OAKLAND’S CANOPY BY THE NUMBERS
Trees in parks
2018 canopy cover (from 9% in flatlands to 43% in the hills)
Trees lost each year
Plantings needed each year to increase tree cover by 1%
Cost per year of planting that many trees
U.S. Forest Service grant to aid Oakland’s urban trees
How much San Francisco outspends Oakland on urban forestry (with 1.77x the trees)
Everyone knows to seek shade on hot days. But it was a mild spring day at Oakland’s Hoover Elementary School—just 65 degrees Fahrenheit—when Wanda Stewart realized just how powerful the sun could be. For that day, Stewart, and Green Schoolyards America, checked the temperature of the black rubber padding under the school’s play structure. It was 152 degrees—nearly hot enough to cook an egg.
“That was the day that I went, ‘Wow. We need to find a way to shade these children,’ ” says Stewart, executive director of the West Oakland nonprofit Common Vision, which plants fruit tree orchards at low-income schools.
Soon, some of the most exposed parts of the city will get some shade. A new $8 million Inflation Reduction Act grant from the U.S. Forest Service aims to kick-start the restoration of Oakland’s tree canopy and address the historically uneven tree coverage that has shaped the city’s urban landscape for decades.
Though Oakland is a city named for a tree (the coast live oak), its tree coverage has been declining for years, and the distribution of those trees—abundant in the hills, few in the flatlands—means lower-income neighborhoods get the brunt of the sun. In one 2020 study, Oakland was found to have the most unequal tree coverage of 40 cities nationwide.
The decline dates back to the 2008 recession, when the Oakland city council cut the city’s 35 tree services staff members to 16. The tree services department stopped planting new trees or pruning existing ones. Recently, Oakland has been losing nearly 6,000 trees every year that haven’t been replaced.
This story is part of Wild Billions, a Bay Nature project exploring the impact of big federal money on Bay Area nature.
More on urban trees in this series:
- As Cities Heat Up, USDA Grants $42 Million for Urban Trees Around the Bay
- Oakland Offers a Plan to Aid Its Troubled, Unequal Tree Canopy
With limited resources, the tree services unit—which once planted an average of 1,000 trees a year—has been prioritizing high-risk emergencies, like trees that are about to fall, over routine maintenance. There’s a backlog of trees in need of removal. In the city’s project narrative for restoring its urban forest, staffers wrote: “Street trees throughout Oakland are in dire need of attention … Many whole tree or large branch failures could have been prevented each year had proactive maintenance and pruning been performed in proceeding [sic] years.” The narrative continues: “This is an example of how Oakland has failed its disadvantaged communities.”
Oakland has a plan. It’s a big one.
The Forest Service grant arrived just as the city released a draft of an ambitious 50-year plan to reinvigorate its urban forest and address its tree inequities. The plan will likely be presented to the city council to vote on its adoption in the first quarter of 2024. The goal is to “kickstart the tree maintenance,” says David Moore, a city tree supervisor, who contributed to the plan’s development.
“Trees are a social justice issue,” he says. “We need everyone’s participation.”
Historical photos, timelines, charts, and tree clip art fill the plan’s 177 pages. The first four chapters provide an overview of Oakland’s current urban forest, and highlight its management and the equity-based approach the city will take to restore it. The last chapter outlines potential next steps, including 70-plus potential action items like reinstating a citywide tree maintenance and planting program and inventorying the city’s trees every 10 years. The plan is meant to be a “living document,” which the city will update every five to 10 years “based on the changing needs of Oakland’s trees, community priorities, and implementation progress.”
But how it all pans out will depend on funding. “Oakland’s urban forestry program lacks a dedicated funding source and instead relies on a variety of funds that shift and change each budget cycle,” the plan notes. The $8 million from the IRA will help get this plan started, though it falls well short of the $22.5 million the city asked for, which was intended to fund the plan’s first five years.
Just to halt the decline and maintain the current tree canopy would require planting nearly 6,000 trees per year. In its original, larger grant proposal, Oakland aimed to plant 800 trees per year in disadvantaged neighborhoods. That much money could pay for 4,000 trees over five years, still just a fraction of what’s needed. But having received much less—the grant program was overwhelmed with applicants—the city and its partners are now paring down their ambitions. “We are in the process of rescoping,” Moore wrote, and added, “We are re-prioritizing services according to equity priority.”
The city is doing so with the help of its two nonprofit partners, Common Vision and the Oakland Parks and Recreation Foundation. “Teaming up with others allows you to go further,” said Stewart, of Common Vision. “And that’s the thought that we all have in terms of this grant.”
Public to city: ‘More native plants!’
The public has had a lot to say about its trees. In the month and a half since the draft’s release, people have posted more than 800 comments on the online plan. They ask for multilingual fliers on the benefits of trees. They encourage property owners to fund street tree plantings. They request tree planting along particular streets, like International Boulevard or Fruitvale Avenue. They voice concerns over sudden oak death, and make comparisons to other cities’ tree management.
But again and again, commenters clamor for the same thing: “Please add more native plants and trees to the City of Oakland’s Urban Forest Plan!” Of the 64 trees approved by the city for public planting, eight are native species, they note. Though some commenters acknowledge the need for diverse species as the city looks toward an uncertain climatic future, most express concern over the lack of native species.
Joe McBride, a UC Berkeley emeritus professor of urban forestry, reviewed the draft. “I think more native species could be used, especially species from southern California that are more likely to do well as the climate gets warmer,” wrote McBride in an email. “I think the concern over so few native species identified in the plan is a valid concern.”
Native trees—particularly clusters or corridors of native trees and natural habitat—are important to consider because “they drive biodiversity,” according to Robin Grossinger, a scientist formerly with the San Francisco Estuary Institute’s urban forest lab who founded Second Nature Ecology and Design, an urban design consulting firm. Often, a more biodiverse natural area is a more resilient one, particularly in the face of a changing climate, and, Grossinger notes, “exposure to biodiverse nature benefits people’s health and well-being.”
Moore, the city’s tree specialist, emailed that “many of the comments about tree species are beyond the scope of the Plan” and would be most effective during the plan’s later phases. Implementation, he writes, is to be determined, and depends on the plan getting approved and funded. “The City will continue to use the most current climate research and arboricultural best management practices to choose appropriate tree species,” wrote Moore. “We appreciate so many people being interested and passionate about Oakland’s trees.”
The (ecological) work that trees do
BY THE NUMBERS
Estimated carbon Oakland trees absorb each year
100 million gallons
Estimated stormwater Oakland trees intercept and absorb
Estimated air pollutants Oakland trees remove each year
2–9 degrees Fahrenheit
Cooling effect Oakland trees can provide during summer
More than 30
Days per year Oakland temperatures are expected to rise above 86 degrees F, by the end of the century (currently under 7 days per year)
Do trees need so much attention? On the surface, they can seem like embellishments on the urban landscape, not critical in the way shelter, water, safety, and food are. But the trees that grow amid the concrete are public infrastructure, underpinning the health of our urban ecosystems—and the health of its residents. “Urban trees are the hardest working trees in America,” says Beattra Wilson, the Forest Service’s assistant director for urban and community forestry. City trees provide shade, famously—but they also sequester carbon, save buildings energy, filter stormwater, reduce runoff, and provide habitat for wildlife. (Also, “unlike other types of infrastructure that lose value, with proper maintenance the value of Oakland’s public trees actually increases over time,” as the city’s draft Urban Forest Plan says.)
As the Bay Area warms—potentially 8 degrees Fahrenheit by 2100—our urban trees will become even more important, experts say. This is especially true in areas with lots of paved surfaces where temperatures rise much higher, and heat lingers longer. “Studies have shown, if we could plant more trees in the city centers, this heat island effect will be diminished,” says McBride, professor emeritus at UC Berkeley.
Trees actually cool their surroundings, and not only by shading them. They do it by sweating, in a way; it’s called evapotranspiration. As trees draw water up from their roots, the water transforms from liquid to gas. As that water evaporates, the tree pulls in heat from its surroundings—thus cooling them—much like what happens when an ice cube melts. The water vapor exits through tiny, mouth-like openings on the outsides of each leaf, and the tree transpires.
Trees can also purify the air, removing pollutants through two different processes, McBride says. Some pollutants attach electrostatically to the surface of leaves. Some, like ozone, are absorbed through those mouth-like openings in leaves and enter the cellular spaces inside.
In studies in California and around the world, scientists have found that more urban tree canopy coverage is generally associated with healthier residents—less serious asthma, diabetes, and blood pressure, and even better social cohesion. (Though causality is hard to pin down, as MicBride and other researchers have noted. It’s possible the correlation, or some of it, can be explained by the fact that wealthier people can simply afford both better health care and more forested real estate.)
But the host of benefits trees provide are spread unevenly across our cities.
It’s no accident there are fewer trees in the flatlands
The East Bay flatlands that stretch across Oakland and Berkeley today are markedly less forested than the Oakland and Berkeley hills, tree canopy data shows. The reasons are complicated. Stewart, of Common Vision, sums it up this way: that city planners of the past “didn't seem to know to care for those communities in those places.”
Most notorious is the influence of redlining, which began in the 1930s. Stewart herself lives in one of the previously redlined parts of the flats, in Berkeley—south of Dwight Way,
“where the trees stop.” Residents living south of Dwight, mostly people of color, were denied loans and access to credit, because their neighborhoods were deemed “hazardous” lending locations. The Home Owners’ Loan Corporation (HOLC), a New Deal creation, marked such neighborhoods in red on maps—hence “redlining”—across the country, including the Bay Area cities of San Francisco, San Jose, Oakland, Berkeley, Albany, Alameda, Emeryville, Piedmont, and San Leandro. The practice standardized and legitimized the devaluation of low-income communities of color. And it discouraged investment in these areas.
In the 1950s, so-called urban renewal piled onto the flatlands. Developers seized and tore down neighborhoods they considered blighted, displacing thousands, including many Black and brown people who had moved into the area for war industry jobs. At the same time, infrastructure was routed through the flatlands. Instead of trees and parks, these neighborhoods got highways and BART lines.
More than a half-century after redlining was outlawed, its effects still shape communities—and their tree coverage. Nationwide, areas once designated as “most hazardous,” or Class D on the HOLC lending maps—like where Stewart lives—had the least tree coverage, Forest Service researchers determined in a 2022 study. In Oakland, the disparity is stark, with 57 percent tree cover in neighborhoods once deemed Class A (considered least risky lending locations), to 11 percent in the former Class D areas.
For more than a decade, the city of Oakland has been triaging its tree efforts—neither maintaining its trees nor planting new ones, and dealing just with the highest-risk tree problems. (Florence Middleton)
The city itself has found similar tree inequities across city council districts. In 2020, the city reported that District 4 residential areas—covering part of the Oakland hills—had 43.2 percent tree cover, compared to 5.3 percent in District 3, which covers more flatland areas. The flats often experience greater urban heat island effects than the more forested hills, according to Oakland Sustainability Manager Daniel Hamilton.
Fixing these inequities will take decades, Moore knows. “You can’t just plant a fifty-year-old tree,” he says. “To get the future benefits, you have to really think really far in advance.” And that time is now.
But as Natalie van Doorn, a Forest Service research urban ecologist, points out, “A budget is passed for a year or a few years—it's not on the lifetime of a tree—so there's certainly a disconnect there,” she says. “But things like urban management plans help with creating that context, of what people want to see in the urban forest … It's a good first step.”