In the Fishlake National Forest in Utah, a giant has lived quietly for the past 80,000 years.

The Trembling Giant, or Pando, is an enormous grove of quaking aspens that take the “forest as a single organism” metaphor and makes it literal: the grove really is a single organism. Each of the approximately 47,000 or so trees in the grove is genetically identical and all the trees share a single root system. While many trees spread through flowering and sexual reproduction, quaking aspens usually reproduce asexually, by sprouting new trees from the expansive lateral root of the parent. The individual trees aren’t individuals but stems of a massive single clone, and this clone is truly massive. “Pando” is a Latin word that translates to “I spread.”

Spanning 107 acres and weighing 6,615 tons, Pando was once thought to be the world’s largest organism (now usurped by thousand-acre fungal mats in Oregon), and is almost certainly the most massive. In terms of other superlatives, the more optimistic estimates of Pando’s age have it as over one million years old, which would easily make it one of the world’s oldest living organisms. Some of the trees in the forest are over 130 years old.

Unfortunately, the future of the giant appears grim. According to Paul Rogers, an ecologist at Utah State University, the Trembling Giant is in danger. While the mature stems of Pando routinely die from the eternal problems of pests and drought, the regenerative roots of the organism that are responsible for Pando’s resilience are under attack as well. Rogers reported a marked absence of juvenile and young stems to replace the older trunks, blaming overgrazing by deer and elk. Without new growth to replace the old, the Trembling Giant is vulnerable to a catastrophic sudden withering and shrinking.

The quaking aspen is named for its leaves, which stir easily in even a gentle breeze and produce a fluttering sound with only the slightest provocation. The effect of this in Pando–multiplied over the tens of thousands of trees and hundreds of acres–can be unnerving, giving a real sense of life to the ancient, dying, trembling giant. One of the most popular seasons to visit Pando is fall when the leaves turn bright yellow.