The Saguaro Solution

Can a massive effort to replant cacti in the Sonoran Desert restore an ecosystem ravaged by fire?

The cacti arrive in buckets and cardboard boxes, truck beds and plastic cups. Some are prickly green knobs smaller than a fist; others are saguaros (Carnegiea gigantea) a few feet tall—miniature versions of the columnar cacti that live only in southern Arizona, southeastern California, and northern Mexico. Volunteers slip on elbow-length leather gloves buffered with Kevlar and lined with fleece, then wrap the saguaros in chunks of carpet and haul them onto a wildfire-blackened hillside in Arizona’s Sonoran Desert. Saguaros can grow for centuries and reach 45 feet in height or more. Some of these cacti are already so large they demand two people to lift them.

Volunteer crews swarm the charred hills, hurrying to do the heavy lifting and digging in the 70-degree November morning before the day heats up. A Forest Service employee strides among the desiccated white skeletons of prickly pear (Opuntia engelmannii) and staghorn cholla (Cylindropuntia acanthocarpa) with a motorized post-hole digger. He presses it into the dirt. The engine roars like a leaf-blower, reddish earth peeling up from the whirling bit. Volunteers’ shovels clear loose dirt and rock from the freshly dug holes.

The saguaro-haulers steer the saguaros into place, guided by a stripe of spray paint down the cactus’s side that dictates which way needs to face north. On the south-facing sides of a saguaro, its vertical ribs squeeze together, the pinkish spines thick to shade the green skin beneath. On the north-facing side, those pleats and spines are spaced loosely enough to slip a finger between them and touch the skin. Transplant a saguaro with the north side facing south, and it could sunburn and die.

A volunteer pours water over the shriveled, pale stump and hunched roots before others tip the saguaro into the waiting hole. Once the cactus is in place, the team shovels dirt around its base, tamps the soil down, and pours more water over and around it.

“If somebody asks you, ‘Hey, can you hold on to this?’ while it’s tipping and you get a feel of just how much it weighs, it’s a little intimidating,” says Nicole Corey, co-founder of Natural Restorations, an organization that partners with the Forest Service on cacti-transplanting efforts. “Nobody wants a two-inch cactus needle to go through them.”

Many ecosystems evolved to live with wildfire, but the Sonoran Desert is not one of them. Saguaros have no defense against fire, and no ability to rebound from fire damage. In ideal conditions, they grow at a rate of inches per decade, and spend years sprouting a single arm. So when the Bush Fire—spurred by combustive invasive grasses and climate change—burned an estimated 80,000 saguaros in the Tonto National Forest near Phoenix in June 2020, it transformed that desert, including this patch volunteers are working to replant, for lifetimes to come.

After the fire, people might have written the place off as lost. Bec Veerman couldn’t stand to see that. Veerman is the partnership liaison for Tonto National Forest. When the idea of moving a few cacti into the burn scar reached her, she ran with it. What began as a small event for public education blossomed into an effort that has transplanted hundreds of cacti and helped the desert rebound from the Bush Fire and other not-so-natural disasters. The work serves as a kind of pilot project for restoring a landscape never made to burn, and an on-the-ground experiment in whether we can restore ecosystems we have otherwise forever transformed.

In May, almost nothing is in bloom in the Sonoran Desert, and the humidity hovers in single digits. But that’s when saguaros start pushing buds, bulbous knobs of bundled leaves tipped in red, each with extra-floral nectaries that feed numerous insects. In June, which is even hotter and drier, the saguaros bloom crowns of white flowers with sunburst yellow centers. The blossoms open at night, pollinated by moths and bats that dip long tongues into the sunburst, then the blooms shrivel over the course of the day. Their crimson fruit ripens by July, feeding white-winged doves (Zenaida asiatica), mourning doves (Zenaida macroura), and orioles (Icterus cucullatus and Icterus bullockii) while they’re atop the cacti, and coyotes (Canis latrans), javelina (Tayassu tajacu), and Sonoran desert tortoises (Gopherus morafkai) once they’ve fallen to the ground.

“For many species during those months, the saguaros are the lifeblood — they’re the grocery store,” says Jonathan Horst, director of conservation and research with the Tucson Audubon Society. “They’re still providing fruit and food in a time of year when there’s basically nothing else available.”

Saguaros are some of the desert’s tallest vegetation. Their pillar-like tops provide platforms where raptors and ravens nest, while smaller birds make their homes in the crooks between their trunks and arms. After Gila woodpeckers (Melanerpes uropygialis) and gilded flickers (Colaptes chrysoides) poke past the hard, woody structure that holds the plant upright and into its spongey interior, roughly a dozen species, including elf owls (Micrathene whitneyi) and desert purple martins (Progne subis hesperia), can enjoy a nest insulated from the soaring desert heat.

After a saguaro dies, falls to the ground, and turns into a wooden skeleton, it also becomes habitat for ground-dwelling animals, ranging from lizards, snakes, and packrats to poorwills (Phalaenoptilus nuttallii) and other birds that hibernate inside the ribs. “At every step of their lifecycle, once they reach a certain size, they’re valuable for animals,” says Don Swann, a biologist with Saguaro National Park. “And for people.”

The Hohokam people, ancestors of the modern Tohono O’odham, framed their homes with saguaro ribs and lashed pieces of the stiff wood into poles to knock ripened fruit from saguaro tops. Today, Tohono O’odham and Piipaash, or Maricopa, tribal members use similar methods to gather saguaro fruit for food, medicine, and ceremonies. Saguaros play a vital role in Indigenous creation stories, including many tales of humans who become saguaros. In general, Swann adds, Arizonans “feel a kind of reverence and affinity toward the saguaro. For a lot of us, it’s one of the things we really love the most about living here in the desert.”

Yet Arizona’s beloved hillsides of sunlit saguaros, rimmed in gold where the light touches their spines, are in danger of disappearing—and not only from fire. As climate change makes desert summer rains more episodic and crucial winter rain rare, fewer young saguaros are surviving. At Saguaro National Park, drought has killed all but a few young saguaros since the mid-1990s.

Although mature saguaros are incredibly hardy, the conditions their seeds need to sprout and survive are rare. Those conditions—two strong summer monsoons with a wet winter between, with no hard freezes and no long droughts for several years—historically occurred every 20 years or so, which is why mature saguaro forests grow in stair-steps, rather than a gradient. Saguaros cope with these odds by living for nearly 200 years and scattering thousands of seeds each year.

Saguaros start life slowly, reaching an inch to an inch and a half in height in eight years. A saguaro doesn’t start flowering—providing a vital food source and reproducing—until it’s more than 35 years old. Around age 50, the cactus starts growing arms, which also flower. The saguaro’s pleated trunk won’t accommodate a woodpecker cavity until it’s about 8 feet tall, or 80 to 120 years old, Horst explains, and likely won’t host a raptor nest until it’s about 150 years old.

“So when we lose an adult saguaro,” Horst says, “it’s not something that’s being replaced in our lifetime.”

In the Sonoran Desert of the past, bare, rocky soil sprawled between clumps of shrubs and cacti. That soil hardened into a firm crust colloquially called “desert pavement.” When that pavement is stepped on, chunks of the crust flake, releasing a powdery layer beneath. As settlers brought cattle to graze the sparse native grasses in the late 1800s, their hooves chopped through the crust. The fine desert dirt began to blow away. Worried about losing the landscape, ranchers and government agencies imported nonnative grasses to hold down the ground. Many came from the African savannah, where they evolved with wildfire. Settlers imported other grass species for landscaping or cattle forage.

The result is a sea of red brome (Bromus rubens), Mediterranean grass (Schismus barbatus), fountain grass (Pennisetum setaceum), and buffelgrass (Cenchrus ciliaris), punctuated by islands of cacti. In the northern Sonoran Desert, near Phoenix, red brome is the primary troublemaker, says Mary Lata, a fire ecologist with the Tonto National Forest. Red brome starts growing when winter rains begin. Then in spring, when the moisture turns off for months, the grass dries to a tinderbox.

Around July, monsoonal summer storms roar into the Sonoran Desert from Mexico, bringing about half of the region’s annual precipitation—along with lightning. Historically, lightning would have ignited a few fires in the Sonoran Desert. They were infrequent and small, because the desert had little fuel for burning. “You would get a lightning strike, it would burn up a little chunk, and then it would go away,” says Lata.

Today, the non-native grasses that grow in a knee-high carpet between the shrubs and cacti act as fine fuels—kindling—to carry fire in a new way. The Bush Fire started in 2020 when an overheating vehicle pulled off the road and the brakes sparked roadside grasses. Wind and dry conditions spread the fire over 194,000 acres of the Tonto National Forest. Each of the last three years has seen fires of more than 100,000 acres in southern Arizona. Twenty-five percent of the Tonto’s share of the Sonoran Desert now has burned, Lata estimates, and she expects more to burn in years to come.

The Sonoran Desert ecosystem is “only” about 10,000 years old, meaning it’s inherently unstable, Lata adds, with a blend of species still sorting out hierarchy and patterns. Some are adapted to live with fire. Others aren’t.

“When you have that kind of a mix, it’s easy, ecologically, for it to get pushed one way or another,” Lata says. Humans are nudging the entire system to favor species that can survive fire, such as sugar sumac (Rhus ovata), mesquite (Prosopis velutina) and varieties of acacia that have taproots extending several feet underground.

Saguaros and other cacti, in contrast, are among the species on the losing end. Most grow fine roots just below the surface, where they can be easily scorched by fire. The saguaros that don’t die immediately—by exploding into flames—usually die in the following years, their fire-scarred trunks vulnerable to infection or due to starvation because they cannot photosynthesize through their fire-burned skins.

The first time Corey, with Natural Restorations, drove through the Bush Fire’s scar, she cried. “It was just so devastating to see saguaros that had been here long before we were born just torched.”

Climate models predict more frequent and extreme droughts that will dry soil and plants. Together with the increased invasive species, such droughts could dramatically alter desert ecosystems, affecting habitat and wildlife as well as downstream water quality. After the Bush Fire burned through watersheds for the Salt and Verde rivers, sediment and ash choked two of the Phoenix area’s only perennial rivers. The cycle is set up to reinforce itself, where the landscape burns, then burns again.

Without help, and perhaps even with it, coming centuries could see saguaros relegated to rocky slopes where boulders break the blanket of invasive grasses. The thick forests of the massive cacti fuzzing the horizon line could become a sight of the past.

In many places where wildfire resets landscapes, the Forest Service and other land management agencies take a hands-off approach, trusting that nature will heal itself. But in the case of the Sonoran Desert, says Bec Veerman, the fires themselves are unnatural, fueled by invasive grasses. “If you have a hole in the ground after any kind of disturbance, whether it be a flood or a fire or whatever, something is going to grow there,” she explains. “So we just want to make sure that we replace it with something that we want. Because otherwise, we’re going to continue to see [more of] these massive fires and be able to do less and less about it.”

After the Bush Fire ravaged the Tonto National Forest, Veerman started calling around to plant nurseries, looking for a few saguaros to transplant. Kelly Kessler, a biologist with the Tonto, had mentioned moving about 10 saguaros. But as Kessler recalls, Veerman had bigger ambitions: “Let’s do 400 instead,” she suggested.

Veerman, who wears eyeliner even for a day working in the desert and whose tattooed forearms are embedded with cactus spines, brings an infectious enthusiasm to projects, says Kessler—an enthusiasm that pulls in others and makes them want to help, too.

Kessler is the ideas person, demurs Veerman. Veerman jokes that she just likes to throw parties. She gets excited about an idea, and then she gets loud about it. And the ideas take off.

To engage users of public lands in the restoration effort, Veerman has turned planting of cacti into a community event. For the first transplanting party, in November 2020, she selected a busy trailhead near Phoenix where the cacti would be highly visible. She enlisted the help of Copperstate 4 Wheelers, an off-road vehicle club; Natural Restorations, which hires military veterans to clean up trash and graffiti on public lands; and Four Peaks Brewery, whose staff have committed to visiting the replanting site every four to six weeks for a year to water the transplants.

Most of the 400 cacti that volunteers planted the year of the fire were donated from Arizona Wholesale Growers. Eighty were saguaros; the rest included prickly pear, staghorn cholla, barrel cactus (Ferocactus wislizeni), hedgehog cactus (Echinocereus spp.), and ocotillo (Fouquieria splendens), which send up spindly arms rimmed in red blossoms in spring.

Veerman returned in November 2021 with another 320 cacti and even more volunteers. This time, the cacti were salvaged from a site where the Bureau of Land Management was creating a new campground and off-road vehicle area. Someone from the BLM called to ask if the Forest Service wanted to come collect cactus plants there before the area was plowed.

“And we’re like, why, yes, we do,” Veerman says. “And they are very fat, because they got all that rain in this summer, so it’s really good, because they’re nice and healthy.”

A few other saguaros came from construction sites, where Phoenix’s latest housing boom would have bulldozed them. Saguaros are often transplanted for landscaping or from development, and transplanting guides abound. But there are limits. Mature saguaros, some nearly 50 feet tall and with more than half a dozen arms, can weigh several tons. They also depend on, and are held upright by, a web of roots grown in a thin layer through the soil around them for as far from their trunk as the plant is tall. They rarely survive being cut off from that system and are prohibitively difficult to keep upright while they work at reestablishing roots. Smaller, younger saguaros often survive being moved.

While Veerman was confident they could relocate a few saguaros to the burn scar, she didn’t know if they could salvage something from the saguaros the fire damaged but hadn’t yet killed. There, the experimental work began with cutting off a still-green arm, letting it scar over for a few weeks, then planting it right back where it came from. They knew the technique worked with prickly pear and cholla, but, Veerman says, “I was always told you can’t do it with saguaros.”

Turns out you can—“it’s just a little bit trickier,” Veerman explains. The removed arm is wrapped in a ribbon with GPS details for exactly where the cutting was taken, and they replant it alongside the saguaro from which it was harvested. That keeps it in the place its genetics seem well-suited for, rather than guessing at where it might find success. The team is still studying whether it works best to take an arm or cut the top off the saguaro. If more than one cutting is collected, and both survive, the second might be dispersed elsewhere in the burn area. So far, the results are promising, but there’s much yet to learn.

“They tend to grow a lot stronger, and they’re already at a 10- to 15-year head start on a regular seedling,” Veerman says. “Mind you, it is still a 120-year-old cactus at this point. So how long it will live is another part of our experiment. We don’t know. Genetically, it’s like, okay, are you 120 years [old] and you’re done? Or is it sort of starting the clock over?”

One issue the effort raises, Kessler says, is that humans now are managing this ecosystem. The question cannot be, How do we restore an ecosystem to the way it was, but, How do we govern our ongoing effect? “As soon as we put our hands in,” she says, “we have to keep our hands in.”

On a November morning, I headed to a busy trailhead a half-hour’s drive west of Phoenix to the annual planting event to help the desert heal from the Bush Fire. Once, the view had been a vibrant, thorny landscape of prickly pear and staghorn cholla and saguaro, with scattered wildflowers, and occasional palo verde trees (Parkinsonia florida) offering pockets of shade. Now, for miles, the hills offer only smears of black, the collapsed starbursts of dead yucca and spindly outlines of burnt trees. “This is really hard to see,” says Rebecca Davidson, the Southwest region director for the National Forest Foundation, a Congressionally chartered nonprofit that fundraises for and supports programs the Forest Service administers.

At the trailhead, volunteers sign waivers and pick up t-shirts. Then everyone is handed a packet of seeds to scatter, and pointed to a cactus to plant. Davidson insists I don a pair of the leather gloves, which feel like oversized oven mitts, and then carry a tiny hedgehog cactus to its new home. It is featherweight and smaller than my palm. I tuck it in alongside a sheltering rock, then accidentally pull it back out again as its hooks catch in one gloved finger after another. I nudge it back into place again until it stays.

The National Forest Foundation joined for the second season of desert rehab work—“new to this, but really excited to be here,” Davidson says—and is helping to firm up the project for the long haul. Their first priority is to construct a cactus plant nursery to house collected saguaros and cuttings while they scar over, along with a watering truck and other planting materials and tools. Although many national forests operate their own nurseries, the agency has never had to grow cacti before, Veerman says: “These fires are new—this is all new to us.”

The Forest Service also isn’t alone in catching on to the need for this work. Natural Restorations is pursuing additional grant funding for cacti relocations, often working with an engineer who salvages cacti that would otherwise be plowed for development. The Tucson Audubon Society is seeking funding to remove invasive species and transplant native species in the fire scars from the Bush and Bighorn Fire, a lightning-start that burned 119,978 acres near Tucson in 2020. They’re also helping with saguaro migration, planting them in places forecast to be good saguaro habitat 100 to 150 years from now.

“By the time climate changes [more drastically], they’ll already be big enough to provide all the ecosystem services we want them to be able to provide,” Horst says.

As the transplanted cacti take root in this hotter, drier Sonoran Desert, the people who put them in the ground watch carefully—documenting every step, photographing these sites as they recover. Drones routinely zip overhead, taking thousands of aerial images of replanted plots that are then stitched together and geo-referenced. The resolution lets project managers zoom in to a couple of centimeters to assess whether vegetation has survived: All the saguaros transplanted in 2020 were still alive in late 2021. Some of the prickly pears had grown a new paddle. None of the 10 ocotillo had survived.

Veerman is frank—maybe these are modest gains, a tiny solution to a massive problem, limited by logistics and basic ecological principles. “You, as a human person, cannot ‘restore’ anything,” she says. “You can only supply an ecosystem with the materials so that it can restore itself.”

A saguaro might be only one piece of that ecosystem, but it’s a key piece. Returning it to its home is a step toward reimagining our planet not as fixed and final—a finished product—but as a globe that’s continuously shifting and evolving, with humans an integral part of it.

No rain is expected for months after the planting, but when it comes, all the recently transplanted barrel cacti will flush red. The slopes will seem to glow with small fires, but this time, they’ll blaze with possibility instead of death. The seams of saguaros will swell outward, their spongelike interiors fattening with water. “Rain roots” that sprout within hours of the storm will capture even more of its moisture and store it for the long wait until rain comes again. All the while, the desert will shelter bobcats and bats, hummingbirds and woodpeckers, butterflies and moths. Here, at least for now, will be a Sonoran Desert still singing itself to sleep as the insects, birds, and coyotes come out in chorus with the twilight and stars.

Elizabeth Miller

Lauren Owens Lambert

Elizabeth Miller is an independent journalist who has written about environmental issues around the American West for publications including Backpacker, Outside, Scientific American, and The Washington Post. She’s been anthologized in Best American Travel Writing and won awards or grant support from the Society of Professional Journalists, National Geographic Society’s COVID-19 Emergency Fund for Journalists, and Institute for Journalism and Natural Resources.

Ash Ponders

Lauren Owens Lambert

Panamanian, Tisoy multimedia artist Ash Ponders lives in the Sonoran Desert making visuals rooted in the history of both the environment and the people who live there for news and art galleries. They're also an award-winning poet and translator. They desperately want you to follow them on Instagram @ashponders.

Kendra Smith

Lauren Owens Lambert

Kendra Smith is a documentary photographer based in Bentonville, Arkansas. She has a multi-disciplinary background in photography, cultural anthropology, and communicative arts. When she's not behind the camera, Smith is with her two pups outdoors, cooking, gardening, or traveling the world.

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