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annual rings

annual rings, the growth layers of wood that are produced each year in the stems and roots of trees and shrubs. In climates with well-marked alternations of seasons (either cold and warm or wet and dry), the wood cells produced when water is easily available and growth is rapid (generally corresponding to the spring or wet season) are often noticeably larger and have thinner walls than those produced later in the season when the supply of water has diminished and growth is slower. There is thus a sharp contrast between the small, thick-walled late-season wood cells produced one year, and the large, thin-walled cells of the spring wood of the following year results. Where the climate is uniform and growth continuous, as in wet, tropical forests, there is usually little or no gross visible contrast between the annual rings, although differences exist. When rings are conspicuous, they may be counted in order to obtain a reasonably accurate approximation of the age of the tree. They are also reflective (by their range of thickness) of the climatic and environmental factors that influence growth rates. The science of dendrochronology is based upon the phenomenon of variability in the thickness of annual rings.

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"annual rings." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. 20 Aug. 2017 <http://www.encyclopedia.com>.

"annual rings." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. (August 20, 2017). http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/annual-rings

"annual rings." The Columbia Encyclopedia, 6th ed.. . Retrieved August 20, 2017 from Encyclopedia.com: http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/annual-rings

annual ring

annual ring (growth ring) Concentric circles visible in cross-sections of woody stems or trunks. Each year the cambium layer produces a layer of xylem, the vessels of which are large and thin-walled in the spring and smaller and thick-walled in the summer, creating a contrast between the rings. Used to determine the age of trees, the thickness of these rings also reveals environmental conditions during a tree's lifetime.

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"annual ring." World Encyclopedia. . Encyclopedia.com. 20 Aug. 2017 <http://www.encyclopedia.com>.

"annual ring." World Encyclopedia. . Encyclopedia.com. (August 20, 2017). http://www.encyclopedia.com/environment/encyclopedias-almanacs-transcripts-and-maps/annual-ring

"annual ring." World Encyclopedia. . Retrieved August 20, 2017 from Encyclopedia.com: http://www.encyclopedia.com/environment/encyclopedias-almanacs-transcripts-and-maps/annual-ring

annual ring

annual ring See growth ring.

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"annual ring." A Dictionary of Biology. . Encyclopedia.com. 20 Aug. 2017 <http://www.encyclopedia.com>.

"annual ring." A Dictionary of Biology. . Encyclopedia.com. (August 20, 2017). http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/annual-ring-1

"annual ring." A Dictionary of Biology. . Retrieved August 20, 2017 from Encyclopedia.com: http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/annual-ring-1

annual ring

annual ring See tree ring.

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"annual ring." A Dictionary of Ecology. . Encyclopedia.com. 20 Aug. 2017 <http://www.encyclopedia.com>.

"annual ring." A Dictionary of Ecology. . Encyclopedia.com. (August 20, 2017). http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/annual-ring

"annual ring." A Dictionary of Ecology. . Retrieved August 20, 2017 from Encyclopedia.com: http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/annual-ring

annual ring

annual ring See TREE-RING.

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"annual ring." A Dictionary of Plant Sciences. . Encyclopedia.com. 20 Aug. 2017 <http://www.encyclopedia.com>.

"annual ring." A Dictionary of Plant Sciences. . Encyclopedia.com. (August 20, 2017). http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/annual-ring-0

"annual ring." A Dictionary of Plant Sciences. . Retrieved August 20, 2017 from Encyclopedia.com: http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/annual-ring-0