Which tree lives the longest?

Great Basin bristlecone pines in the western United States are the longest-lived individual trees known, with one specimen named Methuselah confirmed to be over 4,850 years old — meaning it was already a mature tree when the Egyptian pyramids were being built. These gnarled trees survive in harsh, high-altitude environments where their slow growth and dense, resinous wood resist rot and insects. If clonal colonies are counted, a stand of quaking aspen in Utah called Pando shares a single root system estimated to be tens of thousands of years old, making it one of the oldest and heaviest living organisms on Earth.