Soumaya Belmecheri, Valerie Trouet and Matt Meko from the Tree-Ring Lab were part of the group that identified the oldest known living tree in Europe while collecting samples in the Pindus Mountains of northern Greece. The group named the tree Adonis, following a tradition of assigning names to other ancient trees (such as Methuselah or Prometheus). Only dendrochronology, the science of tree-ring dating, can accurately determine the age of trees, since estimates from size or appearance are often completely mistaken. Adonis is a Bosnian pine (Pinus heldreichii) with an appearance and setting similar to the oldest known trees, the bristlecone pines of the White Mountains of California. Like them, it is relatively small, growing by tiny amounts each year, and is surrounded by open ground high up in the mountains rather than being part of a dense forest. Paul Krusic from Stockholm University in Sweden led the group (which also included researchers from the University of Mainz in Germany), and was not seeking the oldest tree: the main aim of the expedition was reconstructing past climate from long tree-ring chronologies. This was not the first dendrochronological sampling expedition to the Pindus Mountains of Greece, and one of the earlier trips was run by Ramzi Touchan of the University of Arizona Tree-Ring Lab, but none of the others had identified the Adonis tree.