhoods and cities holistically. Policies should promote a diversity of everyday experiential environments through planning and design. Biophilic spaces should be one tool in a large toolbox. This session will explore the role trees play in making great neighborhoods and cities. Good design is key. Tree-less residential and mixed-use streets that are walkable to green space can provide an equally sustainable ideal to pervasive tree canopies. This model affords residents meaningful biophilic interactions. It also affords sustainability and resiliency advantages. Presenters will discuss case studies and implications for green city design. As advocates for green cities, we need to better assess quality over quantity for urban trees.

Since 2012, TreePhilly has pioneered a community-based yard tree giveaway model by working with residents throughout Philadelphia to increase urban canopy on private property. We are now piloting ways to use this model to prepare Philadelphia’s urban canopy for climate change. By utilizing the most current science on assisted migration, TreePhilly strives to work with its community partners to turn low-canopy urban landscapes into thriving communities of climate adaptive trees that can protect biodiversity and stand the best chance at ensuring the future of the urban canopy for all Philadelphians.

This presentation will explore our framework for selecting climate-adaptive yard trees for our region, and look at a few of the most resilient tree species to plant today in urbanized areas. Additionally, we will look at how the hottest and most vulnerable neighborhoods can lead the way on climate-adaptive urban forestry. Philadelphia has found that some neighborhoods are up to 22 degrees hotter than others: by working with these communities, we can evaluate the resilience of different tree species in conditions resembling what is projected for our region this century. In this way, we aim to demonstrate how environmental justice and climate adaptation are both complementary and essential in preserving the future of our urban canopies.

The pre-colonial landscape of the Washington, D.C. region was primarily deciduous forest and wetland. Forest was logged and wetlands were filled for agriculture, roads, industry and development. The remaining forest is fragmented. A few remaining wetlands are found along the banks of the Anacostia and Potomac Rivers. Should land managers revert back to forest when possible, or emphasize other landscapes such as meadows or wetlands? When considering biodiversity, which species should be prioritized? Conservation organizations such as Partners in Flight prioritize species that are not generalists; for example cardinals can adapts to nesting in woody shrubs such as the non-native bush honeysuckle, while the Arcadian flycatcher requires deciduous forests to nest. Dozens of insects use the Swamp White Oak as a host plant including leafhoppers, beetles and gall wasps, while the caterpillars of butterflies and moths feed on the leaves. These insects are favorite food of woodpeckers, warblers, and flycatchers. Acorns are eaten by Blue Jays, Grackles, Red-Headed Woodpeckers, raccoon, mice and squirrels. According to research by entomologist Doug Tallamy who studied Lepidoptera, the caterpillars from butterflies and moths, sycamore provide food for 45 species of caterpillars, and tulip poplar, 21. Both tree species seed themselves readily in the region, but have less wildlife value than oaks (532) cherry (456) and willow (455.) Likewise, open sunny areas are an important source of biodiversity for many species in this region. The nectar and pollen of the Wrinkle-Leaf Goldenrod attracts bees, wasps, butterflies, skippers, and beetles. A variety of insectivorous birds feed on the insects while Indigo Bunting and Eastern Goldfinch feed on the seeds. Meanwhile, the widely planted English Boxwood and the butterfly bush attract one species of Lepidoptera while Nandina attracts none. (Tallamy, Conservation Biology, 2009 Aug 23.) When land owners are considering how to manage their land, be it a few hundred square feet to hundreds of acres, should they plant trees, meadows or wetland? This presentation will share professional experience aquatic habitats, meadows and reforestation projects and consider how research in conservation biology can be utilized to increase biodiversity at a local level.

This workshop will focus on the lessons learned from the ongoing environmental work in the neighborhood of Hunting Park in Philadephia. In the last seven years, Esperanza has worked on the implementation of the Hunting Park Neighborhood Strategic Plan which focuses on many areas, including protecting our open spaces and the environment. Through a targeted community engagement strategy, Hunting Park has become a model in community greening efforts. Through this workshops, attendees will learn the importance of community engagement, how to reach underserved communities, and how to develop a strategy to allow residents to own the change in their communities.

Canopy summaries and accessible technology are effective tools to assess urban forest health and foster informed action through citizen science and public participation. Compiling the data that informs these public-facing tools is most effective when launched from a collaborative, partner-based approach.

Livable cities require a combination of effective policies, systems changes, and shifts in daily behaviors of its residents. Washington, DC's and Montgomery County's MS4 permits and policies strive to foster voluntary behaviors to improve sustainability. Non-profit organizations like Rock Creek Conservancy leverage these policy incentives to cultivate individual environmental stewardship. For example, the Conservancy's Downspout Disconnection program, in partnership with DC Water's Clean Rivers Program, has shifted social norms such that green infrastructure is increasingly adopted by (diverse) homeowners. Rock Creek Conservancy (RCC) restores Rock Creek and its parklands as a natural oasis for all people to appreciate and protect. 5,000 RCC volunteers per year engage in direct restoration service drawn to the work by the appeal of these unique, urban natural spaces. RCC's model of people-powered restoration uses those volunteer experiences to build a sense of place and community, affirm and build volunteers' identity as 'a Rock Creek person,' and, in combination with other social marketing efforts, an understanding of how to protect Rock Creek in daily life (environmental action). By mobilizing volunteers with the tools to become good neighbors to public lands, Conservancy programs create livable cities providing health benefits for all people to enjoy. This presentation will walk through the theory of change that underlies this work.

Developed through Land-Grant Research and Extension work, the Master Naturalist programs' curricula primary focus on various rural and suburban landscapes. Topics include large land-management, restoration, and natural resource conservation. Within the densely populated District of Columbia, much of this material does apply. As the land-grant university of the nation's capital, the University of the District of Columbia (UDC) had to reconceptualize the Master Naturalist Program for the urban context. This presentation identifies key questions and the development of creative solutions to address them. How can Master Naturalist Program adapt to urban landscapes? Within a small geographic region, how can we fulfill the mission of the program? How can we meet the objectives of the volunteers? Most important, how can we engage urban residents in their natural environments? To answer these questions, we looked at non-traditional volunteer opportunities and participant engagement. We also focused on the interactions between the human-built environment and natural system. These innovations worked towards enriched programmatic environmental stewardship within the District and beyond.

Trees and forests are critical for sustainability, resilience, and well-being in cities, yet remain under-appreciated as formal green infrastructure elements. Managing and conserving urban forests to provide ecosystem services requires an improved understanding of the ecological functional of forests across urban contexts. For example, trees mitigate stormwater runoff in cities, but the amount of stormwater that trees can remove through hydrological functions in real urban settings is not well characterized. This limits the use of trees and forests as strategies to manage stormwater runoff. To address this gap, we introduce a novel research framework that uses ecohydrological approaches to assess the stormwater retention benefits of urban trees in different management settings. Using this framework, we have established monitoring sites in Montgomery County and Baltimore City, MD. Monitoring sites include patches of urban forests, a cluster of trees over mowed grass, and single trees over mowed grass and along a street. At these sites, we use sensors to measure tree sap flow and soil moisture dynamics along with local environmental conditions. We compare these ecohydrologic variables for different tree species and management contexts using data collected in summer and fall 2018 and explore how environmental drivers of transpiration vary across urban forestry site types. Management context strongly drives stormwater ecosystem services provided by trees (transpiration rates) by influencing the physical environment, including temperature, relative humidity, and VPD as drivers of tree water use. We discuss the interaction of environmental drivers and management context in light of socio-ecological factors of the surrounding managed landscape that inform a typology of urban forests. These data will ultimately help to inform guidelines for practitioners using urban trees and forest patches to manage stormwater flows. Our results will contribute to policy and practice by defining a nutrient reduction credit for urban tree canopies across different management settings in the Chesapeake Bay watershed.

Habitat loss and fragmentation are leading threats to biodiversity and ecosystem function worldwide. Forests in the Chesapeake Bay watershed provide valuable ecosystem services, such as wildlife habitat, clean air and water, carbon storage, and recreation opportunities. However, forest area and connectivity have decreased with increasing development. As urban and suburban areas continue to grow in the Chesapeake Bay watershed, it is increasingly important to identify areas most affected by development and ways to mitigate potential negative changes. We ask, first how do expanding urban areas contribute to fragmentation, and second, how does this fragmentation affect biodiversity and ecosystem services? We are revisiting forest fragments surveyed in the 1970s from three Maryland counties to examine plant diversity and structure, songbird diversity, and a variety of ecosystem services. The forest fragments span an urban to rural gradient, vary in size and connectivity, and are surrounded by different land-uses. Our initial efforts suggest that forests in more urban areas have decreased in size and connectivity, whereas fragments in more rural areas have either maintained or increased in size. Initial re-surveys of vegetation suggest that invasive plant species have increased in all forest fragments. Additional vegetation and songbird surveys will be conducted in Summer 2020, and we predict that bird populations will be influenced by various fragmentation metrics, such as connectivity, size, and the proportion of forest edge. We are continually seeking to work with local partners to combine data collection efforts and synthesize existing data from forest fragments in the Chesapeake Bay watershed, with the goal of using these data to develop models forecasting potential ecosystem outcomes to provide information to managers, stakeholders, and policy makers alike.

Aboveground forest carbon sequestration is known to be a function of allometric relationships, stand history, and edaphic conditions. We investigate how the heterogeneous edaphic conditions, within two well-document naturally assembled urban brownfields influence the allometric relationships of the dominant species Betula populifolia Marsh and Betula pendula Roth. Diameter at breast height (DBH), height, mass and age of B. populifolia on four plots that exhibited considerable differences in soil metal load at the first site (Liberty State Park, New Jersey USA) were measured to demonstrate carbon sequestration potential.In addition, we also measured DBH and height of Betula pendula Roth a closely related European species at a similar brownfield in Germany (Landschafts Park, Duiesberg Nord). Site conditions did not appear to impact total tree mass to diameter relationships. However, mean DBH at the various sites ranged from 6.7 to 9.8 cm and the mean height from 637.4 to 911.8 cm. In addition, above ground woody biomass ranged from 40017 to 71935 kg ha-1. Apparently resource allocation between growth and maintenance within the heterogeneous edaphic conditions of the urban context clearly results in considerably different growth rates and stocking densities. In addition, DBH/Height relationship of B. pendula were statistical equivalent(p ≥ .001, two sample equivalency test) those of the B. populifolia. In conclusion, since resource allocation between growth and maintenance within the heterogeneous edaphic conditions clearly results in considerably different growth rates and stocking densities, it will have significant impacts on C models for urban areas. However, having demonstrated similarity between growth rates of analogous species from the USA and Europe broad scale modeling is viable.

Liza Paqueo, Urban Outreach and Partnership Specialist, will discuss Beyond Trees, a network that aims to link like-minded partners working in cities across the globe and provide a means for exchanging best practices, latest research and a platform for collaboration.

Mike Rizo will focus on how USFS-IP builds conservation awareness by starting at the household level. By fostering an appreciation for nature in one’s home, a strong foundation is set family by family. However, awareness is not enough. Families are encouraged to take action in their own way. Most of the communication is done by word of mouth, and the results are almost magical. Household networks become part of larger community networks, which in turn continue to tier up to regional, national, and international levels. These networks are created through specialized training that incoporate vehicles such as monarch butterflies and other cultural elements to draw families into the conservation. Awareness that leads to action is key. Maximum impact happens when the dots are connected.

Al Zelaya will discuss how The US Forest Service International Programs has collaborated with Davey Tree and other partners to introduce i-Tree urban forest assessment tools and community engagement strategies in several countries including Mexico, the Philippines, Egypt and Colombia. This collaborative effort has created a framework for international technology transfer, knowledge sharing and lessons in the diffusion of innovation.

Washington DC's Urban Forestry Division (UFD) directly manages public trees on the street, in parks and schools, while indirectly managing trees on private property through a tree ordinance. Urban Forestry Division manages the urban forest for existing pests and pathogens, while also employing a variety of proactive strategies to address new and emerging forest health issues. UFD employs traditional and novel methods for early detection of non-native forest insect pests in collaboration with the US Forest Service and USDA APHIS. Planning ahead for future forest health issues includes partnerships with university researchers to ensure the District's urban forest is resilient to emerging pests and pathogens, as well as urban warming. Lastly, UFD employs an annual survival study to determine which trees are thriving. This study can be used to incorporate and assess new tree species and cultivars better suited to future conditions.

"The Fairfax County Urban Forest Management Division (UFMD) has been overseeing tree preservation and planting efforts related to construction sites for many years on a site by site basis, in addition to monitoring and managing outbreaks of destructive insects and diseases in an effort to preserve the urban forest. County wide efforts to assess tree cover extent and forest composition have occurred over time in the form of one-time I-tree surveys, tree canopy estimates generated using remote sensing technologies, and public park system-wide assessment of invasive plant communities. These efforts are significant and beneficial, however they offer only snapshots of the urban forest, whether that be loss and replacement of tree canopy in development projects, or single measurements of the extent of canopy at a point in time. Feasibility studies, pilot programs, and additional mapping/modelling efforts provide important information for more comprehensive management of the urban forest. Armed with information including forest composition, extent, and relative health, potential loss could be modelled for any threat to the urban forest, allowing managers time to prepare for insects, diseases and plant species that could cause negative impacts to our forests, begin work to improve the health of forested areas that are already protected in the long term, and to develop new mechanisms for helping ensure the success of tree canopy following development activities. Greater detail about forest composition and changes over time will better inform management of preserved forests, while opportunities may also be found for cooperation with the development community to locate new building and infrastructure in areas that will be less impactful to existing forest resources. "

Many cities have set ambitious urban tree canopy cover goals with the expectation that urban forests will provide ecosystem services as functional green infrastructure. Several studies have explored how socioeconomic factors and urban form influence urban tree canopy within a city. Others have looked at links between local legislation and canopy cover. However, less is known about urban tree canopy and governance across multiple different cities. To address this gap, we compared the management practices of 43 municipalities in Florida (United States) to investigate their potential impact on tree canopy coverage. We analyzed differences in canopy cover between the cities based on 1) municipal forestry management practices, including whether the municipality had an arborist, tree ordinances, a municipal tree inventory, and a canopy cover goal, and 2) community sociodemographic data. We found two factors significantly predicted canopy coverage. Housing density had a negative relationship with tree canopy. On the other hand, municipalities with heritage tree protections had a 6.7% more canopy coverage. Our research suggests that heritage tree protections targeting old or large-stature urban trees have a measurable impact on tree canopy retention. This finding is important considering the state of Florida recently passed a law (FL HB 1159), which deregulates municipal and county control of tree trimming, pruning and removal on residential property when a tree is deemed 'dangerous' by a Certified Arborist or licensed Landscape Architect. Future research should evaluate the association between ordinances and tree cover in other states and regions, as well as look at changes in canopy over time within single communities.

An increasing number of tools exist to quantify the ecological services trees provide, however the cultural values of trees remain difficult to assess. Trees provide important cultural services known as existence values, intangible values assigned by people based on our beliefs, experiences, and perceptions. People engage these cultural services through recreation and tourism for our mental and physical health. Furthermore, trees offer aesthetic qualities and inspire culture and the arts, sometimes inspiring spiritual experiences and enhancing our sense of place. This presentation examines the existence values of trees in the national parks of the National Capital Region through individual tree stories. By telling the stories of significant trees in this context it is possible to appreciate many of the indirect values they provide. The focus is on legacy trees on the National Mall, in Rock Creek Park, and across Monocacy Battlefield. The trees have witnessed and made history. They anchor places and symbolize spiritual and political ideas. The presentation highlights 15 significant trees, including the Worthington white oaks at Monocacy Battlefield. These white oaks are the only above ground remains of an historic African American dwelling at the foot of Brooks Hill. Because trees have finite lives, telling their stories is a critical means of assessing and recording their cultural value. It is also important to fulfill the National Park Service's goal of preserving the quality and character of landscapes for future generations. To remember these legacy trees in the future, their stories must be told now.

Prince George's County DPW+T has managed county roadside trees for almost 20 years under the direction of Wayne Lucas. Since the Right Tree, Right Place Program's inception as a Bradford Pear removal-and-replacement program a decade ago, Mr. Lucas has grown the program into a significant urban forestry initiative. With limited staff and modest funding, it now plants five times as many trees as it removes, focusing particularly on low-tree canopy streets across the County to gradually resolve the local distributional inequities in urban tree canopy. Even as Prince George's County rapidly expands and densifies key urban areas, the Right Tree, Right Place Program is helping to make those areas livable in the long-term. And it does all of this with significant resident engagement and input: presentations at community meetings, a voluntary community approval process, postcard mailings to inform residents before tree work ever starts, and, above all, thousands of face-to-face interactions, phone calls, and emails with residents every year.

Washington DC, the “City of Trees”, has a long history of embracing urban forestry. Substantial investments in tree planting over the past 150 years has resulted in a great inheritance of legacy trees. Many of these trees “co exist” with over 700 miles of overhead power lines. Get a historical perspective of the Washington DC Municipal and Utility Arborist’s management of the “green and gray” infrastructure interface. How has Pepco’s utility reliability performance improved while Tree Canopy has increased.

Today, many cities around the globe are planting street trees to mitigate the effects of climate change. However, this practice is not a new phenomenon. As I will show in this lecture, cities like New York City and Berlin during the nineteenth century began to systematically plant trees to improve the urban climate. I will present the history of street tree planting within its larger social, cultural, and political contexts. Street trees–variously regarded as sanitizers, nuisances, upholders of virtue, economic engines, habitat, and more–reflect the changing relationship between humans and nonhuman nature in urban environments.

Sonja Duempelmann | Associate Professor of Landscape Architecture at Harvard University Graduate School of Design