Superlative

The drive west out of Rifle on Interstate 70 is a study in Western panoramas. The freeway chases the Colorado River for about 80 miles before parting ways at the Utah border. From there the river breaks left, along the southern edge of Arches National Park, cutting a path through the middle of Canyonlands before proceeding south to the Grand Canyon.

I longed to follow the great river, but the road ahead of me offered a natural treasure just as rich. I was going back to Pando.

Forest ecologist Burton Barnes hadn’t just made a spectacularly good guess as to the Fish Lake aspen clone’s immense size. He had also proffered an estimate of its age. By comparing the distinct appearance of the clone’s leaves to similar-looking fossils, Barnes concluded it could be as old as 800,000 years.

Cope’s Rule specifically refers to evolution of increasing size, but the basic principle could be applied to any attribute of life. There’s always room at the top, after all. Room to grow heavier. Room to grow taller. Room to grow older. And as something grows in one way, it often grows in others.

If Barnes’s estimate about Pando’s age is true, it wouldn’t just be the oldest known organism in the world, but the oldest by a spectacular factor—perhaps even the oldest that ever lived. By Barnes’s reckoning, the great plant’s birth may have come alongside some of our earliest human ancestors: the same time Homo erectus began to harness fire and our forebears’ brains began a rapid evolution in size and complexity.¹

Human DNA has changed significantly in the millennia that have come and gone. But the essential code written when Pando was created—the very record of that time and place as expressed in an aspen genome—remains as it ever was, such that running your fingernails along its chalky white bark puts you into visceral contact with life not only as it is, but as it has been, perhaps for as long as we have been.

As was the case with Barnes’s estimate about Pando’s incredible size, though, plenty of people have expressed doubts about his guess on its age. But while we now know, with a significant degree of certainty, how far Pando’s genes have spread across the Fish Lake Basin in terms of acreage, its age has proved harder to confirm.

The age of most trees is relatively easy to determine, and just about everyone knows how to do it. It starts with a clean cut across the trunk. Once the rings are exposed, the counting begins. With some scientific caveats, each ring represents a year.

Clonal stems can be aged in this way, too. I haven’t cut down any of Pando’s stems, but there are plenty, fallen in the natural way, lying about on the ground, and forest managers have cut many of these into easily countable cross-sections. One I counted, on a cold fall afternoon, had 87 rings. Another had 94. Another still had 103. But none of the stems are as old as the clone itself; not even close. Like the hair on a person’s head, new ones emerge as older ones die, but the forest remains.

Some have concluded this somehow disqualifies clonal organisms as life-forms worthy of a superlative description like “oldest.” I disagree. An aspen clone is not unlike you and me. When we look at ourselves in a mirror, we might recognize our face as the face we’ve always had, but it’s not, and all it takes is a look at a photo from ten years earlier to be reminded of that fact. The cells that make up our skin last a few weeks, at best. The cells in the rest of our body die and regenerate at rates varying from every few days to every few decades. You likely still have some living cells that were with you at your birth, but not many, and each day there are fewer. Over time, as our cells come and go, our appearance changes. So no, you are not the you that you were—but you are still you.

You, however, most likely have a record of your birth. Pando doesn’t. So how can we be sure it’s so old? The short answer is that we can’t be. Not yet, anyway.

Some have reasoned that the maximum known growth rate of aspen clones can be divided into a clone’s total size to give a minimum possible age. Using such a formula, some researchers have guessed that Pando might be about 80,000 years old, and in recent years popular opinion has coalesced around that figure.² That’s a far cry from Barnes’s estimate, but even at 80,000, Pando would still be the oldest living organism we know of by a significant factor, and its birth would have come around the same time that humans began to take their first steps out of Africa.

However, there are clear limitations to such an estimate. Aspen exhibit tremendous genetic diversity and live in a lot of different habitats. And just as humans carrying different genes and living under differing circumstances grow in different ways—Dutch men are six feet tall on average, for instance, while their average Indonesian counterpart is 5-foot-2³—we can safely assume that aspen also will grow to different sizes under different genetic and ecological circumstances. Pando could be an amazingly fast-growing specimen; 80,000 years could be liberal. But there’s also the matter of the fires, floods, landslides, and herbivores that, over thousands of years, could have taken big bites from the clone’s size. Pando might actually be quite a bit smaller now than it once was; 80,000 years could be conservative.

Soon, we might have a better idea.

When I met him in 2018, Jesse Morris, who works at the University of Utah’s Records of Environment and Disturbance Lab,⁴ told me he was hoping to secure grant funding to take sediment cores from the middle of Fish Lake.

Most lakes in the region were formed by glaciers, Morris explained, and are somewhere in the neighborhood of 8,500 years old. Fish Lake, though, was formed tectonically as the Great Basin pulled away from the Colorado Plateau. “That lake might be a million years old,” Morris said.

And Morris estimates that under Fish Lake, which is more than 100 feet deep in places, there may be 30 or 40 meters of compacted sediment—a gold mine of evidence about past climates and, potentially, what plants lived nearby tens of thousands of years ago. “It’s actually pretty fortuitous, and a really unique opportunity, to have such a long-lived organism next to such a mind-bogglingly old lake,” he said. “You couldn’t ask for a better situation.”

The lab where Morris works has had some success using sedimentary pollen fossils to reconstruct climates that existed thousands of years ago. Using the pollen fossils, the team has even demonstrated the ways in which aspen in the Rocky Mountains moved upslope during a period of drought more than 4,000 years ago.⁵

Morris doesn’t know if it would be possible to tie exceptionally old pollen to a specific aspen clone. But if aspen pollen disappeared altogether from the samples as the researchers moved deeper and further back into time, it would give them a much more definitive “oldest possible” age.

Knowing Pando’s age with greater certainty wouldn’t just give a few in-the-know folks another superlative fact to pull out on bar trivia night. It would help all of us understand the upward limit for how long a specific genome can exist in our world. It would tell us something about the potential longevity of the fundamental building blocks of life on our planet. And it could tell us something about ourselves.⁶

This is what cancer researcher Josh Schiffman was trying to do when he broadened his research focus to include not just the experiences of people, but tragically cancer-prone dogs and providentially cancer-free elephants, too. The result of that inquiry, as we know, has fundamentally shifted a lot of thinking about how to fight cancer.

And this is why the question of Pando’s age is so important. Plants aren’t people, but we share a common eukaryotic ancestor, which means we share quite a few genes. And of course, aspen are even more closely related to other plants. The strategies Pando has used to stay fit for this world, millennium after millennium, could inform our own efforts to survive and thrive on this quickly changing planet, particularly when it comes to ensuring the survival of other plants.

So it would indeed be shameful to set aside this organism’s longevity as a mere curiosity. For it might also be the source of excellent knowledge, if only we seek to answer the questions “Why is it old?” and “Being old, how did it get that way?”

HOW STERILITY CAN HELP AN ORGANISM GROW OLD

The genetic research Karen Mock did on aspen didn’t just help substantiate Pando’s claim to fame as the world’s largest known organism. It also revealed a rather big genetic curiosity: A surprising number of aspen, Pando among them, had three sets of chromosomes.

Most eukaryotic species have two sets. And a lot of aspen are diploids, too (as are we). But when Mock and her team studied aspen across North America, they found that up to two-thirds of the plants in some regions were triploids. That came as a bit of a surprise, because everything we know about biology tells us that triploids typically have one heck of a hard time reproducing, since their cells can’t properly undergo division.

Research from two other species—both also clonal—is helping put Pando’s sterility into context.

The first is another contender for the title of “world’s oldest plant,” the last known member of the species Lomatia tasmanica, also known as King’s holly. The plant was first identified by naturalist Denny King in 1934, but it wasn’t until 1998 that carbon dating of identical-looking fossil leaves found nearby revealed the plant might be 43,000 years old—and perhaps even older.⁷ While the plant does produce pink flowers, it doesn’t produce fruit or seeds because, just like Pando, it’s a triploid.

Across the Bass Strait is another part of the puzzle, Grevillea renwickiana. There are fewer than a dozen individual specimens of G. renwickiana left in the world, all of them in the plant’s native Southeast Australia. And, like Pando and L. tasmanica, the plants are triploids. Sterile as a mule.⁸

While there aren’t many G. renwickiana left, the survivors are doing just fine and dandy. One, in fact, is spiderwebbed across an area near the Endrick River, in Morton National Park, that stretches out for nearly 82 acres. That’s not much less than the territory claimed by Pando.⁹

Mass sterility ought to spell the end of a species. But conservation geneticist Elizabeth James, perhaps the world’s leading expert on G. renwickiana, told me it probably makes a lot of sense that these three plants are survivors. “If they’re sterile, they don’t spend energy on reproduction,” she said.

“But if they don’t spend energy on reproduction won’t they eventually die off?” I asked.

“They are certainly evolutionarily stagnant,” she said, “but the ones that are left seem to be flourishing.”

Instead of creating lots of flowers and seeds—which are the most complex parts of a plant and take a lot of energy to produce—the triploid plants can dedicate available water, sunlight, and nutrients to building robust root systems. “That could give them an edge,” she said.

I don’t know a parent who can’t relate. Who among us doesn’t feel as though their children have taken years off their lives?

Jokes aside, though, there is actually a lot of evidence of an inverse correlation between fertility and longevity. In nearly every organism that has been studied over the past half century, in fact, reproduction shortens lifespan.¹⁰ And when researchers from Moscow State Univesity investigated the relationship between lifespan and fecundity in 153 countries around the world, they found a highly significant negative trend; after controlling for religion, geography, socioeconomic factors, and considerations of disease, they still observed a trade-off between the average number of children and life expectancy.¹¹

Those trade-offs are scientifically significant but relatively slight, though. What more likely accounts for the apparently exponential longevity of plants like P. tremuloides, G. renwickiana, and L. tasmanica is their interconnected root structures. Surface soil protects them from short-term environmental shifts that could kill plants reliant on sexual reproduction.

“If you have diploids producing seeds,” James said, “and the environmental conditions change and the seeds don’t get to germinate, then an entire generation can disappear. Once that individual dies, it’s gone, whereas the triploid ones can get going again.”

To see where this sort of knowledge might come in handy, it’s helpful to think about the sort of world scientists believe is coming as a result of human-caused climate change. There’s virtually no doubt the planet is getting hotter. What we also are coming to understand is that weather extremes—from hurricanes to heat waves to historic droughts—are a part of the price we’re paying for unleashing vast quantities of greenhouse gases into our atmosphere.

What plants are most likely to survive such disturbances, and even mitigate the resulting ecological instability? Perhaps, James suggests, it will be those like P. tremuloides, L. tasmanica, and G. renwickiana, which have been doing so for millennia without the need for renewal by germination.

It’s difficult to know with certainty how old the last surviving G. renwickiana clones might be. “But they’re surely really old,” James told me. The diploid version of G. renwickiana may have died out many thousands of years ago, she said. The triploids, though, may be around for thousands of years to come, even in the face of climate change.

If we don’t kill them off in other ways, that is. Because, let’s face it, humans have a knack for bringing an end to things that Mother Nature has kept going for a very long time.

HOW ANCIENT ASPEN ARE TEACHING US ABOUT INTERCONNECTEDNESS

Eight hundred thousand years? Eighty thousand years? Whatever we learn about Pando’s age, this much is certain: The aspen clone was around long before white settlers colonized this area of North America in the 1800s.

Will it outlast us? That is far less certain. Because this amazing organism, which might very well be the oldest living thing on our planet, now appears to be dying.

When wildland resources researcher Paul Rogers first took a walk through Pando in 2010, he was unsettled by what he saw. It was as though the plotline from P. D. James’ dystopian novel, The Children of Men, had been rewritten with “Pando” in the place of “people.” In James’ 1992 book, and Children of Men, the 2006 film adaptation, human children have inexplicably stopped being born, and the aging population that remains on Earth has been thrown into chaos.

Pando still had many “geriatric” stems, some 100 years old and likely even older. There were plenty of “senior citizens” as well—those in their seventies and eighties. There were very few young adults, though, and just a smattering of teenagers. And there were almost no children. The new stems had simply disappeared.

“Something has been disrupted,” Rogers told me as we hiked through an area of the clone that had been particularly hard hit, where recently fallen stems covered the ground like pick-up sticks, leaving nothing behind but a clear view of Fish Lake. “There really hasn’t been any new growth for three, four, five decades.”

Even more alarming to Rogers was that few people had so much as taken notice. This great and ancient thing was tumbling off Cope’s Cliff, and no one was doing anything about it.¹²

That might be the right course of action if Pando had simply reached the end of its remarkably long life. But that’s not likely what was happening.

“The evidence certainly suggests that something has changed in the recent history of this plant,” Rogers said. And identifying the assailant in this mystery wasn’t tough. The Fish Lake clone was humming along, alive and well, for millennia, and then we showed up.

But like a game of Clue, it’s not enough to know the culprit. We’ve also got to figure out what the weapon was.

One guess: fire. Or rather the lack of it. Aspen thrive in the midst of disturbance. Cut down a clone’s stems, and a healthy aspen root system will send up many more in replacement. Allow a fire to rage through a colony, and new suckers will often follow the path of the flames. But Fish Lake is a popular recreation area, and with cabins scattered throughout its forests—including a few dwellings that are actually situated within Pando’s boundaries—state fire managers hadn’t sat idle. The fires, which once, quite naturally, came through here every now and again, have been stopped.

Another potential weapon: climate change. One joint research effort from the US and Canadian forest services demonstrated that regions impacted by drastic aspen die-offs are those that have experienced hotter temperatures and drier winters in recent years.

Rogers had yet another theory: deer and elk. Too many of them. It had been some eighty years since the region’s chief predator, the gray wolf, had been exterminated. That timeline roughly coincides with the last big generation of stems in Pando. The area’s mountain lion population had also been drastically reduced in the past century, first by a bounty program that claimed nearly 4,000 cats between 1913 and 1959, and later by game regulations that permitted hunters to take any number of big cats at any time without a permit.¹³

To understand the impact of predators on aspen ecosystems, it’s helpful to head north from Pando—just about 350 miles, as the crow flies—to the Crystal Creek area of Yellowstone National Park.

The last of Yellowstone’s endemic gray wolves was exterminated in 1926. Then, in the mid 1990s, thirty-one wolves were reintroduced to the park, and it didn’t take long to see their impact. There were 18,000 elk in Yellowstone at that time. They were always hungry, and one of their favorite snacks were the leaves from young aspen stems. But the wolves were always hungry, too, and one of their favorite snacks were the elk. When the wolves started doing what wolves do so well, the elk were no longer able to stay in one place for long periods of time and munch through entire groves of aspen. Soon, Yellowstone’s aspen woods, like those in Crystal Creek, were flourishing.

Wildlife ecologist Dan McNulty, who has studied the wolves-to-trees phenomenon, said it could be many more years before it’s clear whether Yellowstone’s aspen have been saved. “The outlook for aspen in Yellowstone is promising, but not assured,” he told me.

One thing was clear, though: The wolves’ impact didn’t stop at reduced elk and increased aspen. The ripples kept going and going. The bigger, healthier aspen woods offered habitat to birds and building materials for beavers, whose dams help raise the water table, thus providing habitat for even more trees.¹⁴

Rogers couldn’t unilaterally reintroduce predators into Utah—there are a lot of hunters, farmers, and ranchers in that ultra-conservative state who would have something to say about that—but he wanted to know what Pando would look like if the local ungulates couldn’t use that great and ancient organism as an all-you-can-eat salad bar.

“There’s really nothing at all to keep them from bedding down in an area and just eating for a week or a month,” he told me during a hike in the woods one day, “if they find a particularly tasty aspen.”

I reached for the nearest stem, leaping to grab an aspen leaf. I popped it into my mouth like a piece of fresh spinach. It tasted like chewed-up aspirin.

“This is not a particularly tasty aspen,” I said, trying to spit and finding the leaf had robbed me of my saliva.

“You’re not an ungulate,” Rogers laughed. “And besides, they tend to like the young leaves.”

“Unless there is a wolf chasing them?” I asked.

“Right,” he said. “But since we don’t have wolves, we built a fence.”

He led me to the gate of a fenced-off quadrant of the clone, an area known as the “research restoration area.” The first two suspects in Pando’s slow death, fire and climate change, would be hard to measure, particularly in the short term. But the third, the impact of deer and elk, could be controlled. Hence the fence—which at that point was just a month old.

It was Rogers’ first trip to Pando since that fence had gone up. He wasn’t expecting to see a big difference in that time. Even if the ungulates were part of the problem, he told me, fire and climate change, and “God only knows what else,” were almost certain to be accomplices. Fixing one thing alone wasn’t likely to save Pando.

But then he saw it: A tiny sucker stem, seven inches at most, peeking out of the ground near a rock, with just a few bright green leaves jutting from the top.

And then, near a fallen log, he saw another.

His amble picked up pace. Soon he was darting about the forest, this way and that, jumping over fallen stems, spinning around to find sucker after sucker after sucker, running his fingers over the leaves of shin-high shoots.

“Here’s one,” he called out. “And here’s another . . . and another!”

He didn’t look much like a scientist in that moment. He was more like a boy at play in a hundred-acre wood. By the time the sun began to set, though, he’d reclaimed a more composed disposition. “It’s way too early to say what this means,” he told me. “It’s promising, for sure, but we need to wait to see what happens.”

I didn’t fully understand Rogers’s excitement on that day. But five years later, I was back in the clone, walking the fence line with what I can only imagine was the same sort of oh-my-God-this-really-worked glee that Rogers had been trying to contain on the day he introduced me to Pando.

Inside the fence, the tiny shoots we’d spotted years earlier were sturdy stems now, and the ground was brimming with more first-year suckers.

And outside the fence? Almost nothing.

It’s still too early to say whether Pando’s revival within the fence will lead to the sort of resurgence of biodiversity seen in Yellowstone. But it’s not debatable that over-grazing by ungulates has been a key factor—if not the key factor—in the Fish Lake clone’s decline.

It would be expensive, albeit feasible, to build a fence around the entirety of Pando’s perimeter. We could, I suppose, save this ancient thing that way. But that is not a scalable solution. We cannot build a fence around every aspen clone.

We could, however, listen to the voice of the father of wildlife management, Aldo Leopold.

“I have lived to see state after state extirpate its wolves,” Leopold wrote in 1945. “I have watched the face of many a newly wolfless mountain, and seen the south-facing slopes wrinkle with a maze of new deer trails. I have seen every edible bush and seedling browsed, first to anaemic desuetude, and then to death. I have seen every edible tree defoliated to the height of a saddlehorn. Such a mountain looks as if someone had given God a new pruning shears, and forbidden Him all other exercise. In the end the starved bones of the hoped-for deer herd, dead of its own too-much, bleach with the bones of the dead sage, or molder under the high-lined junipers.”¹⁵

Inherent in Leopold’s essay, called “Thinking Like a Mountain,” was a simple plea: Allow predators to play their rightful role in the ecosystems in which they evolved.

If we do, we might save some of the oldest living things in our world. And we’ll most certainly save more than that.

WHY BRISTLECONE PINES ARE TAKING THE HIGHER GROUND

I had what amounted to a treasure map. A few clues about pinecone washes and switchback trails. A basic description of where to look and what to look for. And a very old photo.

But there were thousands of bristlecones along the trail. Twisted and gnarled, grasping and desperate, still against the stark blue sky. They looked like demons frozen while trying to escape hell. And the idea of finding one specific tree, among all of those in the Ancient Bristlecone Pine Forest in California’s rugged White Mountains, seemed daunting at best.

But I kept hiking, searching for the clues I’d been given. And then I saw it.

Methuselah.

At 4,850 years old, it is the oldest known single tree on our planet, germinated at the same time that the first pyramid of Egypt was built. Only a few people know where Methuselah is, and they have been protecting its location like the Ark of the Covenant.

Here is why: A few decades back, when Methuselah was marked with a sign, visitors were taking samples of it home with them. They were, forest officials worried, going to “love it to death.” So the park rangers took down the sign, resolving to give the world’s oldest tree a shot at continuing to be the world’s oldest tree.

There was an interesting duality at play in that decision. On the one hand, researchers who study bristlecone, like the University of Arizona’s Chris Baisan, say the age of individual trees—even superlative ones—isn’t scientifically important. “If you’re a scientist rather than a trophy hunter,” Baisan said in 2015, “you don’t need the oldest individual.”¹⁶ On the other hand, tree-ring researchers and forest officials have gone to great lengths to protect Methuselah, which doesn’t make a lot of sense if Methuselah itself really doesn’t matter.

It was around the time Methuselah’s sign came down that a dendrochronologist named Tom Harlan began telling people he had identified a bristlecone that was even older. No one who knew Harlan seems to believe he would just make up such a claim, but the longtime University of Arizona researcher declined to publish his findings, and took the secret of the tree’s location to his grave in 2013.¹⁷ Harlan’s colleagues looked through his notes and collection of core samples for clues about the mystery tree. There was no sign of it.

It’s possible, I suppose, that Harlan was spinning a tale to give Methuselah a bit more breathing room. But Harlan’s colleague at the University of Arizona, Matthew Salzer, said that if the tree does exist, he thinks he knows the area where it might be. He has considered going to find it, and I’ve begged him to take me if he does.

And yet I’m not sure I want to know for certain. There’s something sacred about walking through the White Mountains without knowing which, among all of the ancients, is the holiest of holies.

The first time I hiked the Methuselah Trail, I didn’t know which of the trees was oldest. And so my awe was incited on that day not by age, but by the relationship between age and size. Having witnessed the way thousands of years of growth could turn an aspen clone into an organism of godlike proportions, one of the first things that struck me about the ancient bristlecones in the White Mountains was just how very small they seemed. It would have taken mere seconds to climb their gnarled trunks and reach their upper branches.

Like most trees, bristlecones add a ring for each year of their lives, and some of these had been doing so since before Stonehenge was constructed. Each year’s growth, though, comes in mere fractions of a millimeter—it is nearly impossible to accurately count the rings of a very old bristlecone with the naked eye.

It makes sense that the bristlecones of the White Mountains grow so slowly, Salzer told me when we met up, early one fall semester, in his lab at the University of Arizona, the same school where Harlan once worked. Bristlecones, Salzer said, live in some of the most inhospitable conditions imaginable, especially those at the highest reaches of the treeline, 11,000 feet above sea level, where temperatures stay below freezing for long stretches of the year, and where it can be extremely dry during the short growing season. “So they just take their time,” Salzer said.

Only a few living bristlecones reach ages approaching Methuselah. But there is no shortage of dead bristlecones scattered about in the White Mountains, and some have been lying in state for thousands of years. By matching and overlapping the ring growth patterns from both living and dead trees—not unlike how the scientists in Rifle, Colorado, used overlapping segments of DNA to piece together longer sequences—Salzer is close to completing a 10,000-year timeline of bristlecone growth. “There are just a few puzzle pieces left,” he said. “We just have to find the right pieces.”

Matching the rings is both art and science. Elevation, slope, soil, and other factors can impact how individual trees grow from year to year, even within short distances of one another. So dendrochronologists search the rings for signs of climate events massive enough that they impacted every tree alive at a certain moment in time. Looking through a microscope in his lab, Salzer pointed out one such section in a bristlecone core sample that, to my untrained eyes, seemed “fuzzier” than the others. “That’s a frost ring,” Salzer told me. “Those coincide with large volcanic eruptions that sent a layer of dust across the world, and they’re widespread—you’ll see them in bristlecones from all over.”

The frost ring I was looking at marked the year 627 AD, about the same time Muhammad conquered Mecca. Salzer and other tree ring researchers have found similar aberrant rings in bristlecone pines from 536 AD—when “the sun gave forth its light without brightness,” as the early Byzantine historian Procopius wrote of the global “dust veil” that led to widespread crop failures and famine¹⁸—as well as 687, 899, 1201, 1458, 1602, 1641 and 1681 AD.¹⁹ While the 10,000-year timeline is still coming together, such markers have enabled Salzer and his team to develop a robust data set exposing a 4,650-year timeline of bristlecone growth, and demonstrating the tree’s slow-and-steady strategy for a long, healthy life. Over more than four millennia, the median annual ring growth was less than .4 millimeters, about the thickness of a human fingernail.

But something has shifted, recently, in the highest altitudes of the White Mountains. There, as of late, the bristlecones have been growing like gangbusters. Or relative gangbusters, at least. From 1951 to 2000, their growth averaged .58 millimeters—a mark that stands as a record within the timeline, and which had only even been approached once before.²⁰

There could be a lot of explanations for this phenomenon, but when Salzer’s team looked at the growth of rings during the period in which we have reliable temperature data, they saw a strong correlation between annual mean local temperatures and ring growth. This work is offering us much-needed context for the drastic climate changes we’re now seeing in our world, and further proof—not that we should need it at this point—that these changes aren’t simply part of some larger, longer cycle.

Bristlecone pines are canaries in a global climate coal mine. But instead of dying of carbon monoxide poisoning, as those little yellow birds once did to warn miners of deadly gases, they’re growing faster—and in higher places—as a result of warming temperatures.

I saw this in living color when I hiked to the uppermost reaches of the visible treeline in the White Mountains. There, at just over 11,000 feet, I stood next to one ancient tree and scanned the area for another, then walked in the straightest route I could to reach it, looking up-mountain every few steps for signs of life.

It didn’t take long to spot them, stark green against the pale gray terrain. Tiny but tough. Little bristlecones, climbing ever higher. We had changed the world, and they were chasing the thermal limits of their expanding biological niche—going where no tree had gone before, because now they could.

It can be hard to wrap one’s mind around how old bristlecones are. For me, it’s even harder to think about the life these little saplings could potentially have ahead of them—if we don’t ruin it, of course. After all, when the ones I saw above the historic treeline in the White Mountains are as old as Methuselah, we will be nearing the year 7,000 AD.

If they make it that far, and if we are not there to stop them from doing so, they might even just keep getting older.

But not aging. That’s a different thing altogether.

HOW TREES, WHALES, AND POLYPS CAN HELP US LIVE LONGER

Everything ages. We know this, right? Over time, the cells that make up every form of life on this planet begin to break down, misfire, and go just plain buggy. Eventually, they are no longer capable of sustaining life.

At least, that is how it goes most of the time. And that’s how researchers assumed it went for bristlecones, too, albeit at a much slower rate. They just hadn’t actually seen it. So, in the early 2000s, a research team from the US Institute of Forest Genetics began looking for signs of bristlecone senescence in every place they could think of, examining trees as young as 23 and as old as 4,713 years.

They looked in the xylem, which carries water from roots to shoots and leaves. They looked in the phloem, which moves the sugars and other metabolic products created by photosynthesis. In both they were searching for changes in the efficiency of these cellular transport tissues.

They looked for changes in shoot growth—differences in how fast and far the trees grew. They looked at the viability of pollen. They weighed the seeds. They studied how effectively the seeds germinated.

Other scientists were looking for signs of aging too. One group, from the McKnight Brain Institute, at the University of Florida, took a long, hard look at the plant’s telomeres, those chromosome-protecting caps from our frog discussion, which, as they deteriorate, leave organisms, including humans, more vulnerable to age-related illnesses.²¹

They looked everywhere.

And you know what they found? Nothing. There were simply no signs of senescence.²²

Nearly two decades have passed, and we’re not a whole lot closer to understanding why this happens—or doesn’t happen—than we were back then. The best guess among scientists who have studied the inner workings of bristlecones, though, is that something is happening in the bristlecones’ meristems, the accumulation of cells on the ends of roots and shoots that generate new growth—the plant version of stem cells—and permit continued growth year after year.

This is what makes bristlecones so good at telling us what climates were like, long before we began keeping records. It’s not just that they’ve been keeping track for a long time; it’s that they’ve done it so consistently. Since bristlecones don’t appear to behave differently as they age, they exist as a reliable recording device of the conditions in which they have lived from year to year, so much so that archeologists have actually used bristlecones to calibrate radiocarbon dating. The size, patterns, and density of the trees’ rings, and the stable isotopes trapped within those rings, can offer us a view into past climates, water availability, humidity, and atmospheric circulation going back for thousands of years.

But organisms that don’t seem to age—those that scientists say experience negligible or even no senescence—don’t just tell us about our pasts. They might also be a key to our future.

To Daniel Martínez, there’s no subject in science that has as much potential to be a global game changer as negligible senescence. And he wonders why more researchers aren’t pursuing answers. “Unless we do not believe that negligible senescence is real,” the Pomona College biologist wrote in 2012, “it seems that we should seek a better explanation for it.”²³

My friend and sometimes collaborator, David Sinclair, who studies aging at his lab at Harvard Medical School, wholeheartedly agrees. He believes life-forms like bristlecones can play a key role in helping scientists identify which human genes are the most promising targets for biomedical interventions intended to slow, stop, and even reverse the symptoms of aging. “People look at a really old tree and they think, ‘Well, that’s about as different from me as different gets,’” he told me in 2017. “They forget that we all emerged from the same place and, in the great scale of things, we diverged from one another on the tree of life a relatively short time ago. We carry a lot of the same genes.”

Still, he said, it can be hard to get people to believe they have anything in common with organisms that, at first blush, seem so different. That’s why he likes to start conversations about the comparative genomics of aging by talking about one of our relatively close cousins—the bowhead whale. “All mammals are warm-blooded, produce milk, and have a very specific brain structure that isn’t found in other animals,” he said. “On top of that, whales are highly social and have complex methods of communication, just like humans.” Not surprisingly, we share a lot of genes—nearly 13,000 of them, including one called FOXO3, a variant of which has been implicated in human longevity.

While humans live longer than most mammals, bowheads blow us out of the water. With lifespans of 200 years or more, they are the longest-living mammals we know of. “What’s really interesting is that the bowhead has a variation in FOXO3 you don’t see elsewhere,” Sinclair said.

Once you recognize that a close cousin is doing something special with a gene we share, Sinclair said, it becomes easier to appreciate what we might learn from organisms that aren’t so closely related, but also share that gene.

Among these life-forms is the creature Martínez studies in his lab at Pomona, Hydra vulgaris, a freshwater polyp related to jellyfish. Martínez didn’t believe the rumors he first heard, in graduate school, that hydra might be immortal under the right circumstances. But since no one else was looking into the matter, he decided to disprove the notion himself.

Hydra typically grow no bigger than a half an inch, and don’t last very long in the wild. So Martínez figured it wouldn’t take long to prove they can’t, in fact, live forever. “I thought it would take about a year and a half,” he told me. “Four years later I had to publish a paper saying I was wrong.”

One potential reason for the long lives of hydra? Stem cells. Hydra are almost entirely composed of them. So as long as the polyps in Martínez’s lab get what they need to keep making more stem cells—clean water and a few brine shrimp to eat every other day—they can always replace old cells with new cells, and have managed to do so thus far without any sign of slowing down.

It’s not enough to just have a big supply of stem cells, though. Key to Martínez’s investigations of his hydras’ amazing longevity is what their genomes direct those stem cells to do in response to cellular stress and when regulating the expression of genes involved in cell growth.²⁴ And that path of inquiry has led Martínez and other hydra researchers to FOXO3, which is a critical regulator of stem cells in H. vulgaris.

When you see one organism doing something with a gene, it might be interesting. When you see two, it could be a coincidence. When you start seeing many—and the gene they’re doing it with is one we also share—that’s a lead.

FOXO3 and its homologs in other organisms “appears especially important, forming a key gene in the insulin/insulin-like growth factor-signaling pathway, and influencing life span across diverse species,” a team led by Philip Davy of the University of Hawaii’s Institute for Biogenesis Research wrote in 2018.²⁵ When researchers like Martínez add new insights about what the gene does in organisms like hydra, the team wrote, it offers us a new way to look at “the molecular, cellular, and physiological processes that modulate aging and longevity in humans.”

A few decades into his investigations, Martínez is now more convinced than ever that his initial hypothesis was dead wrong. After all, the little guys in his lab are still going strong—and other scientists are seeing similar results. In one study, Martínez teamed up with hydra researchers in Germany and Denmark to examine twelve different cohorts of hydra. Almost all of the cohorts had intriguingly low mortality rates—amounting to about one annual death in 167 individuals. Some deaths couldn’t be explained, but most were the result of a lab accident, like when an individual hydra would become attached to the lid of the culture dish and dry out.

And here’s the remarkable thing: That death rate didn’t change regardless of whether the hydra were a year or more than forty years old. Like the bristlecone pine, they have not shown any signs of aging, even after a lot of research. One of Martínez’s studies, for instance, included more than 3.9 million days of observations of individual hydra—the equivalent of looking at 100 hydra for more than 100 years.²⁶

They’re all still swimming along—as happy as a clam.

Well, as happy as most clams.

HOW THE DEATHS OF A FEW VERY OLD ORGANISMS EXPLAIN WHY SCIENTISTS ARE HESITANT TO STUDY SUPERLATIVES

August 7, 1964, is a day that lives in infamy among biologists, ecologists, and pretty much everyone else who has heard the story.

It was on that day that a University of North Carolina graduate student named Donald Currey broke a boring tool while trying to assess the age of a bristlecone pine that had caught his fancy near Wheeler Peak in eastern Nevada. Reasoning that the tree itself, in the middle of plenty of similar specimens, wasn’t worth the chance of breaking yet another expensive borer, he asked US Forest Service officials what he should do.²⁷

“Cut ‘er down,” he was told by a forest supervisor named Slim Hansen.

Forest service sawyers helped Currey take down the tree, and gave him a cross section of its trunk, which he took back to his motel room. That’s where he started counting the rings.

Three thousand . . . four thousand . . . four thousand five hundred . . .

“And we ended around 4,900 years,” Currey told NOVA in 2001, in the only interview he ever granted about what he’d done. “And you’ve got to think, ‘I’ve got to have done something wrong. I better recount. I better recount again.’ “²⁸

He looked again and again. And slowly it hit him. He’d helped kill what was then thought to be the oldest tree in the world. The tree was at least 4,862 years old, meaning it had come into being right around the founding of Troy.

A local newspaper reporter named Darwin Lambert was furious. In an essay for Audubon called “Martyr for a Species,” he accused Currey of murder. In the aftermath of the tree’s death, Lambert later wrote, “we felt that we were walking home from a loved patriarch’s funeral.”

Several cuttings from the tree, also known as Prometheus and by its specimen reference number, WPN-114, wound up at the University of Arizona. Matt Salzer, the dendrochronologist who taught me about frost rings, told me there’s a persistent rumor that the tree’s remains are cursed. “These pieces,” he said, drawing several thick sections of wood from his shelf, “came here by way of a nervous researcher.”

He placed the pieces on his desk, spinning and flipping them until the ancient puzzle came together in the form of a six-foot section of what once was the world’s oldest known tree. Down the center, meandering like a river, was a line marked with tiny sticky tabs, representing the centuries the tree had survived before its untimely end.

In that moment I could not have cared less if the wood actually was cursed; I had to run my fingers along the line, pausing near the year in which the United States declared its independence, and then again next to the birth of Christ. When I got to the start of the rings, I traced a circle with my index finger on wood that was 126 times older than I was, and which, but not for a rather colossal mistake, would almost certainly have outlasted me.

And I felt sad. Both for the tree and the man who had destroyed it.

Currey would go on to become a popular professor in the geography department at the University of Utah, where he was well-known for his studies of the treeless salt flats of Utah’s west desert, but he carried the ignominy of what he had done to Prometheus all the way to his death in 2004—and even beyond.²⁹ Currey’s tale has been told repeatedly over the decades. Someone even included it on a video called “5 biggest mistakes in history,” right next to Mao Zedong’s ecologically nightmarish Four Pests Campaign, which may have intensified China’s Great Famine, and the Union Carbide chemical spill, which may have killed as many as 16,000 people in India.

Those sorts of histrionics aside, history is always doomed to repeat itself. Sure enough, two years after Currey’s death, another superlative organism died at the hands of researchers.

This time the victim wasn’t an ancient tree, but a quahog clam, Arctica islandica, that was hauled up from the frigid ocean floor, 260 feet below the surface along with about 200 others of its kind, by researchers studying climate change. Quahogs are known to live for hundreds of years and, much like trees add rings to their trunks, the clams add a growth band to their shells for each year of their lives. Those bands carry tremendous information about the environment in which they were created; as with tree rings, the bands are bigger when growth conditions are more favorable.³⁰

Quahogs are also among the most commonly fished clams (if you’ve eaten clam chowder, you’ve likely digested the flesh of an animal that was hundreds of years old before it was caught), so the scientists didn’t think it was a big deal to immediately throw all of their samples into the freezer on their boat, just like fishermen do.

It was only when they got back to the lab and started to count the bands that they realized that among their catch was a clam older than anything they’d ever studied before.

An initial count put the clam’s age at 405. A second look, plus radiocarbon dating, added another century. The clam, dubbed “Ming”—for it was during that Chinese dynasty that it had been born—was 507 years old when it was killed.

The researchers who killed Ming have so far been spared the level of notoriety bestowed upon the man who killed Prometheus, but they’ve had their fair share of haters, too. The Independent called Ming’s death “A Clamity!” Others were less kind. “We’ve had emails accusing us of being clam murderers,” marine geologist James Scourse told the BBC.³¹

If scientists didn’t already have plenty of reasons to be reluctant to search for and study superlative species, the tales of Prometheus and Ming might offer even more pause. Research always carries a risk to the thing being studied; anyone who tells you otherwise is prevaricating. And when scientists screw up something superlative, whether that screw-up is the result of actual negligence or happenstance, the reaction is going to be amplified

And yes, the felling of Prometheus and the freezing of Ming were accidents, and might have been avoided—in both cases the research objectives likely could have been achieved without killing the things being studied. But both instances came with significant scientific benefit.

The sections of Prometheus I saw in Salzer’s lab have been used to build dendrochronologies that are helping us understand past, present, and future climates. Ming’s shell has been used in the same way—by comparing the patterns of its bands to those of other quahogs, scientists were able to show that human-caused climate change has begun to disconnect marine and atmospheric systems that, before we started mucking things up, always operated in sync.³² That’s an exceptionally important finding, one that speaks to a tragedy far greater than the death of a very old animal.

And it’s worth noting that Ming actually wasn’t the oldest animal ever found. Not even close. That record belongs to another ancient inhabitant of the sea.

HOW THE WORLD’S OLDEST KNOWN ANIMAL IS HELPING US UNLOCK THE OCEAN’S DEEPEST SECRETS

The oldest animal in the world doesn’t look much like the things most people see when they picture animals. It doesn’t have a mouth or eyes. It doesn’t have legs or flippers.

But Monorhaphis chuni is an animal. And it’s really old.

M. chuni is a member of a class of animals called hexactinellids, also known as glass sponges. I suppose its top is fairly sponge-like. To me it looks like a big tan loofah. But the bottom resembles something Superman’s ancestors on Krypton might have taken to battle, sort of like a 9-foot glass throwing spear. That’s the sponge’s silica spicule, a long, skeletal leg that attaches it to the bottom of the ocean.

This sponge is at the heart of yet another story about the accidental killing of an ancient thing. It had been living a peaceful and very long life at a depth of more than 3,500 feet in the Okinawa Trough in the East China Sea when, in 1986, it was unceremoniously dredged up. At the time it was provided to the Chinese Academy of Sciences, no one knew what to do with it. It was regarded as an oddity—the longest hexactinellid anyone had ever seen. For that reason, it was fun to take photos with. That was about it. The sponge spent the next quarter century on a shelf.

Some researchers had hypothesized that hexactinellids could potentially reach ages upwards of 20,000 years, which would, if confirmed, put them squarely on the throne of the world’s oldest animal. But until rather recently no one knew how to test that theory, and since hexactinellids are rather hard to get a hold of, no one had put much thought into it. A few years ago, though, a paleoclimatologist named Klaus Jochum, who had been on the hunt for novel ways of understanding ancient climates, heard the academy had possession of the longest intact hexactinellid spicule anyone had ever seen. So he asked to take a look.

Cross sections of the cylindrical silica leg revealed a concentric growth pattern, just like a tree’s. And the rings were different sizes and widths, just like a tree’s. But even under intense magnification it was hard to see where one silica layer stopped and another began, and without a lot of other samples of M. chuni—preferably ones measured over time in a place where the seafloor climate was being closely monitored—it wasn’t clear whether the rings appeared annually, as they do on a tree and as bands do on a clam, or at some other rate of growth.

But when Jochum’s team members tested spots along the various rings for oxygen isotopes and magnesium-to-calcium ratios—common proxies for ancient sea temperatures—they saw something fascinating. At the youngest, outer layers of the spicule, their analysis offered an inferred temperature of 4 degrees Celsius, which aligned quite precisely with the environment at the bottom of the Okinawa Trough at the time the specimen was taken from the deep. As they tested the rings closer to the center, they saw four spikes in inferred temperatures, likely the results of temporary hydrothermal activity. Overall, though, the scientists saw a very gradual shift remarkably consistent with other research conclusions about how the seawater in that region of the world has been slowly warming since the last ice age.

And, at the very center, where the skeleton is oldest, the tests suggested a temperature of 1.9 degrees Celsius—which scientists believe to have been the temperature in that part of the deep sea 11,000 years ago. This long-dead sponge was the world’s oldest thermometer.³³

As scientists should be, they were careful with their proclamations, offering a 3,000-year window on either side of their estimation. The specimen could have been as old as 14,000 years and as young as 8,000. Even taking the most conservative estimate, though, it was the oldest animal ever identified, and by a longshot. Fifteen Mings could have come and gone in its lifetime.

When this sponge was born, humans were a distinctively social, problem-solving, tool-using hominid, but we were also a species that had yet to make a significant impact on the planet itself. By the time the sponge died, our species was deep into a 200-year reign of terror that has led to a global mass extinction and a rapid shift in climate.

That makes M. chuni an exceptionally valuable resource. Just as bristlecones can offer us a view of how we have changed the climate 11,000 feet above sea level, and in the same way that quahog clams can tell us what our impact has been in the shallow sea, sponges offer us the potential to understand the paleoclimate of the deep ocean—and stand as witnesses to our impact there, as well.

That’s not all they can teach us.

WHAT SPONGES, TREES, AND WHALES CAN TEACH US ABOUT HUMAN LONGEVITY

At the heart of M. chuni’s remarkable success, individually and as a species, are three things: simplicity, stress, and cellular survivability.

The specimen that was dredged up from the Okinawa Trough lived a really simple life, its movements confined to the slow currents of the deep sea. Hexactinellids don’t even have the tiny, ever-spinning flagella that other sponges use to pump water and nutrients through their bodies—the glass sponges simply accept whatever tiny particles of food the ocean offers, which would have amounted to a similarly tiny meal, every day, for the roughly 4 million days of the sponge’s life.

A simple life is not necessarily one that lacks stress, however. Indeed, there is perhaps no environment in the world that exerts greater physical pressure on an organism than the deep sea. At the bottom of the Okinawa Trough, the pressure is nearly 1,500 pounds per square inch, and the temperatures may have fluctuated, over the millennia of the sponge’s long life, from as low as a darn-near-freezing 0.8 degrees Celsius to as high as take-a-swim-to-cool-off 10 degrees Celsius. But like a boxer getting ready for a bout—training every day for hundreds of millions of years—hexactinellids have been “working out” against these stresses for a very long time, resulting in organisms that are as tough as a heavyweight champion. A less stressful environment would have produced a less fit species, one that simply couldn’t survive for so long.

Stress can be the very thing a species needs to evolve into a long-lived being—provided, that is, that there’s an easy way to regenerate when their cells succumb to that stress. M. chuni has that going for it, too. Sponges are packed with stem cells. So sure, they might exist in an environment akin to living next to a madly swinging wrecking ball, but they also have a built-in brick factory with which to rebuild.³⁴

The simplicity-stress-survivability equation doesn’t just apply to sponges. We see it in all of the other long-lived organisms we’ve been discussing, too. Aspen, for instance, live pretty simple lives, starting with their very genes. P. tremuloides has one of the shortest genomes among trees, with just 550 million base pairs. And, as you might recall, neither the aspen nor two other massive and ancient species, L. tasmanica and G. renwickiana, let life get complicated by trivialities like sex. They’ve figured out a simpler way to survive, and thrive.

If you were to spend a night in Pando’s enormous embrace, though, you’d be treated to a visceral understanding that its simple life isn’t a stress-free one. It gets really cold at 9,000 feet above sea level, and the forest floor disappears for months at a time each year under a thick blanket of snow. And even before we killed off the wolves and cougars, there were always deer and elk there that liked to munch on aspen shoots. Add to that the fires that have swept through the forest for millennia. That’s some serious stress.

But Pando has a steady supply of the kingdom Plantae’s equivalent to stem cells—meristematic cells, which are found at the tips of roots and shoots all over the organism. Cut down a stem, burn it to the ground, eat through it with beetles, chomp it up in the mouth of an ungulate—whatever—and these undifferentiated cellular supply points will get immediately to work, dividing rapidly to produce new shoots. University of Barcelona biologist Sergi Munné-Bosch, an expert in plant senescence, once described meristems as “the kings” in a botanical game of chess—so long as one meristematic cell remains alive, the game continues. All other tissues, he wrote, “will play an altruistic role to serve the meristems.”³⁵

The bowhead whale is yet another example of the longevity trinity at work. It too lives a relatively simple life. Unlike most other whales, it doesn’t migrate; it lives its entire life in arctic and subarctic seas. It is among the slowest swimming and least social cetaceans. It also lives a life of constant stress. It’s damn cold in the Arctic Ocean, and zooplankton can be hard to come by for long stretches of the winter. And, sure enough, when an international team of geneticists sequenced the bowhead genome in 2015, its members found species-specific mutations that appear to promote DNA repair, cell-cycle regulation, cancer suppression, and aging—a well-stocked armory of genetic weapons with which to do battle against the wear-and-tear of a long life in the frigid sea.³⁶

Again and again, research has shown that organisms that manage to eke out longer existences in this world benefit from a combination of very basic lives, challenging environments, and cells that can “turn-to” when replenishment is needed.³⁷

Can humans similarly master the simplicity-stress-survivability equation? John Day thinks so. And when the Stanford- and Johns Hopkins–educated cardiologist met me in southern China in 2016, he was determined to prove it.

He started by introducing me to Matao, who was spiritedly walking back and forth between her home and a spot by the river where she had been preparing vegetables by the armful: squatting down, cutting the greens, scooping them up, and then going back for another load—and another, and another. And smiling all the while.

I might have pegged her for a spritely eighty. In fact, Day told me, she was 101.

I couldn’t help but laugh. “Chuckle all you want,” Day said. “She’s the youngest of this village’s centenarians. And not even the most active.”

The elders of Bapan, which straddles the tranquil Panyang River near the Chinese border with Vietnam, don’t have formal records of their births. Owing to this, Bapan was passed over as a “Blue Zone,” a term coined by demographer Michael Poulain to refer to places around the world where people live abnormally long lives. These are places like Okinawa, which has approximately one centenarian for every 2,000 residents. By Day’s estimate, though, Bapan might be one of the bluest places in the world. It is a town where about one in every 100 residents has reached the century mark, and plenty more are right in line behind them, living incredibly healthy and active lives well past the point at which many people in the Western world would tell you they’d rather be dead.

Among the villagers were several who had surpassed 110 years.³⁸ The eldest at the time of my visit, named Boxin, was reportedly 116 years old, and still waking every day from his wooden bed mat to greet the travelers from across China who make pilgrimages to this place to learn the secrets of his remarkably long and healthy life. But what Boxin tells these travelers is that there really aren’t any secrets, just some really good lessons for life.

Day has distilled these lessons down to seven basic principles built around food, motion, mindset, community, rhythm, environment, and purpose. “Underlying all of these things is simplicity,” Day told me one day as we walked across a gently swaying footbridge to meet with some farmers on the other side of the river. “The people here don’t need exercise regimens and dieticians to help them live healthy lives; they simply live healthy lives.”

That doesn’t mean they’ve had stress-free lives. Much to the contrary. The elders here work seven days a week in their fields, and do so well into their nineties and hundreds. Over the decades, they have faced war and political persecution. During the Cultural Revolution, some were tortured and others threatened with execution.

Simplicity? Check.

Stress? Check.

All that was missing from the universal longevity equation, as I was coming to understand it, was some manner of superior cellular survivability.

“Funny thing about that,” Day told me. “The tests I’ve run, the studies I’ve been reading, they don’t indicate anything different about these folks. They’re no more genetically equipped for longevity than you or me.”

That doesn’t mean their bodies aren’t unusually well-equipped for cellular survivability. It means all of our bodies are—or can be.

When we eat fresh and unprocessed foods. When we live lives of constant motion. When we approach the world with optimism, surround ourselves with people we love, live our lives in a reliable rhythm, seek out healthy environments, and find purpose in our lives. When we do these things, our cells become survivors. And that’s not just a gift we give ourselves. Both socially and epigenetically, through the power of inheritable genetic expression, we’re handing good habits and healthy genomes to our children, grandchildren, and great-grandchildren—and increasing the odds that we’ll get to spend a lot more years with them.