Carbon dating of wood
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 (1452–1519) 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.Critical to the science, trees from the same region tend to develop the same patterns of ring widths for a given period of chronological study.Researchers can compare and match these patterns ring-for-ring with patterns from trees which have grown at the same time in the same geographical zone (and therefore under similar climatic conditions).Diagram of secondary growth in a tree showing idealised vertical and horizontal sections, a new layer of wood is added in each growing season, thickening the stem, existing branches and roots, to form a growth ring Horizontal cross sections cut through the trunk of a tree can reveal growth rings, also referred to as tree rings or annual rings.Growth rings result from new growth in the vascular cambium, a layer of cells near the bark that botanists classify as a lateral meristem; this growth in diameter is known as secondary growth.
As well as dating them this can give data for dendroclimatology, the study of climate and atmospheric conditions during different periods in history from wood.
Currently, the maximum span for fully anchored chronology is a little over 11,000 years B. In 2004 a new radiocarbon calibration curve, INTCAL04, was internationally ratified to provide calibrated dates back to 26,000 B. Dendrochronology practice faces many obstacles, including the existence of species of ants that inhabit trees and extend their galleries into the wood, thus destroying ring structure.
European chronologies derived from wooden structures initially found it difficult to bridge the gap in the fourteenth century when there was a building hiatus, which coincided with the Black Death, Given a sample of wood, the variation of the tree-ring growths provides not only a match by year, it can also match location because the climate across a continent is not consistent.
A tree-ring history whose beginning- and end-dates are not known is called a floating chronology.
It can be anchored by cross-matching a section against another chronology (tree-ring history) whose dates are known.