One of the largest living organisms on Earth is a single forest of genetically identical trees.

In Utah’s Fishlake National Forest grows a quaking aspen colony known as Pando, made up of tens of thousands of trunks that look like individual trees but are actually genetically identical stems sprouting from one single, massive root system. The whole colony covers over 100 acres and is estimated to weigh more than any other known organism on the planet.

Because it spreads by sending up new shoots from its roots rather than relying only on seeds, Pando has been able to persist and regenerate itself for an extremely long time, even as individual trunks age and die off and new ones take their place. Researchers now monitor it closely, since grazing animals eating the new shoots have been preventing the colony from regenerating as it once did.