The St. Croix Elm



Surrounded by wooded hills and a winding stretch of country road, Chris Bliska's 40-acre property in Afton has everything a farmer might want: a red barn, three horses, an old yellow lab, an apple orchard, an apiary, a wild blackberry patch, and a beautiful lodge-style home. Save for the passing cars and the occasional thrum of farm equipment, it's as quiet and pastoral as a Robert Frost poem. Which makes the giant standing at the bottom of the driveway all the more startling.

At nearly 100 feet tall and with a trunk diameter of more than six feet, it's the largest American elm you will ever see. To say the tree is in the front yard isn't quite right—it basically is the front yard. At its widest point, the crown spans about 110 feet, sheltering anyone who steps near. Go closer, and the tree's quirks emerge: The trunk splits near the bottom, creating the illusion of two trees pushed together, their limbs bending octopus-like in every direction.

Like a lot of natural wonders, the tree has a mystical quality that no amount of cold, hard science can explain. You find yourself wanting to embrace it like that kid from The Giving Tree, though good luck wrapping your arms around the massive trunk carpeted in thick green moss, its bark fissured and gray.

When Bliska and his then-wife Tricia came to Afton and bought the property in 2001, they knew the tree was special, but they had no idea how special. "We weren't even sure it was an elm," Bliska says. So Tricia, who was working on her master's degree in agriculture at the University of Minnesota, asked one of her professors to help.

Bliska was happy with the verdict. A few elms had dotted the property at his previous home near Lake of the Isles, but the trees eventually died, and he was determined not to lose another, especially one this perfect. The couple named their new spread Elm Tree Farm and began searching for someone to tend to the behemoth in their front yard. They ended up hiring a local arborist and plant pathologist who they'd been told was something of a tree whisperer. A guy named Mark Stennes.

When Stennes visited Elm Tree Farm in the summer of 2002, he couldn't believe what he saw: a specimen so perfect that he just stood in silence, trying to remember to exhale every now and then.

The tree's architecture wasn't even the most remarkable thing about it, though. When Stennes walked the Bliska's property, he saw that other elms in the area were dead or dying. The big guy out front, however, appeared healthy. How, he wondered, had the 100-year-old giant survived all these years while its brothers and sisters had been wiped out?

Dutch elm disease is the black sheep of the sac fungi phylum. A minor tweak in its molecular makeup and it could be saving lives.

On a recent afternoon, Stennes answers the door to his New Brighton rambler with a hearty "Come on in!" He walks through the living room— past his wife and a blaring TV—and slides open a screen door and steps out into the spacious backyard. Here, the trees—red oaks, river birch, and elms of all shapes and sizes—are backlit by the sunset.

Stennes, now 62 and a dead ringer for Walter Mondale in his ambassador years, planted most of them when he and his wife moved into the house 30 years ago. "Not a bad spot, eh?" he says, sitting down at a picnic table in the grass. He places his hands—scarred from years of planting, climbing, and cutting—on the table and delivers a brief history of each of his trees, speaking with an affection normally reserved for one's kids. This affection, he says, goes back to his childhood in Bemidji, where he grew up a "lover of wild things."

It's also where Stennes's lifelong obsession with trees, and with elms in particular, was born. In 1964, when he was in sixth grade, he read a newspaper article about a tree-killing fungus called Dutch elm disease, which had begun a rampage that would eventually take out millions of elms across the United States, Europe, and Asia. Soon after reading that story, Stennes visited some relatives in the Twin Cities who had recently had elms removed from their front yard. He wondered if the fungus was to blame. After returning home, he wrote up his theory for a school assignment.

He eventually earned a degree in forest science from the U of M in 1975, and soon after he was hired by the state to be a tree inspector, tasked to track down the very killer that had piqued his interest in elms a decade earlier. The gig required Stennes to plant healthy specimens and to destroy diseased trees through a process known as "sanitation."

It was backbreaking work, made more difficult by a formidable foe. Dutch elm disease is the black sheep in the sac fungi phylum, whose more upstanding members include morel mushrooms, yeast, and penicillin. A minor tweak to its molecular makeup and it could be saving lives or, at the very least, getting us nice and drunk. Instead, it became one of the 20th century's most notorious and destructive plant cancers.

Its method is brutal and efficient. First, it infects the bark beetle, a small insect that breeds in elm logs. The contaminated beetle then feeds on the branches of a healthy elm, passing the spores into the tree's vascular tissue. The tree responds by plugging its vessels to try to stop the fungus from spreading, which prevents water and nutrients from traveling up its trunk. In other words, the disease effectively induces elms to commit suicide.

Once infected, the tree's branches wilt and its leaves turn pale yellow, then brown. Diseased elms die anywhere from three weeks to a year or more after infection. And while any type of elm can get the disease, the American elm is especially susceptible, which is where our story gets personal for people like Stennes.

"People wanted a guaranteed treatment. When they didn't get it, they stopped planting the American elm. They forgot how perfect it is."

- Mark Stennes

In the 19th century and much of the 20th, Ulmus americana was arguably the most loved—and most planted—tree in the United States, valued as a shade tree and as a symbol of American strength (the famous "Liberty Elm" in Boston was a gathering spot for patriots during the Revolutionary War). Looking at old photos of city streets, it's easy to see why it was the preferred boulevard tree for municipalities across the country. When American elms grow up and over roadways, their canopies merge and create a tunnel effect, giving those below the feeling of moving through a leafy cathedral.

Then along came the killer, which supposedly originated in Asia but takes its name from the Netherlands, where it was first described in 1921. From there, it terrorized Western Europe and then hopped a boat to New York in 1928. The rest is the stuff of 1950s nuclear fallout films. The U.S. Forest Service estimates that 77 million elms were present in America's urban areas prior to the introduction of the deadly spore. In the fungus's late-'70s heyday, that number dwindled near zero. Municipalities everywhere had planted elms and little else for at least a century, and they now saw the error of their ways in gruesome, landscape-altering detail (sadly, it took many cities another couple of decades to embrace biological diversity as a planting strategy).

If you grew up in the Midwest or the Northeast during the killer's reign, you remember the Day-Glo orange ring that city workers spray-painted around the trunks of sick elms, the signal that yet another tree was coming down. Stennes remembers more vividly than most: While doing graduate-school work in the 1970s, he saw the disease clear-cut entire Minnesota boulevards. In just one year, 1977, Dutch elm took out 192,211 trees in the seven-county metro area—31,475 in Minneapolis alone. "I kept thinking, sanitation is great," he says. "But if a tree gets sick, it's gonna die."

What he really wanted to do was figure out a way to prevent the disease. When he mentioned this to one of his old professors, D.W. French, a forest pathologist who was one of the few to strike warnings about Dutch elm disease prior to its arrival, French pointed Stennes to a few chemical fungicides, treatments that had made big claims but had yet to be proven effective. Stennes convinced French to give him an assistantship in plant pathology at the U of M so he could study and figure out how to control the killer. Through research and field tests, Stennes discovered that Arbotect, one of the chemical treatments, could be made effective through proper dilution and injection. It soon became the industry standard—a vaccine for healthy elms and a sort of chemotherapy for sick ones.

Upon completing his master's degree, Stennes took Arbotect on the road, teaching others around the country about how to properly apply his techniques. "I was kind of a rock star in the '80s," he says. "We saved thousands of trees with that fungicide." But Arbotect was no magic bullet. Elms continued to die along boulevards, and instead of planting more, cities replaced them with cheap, easy-to-produce ash trees, which Stennes calls "the ugliest f---ing tree."

Meanwhile, the public lost faith in the once-mighty American elm. It became a fond but distant memory, a metaphor for a version of America that no longer exists. And though Stennes continued to work tirelessly combatting the disease, what he really hoped for was a revelation.

"People wanted a guaranteed treatment for the fungus," says Stennes. "And when they didn't get it, they stopped planting the American elm. They forgot how perfect it is. But I didn't."

"There are a few ratty elm trees left around the Twin Cities, but none as majestic as Chris's."

- Debbie Lonnee

I guess I had an epiphany," says Stennes. He's referring to the theory he developed about Bliska's elm after he first visited in 2002. He considered the facts: For thousands of years, oak trees dominated upland forests in Minnesota, with the elm being a close second. A tough plant that grows like a weed, the elm—at least before Dutch elm disease arrived and ruined the party—could often live to 100 years or more and reach heights of more than 100 feet.

All of which is why Stennes was so surprised when he saw Bliska's tree. He knew that to live more than 100 years, the elm would have had to endure an extraordinary amount of infection.

So he began "rattling cages and knocking on doors," eventually drumming up grant money for the U of M to look at the tree. "I'm incredibly stubborn," he says. "I bugged the U until they had no choice but to listen."

In 2005, researchers from the school's forest pathology department finally went to Afton to visit Elm Tree Farm. They took some cuttings and brought them back to a lab at the U of M's St. Paul campus, where they grew clones for testing.

Next came an inoculation trial, in which lab workers drilled holes in the stems of the seedlings, injected them with a liquid containing spores of Dutch elm fungus, filled the holes, and waited. To everyone's dismay, the clones died off. The researchers set them outside and moved on to other projects. Stennes, who theorized the tree would be able to tolerate the fungus, took the news especially hard.

But then, a month later, the clones had survived, and the scientists wondered if such a recovery could occur in the field. Clones of the elm were planted around the U of M Agricultural Experimentation Station, then given a similar trial to those grown in the greenhouse. The trees thrived.

While the clones were being tortured for science, Bliska applied to patent the tree so he could control its future should its cultivars ever be commercially viable. He hired a patent attorney to do the paperwork and consult Stennes. "The U had its doubts that we'd ever get the tree patented," says Bliska. "And, frankly, so did I."

Though it's not uncommon to patent plants, Bliska's elm was unique in that nobody, not even researchers, could explain why the tree could tolerate the Dutch elm disease fungus. Chad Giblin, a research fellow in the U of M's Department of Forest Resources, had led two of the field inoculations. He had his theories, as did others (one being that the tree's unusually small vessel diameter slowed the spread of disease), but there was no proof. So when the patent office asked what made the tree so special—why it should get a patent, essentially—Bliska wasn't sure what to say. He consulted with Stennes, who, without missing a beat, replied, "What's unique about it is the fact that it exists—that it's alive."

"I'd like to leave something behind. That tree would be a good one."

- Mark Stennes

Bliska included his ex-wife, Stennes, and the U of M on the patent. He and Stennes, who had named the tree the St. Croix Elm, then approached Bailey Nurseries in Newport, one of the largest wholesale nurseries in the country, with a proposition. Debbie Lonnee is in charge of acquiring new plants for Bailey. When her department sees a promising variety, she grows and tests it to determine its commercial potential. "I grew up in Mac-Groveland in St. Paul, and I remember my street had a total shade canopy of elm trees," she says. "By the time my parents moved in the 1990s, there were no elms left."

On Stennes's recommendation, Lonnee and other Bailey employees visited Bliska's elm in 2006. "My jaw dropped when I saw it," she says. "There are a few ratty elm trees left around the Twin Cities, but none as majestic as Chris's."

Bailey Nurseries took its own cuttings and spent the next few years growing them in a bare root field to see if they would thrive in a nursery setting. Bailey liked what it saw, so when Bliska asked the nursery to manage the licensing and growing of his elm, Lonnee says it was a no-brainer. Bailey will harvest the first crop of St. Croix Elms this fall and ship them to eager wholesale nurseries, retailers, and growers in the spring of 2015.

Lonnee estimates that the St. Croix Elm will retail for about $100 for a 4- to 5-year-old tree standing anywhere from six to 10 feet tall. That's slightly more expensive than other elm varieties due to its higher-than-average royalty rate: $2 per tree, which will be split among the patent holders.

"I'm very hopeful for the St. Croix Elm," Lonnee says. "But it's a gamble any time Bailey releases a new plant." There have been other attempts at producing disease-tolerant elms, but none have been particularly successful. The "Princeton" elm, developed in a New Jersey nursery in 1922, is sold and planted around the world. But it has shown only moderate tolerance to the fungus. While the "Valley Forge," released by the U.S. National Arboretum in 1995, has the opposite problem: It boasts a high level of disease tolerance but is slow to reproduce. Lonnee hopes that the St. Croix Elm can combine Valley Forge's efficacy with Princeton's marketability. "The patent on the St. Croix Elm lasts for 20 years," she says. "Sometimes it takes that long for a tree to catch on."

Stennes doesn't have 20 years. The shepherd of the St. Croix Elm is battling liver cancer, a diagnosis he received two years ago. He stopped working in early 2013 and today has just enough strength to mow the lawn and tend to his own trees. "I know my odds," he says at the picnic table. "At this stage, my days are numbered." It's tempting to see his work through the prism of his own illness, a connection Stennes doesn't shy away from. "Liver cancer hides behind the shower curtain, waiting for you to come in," he says. "Dutch elm is in your face, out in the open. It's a failure of our society—of the things we deem valuable—that we dealt with Dutch elm so late."

There's urgency in his voice, which slurs a little these days, a side effect of the morphine he takes to ease his discomfort. Seeing those seedlings prosper in Minnesota would bring him peace. "I'd like to leave something behind," he says. "That tree would be a good one." And, he says, if his wife of 40 years and three adult daughters get a nickel or two down the line, all the better.

Asked if he thinks his discovery of the elm in Afton was a foregone conclusion given his early interest in trees and eventual career path, he nods. "In some ways it was preordained. The good Lord does for us what breeders can't. It gives us those rare oddities with just the right combination of genetically controlled characteristics. But I know I'm incredibly lucky to have found that tree. One in 250,000—that's the number of elms that are tolerant to the fungus."

That doesn't actually sound that rare, until you consider the slim probability of an expert like Stennes stumbling upon such a tree in the first place. What if Bliska hadn't owned the St. Croix Elm back in 2002? What if some other arborist got the call? Maybe the tree would have remained an anonymous miracle, like all those supposed cures for disease that await discovery in the Amazon.

Stennes rises from the table and walks toward the house, moving cautiously and with a slight hunch, clearly weakened by his illness. "I want to show you something," he says. He stops by the side of the garage and points to a short, scruffy-looking elm with unruly branches hanging out over the trunk like big green dreadlocks. "St. Croix," he says. "One of the copies. It could use a trim, but man is it doing well."

Chris Clayton is a Twin Cities writer and editor.

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Trees are as close to immortality as the rest of us ever come.

- Karen Joy Fowler