One root system in Utah grows 47,000 trunks that are all a single organism

Every trembling trunk across 106 acres of Utah's Fishlake National Forest known as Pando is genetically identical, joined underground by one continuous root system rather than being separate trees. DNA testing confirmed the single clone in 2008; it's estimated to weigh about 6,000 metric tons, likely the heaviest known living organism, with a root system that may be thousands of years old.

— Jennifer DeWoody, Carol A. Rowe, Valerie D. Hipkins and Karen E. Mock, "Pando" Lives: Molecular Genetic Evidence of a Giant Aspen Clone in Central Utah — Western North American Naturalist, Vol. 68, No. 4, 2008