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Dendrochronology (or tree-ring dating) is the scientific method of dating tree rings (also called growth rings) to the exact year they were formed in a tree. As well as dating them, this can give data for dendroclimatology , the study of climate and atmospheric conditions during different periods in history from the wood of old trees.
The oldest trees are determined by growth rings, which can be seen if the tree is cut down, or in cores taken from the bark to the center of the tree. Accurate determination is only possible for trees that produce growth rings, generally those in seasonal climates.
This is a list of the oldest-known trees, as reported in reliable sources. Definitions of what constitutes an individual tree vary. In addition, tree ages are derived from a variety of sources, including documented "tree-ring" (dendrochronological) count core samples, and from estimates. For these reasons, this article presents three lists of ...
Blue rings found in the stems of trees and bushes in Norway point to a historic cold period in the late 1800s, but the exact cause of this climatic event remains unclear, scientists say.
Tree rings are wider when conditions favor growth, narrower when times are difficult. Other properties of the annual rings, such as maximum latewood density (MXD) have been shown to be better proxies than simple ring width. Using tree rings, scientists have estimated many local climates for hundreds to thousands of years previous.
This standing tree may have died hundreds of years ago. Scientific matching of dead trees' growth rings with living ones has created a 9,000-year-long record. Bristlecone pines are known for attaining great ages. The oldest bristlecone pine in the White Mountains is Methuselah, which has a verified age of 4,856 years.
The utility of tree-ring dating in an environmental sense is the most applicable of the three in today's world. Tree rings can be used to reconstruct numerous environmental variables such as temperature, precipitation, stream flow, drought society, fire frequency and intensity, insect infestation, atmospheric circulation patterns, among others. [2]
Tree rings are records of the influence of environmental conditions, their anatomical characteristics record growth rate changes produced by these changing conditions. The microscopic structure of conifer wood consists of two types of cells : parenchyma , which have an oval or polyhedral shape with approximately identical dimensions in three ...