Each ring marks a complete cycle of seasons, or one year, in the tree's life.
In his Trattato della Pittura (Treatise on Painting), Leonardo da Vinci was the first person to mention that trees form rings annually and that their thickness is determined by the conditions under which they grew. S., Alexander Catlin Twining (1801–1884) suggested in 1833 that patterns among tree rings could be used to synchronize the dendrochronologies of various trees and thereby to reconstruct past climates across entire regions.
The rings are more visible in temperate zones, where the seasons differ more markedly.
The inner portion of a growth ring is formed early in the growing season, when growth is comparatively rapid (hence the wood is less dense) and is known as "early wood" (or "spring wood", or "late-spring wood" Many trees in temperate zones make one growth ring each year, with the newest adjacent to the bark.
“Just a little note to say thank you for your services.In addition, particular tree species may present "missing rings", and this influences the selection of trees for study of long time spans.For instance, missing rings are rare in oak and elm trees.During the latter half of the nineteenth century, the scientific study of tree rings and the application of dendrochronology began.In 1859, the German-American Jacob Kuechler (1823–1893) used crossdating to examine oaks (Quercus stellata) in order to study the record of climate in western Texas.