Which tree species forms Pando, one of the world’s largest and oldest clonal organisms?

Pando is formed by the quaking aspen species Populus tremuloides.

Pando is a clonal colony in Utah, United States, made up of genetically identical quaking aspen stems connected by one extensive underground root system. The visible trunks are often called individual trees, but genetically they are parts of one organism. The name Pando is Latin for “I spread.”

The colony occupies about 43 hectares and has thousands of trunks. Its age is difficult to determine because the root system is far older than any single stem; estimates commonly place its origin in the range of thousands of years.

Pando is not the same as the oldest individual tree. Bristlecone pines hold notable records for individual-tree longevity, while Pando’s distinction comes from clonal growth. Browsing by deer and elk, along with reduced regeneration, has raised conservation concerns because young stems may fail to replace older ones.