The biggest living thing on Earth is being nibbled to death.
A tree is sometimes more than just a tree. Quaking aspens, North America’s most widely distributed tree, often reproduce through cloning. What appear as individual trees are instead collections of genetically identical stems. White trunks with shimmering leaves—green in spring; yellow, orange, pink, or red in fall—shoot up as suckers from a single massive root system. Each clonal aspen stand is a single being.
A single aspen clone often covers less than an acre, but sometimes more—even much more. Sometimes a tree is its own forest.
In south-central Utah, up near 9,000 feet on the Colorado Plateau, in a stretch of national forest dotted with juniper and sagebrush, there stands a peculiar aspen grove. Instead of dozens or even hundreds of clonal trunks, there are 47,000, all connected to a single root structure. Known as Pando—Latin for “I spread”—this behemoth stretches across 106 acres, an area twice the size of New York City’s Grand?Central Station.
Pando is a celebrity. In 2006 it appeared on a postage stamp. In 2014, Utah adopted quaking aspens as the official state tree.?And yet, through the way we’ve managed the land and animals around Pando, it’s being destroyed, one clone at a time.
The problem with Pando
Pando is a thing of mystery. Beginning a mile east of Mallard Bay, on Fish Lake in Utah’s Fishlake National Forest, its 440 stems per acre—about one every 10 feet on average—spread over tens of thousands of yards of volcanic rock, interspersed with boulders, some as big as cars. How did this beast get so big? Nobody really knows. But the fact that it did, and that aspens are so common in the Northern Hemisphere, suggests there may be even bigger single-clone groves waiting to be discovered.
Rogers has spent endless hours in the sway of Pando. He’s written poetry about it, felt his smallness beneath its bigness. Its peacefulness moves him in ways he’s not quite able to articulate.
The stand was brought to the world’s attention by a University of Michigan scientist named Burton Barnes. In the mid-1970s he walked through it and compared leaves on neighboring trees, using them to distinguish between stems originating from a single root system and unrelated trees nearby. Decades later, other scientists sampled DNA from 209 stems across Pando. They showed Barnes had been right. This enormous stand of aspens was all one plant.
It has been known for quite some time that Pando has a few health problems. In the late 1980s, as part of an experiment, the U.S. Forest Service clear-cut two small patches. Nothing grew back. In 1992, they cut another area and fenced it off. That part of Pando is now a very dense stand of about five-inch-diameter trees, all about 35 feet tall.
How could that be? If you cut or kill or burn or scar aspen, its response is to make new babies. Stanley Kitchen, an emeritus research scientist with the Forest Service, has seen aspen groves resprouting with 3,500 shoots per acre—“so many that it’s like walking through a corn field.” Fertility isn’t the problem.
In 2018, researchers finally diagnosed Pando’s afflictions with clarity. At 65 monitoring plots, Rogers and a colleague tracked dead and live trees, stem regrowth, shrub cover—and mule deer feces. The strongest indicator of forest health was regeneration, and the presence of deer corresponded with poor regeneration.
From August to October, when flowers and other plants dry out, mule deer graze and browse in Pando, packing on protein for the fall. About that same time, ranchers with permits to graze cows on nearby forest units pass through for about two weeks a year. All those animals converge on Pando’s shoots, mowing them down before they can become trees.?