It or she or him is called Pando and is located at Fishlake National Forest in Utah. Pando spans 106 acres (42.8 hectares) and weighs about 13 million pounds (6,000 metric tons), making it the world’s largest living organism by weight and landmass. Pando is approximately 47,000 genetically identical aspens.

Is it the world’s oldest tree? If you count clonal colonies, Pando is estimated to be between 16,000 and 80,000+ years old, making it one of the oldest living organisms on Earth.

If you mean a traditional single-stem tree that grows from a single seed without cloning via roots, the title belongs to Methuselah, a Great Basin bristlecone pine in California that is over 4,800 years old.