Earth’s Oldest Living Residents Are Threatened by Climate Crisis

December 14th, 2020 - by John Branch / The New York Times

They Are Among the World’s Oldest Living Things. The Climate Crisis Is Killing Them

John Branch / The New York Times

 (December 13, 2020) —California’s epic wildfires in 2020 took deadly aim at the state’s most beloved trees. In a relative instant, countless ancient redwoods, hundreds of giant sequoias and more than one million Joshua trees perished. The blackened wreckage sends a clear message. These trees are in the fight of their lives. “It’ll never come back like it was,” one botanist said, standing among thousands of destroyed Joshua trees. “Not with climate change.”

California’s redwoods, sequoias and Joshua trees define the American West and nature’s resilience through the ages. Wildfires this year were their deadliest test.

They are what scientists call charismatic megaflora, and there are few trees anywhere more charismatic than the three most famous species in California. People travel from around the world simply to walk among them in wonderment.

The giant sequoia. The Joshua tree. The coast redwood.

They are the three plant species in California with national parks set aside in their name, for their honor and protection.

Scientists already feared for their future. Then came 2020.

The wildfires that burned more than four million acres in California this year were both historic and prophetic, foreshadowing a future of more heat, more fires and more destruction. Among the victims, this year and in the years to come, are many of California’s oldest and most majestic trees, already in limited supply.

In vastly different parts of the state, in unrelated ecosystems separated by hundreds of miles, scientists are drawing the same conclusion: If the past few years of wildfires were a statement about climate change, 2020 was the exclamation point.

This past summer in the Sierra Nevada, a fire ecologist named Kristen Shive camped in one of the few remaining ancient groves of giant sequoias, among trees as old as the Bible. This fall she revisited the grove, and stood somberly among the dead.

“They’ve lived through literally hundreds of fires in their lifetimes,” Dr. Shive said. “Now we’re seeing them killed in one fell swoop.”

To the south, Drew Kaiser, a botanist, hiked through what had been one of the largest remaining stands of the Joshua tree, the otherworldly yucca, in the Mojave National Preserve.

Historically, the desert is not a place prone to rampaging wildfire. But Mr. Kaiser beheld a colorless moonscape dotted with the skeletal remains of collapsing Joshua trees. He estimated that 1.3 million had been destroyed in a single blaze in August.

“I love Joshua trees,” Mr. Kaiser said. “I can’t stand to see them go.”

Far to the north, near the Pacific Ocean, an environmental scientist named Joanne Kerbavaz inspected old-growth redwoods, the tallest trees on earth. She has been coming to Big Basin Redwoods State Park to roam the forests since she was a little girl.

“The smell of redwood in the summertime was the aroma of my youth,” she said.

In August, fire swept through 97 percent of the park, home of 4,400 acres of old-growth redwood trees. When Ms. Kerbavaz returned in November to clamber through the destruction, all sense of timelessness and continuity had been rearranged.

“The forest I saw as a kid will not be back for some time,” she said.

Giant Sequoias

Joshua Tree

Coast Redwood

The enchantment that California’s forests provoke can be scientific or spiritual. For the state’s three famous plant species, it is probably both. The allure stems from each one’s unique blend of size, shape and age. Their heft, their height, their persistence. Their sheer audacity.

They are never found together. Yet they share an uncommon ability to silently stand there and elicit a reaction — gasps, giggles, photographs, memories. How many other trees can attract a crowd?

Resiliency is key to their magnetism. They survive where others would not. They stand their ground, with panache. Sequoias and redwoods can live thousands of years on their way to dwarfing most everything around them. Joshua trees are the most good-natured of desert plants, frozen in dance poses as they endure the harshest of environments with flair.

They have a timeless quality that can make their onlookers feel small and impermanent by comparison, the way a night sky does to stargazers. We know they will outlast us.

That is why 2020 is particularly alarming. Each of these species already faced a rising onslaught of threats to long-term survivability, from drought to development, blanketed by the unknowable future effects of climate change.

But this year’s wildfires, fueled by a century’s worth of forest mismanagement and the quickening pace of global warming, threatened them like never before.

“Fire behavior is always, always, a product of fuels, weather and topography,” Dr. Shive said. “And we’ve had very excessive fuels and we are turning up the thermostat. So we’re really setting ourselves up.”

While there is not broad concern about any of the species going extinct — yet — 2020 injected a new sense of urgency.

Rather than lose one or two “monarch” sequoias in a year to old age, hundreds or thousands have been wiped out at once. Rather than the slow, almost imperceptible migration of the Joshua tree toward higher latitudes, more than a million were consumed in two days.

These losses, and the losses likely to come, are not something to be measured in mere acres. These are not mere numbers, not mere trees. To those who come from around the globe to bear witness, and especially to those in California, they represent something both bigger and more personal.

“Losing them changes the identity” of revered expanses of the American West, said Tadashi Moody, an environmental scientist for the California Department of Forestry and Fire Protection. “It changes our relationship to those places.”


SEQUOIA CREST, CALIF. — Until a few years ago, about the only thing that killed an old-growth giant sequoia was old age.

Not only are they the biggest of the world’s trees, by volume — the General Sherman Tree, considered the largest, is 36 feet in diameter at its base and 275 feet tall — they are among the oldest. At least one fallen giant sequoia was estimated to have been more than 3,200 years old.

They last so long that, historically, only one or two of every thousand old-growth trees dies annually, according to Nate Stephenson, a research ecologist for the United States Geological Survey.

Fire always was a frequent visitor to sequoia groves, but rarely a threat. Mature sequoias are virtually fireproof because the bark can be several feet thick. The crowns, the top where branches and needles are, are so high that they stayed above the fray of fire, out of harm’s way.

Until now.

Dr. Stephenson was home in Three Rivers, Calif., this summer as the Castle Fire raged in the nearby mountains. Ash and debris fell from the sky, big enough to be identified.

“I could go, ‘Oh, there’s a fir needle, that’s incense cedar, that’s oak, that’s a pine,’” Dr. Stephenson said. “Then I saw a piece of giant sequoia ash, and that really drove it home. I thought, ‘Oh, no, I bet some of those sequoias, their crowns are burning.’”

Since 2015, nearly two-thirds of the roughly 48,000 acres of giant sequoia groves have burned — about half of that since August. The amount of groves burned in the past five years is double what had burned in the previous century.

But it is not just the number of fires or acres they consume. Fires are burning bigger, hotter and higher than ever. A historic drought from 2012 to 2016 and huge infestations of bark beetles killed millions of trees in the mixed-conifer forests of the Sierra Nevada, leaving them behind as kindling.

Within those dying forests are the remaining giant sequoias, in roughly 70 groves speckled in the California mountains, rooted in the fray. Today’s fires are so big, so hot, that they can create their own weather systems, whipping up fire-spreading winds and creating columns of heat and smoke tens of thousands of feet high.

“The apocalyptic chickens are coming home to roost, way sooner than we thought,” said Christy Brigham, the resource manager at Sequoia and Kings Canyon National Parks, home to dozens of the remaining sequoia groves and many of the biggest trees in the world. “We are seeing impacts now that we thought we would see in 50 years.”

The Stagg Tree, considered the fifth-largest tree in the world, was saved this year, perhaps by sprinklers.

In some ways, sequoias depend on fire. Their egg-sized cones are glued shut by resin, and extreme heat from fire dries them out and spreads seeds, like flakes of oatmeal, across the forest floor.

In the centuries before California was settled, scientists believe, about 4 million acres burned in a typical year, mostly in tiny freckles across the landscape — including in sequoia groves. They were a combination of natural fires that generally burned themselves out and prescribed fires managed by indigenous people.

Researchers studying a 1,400-year history etched into the rings of tree cores found evidence of fires at least every 30 years among sequoias. The forensic evidence stops about 100 years ago, as fire became seen as a threat to be suppressed, not part of a cycle to be managed. The forests thickened.

There is consensus among scientists that California must, in part, burn its way out of the current predicament with more prescribed fires — controlled, low-level burns designed to prevent catastrophic blazes later. But setting fires intentionally is a sticky undertaking, given all the jurisdictions and the landscapes crowded with people.

“We probably are never going to get back to 4 million acres of healthy, wonderful fire each year,” Dr. Shive said. “But we need to pick priority areas.

Bark beetles have killed millions of trees in the West. Now they are being found in giant sequoias, an ominous sign.

Prescribed burns are easiest, though not easy, in remote locations like national parks. Sequoia National Park, the nation’s second-oldest, has been doing them since 1968, longer than any national park in the West.

The program was long considered a model of forest maintenance, at least before this year’s fires devoured parts of the national park. Now, the few hundred acres of prescribed burns in a typical year have proved little match for today’s megafires.

“Now, I’m like, ‘Dude, that is not good enough — we need to rethink this whole thing,’” Dr. Brigham said. “If we can have 16,000 acres of sequoias burn up in a wildfire in a single year, we cannot go 200 acres at a time. It’ll be all burned up in uncontrolled wildfire before we’re done.”

On a late-October afternoon, Dr. Stephenson toured a grove that included the General Grant Tree, the world’s third-largest. A wildfire swept through a portion of the grove in 2015, after park officials had prescribed a burn to one side of a hiking trail.

That trail now serves as a stark dividing line. On the side that had been recently burned, just one of the 111 old-growth sequoias was killed. On the other side, about 30 percent of the large sequoias were dead, along with most other big conifers.

“Prescribed fire is so good at reducing damage when wildfires come,” Dr. Stephenson said.

Dr. Stephenson said that giant sequoias can suffer 90 percent “crown scorch” — extreme heat that does not consume the needles, but turns them brown and lifeless — and still survive. What is killing the trees now, he and others said, are flames that reach the crown at the top — torching the crowns, like a giant matchstick.

Damage is mounting.

In 2017, fire swept through the Black Mountain Grove in Sequoia National Forest, killing nearly a third of the 183 old-growth sequoias that were surveyed. About the same time, a nearby blaze killed almost half the 104 mature sequoias in the Nelder Grove.

The starkest example in 2020 might be in Alder Creek Grove, one of 19 groves to burn this year. It is home to 483 ancient sequoias with a trunk diameter of six feet or more, among them the Stagg Tree, thought to be the fifth-largest in the world.

Alder Creek had been the last major stand of sequoias in private hands. The Save the Redwoods League, founded in 1918 to protect redwood forests (and, increasingly, sequoias), bought the 530-acre grove for $15.7 million just last year.

Giant sequoias share the forest with other large conifers, often dwarfing them, and historically stayed above the fray of most fires. That has changed.

Dr. Shive, the league’s chief scientist, spent much of this year surveying the rugged property and pondering the grove’s long-term health.

In September, the Castle Fire crept nearby, paused on a ridge, and swept through in a matter of hours.

In October, Dr. Shive wandered through blackened parcels, counting dead old-growth sequoias. There were at least 80, and some areas had not yet been surveyed. Across the range of giant sequoias, this year’s death toll could be in the thousands.

The Stagg Tree survived, perhaps in part because firefighters had hastily run hoses and turned on sprinklers at its base. But it will take more than sprinklers to fight off the likely destruction to come to the giant sequoias.

“They are literally irreplaceable,” Dr. Shive said. “Unless you have 2,000 years to wait.”


MOJAVE NATIONAL PRESERVE, CALIF. — On the August day when fire broke out on Cima Dome in the Mojave National Preserve, the California desert already was making international headlines. The thermometer at nearby Death Valley had reached 130 degrees, the highest temperature reliably recorded on Earth.

As photos of tourists smiling at the thermometer ricocheted around the world — a paradoxical bit of gee-whiz glee on a day portending a dire future — a million Joshua trees were on fire.

Cima Dome is a broad mound, a gentle and symmetrical arc on the vast desert horizon. It is visible from the interstate connecting Los Angeles and Las Vegas. Scientists considered it home to the world’s densest concentration of Joshua trees.

“To the untrained eye or the person not familiar with this region, most wouldn’t even notice it as they go by at 90 m.p.h.,” said Todd Esque, a desert ecologist for the United States Geological Survey. “But for those who do know, this is a huge loss.”

Joshua trees — a yucca, not a tree, named by Mormon settlers — already teeter toward trouble. Their range is shrinking, and they are not well-suited to outrun the quickening pace of climate change. Scientists worry that future visitors will find no Joshua trees in Joshua Tree National Park, the way some worry that Glacier National Park will be devoid of year-round ice.

“It’s a possibility,” Dr. Esque said.

Now wildfires, scarcely a threat historically, are taking out huge swaths at once, aided by climate change and invasive grasses.

The Dome Fire consumed 43,273 acres and killed most of the estimated 1.3 million Joshua trees it burned, according to Mr. Kaiser, the vegetation program manager for Mojave National Preserve.

“Cima Dome was a model for where the Joshua tree could persist for the next 100 years,” Mr. Kaiser said. “It was a beautiful, lush, decadent Joshua tree forest. But they’re wiped out.”

While there are plans to replant the millions of dead with thousands of young Joshua trees, “It’ll never come back like it was,” Mr. Kaiser said. “Not with climate change.”

Joshua trees can grow more than 40 feet tall with spiky, Seussian eccentricity. They typically live about 150 years.

But their range is shrinking faster than the trees can spread to more livable climes — higher in elevation and latitude, generally. The species is thwarted by slow migration (their large seeds, once transported by ground sloths that are now extinct, do not travel far from where they fall) and the overall population appears to be aging. Even at Cima Dome, there were relatively few young Joshua trees.

 “Once you get an adult Joshua tree, they’re somewhat impermeable to anything but fire and bulldozers,” Dr. Esque said.

Those are persistent threats, too. Humans chop down Joshua trees to make room for neighborhoods, roads, even solar farms. And with Joshua trees often sharing the landscape with ranching, invasive grasses are fueling more fires than ever.

While the Dome Fire was shocking in its scope and ferocity, it was not surprising to the scientists who know the area best. “This was just a fire waiting to happen,” said Debra Hughson, chief of science and resource stewardship at Mojave National Preserve.

For more than a century, until 2002, cattle grazed on Cima Dome. Among the legacy of livestock is invasive perennial grasses like red brome. Weirdly, though, those same grasses may have helped the Joshua tree flourish.

Young Joshua trees need a nurse plant to hide under, and the prickly, woody blackbrush — unappetizing to livestock — is a perfect partner. As cattle chomped on grass, leaving vegetation sparse enough to prevent potential fires from spreading, Joshua trees took hold on Cima Dome more than in other places.

 “A lot of what we were calling a year ago ‘the largest and densest Joshua Tree forest in the world’ probably didn’t exist in the early part of the 20th century,” Dr. Hughson said.

And after cattle were banned, and the invasive grasses grew uninterrupted, “It was just waiting for a spark,” she said.

The spark came in August, with a lightning strike. With resources stretched because of so many other California fires, the Dome Fire spread uncontrolled. It jumped from Joshua tree to Joshua tree and across park roads and fire lines, fueled by winds that became swirling firenados.

In two days, the blaze had done almost unimaginable damage.

“I was preparing myself for the worst,” Mr. Kaiser said as he toured the burn area. “And it pretty much was the worst.”

One of the densest remaining stands of the charismatic yucca species “was just waiting for a spark,” one scientist said. It came, in an August lightning strike.

In late October, in spots that the fire did not reach or somehow missed, the desert grasses were the yellowed hue of fall. Unaffected green-spiked Joshua trees stood in kooky stances.

But from atop Teutonia Peak, a rock outcropping that rises above Cima Dome, the view was bleak. Most of the landscape was charred gray for miles in every direction. Tiny cars and trucks slithered on the interstate far in the distance, a dozen miles downhill. A sea of blackened Joshua trees, stripped of life, stood over the desert floor.

Life has a way of hiding in the desert, and a close examination revealed signs of green life poking through the sand. But a million Joshua trees will never rise again.


BIG BASIN REDWOODS STATE PARK, CALIF. — Signs of hope can be hard to spot in the devastation of forest fire, but they come color-coded.

They were there in Big Basin park, among the old-growth coast redwoods torched six weeks earlier.

Redwoods, the tallest of earth’s trees, are the rare conifer that can resprout after catastrophic events, a secret weapon to longevity. Killing one with fire is difficult.

But it is not impossible.

Here and there, during a tour on a sunny November day, the emerald green of new growth poked out of the soil at the base of blackened trees that might otherwise be dismissed as lifeless. Some inspections required a skyward gaze to see upper branches already fuzzy with green sprouts, like Chia Pets.

Ms. Kerbavaz came across one giant called “Father of the Forest.” Redwoods can live 2,000 years, and this one was black to the top. But about 200 feet up, there were signs of life.

“It’s got green,” she called out to those climbing through the thicket behind her. “It’s not dead yet.”

Still, plenty of towering trees offered no such signal. The hope is that somewhere near 90 percent of the old-growth trees will live. But that means 10 percent were lost.

“If anything is programmed to survive, it’s the coast redwoods,” Ms. Kerbavaz said. “But I keep coming back to climate change. I think that’s the thing that changes the ground rules significantly.”

The extinction of redwoods is hard to imagine, with a cool, soggy range still measured in the millions of acres. The fear is for the relatively few remaining old-growth trees.

An estimated 95 percent of them were chopped down, mostly to fuel California’s building booms in the late 1800s and early 1900s. And while those that remain are mostly protected in places like national and state parks — Big Basin was California’s first state park, in 1902 — fire is the latest wildcard to their future.

“We only have 5 percent of the range left in old growth, which is so little,” Dr. Shive said. “Yes, they can sprout back, but how much can they take?”

In the Bay Area this year alone, she said, close to 10 percent of remaining old growth was burned. “And that’s one fire.”

The coast of northern California was long thought to be relatively immune to the kinds of fires now ravaging the state on an annual basis, with its misty forests, cool ocean breezes and midsummer fog. But recent fires, like the one that burned most of Big Basin Park, shattered whatever illusions of safety and distance remained.

Trees in Big Basin State Park were severely scorched, but green shoots raise hopes for survival.

“Suddenly, fire is part of the conversation in ways that it hasn’t been before,” said Lenya Quinn-Davidson, area fire adviser for the University of California Cooperative Extension, who lives near Redwood National Park.

The redwood, unlike its splintery cousin, the giant sequoia, is prized for its hard wood. The range has shrunk in the past 150 years from an estimated 2.2 million acres to 1.6 million acres. Some two-thirds remain in private hands, unprotected. Some is still harvested for timber.

The Save the Redwoods League was founded a century ago to try to stop the cutting of old-growth trees. The group eyes groves it wants to protect, raises money to buy them, and shepherds them to public parks and preserves.

With most old-growth trees in public hands, the mission increasingly involves purchasing younger redwood forests around them, creating a protective “buffer,” said Sam Hodder, the league’s president.

“We’re doing what we can to put those forests on the trajectory to be the old-growth forests of the future,” he said.

The goal, Mr. Hodder said, is not to turn old redwood forests into outdoor museums, but to maintain a range of vital ecosystems, partly as a hedge against climate change. Redwoods and sequoias, he said, “store more carbon per acre than any other forest system in the world, by a long shot.”

Research has indicated that there have been centuries of regular fires in redwood forests, sometimes every decade or two and most likely set by indigenous people looking to occasionally clear space for other plants. It is unusual to find an old-growth redwood without obvious fire scars at the base.

Redwoods, unlike their cousin the giant sequoia, can resprout from their roots, a key to their regeneration.

As if to provide more proof of its resilience, even when a redwood is chopped down it is not always defeated. Dead redwoods often sprout several more trees around the stump, a “fairy ring” that defines second-growth forests.

But those next-generation forests have less fire tolerance than old-growth forests, with their lower canopies and thinner bark.

And since redwoods share the forests with a broad range of species, from deciduous oaks to Douglas firs, the land can be thick with vulnerable trees and underbrush — potential fuels that can feed ever-bigger blazes.

Among the growing concerns is sudden-oak death, creating the potential for more deadwood to burn among the redwoods, not unlike the drought-stricken fallen pines now fueling fires in sequoia groves.

“Like a lot of California, our redwood forests are pretty departed from their historical condition and their more fire-resilient conditions,” Ms. Quinn-Davidson said. “All this brush, the understory, all the thick duff and fuels — I don’t think that’s what they looked like, historically, when they had more frequent fire.”

Big Basin may look that way in a few years. It is a wildly popular park, within a two-hour drive of millions of people, but likely will remain closed for at least another year until it is deemed safe for tourists to return.

As Ms. Kerbavaz surveyed the heart of the park recently, climbing over fallen trees and practically spelunking into smoldering stumps, the buzz of distant chainsaws was punctuated by the occasional whomp of falling trees, deemed too weak to leave standing, near Highway 236, the scenic two-lane that cuts through the park.

Ms. Kerbavaz was among those desperate to save as many as possible, unsettled by the idea of losing 1,000-year-old trees to the whim of a road worker. One in particular she wanted to keep, not realizing how close it was to collapse.

“I was pleading for more time to assess,” she said. “And within a week it had fallen down.”

Near the burned-out headquarters of Big Basin is a loop trail through some of the park’s biggest redwoods, a path made largely impenetrable by the fallen trees.

Somehow, a sign at the trailhead survived.

“The Amazing Ever-Living Redwood Tree,” the sign read.

The tree behind it had burned and toppled.

“Almost fire-proof!” the sign declared.


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