What is the oldest known living tree species?

The oldest known living tree species is the Great Basin bristlecone pine (Pinus longaeva). This species is found in the White Mountains of California and Nevada in the United States. Some of these trees have been dated to be over 5,000 years old, making them the oldest known living individual trees on earth.

The Great Basin bristlecone pine has adapted to survive in harsh environments and has slow growth rates, which have contributed to their longevity. The trees have resinous wood that makes them resistant to insects, fungi, and erosion.

Scientists have used various methods to determine the age of these trees, including dendrochronology, carbon-14 dating, and cross-dating. These methods involve analyzing the growth rings of the tree or the isotopes in its wood to determine its age.

While the Great Basin bristlecone pine is the oldest known living tree species, there are other trees that are believed to be older as clonal colonies. These include the Trembling Giant (Pando), a clonal colony of quaking aspen in Utah that is estimated to be around 80,000 years old.