California's Ancient Redwoods Face New Challenge From Wildfires And Warming Climate

Dec 8, 2020
Originally published on December 8, 2020 7:20 am

After this year's historic wildfires, California's oldest state park — Big Basin Redwoods — looks more like a logging village than an iconic hiking and camping mecca.

There's a near constant buzz of chainsaws. Rumblings from trucks and logging skidders fill the air as crews busily cut charred, fallen trees and chop down "hazard trees" rangers worry will topple on to the park's roadways.

It's estimated the wildfire, awkwardly named the CZU Lightning Complex Fire, burned through 97% of Big Basin's more than 18,000 acres, scorching its 4,400 acres of ancient redwoods and obliterating most of the park's infrastructure for camping and recreation.

"All of the historic structures in the park, totally destroyed, save one residence," Joanne Kerbavaz says. The California state park senior environmental scientist is standing in ashes and bits of charred beams. This is where a log-cabin-like visitors center and museum once stood, built by the Civilian Conservation Corps during the New Deal.

"It's truly tragic from the perspective of all of the generations of people who grew up coming here and enjoying this," she says.

Big Basin — and big swaths of California — are still recovering from historic wildfires that ravaged the state this year, displacing tens of thousands of people and wildlife, burning more than 4 million acres and killing at least 33 people. They also ripped across groves of giant, coastal, old-growth redwoods here in the Santa Cruz Mountains. And while these trees are incredibly resilient, there's concern that even they may find it harder to rebound amid the mounting impacts of climate change.

At Big Basin little remains of the historic headquarters and visitors center built by the Civilian Conservation Corps during the New Deal. Much of the infrastructure, including the nature center and campgrounds, were badly damaged by the CZU Lightning Complex Fire.
Eric Westervelt / NPR

Capturing fog drip to adapt to fire

These ancient trees are among the oldest and tallest on earth. Some are 1,000 to 2,000 years old. Redwoods capture more carbon dioxide than any other tree, and provide critical habitat for birds and scores of other species. Many of Big Basin's old growth will be just fine, Kerbavaz says. "A lot of the constituents of this forest are very much able to deal with fire."

Wildfire, of course, is a vital, natural part of forest regeneration. Burning away underbrush and built-up fuel helps replenish forest nutrients and opens paths to new growth. Redwoods have evolved to adapt. Their tall crowns capture moisture from fog, mist and low clouds, called fog drip, that helps them survive drought and infernos. Water from fog, studies show, can be more important to redwoods than winter rainfall.

But now, Kerbavaz and other scientists who study the trees worry the redwoods will face new challenges rebounding in hotter, drier conditions than they're used to, and with radically changing weather patterns.

"As the climates changes, [redwoods] could be restricted to just areas that really meet their needs," Kerbavaz says, while walking near Opal Creek in Big Basin's historic core. That would be "areas that get summer fog, that helps give them extra water, and also helps mediate the moisture loss from the temperature."

It's estimated the state's recent five-year drought killed more than 120 million trees across wide swaths of California's forests. Redwoods, experts say, survived better than many mixed conifer forests. Scientists are now tracking how California's redwoods are being affected by a warming climate, especially fog patterns past and present.

Logging crews at Big Basin are busy removing "hazard trees," including parts of giant redwoods and other tree species that fell or are at risk of falling on to park roadways after the wildfire. The camping and hiking meccas will likely remain closed for a year or longer.
Eric Westervelt / NPR

"It's the fire climate feedback that's really driving this"

The trees here at Big Basin are hardly the only ones at possible risk.

"I'm concerned that we're seeing much more of the forest impacted by these issues," says Greg Asner, who runs the Center for Global Discovery and Conservation Science at Arizona State University. "It's the fire climate feedback that's really driving this."

Asner has studied and mapped California's forests for more than two decades, flying airplanes with cutting-edge technology to track just how much water is in trees' canopies, and other key markers of environmental change.

He worries that more catastrophic wildfires, combined with warmer temperatures and the potential for ever decreased fog and rain, may be altering the playing field for California's forests.

"These issues are recurring so frequently," he says, "that the system cannot go through some sort of rebound or recovery that we all ... in Biology 101 learned about in high school."

Four years of devastating, historic wildfires, Asner says, should be a loud alarm bell for the region. To save more of the forests, he says California must dramatically expand targeted forest thinning and intentional burning.

"It's kind of like sacrificing something for the greater good," he says. "Without that, it's just all reactive, it's all putting out fire."

But how California does that at scale, across its vast forests and in the wake of a deadly pandemic, remains a huge financial, logistical and political challenge.

One silver lining, the fire this time affords forest experts a great chance to study and map how this ancient and complex ecosystem bounces back.

A few months after the devastating wildfire roared through Big Basin Redwoods, new growth is already visible across the charred forest floor and in the canopies of redwoods and other trees.
Eric Westervelt / NPR

Hopeful signs of endurance

"This is the kind of event we wouldn't wish on the park," Big Basin's Kerbavaz says. But "hopefully we're going to learn more about these trees, this forest, and how to maintain it well into the future."

We walk across forest ground blackened to a crunchy charcoal, up to what's called a "fairy ring" — a circle of towering old-growth redwoods with an opening in the middle where an even larger tree, call it a parent tree, once stood.

We gaze at trees blackened far up their towering trunks. Yet just a few months since the fire, Kerbavaz points to signs of new life.

"That looks like at least 200 feet up, there are green sprouts coming out of the stems on the side of the tree there," she says.

Elsewhere are other hopeful signposts of endurance and resurgence. At the base of a cluster of near-dead tanoak trees, 4 feet high green offshoots are jutting skyward. Huckleberry and manzanita bushes are sprouting.

Big Basin will recover, she says, but the park will be different.

"We only have about 5% of the old-growth trees that we had at the time of the Gold Rush" in the mid-19th century, she says. That makes it all the more important to protect them for the good of the larger landscape. "You can lose a few icons and still keep the forest."

Not long after the latest big fire, the 30-year veteran of the state parks went to one of her favorite spots in the woods for a little inspiration in a tough year. In a grove of old growth that had survived the blaze, she says she just stood and took in the quiet. And she watched the sunlight come through those giant trees.

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California is still recovering from historic wildfires earlier this year. A lot of them were started by lightning. They displaced people and animals. They burned more than 4 million acres, and they killed at least 33 people. The fires also burned into groves of giant coastal redwoods. Those trees are among the oldest and tallest on the earth, and they are remarkably resilient. But scientists say the trees might face new challenges coming back in a warming climate. Here's NPR's Eric Westervelt.

ERIC WESTERVELT, BYLINE: In Big Basin Redwoods in the Santa Cruz Mountains, about 97% of California's oldest state park burned. These days, one of the state's most visited places more resembles a 19th century logging village than a hiking and camping mecca.

(SOUNDBITE OF BUZZING SAW)

WESTERVELT: There's a smell of diesel and sawdust and a near constant buzz of chainsaws and logging skidders as crews busily cut up big charred trees, including some giant redwoods that fell during the fire and ones that officials worry might fall onto the park's roadways.

JOANNE KERBAVAZ: All of the historic structures in the park - totally destroyed, save one residence.

WESTERVELT: Joanne Kerbavaz, a California state park senior environmental scientist, walks through ashes where once stood a log cabin visitors center and museum built during the New Deal.

KERBAVAZ: It's truly tragic from the perspective of all of the generations of people who grew up coming here and enjoying this.

WESTERVELT: The fire also burned through the park's biggest attraction, 18,000 acres of forest. That includes damage to 4,400 acres of iconic old-growth redwoods. Many of them have stood for a thousand years or more. Along Opal Creek, Kerbavaz and I walk across forest ground blackened to a crunch up to what's called a fairy ring, a circle of towering old-growth redwoods with an opening in the middle where an even larger - call it a parent - tree once stood.

KERBAVAZ: A lot of the constituents of this forest are very much able to deal with fire.

WESTERVELT: As we gaze straight up, you see the trees in this ring blackened by fire far up their towering trunks, yet just a few months from the fire, they're also already showing signs of new life.

KERBAVAZ: Even though it is scorched, and there - I'm not so good at measuring that distance from here. But that looks like at least 200 feet up. There are green sprouts coming out of the stems on the side of the tree.

WESTERVELT: Wildfire, of course, is a vital, natural part of forest regeneration - replenishing nutrients and opening paths to new growth. Redwoods have adapted to fire. Their tall crowns capture moisture from fog and mist that helps them survive drought and infernos. But Kerbavaz and other scientists are worried that warmer temperatures with decreased fog and rain are changing the playing field for California's coastal giants.

KERBAVAZ: There are a lot of scientists who are concerned about how climate change will affect the redwood forest. As climate changes, they could be restricted to just areas that really meet their needs - areas that get summer fog, that helps give them extra water and also helps mediate the moisture loss from the temperature.

WESTERVELT: Redwoods and their larger forest ecosystems will now have to bounce back in far hotter, drier conditions than they're used to and in a landscape where drought and fires are more regular, more powerful and more damaging.

GREG ASNER: These issues are recurring so frequently that the system cannot go through some sort of rebound or recovery that we all kind of, in Biology 101, learned about in high school, you know. They're just too frequent.

WESTERVELT: Professor Greg Asner at Arizona State University has studied and mapped the health of California's forests for more than two decades, including tracking from airplanes with high-tech tools just how much water is in trees' canopies, and he says the prognosis overall is not good.

ASNER: Really, it's the fire climate feedback that's really driving this.

WESTERVELT: And the last four years of catastrophic wildfires, Asner says, should be a loud alarm. To save more of the forest, California has to dramatically expand forest thinning, he says, and intentional burning.

ASNER: That's just a must. You know, it's kind of like sacrificing something for the greater good. But without that, it's just all reactive. It's all putting out fire.

WESTERVELT: Walking through Big Basin today, everywhere there are hopeful signs of endurance and resurgence. At the base of a cluster of near-dead tanoak trees, 4-feet-high green offshoots are already jutting skyward. Huckleberry and manzanita bushes are already sprouting. Scientist Joanne Kerbavaz says this iconic park will survive, but it'll probably look different, and so might the redwoods.

KERBAVAZ: I think we can't lose sight. We only have about 5% of the old-growth trees that we had at the time of the gold rush. So we really have to work to protect those, and not just for these trees but for that forest. You can lose a few icons and still keep the forest.

WESTERVELT: Not long after the big fire, Kerbavaz - a 30-year veteran of the state parks - went to one of her favorite spots in the woods for a little inspiration in a tough year. In a grove of old growth that had survived the blaze, she says she stood, taking in the quiet and watching the sunlight come through those giant trees.

Eric Westervelt, NPR News, Big Basin Redwoods Park.

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