What is dendrochronology?
The science of dating wood by a study of annual rings. [These figures and references come from a longer summary e-mailed to me by
Dendrochronology is a science which involves the study of growth ring patterns in trees, and using these growth patterns to establish a chronology of dates. In some areas, fully “anchored” chronologies lasting tens of thousands of years have been established by dendrochronologists, through painstaking inspections of vast numbers of trees and lumber artifacts. Using dendrochronology, scientists can learn a number of interesting things about the natural environment and human history. This science relies on the fact that living trees create distinctive layers known as growth rings for each year of life, and that each growth ring will vary in composition and appearance, depending on the conditions at the time of the growth. During drought years, for example, a growth ring might be extremely slender, reflecting the fact that the tree didn’t grow very much, and in temperate years, a growth ring might be fat, reflecting ideal growing conditions for the tree. By looking at the pattern of rings
Dendrochronology or tree ring dating is a method of dating which makes use of the annual nature of tree growth. Each year trees such as oak, put on a layer of new wood under the bark. The thickness of that layer – the tree-ring – depends on various factors, particularly climate. Conditions favourable to growth will result in a wide ring; unfavourable ones will produce a narrow one. Trees growing at the same time will show similar patterns of tree-rings. This can be seen best by measuring the widths of the tree-rings and plotting them as graphs. There will be some similarity between graphs from contemporary timbers. In order to make use of the information contained in the tree-rings, long ring patterns, known as tree-ring chronologies, have to be constructed for use as reference data. These are produced by overlapping ring patterns from successively older timbers, starting with living trees, then buildings, and finally samples from archaeological sites and peat bogs. The Sheffield Labor
