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To me there’s something special about native California oaks, the big gnarly ones with thick bark and drooping branches. You know the trees I’m talking about; the ones that stop you in your tracks, forcing that involuntary, mouth-gaping stare — the neck benders.

Lately, I’ve been on the hunt for these “Specimen Trees” in the urban area around our neighborhood as we shelter in place and do our part to help flatten the curve. I’ve needed time outside more than usual (as I’m sure you have too), and spending time with these large, urban oaks has been my wild refuge. Not only do these trees provide a much-needed sense of calm for me, they serve as habitat for many species that find refuge among their branches.

Towering above a suburban home, this valley oak provides refuge for a range of wildlife and opportunities for passersby to ground themselves to something distinctively Californian.

A Look Back in Time

When standing at the foot of these giants, it’s fun to hit the imaginary rewind button — to speed a few hundred years back in time and try to picture what things must have been like back in the day. I can imagine hulking California grizzly bears (now extinct but still prominently displayed on the state flag) at the base of the then young oak sapling, gorging on a crop of fresh acorns. And, in the distance, the sounds of a faint, rhythmic thud as Ohlone women smash the same precious fruit into flour.

Can you see it?

The acorns from California’s native oaks were a staple food source for Ohlone people, who actively managed the landscape to ensure the abundance of this crop. Fire was their main tool, and they regularly burned the areas around these trees to stimulate the soil and increase the production of acorns. It’s been a radical realization for me to see these old oaks as not only large specimens that are nice to look at, but as living relics of an ancient, agrarian civilization.

Historic postcard of large oak in San Jose, CA
A postcard from the early 1900s highlights a valley oak tree in what is now San Jose, CA. | Courtesy California Room, San Jose Public Library

Vital Habitat for Wildlife

It’s not just humans that appreciate these giants in our backyard. The oak’s acorns are a favorite for many native species, like California ground squirrels, scrub jays, black-tailed deer and acorn woodpeckers. And, in turn, oaks indirectly sustain species that prey on animals that consume acorns, like pumas, sharp-shinned hawks and gopher snakes. Suffice it to say, they are the essential sustenance nourishing the base of the food chain.

The more I’ve learned, the more I’ve started to see our urban oaks as islands of native habitat, standing tall like giant invitations for wildlife seeking refuge in an otherwise hostile landscape. And there’s more to it than just producing acorns. Their physical presence alone is enough to help sustain life. For example, their dense canopies provide safe cover for birds, and the dead limbs are used as nesting cavities. Oaks also create large amounts of leaf litter that help nourish the soil. Even their downed branches serve as cover for wildlife. They are, quite literally, living refuge.

Acorn woodpecker perched on an ancient California oak
Acorn woodpeckers live in family groups called “clans.” They work together to hoard acorns in the hundreds by wedging them into small holes they’ve made in the sides of trees and telephone poles. Photo: Teddy Miller

It should come as no surprise to hear that oak woodlands are one of the most diverse habitat types in California, with over 300 species of wildlife, 370 fungal species and almost 5,000 insect species found within them at some time during the year. These trees are magnets for life, and that holds true for the ones standing in our urban areas as well.

So as important as it is to protect our vast wild landscapes, it is also important that our urban areas offer refuge for wildlife, especially in the face of climate change as species are forced to move to find what they need to survive. Our urban oaks, no matter what the future holds, will play an important role in our urban landscapes as the drought tolerant, carbon sequestering champs that they are.

Bringing More Oaks to Our Communities

You’ll be happy to hear there’s movement afoot to “re-oak” Silicon Valley through community and private property plantings lead by our partners at the San Francisco Bay Estuary Institute. We’re lucky to have them on the job, as reintegrating oaks within our communities can provide benefits to both people and wildlife.

On my most recent neighborhood walk, my family and I opted for a longer route through previously undiscovered territory. We passed one small yard bursting with native flowers and swarming with pollinators. Centered in the middle of it stood a small valley oak, planted by the family in defiant testament to the typical suburban lawn and as part of the next generation of urban oaks that will help ground us to this place, its history and the wildness of California.

About Post

Peninsula Open Space Trust (POST) protects open space on the Peninsula and in the South Bay for the benefit of all. Since its founding in 1977, POST has been responsible for saving more than 79,000 acres as permanently protected land in San Mateo, Santa Clara and Santa Cruz counties. Learn more

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