When people talk about the biggest living things on Earth, they usually picture blue whales or redwood trees. One of the most impressive organisms on the planet is something you could walk through without realizing it. In Utah’s Fishlake National Forest there is an aspen grove called Pando, and scientists say it is not a forest at all, but a single enormous organism.

What Pando Actually Is

Pando is a clonal colony of quaking aspen. That means all of the visible “trees” are genetically identical stems that sprout from one massive underground root system. Instead of many separate trees, you have one organism with tens of thousands of trunks.

Estimates suggest Pando covers about 43 hectares, or 106 acres, and weighs around 13 million pounds. That is roughly the weight of a dozen or more jumbo jets sitting in one spot.

How Old Is This Thing?

Dating a clonal organism is tricky, but researchers think Pando’s root system is several thousand years old, and recent modeling has suggested a possible age well into the tens of thousands of years. Individual stems only live about a century, but as older stems die, new ones grow from the same root network, so the organism as a whole can persist far longer than any one trunk.

Why Pando Matters

Pando is often cited as one of the largest and heaviest organisms on land. Offshore ecosystems like seagrass beds and coral reefs can also reach huge sizes, but Pando stands out because it is a single genetic individual you can map and study.

It is also in trouble. Browsing by deer and other animals has kept many young stems from surviving, which means parts of the colony are aging without enough replacements. Conservation efforts are underway to protect it so that this massive organism does not slowly fade away.

In Short

• Pando looks like a forest, but it is really one huge aspen organism connected by a single root system that weighs about 13 million pounds.
• Its stems live for around 100 to 130 years, but the root system has persisted for thousands of years, possibly much longer.
• It may be one of the largest living things on Earth, and protecting it means protecting an entire living system, not just a collection of trees.