Heat Domes and Tree Canopy

By Rebecca Bear, President and CEO

The warmest days in modern history took place this month, with record-breaking heat across the globe. In 2021, Washington experienced the worst heat wave in recent history, with 100 deaths between June 26 – July 2. A quarter of those deaths occurred in King County, the state’s most populous and diverse. Adding to the challenge, Seattle is the least air-conditioned large metro area in the US – just 33.7% of Seattle Area households are air-conditioned. 

During heat events, Seattle and King County residents depend on tree canopy for its natural cooling effects. You will find people out in parks, under the shade of trees as a way of staying cool each summer. But unfortunately, not all areas of Seattle and King County have equitable tree coverage. According to the Washington State Environmental Health Disparities map, the industrialized riverways of the Duwamish and Green Rivers, which pass through South Seattle, Tukwila, Burien, and Kent, have the highest environmental health disparities and the highest population of immigrants and communities of color in the state. This same region has the lowest level of tree canopy and lost 3.5% canopy in the last five years. During heat waves, this can result in a 20-degree temperature variance compared to areas of the city with more trees. In 2021, ground temperatures in the Duwamish Valley exceeded 120 degrees Fahrenheit.

Gateway Park North in Georgetown, as seen from above. Photo by Nic Moran.

To counteract the impacts of heat and other impacts of climate change, trees provide a significant natural service to our community. Here are a few important tree canopy facts:

A bulleted list of facts accompanied by graphics that illustrate them. They are: In one year, a mature tree will absorb more than 48 pounds of carbon dioxide from the atmosphere and release oxygen in exchange. Trees in urban areas are responsible for capturing and storing nearly two percent of overall US carbon emissions - representing 20% of all carbon capture in the nation's forests. On average, Seattle experiences 14 unhealthy pollution days a year, with 7 owing to high ozone and 7 owing to high PM2.5. The US Environmental Protection Agency recommends no more than 3.2 unhealthy pollution days each year for each pollutant. When mature, trees shade buildings in the summer and block wind in the winter, reducing the use of air conditioners and heaters, providing both economic and environmental benefits. Trees reduce stormwater runoff, reducing the risk of flooding. Stormwater is a major factor in urban water pollution and environmental justice issues in communities with less trees. Trees increase ecosystem diversity, providing homes for birds, pollinators, and other wildlife.

A major movement is underway to advance tree canopy work throughout the country and world. Recently the State of Washington Department of Natural Resources announced its adoption of the American Forests Tree Equity Partnership, which will drive tree canopy investment throughout Washington State urban forests.  In addition, Mayor Bruce Harrell announced a series of efforts to address the city’s tree canopy goal of 30% coverage including:  

– Over the next five years, plant 8,000 trees on both public and private properties; plant 40,000 trees in parks and natural areas; and perform maintenance on 40,000 trees. 

– By the end of 2023, implement a policy to require three trees to be planted for every healthy, site-appropriate tree removed from city property. The same policy will require two trees to be planted for every tree that dies or is deemed hazardous or invasive. 

– By the end of 2024, develop a Tree Canopy Equity and Resilience Plan for achieving Seattle’s tree canopy goals. 

Looking towards the Space Needle from Maple Leaf Reservoir Park. Photo by Jocelyn RC.

Seattle Parks Foundation is committed to ensuring the effectiveness of city, county and state initiatives focused on tree equity and canopy health. This summer we launched an ambitious effort to create the Seattle Tree Canopy Network. This network will bring together community-driven organizations throughout Seattle and King County and government agencies to address gaps in funding and coordination around tree canopy projects. Our goal is to bring federal, state, local and private and foundation funds together in a coordinated large-scale investment in tree canopy where our communities need it most. We will focus our work in four key areas:

1. Catalyzing community driven canopy work, because when you care about the trees in your neighborhood they thrive!
2. Connecting volunteers to meaningful tree canopy work through partners and projects.
3. Growing green jobs, particularly in communities with low tree equity.
4. Educating the next generation by connecting them to tree canopy projects.

Our grassroots community partnerships and relationships with government agencies make us well suited to be a convenor of this work. But we can’t do it without your support. We must build our team, and we need “all hands in the dirt” helping us ensure the success of this project. If you have an interest in helping see the Seattle Tree Canopy Network thrive, please reach out to us and let us know how you might want to participate. You can also contribute to our efforts by making a donation today.

Send a check

To make a donation by mail, please send a check payable to Seattle Parks Foundation to:

PO Box 3541
Seattle, WA 98124-3541

If your gift is intended for one of our community partners, please add their name in the memo line or with an accompanying note.

A tax receipt will be mailed to you upon receipt of your contribution.

Thank you!

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We accept most cars, trucks, trailers, boats, RVs, motorcycles, off-road vehicles, heavy equipment, and other motorized vehicles. All or part of your donation may be tax deductible.

To get started, simply complete the online donation form or call 855.500.7433 or 855.500.RIDE to speak to a representative. You can also read more at careasy.org.

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