Pando: Eighty Thousand Years of the Same Tree

Near Fish Lake in the Fishlake National Forest of south-central Utah, there is an aspen grove that is also a single organism. It covers one hundred and six acres. It weighs approximately thirteen million pounds. It has been growing from the same root system for many thousands of years, making it both the largest known single organism on Earth by mass and among the oldest. Estimates of its true age vary widely, from several thousand years to tens of thousands, and scientists are still working it out.

The grove is called Pando, from the Latin for I spread. All of the approximately forty-seven thousand individual aspen trunks rising from its root system are genetically identical. Each trunk is not a tree in the biological sense; it is a stem, a shoot growing from a root network that connects them all. When you see aspens quaking in a breeze, all the leaves of a connected grove turning together because the petioles that attach them to their branches are flattened at ninety degrees to the blade, you may be watching thousands of stems of a single organism responding collectively to the wind.

Pando is declining. Researchers studying the grove have documented that regeneration is failing: young stems are being browsed by mule deer and cattle before they can mature into the canopy. The older stems are dying on a normal timeline, but the younger replacements are not surviving long enough to take their place. The root system is still alive, still sending up new shoots. But the above-ground portion of Pando is losing ground. The grove is still enormous. It is smaller than it was.

Fishlake National Forest surrounds Fish Lake, a glacially carved alpine lake at nine thousand feet that gives the forest its name. The forest covers roughly one and a half million acres of the high plateaus of south-central Utah, terrain that the Fremont people farmed and hunted over a thousand years ago. The lake produces a trophy trout fishery. The aspen clone at its western edge has been alive since before the last glacial maximum.

Pando has outlasted thousands of human generations. The question now is whether it can endure deer.