How experts have determined that bristlecone pines, sequoias and baobabs have stood for thousands of years

By Jared Farmer, January 3, 2023

What and where are the oldest known trees on the planet?

If you include plants that can regenerate, the upper age limit could be ten thousand years or more. Such superorganisms, including the famous aspen grove nicknamed “Pando,” are made up of genetically identical trunks connected through a single root system that sends up new shoots over time.

These clonal colonies are impossible to date with precision, because the oldest substance long ago decomposed. Many lists of oldest trees stick to single-trunked plants that produce annual growth rings. These kinds of trees are easier to date. Scientists called dendrochronologists focus on assigning calendar years to tree rings and interpreting data within those rings. By using a hand-cranked tool called an increment borer, they extract core samples without depriving the tree of strength and vigor.

Source: The Science Behind the Oldest Trees on Earth | Science| Smithsonian Magazine