The Bay Area's Famous Redwood Trees Are Struggling

Read the episode transcript here

There were many things Bay Curious listener Julie Menter loved about her Oakland home when she first moved there in 2017. Chief among them were the three towering redwood trees in her backyard, which Menter estimated had been there longer than the house itself.

Last year, one of the trees started to look sick. It had lost almost all of its leaves and, despite Menter watering it, it wasn’t bouncing back. So Menter and her husband decided it had to come down.

“It was so sad,” she said. “And I think it’s sad both for the tree because they’re such beautiful trees, they’re so old and majestic. But also scary to be like, ‘Whoa, this tree is not doing well, the one next to it isn’t, the ones in my neighborhood don’t seem to be doing well.’”

She’s noticed, not just in her backyard but all around Oakland, redwood trees are looking dry and scraggly.

“So I’m wondering, is something happening to the redwood trees in the Bay Area? And if so, what is it and is there anything we can do about it?”

Magical trees

To answer Menter’s question, we first have to understand why redwood trees are unique to the Bay Area. Coast redwoods — which we’re focusing on for this story — stretch up and down the Northern California coast and grow no more than 50 miles from the coastline.

“I don’t think I fully appreciated the redwoods until I went away to school and then came back as an adult,” said Deborah Zierten, an educator with Save the Redwoods League. “This was the place that I would hike to clear my head. So it is a very special place for me here.”

The quiet, cool, almost prehistoric feel of these redwood forests have provided solace to humans for millennia.

The earliest redwood trees existed more than 200 million years ago alongside dinosaurs in the Jurassic period. Their natural range has shrunk a lot in that time, however. Now they live primarily along the coast between Big Sur and the California-Oregon border.

Their range used to extend more broadly, until they endured a period of severe logging in the late 19th century. After the Gold Rush, San Francisco was booming and timber was in high demand. Millions of trees were logged and used to build homes and other structures around the Bay Area. Most of the trees here now have grown since then.

Perhaps their most identifiable feature — besides their reddish-brown bark — is their height. They can grow up to 300 feet tall, a feat that requires some teamwork.

“One of the things that makes redwoods so unique is that they actually hold hands with their roots underneath the ground, and that’s how they’re able to grow to be so tall and not fall down, is that they help each other,” said Zierten.

Their shallow but wide root systems allow them to grow to be the tallest trees on the planet. And the intertwining of their roots helps them exchange nutrients with one another. Their trunks can grow to be immense, up to nearly 30 feet in diameter.

Redwoods can live a very long time, too. In fact, some of the oldest coastal redwoods today were alive during the Roman Empire. Those stands of old-growth redwoods, which now account for only 5% of all redwood trees, can store more carbon than any other forest on the planet.

They have unique ways of reproducing. They produce seeds, like any other tree, but they can also sprout new trees from their roots.

“So, often you will find them in circles that we call fairy rings. Because if a parent tree gets hurt or injured, it will send out these baby sprouts into these circles. And it’s kind of like a little family growing,” said Zierten.

Redwoods prefer cool, moist climates, which is why they’re now primarily found in Northern California. In the summer months, when there’s a lack of rainfall, redwood trees rely on another iconic California phenomenon: coastal fog.

“It’s almost like a sponge sucking in that water,” Zierten said. “Then when their needles get full, also like a sponge, any of that excess water will drip to the ground. And it’s almost as if they’re creating their own rain.”

They’ve adapted to other characteristics of this region, including wildfires. Take the 2020 CZU Lightning Complex fires, for example, which burned through most of Big Basin Redwoods State Park near Santa Cruz. Three years later, that forest is green again and the old-growth redwood trees there are still standing strong.

Now many redwood forests — including 80% of the surviving old-growth trees — are protected either by state and local governments or nonprofits, like Zierten’s Save the Redwoods League.

New challenges

It’s not just Menter’s imagination: Redwood trees are indeed struggling across the Bay Area.

“If you look up now, in most urban areas, I think everybody can pretty much see that there’s some tops that are dying back. There’s a lot of brown foliage in the crowns of these trees,” said Todd Dawson, an environmental scientist at UC Berkeley who has been studying redwoods for decades.

One reason for that suffering is urbanization and the subsequent proliferation of concrete and pollution. Roadways and sidewalks, in particular, are impinging on redwoods’ root systems, essentially suffocating them.

“[Concrete has] a very, very negative impact on the ability of that tree to get the water it needs, get the nutrients it needs,” said Dawson.

In addition to urbanization, climate change is wreaking havoc on redwood trees’ ideal growing conditions. Coastal fog, for example, upon which redwood trees rely for water, is on the decline. In fact, since the 1950s, Dawson said, fog has declined about 30% during the summertime, when redwoods really need it.

That decline, coupled with periods of severe drought in California, is putting a lot of stress on the trees — especially giant sequoias, another type of redwood that lives mostly in the Sierra Nevada. Thousands of trees there have died due to a lack of water.

“The water deficit itself didn’t really kill all those trees,” Dawson said. “It weakened them in a way where other pests and pathogens got in there and basically wiped them out.”

In addition to a lack of water, more intense fires are also affecting redwoods. Though they have adapted to fire over the centuries, they can’t handle the extreme fires we’re seeing now caused by climate change and inadequate forest management.

All in all, Dawson said redwood forests are struggling along their perimeters. As the wildland-urban interface stretches farther and farther into the wild, redwood trees are increasingly exposed to human impacts. They’re losing their buffer.

“I think we’re going to see a patchier world,” Dawson said. “And that’s really disappointing and concerning for me because we sit at the heart of that. Humans are really the ones that are in control and are having the negative impacts that we now see.”

What can we do?

As Menter asked, is there anything we can do to save the redwoods?

As for backyard redwood trees, Dawson said irrigation might work, but it’s more of a Band-Aid solution because “the trees require so much water. They also require pretty special microclimates, meaning that they like it cooler, they like these moist, foggy summers,” he said, “and I think you can’t really recreate those conditions as a person.”

The problems redwood trees are facing now are much more systemic, said Dawson, and that’s how we should approach solutions.

One way to help protect redwood forests is by getting them in the hands of governments and nonprofits, which Dawson said is critical to ensuring the trees’ survival here in Northern California.

“The forests are just so special, these big cathedrals with these amazing, gigantic trees. There’s just nothing like that. And I think anybody who’s ever walked through a forest for the first time just is in awe of what a special place and what a special feel it has. So I’m really concerned about them and I’d love to see those forests protected in perpetuity,” he said.