The road to Mariposa Grove — one of the most iconic spots in Yosemite National Park — climbed gradually, 100 feet in half a mile. Giant sequoias dotted both sides of the road as it snaked deep into the Sierra Nevada Mountains. Their bark, roped like a carpenter’s forearms, wound up, up, up, as much as 300 feet. Their trunks were wider than a dozen people could hug.
“That is the biggest living thing I have ever seen,” I told my friend and hiking companion, Andy, as we stopped to catch our breath. We kept going, trudging through snow that closed the road to vehicle traffic. “Wait a minute,” I said. “That is the biggest …”
Soon we arrived at the grove itself, and those giant sequoias were everywhere, roughly 500 of them, as if we followed a smattering of rose petals and then found a whole pile. Clear blue sky peeked through the tree cover. Snow captured by branches high above jostled loose and fell upon us. Ice crystals floated down and disappeared upon silent impact with the snow, except for when they detonated on my hat, and — OOH! — splattered on my neck. The shin-deep snow along the trail sparkled as if laced with glitter.
Mariposa Grove radiated with beauty and felt ancient; Grizzly Giant, the most famous tree here, dates back 3,000 years. For a moment, I lost myself in the grandeur and forgot why I had come: to look for signs of climate change.
Those signs were everywhere once I paid attention. Dead trees, stiff and white like bleached skeletons, lined the road into and out of the grove — killed by a California wildfire. Across the western U.S., the number and size of wildfires are ever-increasing, due to greater heat and extended droughts caused by climate change.
I could also see evidence of what park stewards are doing to blunt the damage that climate change creates: scorch marks on trees from controlled burns, the absence of deadwood (removed to prevent fires from getting out of control), and the emergence of shrubland, replacing mixed conifer forests after fires. These are all part of the National Park Service’s climate strategy: “resist, accept, direct.”
For much of its 107-year history, the park service followed a philosophy of keeping the parks the same today as they were yesterday, so that tomorrow they’ll be the same as they were today. National parks were considered static warehouses of nature’s beauty. The park service intended to keep them that way forever.
With climate change, that’s impossible.
Climate change is hitting the U.S. hard. It’s hitting national parks harder. That’s because many national parks — 423 facilities covering 85 million acres in all 50 states — sit in austere locations, like Alaska, the fastest-warming state; southwest deserts, already dry and getting drier; and mountainous areas like Yosemite. National parks are warming at twice the rate of the country, according to Patrick Gonzalez, a climate scientist at the University of California, Berkeley, and they’re experiencing a more significant decline in precipitation.
The results are stark: In Rocky Mountain National Park and across the west, tree death has doubled since 1955 due to fire, droughts, and insect infestations. Increased aridity due to climate change across the Mojave Desert — including Joshua Tree National Park, Mojave National Preserve and Death Valley National Park — reduced the number of bird species by 40 percent since 1908, Gonzalez said.
Joshua trees are dying at Joshua Tree National Park, sequoias are dying at Sequoia National Park, and the glaciers at Glacier National Park and Glacier Bay National Park are melting.
If the national park system is the best idea America has ever had, as the novelist Wallace Stegner famously said, allowing climate change to diminish those parks would be among our biggest mistakes. But many people are working to prevent that, as part of a climate-change response that has fundamentally altered the parks’ approach to conservation.
In the last few years, the park service formalized its “resist, accept, direct” decision-making framework, preparing parks to be ready for as many possible climate-change futures as possible.
“We haven’t recognized and worked with the dynamism of nature as much as we really need to,” says Nicholas Fisichelli, who helped formulate the “resist, accept, direct” strategy while working as an ecologist for the National Park Service. “But climate change is forcing our hands.”
Think of a climate change problem like your favorite shirt having a rip. Do you sew it to try to make it good as new? That’s resist. Do you wear it with the tear? That’s accept. Do you buy a different shirt? That’s direct.
Climate-change mitigation efforts under the “resist, accept, direct” framework have been as simple as letting nature run its course and as complicated as sedating ferocious predators, loading them onto helicopters, and moving them across international borders. On a Michigan island, in a California forest, and in a Montana lake, we can already see the results in the wild.
Resist: The wolves of Isle Royale
Some results of climate change are beyond the reach of human intervention. Scientists have known for decades that animals are migrating as much as 10 miles north per decade in the Northern Hemisphere, chasing the temperatures they’re used to. In the mountains, animals move up in altitude for the same reason. What are they going to do when they reach the top and want to keep going?
Park ecologists and managers have been forced to concede that some species are either gone or soon will be. “That’s really hard to digest,” says Fisichelli, who is now president and CEO of the Schoodic Institute, the science and education partner of Acadia National Park. “That’s the reality we’re facing as a society. Nobody wants something to blink out on their watch.”
Which takes us to Michigan’s Isle Royale, a 46-mile-long island in Lake Superior.
To hear a wolf howl is to feel the hair on your arms stand up. To see one — the jagged teeth, the razor claws, the cocky strut born of a life as a predator without peer — is to wonder if you’ll make it to safety before those teeth sink into your calves and the claws shred your back. I saw one at Denali National Park in Alaska. It looked at me like I was delicious.
“You’re putting these animals on the ark. It’s a pretty extreme action when you’re taking a species and moving it out of harm’s way.”
Matt Boyer of the Montana Fish, Wildlife and Parks Department, on relocating bull trout in Glacier National Park
All of Isle Royale is a national park. Wolves arrived there in 1948 by walking across ice from Ontario. In their new home, they helped manage the moose population by eating the weak and dying.
Because of warmer winters, in most years Lake Superior no longer freezes for as long as it once did, which gives wolves less time to cross it. That led to a drop in the wolf population from 50 in 1980 to two in 2016. The loss of wolves led first to an increase in the moose population, and then a decrease when the moose overate their food supply and some starved.
In her work studying Isle Royale wolves, Sarah Hoy, a forest resources and environmental science professor at Michigan Tech University, routinely talks with park visitors who tell her the highlight of their visit was hearing or seeing a wolf.
But does that thrill — a gift many of us receive only in a national park — justify intervening if wolves can’t survive naturally?
Is it better to let moose starve to death, or move wolves in to eat them?
The National Park Service considered four solutions:
-Do nothing.
-Add wolves over a three-year period.
-Add wolves immediately with more possible over the next 20 years.
-Do nothing now but leave the door open to adding wolves later.
It was not an easy decision. They never are. Supporters of adding wolves saw them as a critical piece of the island’s ecosystem and said the loss of them would have far-reaching consequences for moose, the balsam fir that moose eat, and who knows what else. That’s all true. But critics didn’t see it as justification for moving wolves.
“The wolves should decide whether they want to live there or not,” says Kevin Proescholdt, conservation director for the Montana-based Wilderness Watch, which advocates for the preservation of the National Wildlife Preservation System, 111 million acres spread across national parks and other U.S. government land.
The park service ultimately chose to add wolves over three years (which ultimately turned into two because of COVID-19). That fits the “resist” category, since it’s trying to resist wolf population decline. In Minnesota and Michigan, scientists used foothold traps baited with beaver and deer carcasses to capture eight wolves; in Ontario, they shot “net guns” from helicopters to capture 11. The wolves were sedated, caged, examined by veterinarians, outfitted with GPS collars and taken by helicopter and boat to Isle Royale in 2018 and 2019.
As of February 2022, the wolf population had climbed to 28, and together they had eaten 48 moose. It looks like a success. But it’s not a pure win. The new wolves all come from the same family. That could eventually cause genetic problems, which was part of the reason for the earlier decline. The park service might have to consider adding wolves again, Hoy says, though infrequently and not as many as last time.
Accept: A tree by any other name
Andy keeps a bucket list on his phone. “Hug a sequoia” was on it. He crossed it off while walking on a trail from Mariposa Grove back to the welcome center. That trail was passable only because someone had run a snowblower over it. Even on this cold day, even with a foot of fresh snow on the ground, even when conditions suggested attendance would be sparse, someone ran a snowblower through the forest to make the hike doable for guests hardy (or foolhardy) enough to show up.
That speaks to the importance of Mariposa Grove. It also hints at the challenges the park service faces in making decisions about climate change mitigation. If the agency will plow a forest trail to make Mariposa Grove accessible, it’ll go to great lengths to make it worth visiting over the long haul. But the agency needs to have priorities. It can’t snowblow paths to everywhere. Nor can it resist or direct change in every forest.
Much of the park service’s forestry work is meant to resist climate change, to protect the parks’ most popular and beloved areas. That’s why the forest floor of Mariposa Grove looked crisp and clean. Smooth, untouched snow carpeted the ground. Deadwood on forest floors is dry and hyper-flammable because of climate change-caused heat and drought. Instead of leaving deadwood where it was, as it used to do, the park service now strives to get rid of deadwood when it’s feasible. Sometimes workers remove it physically. Sometimes they burn it in small, managed fires.
Driving out of the Yosemite Valley, I saw smoke — and road signs saying the fire was intentional. I parked the car, climbed out, and counted a dozen enormous piles of burning wood — like campfires for people 30 feet tall. Fires like that protect Yosemite Valley and Mariposa Grove: A fire can’t become big with little fuel to propel it. That was the resist strategy, live, in person, hot, and intended to protect these beautiful, awe-inspiring landscapes.
But as wildfire seasons grow longer and more destructive, the park service can’t save every forest. Increasingly often, the park service must decide what to do with forest land after a wildfire.
Elsewhere in Yosemite National Park, in an area called Foresta, wildfire destroyed a pine forest. New life has emerged, as it always will, but it’s not the life that was destroyed. Instead, oaks now dominate the landscape. High up in the Sierra Nevada Mountains, the oaks look out of place without any pines alongside them.
The park service could have planted pines in Foresta — to resist the change brought on by the fire — but it didn’t.
It is, essentially, the same problem that Isle Royale faced, only with trees instead of wolves. The wolf population was considered worth saving. The pines were not, and the park service “accepted” the change there. Its decision was bolstered in part by the fact that oaks were more common in the area 150 years ago, says Garrett Dickman, a forest ecologist at Yosemite who specializes in restoration.
“Was it all oaks and shrubs like it is today? Surely there must have been more pines,” Dickman says. “But for now, I don’t get to know that, so it’s best to accept and watch what happens.”
While Dickman and other scientists told me nobody would have chosen “oak forest” from a list of options after the Foresta fire, it seems to be working out. The black oaks appear to be thriving in the short term. Long term, they are resistant to climate change, and they are important to Native American tribes’ history and culture.
Direct: A fish out of crowded and warming waters
Lake trout, a non-native fish, were introduced into Montana’s Flathead Lake in 1905 and have since migrated to connected waterways. The lake trout prey on the native bull trout, which have lived there for centuries, and eat their food, and within 30 years, the bull trout die out.
This invasion has happened in nine of 12 the park’s lakes where bull trout live. Meanwhile, because of climate change, the water in some Glacier National Park creeks will eventually get too warm for the temperature-sensitive bull trout.
A team of scientists from the park service, the U.S. Geological Survey, Montana State University, and the U.S. Fish and Wildlife Service and Montana’s wildlife department studied whether to move the bull trout from imperiled lakes to safe ones.
Every relocation is likely to be controversial, whether it’s because of the animal that will be moved, where it will be moved to, or how it will be moved.
“It speaks to the severity of the situation when conservation practitioners are even considering translocation,” says Matt Boyer, a science program supervisor for the Montana Fish, Wildlife and Parks Department who worked on the bull trout study. “I think of it as, you’re putting these animals on the ark. It’s a pretty extreme action when you’re taking a species and moving it out of harm’s way.”
The key is to make sure the solution doesn’t cause additional problems. Such projects often fail, the bull trout study said, because of inadequate understanding of all factors that can influence the success of relocation.
So the study sought as much understanding as possible. In searching for a new home for the bull trout, the scientists considered seven locations. They focused on the suitability of each habitat, what fish and other animals were already there, and what the future might hold — such as rising water temperatures due to climate change.
They concluded that Grace Lake, where there were no lake trout or bull trout, best checked all the boxes. It’s higher in elevation than the lakes that the bull trout would move from, and therefore colder. An impassable waterfall between it and where lake trout live means there’s no danger of lake trout ending up there, too. And bull trout’s arrival there would not, scientists believe, cause an undue burden on the existing system.
From 2015 to 2019, scientists moved the fish to Grace Lake. Introducing a species to somewhere it hasn’t previously lived places this project under “direct” in the “resist, accept, direct” framework.
The first goal — for the transplanted bull trout to survive and thrive in Grace Lake — was met. “There are likely hundreds of them in the system now,” says Chris Downs, Glacier’s aquatic and physical science programs leader.
Goal No. 2 is for the transplanted bull trout to reproduce in the wild. Downs says scientists will survey the lake this spring to look for evidence of that.
In the meantime, a complication arose when an increase in beaver dams flooded out what scientists expected to be prime spawning areas. “Since these two species evolved on this landscape together, there is hope the bull trout we moved will adapt to these challenges and find ways to spawn successfully,” Downs says.
In other words, the park service has directed the fishes’ fate as much as it can.
The rest is up to the trout.
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