High in the White Mountains of California stands a bristlecone pine that tells a story of volcanic eruptions more than 3,000 years ago. Using a special drill, scientists took core samples of the tree—the world’s oldest inhabitant, nicknamed Methuselah—and inferred from a series of narrow rings when volcanic ash and soot had blocked out the sun. This field of study, in which tree-ring growth is used to date past climatic events, is called dendrochronology. Practitioners from around the world will gather this year in Beijing to reflect on dendrochronalia such as the effects of air pollution on trees in Tehran and how teak head-coffins are dated in Thailand.
