Cross dating tree rings - Principles of Dendrochronology - University of Tennessee


Tree rings are more than a record of years. Year-to-year variation in the width of rings records information about the growth conditions in the particular year. Insect infestation clearly manifests itself, as does disease or fire damage. Each of these interrupts the normal growth cycle. Day length, amount of sunshine, water potential, nutrients, age of tree, temperature, rainfall, height above ground, and proximity to a branch all impact tree growth and tree ring production. By assuming the outer ring records the most recent year and that each ring signals one year, a researcher can determine the “date” of a particular ring simply by counting rings.

Methuselah is a bristlecone pine, and the world's oldest living thing. His growth rings document nearly 47 centuries of survival. Bristlecones grow so slowly that a century of tree rings adds less than an inch of girth. The precise, extended chronology of these trees is directly responsible for the accuracy of radiocarbon dating.

Radiocarbon Dating


Cross dating tree rings

Cross dating tree rings