dendrochronologii

Dendrochronology is the scientific method of dating tree-ring sequences to the exact year(s) of formation by using patterns of growth rings. Each ring generally represents one year of growth, with ring width, density, and wood anatomy reflecting past climate and site conditions. By comparing patterns of wide and narrow rings across many samples, researchers build master chronologies that can anchor the calendar year for wood from living trees, dead wood, or wooden artifacts.

Methods involve precise measurement of ring widths, sometimes combined with wood density or stable isotope analysis. Cross-dating aligns ring-sequence patterns from different pieces, allowing the construction of long, continuous chronologies. When a sample’s rings can be matched to a known chronology, the exact year of formation for each ring is established. In some cases, a floating chronology can be anchored to the calendar by matching to master chronologies.

Dendrochronology has a long history since the work of Andrew Ellicott Douglass in the early 20th century. Today, it is used in archaeology, art history, and paleoclimatology, to date wooden structures, ships, or beams, and to reconstruct past climate variations. It also plays a key role in calibrating radiocarbon dating, providing a calendar framework for radiocarbon results.

Limitations include the need for well-preserved wood and suitable growth-ring patterns; tropical regions often lack distinct annual rings, and local disturbances can disrupt patterns. The "old wood problem" can complicate dating when the wood used in a structure is older than the event being dated. Despite these caveats, dendrochronology remains a central tool in dating and environmental reconstruction.