Tree Canopy

Tree Canopy

What does this indicator measure?

This indicator measures the percentage of land with tree canopy (weighted by number of people per acre).

The connection to health

Everybody should have trees and other plant life near their home. Trees are beneficial for mental and physical health in many ways. They can provide shade and cool surrounding areas, reduce stress, and promote health, wellness and physical activity.86, 87, 88 Trees are essential to mitigate the effects of climate change, especially extreme heat events. They can also promote physical activity by providing shade and a pleasant environment for walking and bicycling. Expanding the tree canopy in areas without a lot of trees, especially low-income communities and communities of color, can promote healthier communities. Less tree canopy can contribute to poorer health outcomes and vulnerability to climate change. Many cities have conducted tree canopy inventories and discovered major differences in tree canopy between neighborhoods.89 A 2015 study, for instance, examined the distribution of urban tree canopy cover for several major cities and found a strong inverse relationship between tree canopy and Black and Hispanic populations in Los Angeles and Sacramento.90

Where to start?

Improving tree canopies requires many strategies to integrate trees, urban forests and plants in populated areas, as well as policies to set aside areas for parks and greenspace.

The first step to improving tree canopies is to Plan for Trees by assessing current tree canopy conditions and creating a vision for the future. These planning efforts are often referred to as urban forestry—recognizing that forests exist, and should exist, throughout cities and towns. Urban forestry planning should begin by surveying current conditions to understand strengths, gaps, and opportunities. Depending on available budget and needs, planners may conduct a tree census (inventorying individual trees), use technology like LIDAR to assess canopy, or use existing tools like the Healthy Places Index and I-Tree Tools. These assessments should carefully consider equity—looking at canopy by neighborhood, race, income and other factors, as well as conditions such as Impervious Surfaces, Ozone, and Fine Particulate Matter where trees can help protect health. Plans should also provide guidance about the types of trees that meet a jurisdiction’s needs. Trees have very different requirements, and also different benefits and potential liabilities, such as water needs/uptake, allergen and ozone precursor emission, shading, and root interactions with pavement. Tools such as Urban Forest Ecosystems Institute’s SelecTree can help jurisdictions choose trees that are right for their context. Planning efforts should also identify funding requirements and mechanisms to ensure that a jurisdiction can plant new trees, and sustain forests in perpetuity.

With plans in place to guide their efforts, jurisdictions should pursue strategies to Plant Trees. Planting strategies may be led by the public sector, required as part of development, and/or take place in partnership with non-profits, utilities and the private sector. Jurisdictions should look for opportunities to maximize health benefits in addition to tree canopy, utilizing cross-cutting strategies like green infrastructure, green roofs, vegetative buffers, and green schools. While planting new trees is important, its crucial to Protect Existing Trees, and ensure that tools and standards are in place to ensure proper maintenance of trees and forests.

In addition to their tree canopy, jurisdictions should assess and improve greenspaces more broadly. Parks and open spaces can be ideal locations for trees, but they can also offer other benefits such as access to nature and opportunities for physical activity. See Park Access for more information. Jurisdictions seeking to improve green space access should first Plan for Greenspaces. Planning efforts should typically start with an assessment of current park and open space conditions, tree coverage, community needs, health conditions and gaps. In addition to the park access indicator in the Healthy Places Index, planners should consider use or burden measures such as park space per person within service areas, as well as historic capital and operations expenditures by park, neighborhood and user—with an eye to improving access and conditions in communities that have been historically left behind. A variety of tools exist to assess park access and conditions, such as the Trust for Public Land’s ParkScore and Climate Smart Cities Tool, the National Park Service’s Parks, Trails, and Health Workbook, and the Centers for Disease Control and Prevention’s Parks and Trails Health Impact Assessment Toolkit, and the California Department of Parks and Recreation’s Park Access Tool and Community FactFinder.

Because neighborhood residents are experts about their community needs, jurisdictions should ensure that greenspace planning, design and programming incorporates residents’ ideas. California’s Statewide Park Development and Community Revitalization Program offers excellent best practices in community engagement during park planning:

Meet with residents near the project. Hold at least five park design meetings with residents at convenient locations near the project site for residents lacking transportation. Also schedule meetings at various times to accommodate work and family schedules. Invite residents to provide their ideas. Use at least three methods to invite residents and consider language, cultural and access and functional needs, as well as child care and food. Encourage neighborhood youth, seniors, and parents to be a part of the design process so that the needs of different generations are met. Engage in dialogue during meetings. Ask residents to identify their needs and design ideas focusing on these key factors:

Selection of the recreation features and their design; Most practical location of features within the park; and Safe public use and park beautification such as landscaping or art.

Especially in places with high Severely Cost Burdened Low-Income Renters and low Homeownership jurisdictions should work to Stabilize Residents and Neighborhoods before initiating larger scale park construction or rehabilitation to ensure that people are not displaced, if improvements spark increased rents.

In addition to planning, jurisdictions should Make Greenspaces Safe and Active to ensure that they maximize health benefits. Parks should be designed with active uses and safety in mind, and coupled with programming to maximize use, ensure safety, and increase physical activity. Jurisdictions should also ensure that existing parks are well maintained, and that communities know about the parks and activities open to them.

Improving greenspace access and quality can be expensive, but there are several funding tools available to California jurisdictions and park districts. The State Department of Parks and Recreation administers grants through its Office of Grants and Local Services, and has improved or created over 7,400 parks since 1964. ChangeLab Solutions has produced an excellent guide to funding tools—Local Agency Strategies for Funding the Development and Maintenance of Parks and Recreation Facilities in California. In addition to traditional funding mechanisms like taxes and developer fees, this guide suggests partnering with non-profit hospitals’ community benefit programs to fund park improvements. Jurisdictions can also approach their local public health department for assistance in navigating health funding. Jurisdictions should carefully evaluate the distribution of their existing resources and expenditures, for instance assessing their Capital Improvement Plans and budgets to ensure equity in greenspace funding. As part of these processes, jurisdictions should consider auditing existing park facilities and conditions (with community input and participation), assessing the relative equity of past/planned funding allocations, and investing in areas that are park poor, or with overburdened facilities. Budgeting processes should be transparent and open to the public.