PARTICIPANT FEEDBACK ON THE QUESTION: WHAT ARE THE KEY REMAINING QUESTIONS AND CHALLENGES?
Quantifying ecosystem services and other benefits of urban trees
- What is the connection between urban vegetation and public health issues such as domestic violence, crime, and the drug trade?
- How does society currently value biodiversity?
- What tree species are effective for meeting watershed goals and complex food webs, but that also have the appropriate heat/cold tolerance?
- Need to determine quantitative effects of trees on human health based on empirical observations, not just simple correlation studies.
- How can the multiple benefits of urban trees be ranked and quantified so that communities can make informed decisions about the types of tree species they should plant (that will survive in a changing climate), based on their local needs and priorities?
- How far (spatially) do the impacts of a tree-lined street or park extend to the broader urban environment?
- What are the impacts of urban trees on mental health?
- Better quantification of the volume reduction of stormwater due to canopy evaportranspirtation.
- What are the biodiversity benefits of “urbanized” versus “complete” forest systems?
- How do the novel species assemblages seen in urban areas perform compared to fragmented native systems?
- Can we predict what our urban forest will look like in 20-50 years?
- Better quantifying the ecosystem services of individual trees and/or groups of trees would be useful for calculating the monetary value of benefits and for advocating for tree protection.
Environmental economics evaluations of urban forest ecosystem services
- How much are people willing to pay for biodiversity in urban parks?
- How can trees be assigned value for municipal accounting?
Effectively engaging with the public and decision-makers
- How to communicate the idea that urban trees, regardless of location, are a public commodity that benefits all.
- What do urban residents want to know about urban trees?
- What are appropriate methods of translating research so that it is understandable to non-science communities?
- How to engage the community to support expanded and refined urban forestry?
- Cultivating community involvement from the beginning of projects rather than at the end.
- Outreach and marketing strategies that will maximize the effectiveness of ecosystem service results and reports.
- Providing guidance to help municipalities determine “what should our canopy goal be and why?”
Encouraging private landowners to plant and maintain urban trees
- What are effective ways to reach and motivate private landowners to plant and care for trees? Would regulations hamper this effort?
- How to incentivize people to think in a longer time frame and invest in future benefits?
- How are private landowners motivated by what is largely a public good?
Effective management and maintenance of urban trees
- With 50-60 percent tree mortality in urban ecosystems, there is a need to educate tree planters because many trees are being improperly planted.
- Research how tree care and maintenance affect the risk of storm damage or tree failure and the flow of ecosystem service trees provide.
- What is the genetic diversity of urban forests, and how does that relate to tree survival and to broader urban sustainability goals?
- How do trees survive in the long-term under stress? What factors help trees succeed?
- Long-term investment strategies to support urban tree maintenance (e.g., burying power lines)
- How can the number of trees that are removed by power companies be reduced?
Informed tree species selection and planting location strategies to optimize ecosystem services and tree growth
- How do ecosystem services provided by trees vary by species of tree, by how they are maintained, and by their health? These factors are highly variable in cities by neighborhood, street, microclimate, and urban morphology.
- How are best trees selected for dry, dry/wet, wet locations?
- How big do we want our trees? Do we know that more canopy cover actually produces better services? What are the cost issues of size?
- How can research related to climate change be used locally for better plant selection and planning?
- Are green walls just as effective or more effective than trees for absorbing air pollution? (Vertical gardens offer a lot more plantable space in cities).
- Determining the right size of planting programs within urban environments, e.g., a strategic planting of 7,000 trees could have more impact than “1 million tree” campaigns.
- How does the physiological ecology of trees change in an urban setting as opposed to a rural forest setting?
- What ecosystem elements are most important for cultural and psychological benefits (e.g., bird diversity, closed canopy, continuous forest, recreation opportunities)?
- What are the characteristics of effective wildlife corridors in the urban setting?
Coordination, collaboration, and partnerships among stakeholders (e.g., industry; local, state, and federal government; public; and academia)
- How to build a network of stakeholders?
- In light of limited federal funding, what kinds of private sector entities or public private partnerships could support research and data compilation?
- How to streamline local government efforts, e.g., by sharing best practices in reaching urban canopy goals.
- Improving communication between researchers and decision-makers. Models may not be trusted if the decision-maker does not understand how the model was built or run.
- Developing easy to use/follow implementation plans for managers.
Receiving regulatory credit for benefits of urban forests
- How could health benefits of urban forests be quantified in a way that would be relevant to policy?
- How to connect ecosystem services to pollution standards and regulations and national regulatory offsets?
- How do we develop and institute regulations that will support green infrastructure and urban trees?
- Developing ecosystem service metrics that can be used in the regulatory process, and tools that address regulatory issues and are accepted by regulators.
Improving the tools, models, and methodologies to meet users’ needs
- Standardized sampling methodologies that can allow one to see error deviation and confidence level data.
- How to create a street tree inventory that is useful on a county wide scale?
- How confident are we in the air pollution benefit estimates for tools such as i-Tree?
- Need a better understanding of uncertainties in modeling estimates.
- Need low-cost tools that can be used by small cities and communities.
- Can all tools be standardized and linked to ESRI and the Arc GIs suite (e.g., i-Tree)?
- How to incorporate more tree benefit values (e.g., public health variables) into modeling tools?
Balancing competing objectives and values of stakeholders
- How to design projects to meet multiple needs, especially when multiple agencies and programs are involved?
- Balancing multiple land use needs in public urban spaces.
- Who benefits from tree planting and stewardship programs and who does not?
- How to balance increased human density with the space needed for functioning biota.
- How to reconcile the habitat requirements of people and wildlife?
Using urban trees as a stepping stone for design of sustainable, resilient cities
- Moving from specific projects to a more holistic/city-wide green infrastructure approaches.
- Integrating trees with other infrastructure.
- What is the best possible city we can design?
- Identifying indicators of a healthy, functioning, sustainable urban ecosystem.
- What motivates communities to pursue green infrastructure?
- What are effective and efficient strategies for maintaining green infrastructure?
Other questions and challenges
- Defining “urban” in the context of urban forestry.
- Who is responsible for the management of and funding support for urban forestry programs?
- What is the distribution of urban forest resources, services and disservices with respect to socioeconomic patterns?
- What are the opportunities for green job creation for planting and maintaining urban vegetation?
PARTICIPANT RESPONSES TO THE QUESTION: WHAT IS NEEDED TO ADDRESS THESE QUESTIONS AND CHALLENGES?
To improve tools, models, and methodologies
- Develop a new urban tree database that combines abiotic tolerances and ecosystem services provided by a given tree species.
- Develop better urban climate models to study greening scenarios.
- Standardize urban tree canopy assessments so all ecosystem services data can use the urban tree canopy data.
- Create an urban site index by using a multi-city research approach looking at various factors affecting tree growth.
- Develop predictive tools for impacts of extreme weather events on trees and potential actions to reduce those negative impacts.
- Standardize remote sensing technologies (Landsat, NAIP, LIDAR) to support urban ecosystem assessment. (Current studies draw from different platforms and make comparison difficult from one study to another.)
- Develop tools that can assess the multiple benefits of trees, evaluate the ecosystem services for trees in natural areas, and demonstrate the value of green infrastructure intensity applied at subwater-shed and sewer-shed scale for storm-water management.
To support more data, open data, improved data collection and management
- Develop standardized protocols for collecting data across cities.
- Develop tree species lists by region that highlight or identify the species that address multiple objectives (e.g., biodiversity, storm water, nutrient removal, air quality).
- Bring different data sets together for analysis through data aggregation networks.
- Enable managers to build urban forestry program capacity through data clearinghouses by topic (e.g., local code, benefits).
- Validate modelswith more detailed, comprehensive, and standardized data on
ο Sub-community scales on school test scores, disease and mental illness, prescription drug sales, and other direct and proxy measures of public health and well-being.
ο Ecosystem services at the intra-urban scale, to gain understanding of factors driving differences in the flow of services.
ο Stormwater runoff.
ο Tree species performance across urban site and soil types.
To improve public outreach and education
- Survey public attitudes about trees, to better understand what the public needs to know about ecosystem services.
- Produce and widely distribute an easy-to-read set of guidelines and recommendations for increasing tree cover (for use by teachers, local government, landscaping companies, and homeowner associations).
- Develop appealing citizen science and social media approaches to mobilize communities.
- Communicate to the public the connection between compact, transit-oriented land use and preservation of green space.
- Develop user-friendly tools to help cities and communities understand the environmental and economic benefits of planting trees.
- Distill research into usable but qualitative information to be shared with decision makers, policy makers, homeowners, etc.
To foster coordination and collaboration among key stakeholders
- Foster new partnerships among (for instance) urban planners, urban forest and urban wildlife researchers, city managers, city/state epidemidologists, the electric utility industry, as well as partnerships
ο Between green groups and other community organizations such as school sports teams and community religious groups.
ο Between regulatory agencies and urban forestry implementing organizations.
ο Among federal agencies to ensure common acceptance of models and measurements
- Support such collaborations by
ο Designing a forum, such as a community blog, for sharing best practices among local urban foresters.
ο Implementing an urban forestry network that meets regularly to discuss new research and foster an ongoing dialogue.
ο Developing networks of managers and scientists to frame questions and standardize data collection techniques.
To advance research on the biophysical effects of trees and design innovative approaches to incorporate green space into cities.
- Support research on topics such as
ο Water usage of trees, best species for intercepting pollutants, and linking urban tree vegetation and quality of life, especially in Midwest, Great Plains and arid/semi arid regions.
ο Tree sensors and when trees should be removed to maximize benefits or remove trees prior to failure.
ο How trees affect air pollution (including chemistry, meteorology, mixing)
ο Effect of mortality rates for urban trees on ecosystem services models for urban forests.
ο Stormwater benefits of trees as compared to other vegetation types such as nature, grasses and shrubs.
ο Urban tree growth and expectations.
- Develop research infrastructure that includes information exchange, technology, transfer, design standards.
- Address multiple benefits and costs of urban ecosystems holistically and to avoid unintended consequences of decisions, systems analyses should be implemented.
- Conduct comparative and complimentary analyses of green vs. gray vs. hybrid technologies.
To advance social science research involving social scientists, psychologists, and marketers to create and sustain a culture of urban tree stewardship.
- Develop an integrated approach to socio-ecological research.
- Conduct applied research on culture and behavior.
- Conduct cross-comparative studies on cities of different climates, geographies, histories political and economic contexts.
- Add cultural ecosystem services to research agenda.
- Identify and studyi tree-friendly demographics to determine why the residents have positive attitude about trees.
To advance the research needed to help integrate urban trees into regulatory programs and systems. For example:
- Analyze how policies help or hinder extent and health of urban forests.
- Document comparative costs for meeting regulatory requirements and community goals.
- Research on tree canopy standards and ordinances for parking lots.
- Align research with regulatory drivers: air quality, water quality, and development regulations.
To conduct interdisciplinary research to understand the urban natural-human environment. For example:
- Examine correlations between environmental factors, health, food security.
- Determine how accurate models must be to inform decisions.
- Use comparative neighborhoods could be used as multi-disciplinary research sites.
To implement regulatory and policy changes that are more “tree friendly.”
- Refine benefit determinations to meet epa and state environmental standards and guidelines.
- Develop modeling programs and protocols that integrate urban trees into stormwater regulatory analysis.
- Design appropriate policies that manage costs and benefits of urban ecosystem services that are borne by different parties.
- Incorporate changes in building codes, building development, and tax policies that make it easier to meet tree canopy goals.
- Design policies that limit the liability associated with trees.
- Overhaul tax and utility fees to credit green infrastructure and trees, tax impervious cover or lack of trees, and to move to incentive-based structures that are careful to avoid environmental or economic injustice.
- Develop regulatory programs that require developers to pay for the ecosystem services lost when trees are removed.
To develop improved ecosystem service models
- Develop finer scale model resolutions, from city scale to land scale.
- Develop models that calculate the global climate change benefits of urban forests.
- Develop better urban climate models to study greening scenarios.
- Integrate tree modeling programs into stormwater and air quality models.
- Design a meta-framework for developing function- and service-specific models that can be synthesized or used in parallel.
- Design inter-disciplinary models that incorporate economic valuations of urban tree canopies that can be used across the agro-ecosystem.
To identify indicators of tree health and performance
- Improve understanding of the capacity of urban trees to mediate stormwater pollutants.
- Identify the relative performance of trees and other landscape components for improving water quality or quantity (e.g., for pricing stormwater utility).
- To develop regionally-appropriate standards and strategies for enhancing and expanding urban forestry.
To set appropriate tree canopy goals
- Determine the minimum urban tree canopy needed to optimize health and biodiversity benefits.
- Encourage practitioners to set goals for their projects based on desired specific ecosystem outcomes, and to assess success of these goals.
- Set attainable urban tree canopy goals with a better understanding of urban tree mortality.
- Conduct a predictable available tree canopy assessment and accessible tree planting tracking methods.
- Secure adequate resources to support urban forestry efforts.
- Expand the vision of urban forestry to all areas that are human-dominated. (Trees benefit suburban and exurban areas as well as urban areas).
- Use public health as the common denominator for all urban forest benefits (air quality, water quality, wildlife diversity, GHG mitigation, etc.).
- Better integrate the benefits of trees across disciplines to create a matrix that can be embedded in an economic development matrix.
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