Pando or The Trembling Giant is an enormous grove of Quaking Aspen that is an entire forest out of a single organism. This colony of a single male Quaking Aspen is located in the Fishlake National Forest in Utah, in the US. Each of 47,000 or so trees in the grove are genetically identical and has been determined to be part of a single living organism all sharing a single massive underground root system. Pando is truly massive – it covers an area of 43 hectares, weighs 6,000 tonnes and is more than 80,000 years old.

Quaking aspen reproduces via a process called suckering. An individual stem can send out lateral roots that, under the right conditions, send up other erect stems which look just like individual trees but rather clones of single tree.

Pando’s age is often debated. Some experts speculate that less well-studied Quaking Aspens elsewhere in the world could extend more than 80 hectares and be one million years old. Others estimates puts Pando's age closer to 1 million years.

Pando was discovered by Burton V. Barnes of the University of Michigan in the 1970s. Barnes had described Pando as a single organism. In 1992 the Organisation for Economic Co-operation and Development called Pando the world's most massive organism.