Dense tree barriers to cut air pollution are coming to West Oakland

Art Garden Design, the landscape designer that will oversee the planting, will, for the next few weeks, remove old trees, upgrade irrigation, and regrade the site. In March, workers will start planting trees. The project is expected to be completed within five months.

According to Alana Corpuz, the owner of Art Garden Design, Frontage Road is an example of broken infrastructure caused by neglected maintenance. All kinds of activities nearby cause air pollution.

“There’s waste management on 10th Street nearby, a skate park, trash, and people burning metals and there’s so much else happening, but the goal is to create a tree buffer with depth that reduces off-gassing for the community,” she said.

Hyphae Design, an ecology firm in Oakland, designed the tree planting project with foliage from the ground up so that it creates a canopy of leaves and branches where a good amount of pollution gets stuck or drifts up into the atmosphere without coming back down into neighborhoods. The tree species that will be added include fern pines, long leafed yellowwoods, and Japanese blueberry trees, and the shrub species will include California lilacs, manzanitas, and bottlebrushes.

Brent Bucknum, Hyphae’s director, told The Oaklandside that their research has found that the dense planting pattern can reduce between 20% to 40% of roadside pollution. That’s much more than the 1% to 4% drop in pollution seen when trees are randomly placed and separated from one another. Bucknum said that the tree plantings they’ve installed in Louisville have already led to 25% drop in air pollutants.

The project will clean the air even as more of California’s vehicle fleet transitions to electric power. That’s because some of the worst pollution comes from ultrafine particles from brake and tire wear.

“We’re learning that really fine particles are more impactful health-wise because they move through the blood-brain barrier and through the lungs,” Bucknum said. “A lot of people want to just blame the trucks, but it’s actually passenger vehicles and the number of them that are going by this location in West Oakland that has a bigger impact.”

The project, which is a pilot and part of a larger plan to surround all the highways and major thoroughfares in West Oakland with trees, could eventually expand to other highly polluted parts of the city and San Leandro.

The Prescott Greening project includes three different components, the first of which is the Frontage Road planting. If they get more funding, said Bucknum, the teams will work on greening alongside Caltrans land next to the I-880 highway. Dense tree plantings would then become part of road diet construction projects, when major roads have vehicle lanes and parking reduced while pedestrian and bike infrastructure expands.

A decade-old vision of using trees to scrub the air

West Oakland has had polluted air for a long time, dating back to the turn of the 20th century, when it was a key hub for the growing shipping, manufacturing, and transit industries. But starting about 70 years ago, residents started suffering from even higher levels of pollution when highways were built around them and the port underwent rapid expansion.

In the early 2010s, Bucknum’s firm, Hyphae Design, worked with the West Oakland Environmental Indicators Project for years on lead remediation and then developed a “master plan” focused on the potential of re-greening Oakland to reduce pollution, called Adapt Oakland.

But at the time, the technology at their disposal to understand the scope of West Oakland was not very sophisticated.

“We used one or two air pollution sensors from the port,” he said. “But we did this extensive study, and we started to understand that especially depressed areas and sunken areas can collect air pollution, like sunken freeways or on-ramps. So then we did a lot of research that proved some of our hypotheses.”

The group eventually raised its tech game, using lidar technology to find out how many trees were actually present in the neighborhood and then using computer modeling to gain a deeper understanding of how wind spreads or concentrates pollution. The modeling was especially valuable because they could game out many different greenery scenarios.

They eventually found that the 7th Street and Frontage Road interchange, a few feet from I-880, was a major source of pollution entering the Prescott neighborhood. When they looked at a cancer study by Kaiser Permanente in the same area, which focused on residents of a senior housing complex, they found a correlation between emissions and poor health. This likely convinced funders such as the Metropolitan Transportation Commission, the Alameda County Transportation Commission, the Port of Oakland, and the Sustainable Transportation Equity Project to support the tree planting project.

“It showed that the people right next to the freeway were far worse off than those even two or three blocks away in the neighborhood,” Bucknum said.

“It’s like if you were standing in front of a sprinkler in a lawn and you were standing right next to it, you would block the water from hitting people, but if you were just standing really far away, not so much,” said Mei Visco, the Hyphae designer running the pollution models on the project. “It’s kind of a similar thing with pollution particulates,” she said.

Bucknum said they are writing a report that they hope to publish in the spring. In it, they will argue that with $20 million they could significantly expand the project to reduce a large amount of the pollution affecting West Oakland. The report will be presented to Oakland, the port, and the county transportation commission.

It might also include an explanation about how to deal with pollution that is coming from freeways that are elevated. A bigger canopy could help filter, block, and push up pollution into the atmosphere and away from communities.

Like roads, trees will need routine maintenance

As with many infrastructure projects, Bucknum and Visco say consistent maintenance of the greenery may be the most important part of maximizing its potential. And sometimes it’s the cost of that commitment that trips up great-laid government plans.

“We’ve been trying to say to Caltrans that they’re building freeways in environmental justice neighborhoods and so they need to invest in maintenance differently in these areas than they do in other areas,“ he said.

And it appears that the state agency is listening: Hyphae confirmed they are in conversations with the state about similar projects in Stockton and Los Angeles. They are also modeling the costs of possible endowment funds that would allow communities to maintain their greenery.

In the meantime, Hyphae and Art Garden Design are developing the three-year maintenance plan for the Prescott Greening project with Wood Street Commons, the West Oakland nonprofit, for regular, weekly volunteer cleanup.

“If we want to be able to have a better future, a cleaner future, if you want to be able to prevent pollution from getting to people, to lower the heat island, you have to take care of the trees,” Visco said.

This story was originally published by The Oaklandside and distributed through a partnership with The Associated Press.