Dendrochronology

Dendrochronology is the science of dating and interpreting wood and climate from tree rings. Each annual ring records the tree's growth response to weather during that year: wide rings indicate favorable conditions (adequate water, warmth, light); narrow rings indicate stress (drought, cold, shade). By crossmatching ring-width patterns across trees and backward in time using dead wood, researchers construct chronologies extending centuries to millennia, providing archives of regional precipitation, temperature, and hydroclimate independent of instrumental records.