San Diego Has Made Little Progress Growing Its Tree Canopy, And Its Tree-Planting Goals Are Only Getting Steeper

By Emily Busam, the Voice of San Diego

November 14, 2022

In a Facebook group for San Diego moms, conversation recently buzzed about the lack of shade at playgrounds. Moms chimed in about the uncomfortably hot temperatures at playgrounds and concern for children playing in areas with high temperatures and direct sun.

“I have a history of skin cancer in my family, so being wise about sun exposure is really important to me. Playgrounds and picnic areas seem like the most logical places to add shade,” said Erica Keller, a local mother of two.

But San Diego’s missing tree canopy— a major contributor to the lack of shade— is not just a matter of child’s play.

San Diego residents, public health officials, and sustainability experts have all raised concerns about the lack of trees across the city, citing health risks like heat stroke and skin cancer, as well as climate resilience concerns as the planet continues to warm.

The city committed to expanding its tree canopy coverage — which are the leaves, branches, and stems that provide the tree coverage of the ground when viewed from above — in the 2015 Climate Action Plan, with a goal to grow the canopy from 13 percent to 15 percent by 2020. Seven years later they’ve made almost no progress. Tree canopy coverage remains at 13 percent. In some areas, like Barrio Logan, coverage is as low as 1 percent.

In the updated 2022 Climate Action Plan, the city set even more ambitious goals. Over the next eight years, it aims to more than double its tree canopy coverage – from its current 13 percent to 28 percent. By 2035, the plan calls for 35 percent coverage, requiring roughly 100,000 new trees— approximately 8,300 per year. By comparison, the city planted about 1,600 trees in 2019.

The city is now drafting an implementation plan that outlines the actions and funding necessary to enact the 2022 Climate Action Plan. Anthony Santacroce, a city spokesman, said that would spell out how the city could reach its new tree canopy goals.

The city shouldn’t struggle for funding and support for tree planting. Six of the nine Council members prioritized additional funding for tree planting in their budget priorities report this October, and the state’s Department of Forestry and Fire Protection, CAL FIRE, has dramatically increased grant funding available in its Urban and Community Forestry Grant Program–from $29 million to $167 million. The city is awaiting guidelines to determine if that funding could augment tree planting efforts, Santacroce said.

“Expanding our urban tree canopy is not only critical to meeting our emissions reduction goals, it is also a priority for protecting public health as we see increasing heat events due to climate change,” Dave Rolland, a spokesman for Mayor Todd Gloria, wrote in a statement. “Trees were also ranked as one of the highest priorities for residents of underserved communities through engagement on the Climate Action Plan.”

Yet tree planting is still mired in logistical and environmental challenges that could thwart the ambitious Climate Action Plan goals, including a lack of maintenance, limited water resources, and little green space for trees to be planted.

To see maximum benefits, a tree must be at least 40 years old — but the average tree lifespan in southern California is just 7-9 years, city arborist Kurt Peacock said. Short-term funding that doesn’t focus on nurturing trees to maturity contributes to this short life span.

“The city can talk all about planting trees, but after three years, they historically have not been obligated by funding sources to care for trees,” Peacock said. “It’s not enough to install a tree. If we don’t water, it’s all for naught. And it can’t just be the first 3-5 years of a tree’s life. To see trees grow and thrive and reach their full potential, it’s an ongoing commitment that goes on for the whole life of the tree.”

Before the city can allocate resources to tree maintenance, it has to find somewhere to plant them. With much of the city already developed, though, there’s little room for mature trees to be part of the urban landscape. These urban landscapes are where the urban heat island effect, which can cause temperatures to rise as much as 20 degrees according to the NOAA, pose the greatest health risk for vulnerable populations, like the unsheltered.

“Access to shade is part of a harm reduction approach for the unsheltered population,” said Jeffrey Norris, chief medical officer at Father Joe’s Villages, a city homeless shelter. Norris said during extreme weather events, the unsheltered population is at increased risk of health complications and mental stress.

Further, the city’s control of the canopy is limited to public property, which only accounts for 60 percent of the trees in San Diego. Planting trees on private land is essential to meeting Climate Action Plan targets, but finding people and organizations committed to the lifetime care and maintenance of a tree has been difficult, Peacock said. Additionally, 53 percent of households in San Diego are occupied by renters, who are generally unauthorized to plant trees or too transient to keep up with maintenance.

Lastly, water expenses and drought conditions preclude many residents from considering planting a tree, or properly caring for a tree once it’s in the ground, according to Tree San Diego, a nonprofit group focused on increasing San Diego’s urban forest. But Peacock said these concerns may be overblown because young trees need less water than most realize, especially with the proper selection of drought-tolerant trees and irrigation systems.

For parents concerned about their children’s wellbeing, there may still be hope on the horizon.

Of the upcoming $167 million available in grant money through CAL FIRE, $117 million will go towards the greening of schoolyards, according to a CAL FIRE spokeswoman.

As for overcoming logistical and environmental challenges and meeting the lofty Climate Action Plan goals?

“We might have to break some cement,” Peacock said.

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