Environmental Studies

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tree ring

A Dictionary of Plant Sciences | 1998 | | Copyright

tree ring (annual ring, growth ring) A sheath of cells appearing as one of a series of concentric rings in the cross-section of a woody stem. Each ring is usually the result of a single yearly growth flush starting in spring and ceasing in the late summer. The new wood (xylem) cells arise from renewed activity of the vascular cambium. A sharp boundary usually occurs between the rings since cells formed in spring are typically large, thin-walled, and appear pale in colour when compared with the small, thick-walled cells of later summer. In some dicotyledonous species (see DICOTYLEDON) vessel distribution also varies, with most vessels occuring in the early (spring) wood. These ring-porous species contrast with ring-diffuse species in which the vessels are distributed evenly throughout the growth ring. The growth check that causes variable cambial activity may be temperature or water stress or both. In some extreme environments growth may not always be renewed on an annual basis, leading to absent rings (‘missing years’) and false series (multiple rings in the same year). Dating by tree rings is difficult in these circumstances. See also DENDROCHRONOLOGY; VASCULAR CAMBIUM; VESSEL; TRACHEID; and XYLEM.

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MICHAEL ALLABY. "tree ring." A Dictionary of Plant Sciences. 1998. Encyclopedia.com. 31 May. 2012 <http://www.encyclopedia.com>.

MICHAEL ALLABY. "tree ring." A Dictionary of Plant Sciences. 1998. Encyclopedia.com. (May 31, 2012). http://www.encyclopedia.com/doc/1O7-treering.html

MICHAEL ALLABY. "tree ring." A Dictionary of Plant Sciences. 1998. Retrieved May 31, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O7-treering.html

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tree ring

A Dictionary of Ecology | 2004 | | Copyright

tree ring(annual ring, growth ring) A sheath of cells appearing as one of a series of concentric rings in the cross-section of a woody stem. Each ring is usually the result of a single yearly growth flush starting in spring and ceasing in the late summer. The new wood (xylem) cells arise from renewed activity of the vascular cambium. A sharp boundary usually occurs between the rings since cells formed in spring are typically large, thin-walled, and appear pale in colour when compared with the small, thick-walled cells of late summer. In some dicotylodenous species vessel distribution also varies, with most vessels occurring in the early (spring) wood. These ring-porous species contrast with ring-diffuse species in which the vessels are distributed evenly throughout the growth ring. The growth check that causes variable cambial activity may be temperature or water stress or both. In some extreme environments growth may not always be renewed on an annual basis, leading to absent rings (‘missing years’) and false series (multiple rings in the same year). Dating by tree rings is difficult in these circumstances. See also dendrochronology; dendroclimatology; and dendroecology.

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MICHAEL ALLABY. "tree ring." A Dictionary of Ecology. 2004. Encyclopedia.com. 31 May. 2012 <http://www.encyclopedia.com>.

MICHAEL ALLABY. "tree ring." A Dictionary of Ecology. 2004. Encyclopedia.com. (May 31, 2012). http://www.encyclopedia.com/doc/1O14-treering.html

MICHAEL ALLABY. "tree ring." A Dictionary of Ecology. 2004. Retrieved May 31, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O14-treering.html

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tree ring

The Oxford Pocket Dictionary of Current English | 2009 | Copyright

tree ring • n. each of a number of concentric rings in the cross section of a tree trunk, representing a single year's growth.

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"tree ring." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. 31 May. 2012 <http://www.encyclopedia.com>.

"tree ring." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. (May 31, 2012). http://www.encyclopedia.com/doc/1O999-treering.html

"tree ring." The Oxford Pocket Dictionary of Current English. 2009. Retrieved May 31, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O999-treering.html

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Free newspaper and magazine articles

	Geoscience of climate and energy 6. Tree rings as temperature... Magazine article from: Geoscience Canada; 3/1/2010
	History in the heartwood.(New England Dark Day and tree rings) Magazine article from: American Forests; 6/22/2011
	False rings in jack pine and black spruce trees from eastern Manitoba as... Magazine article from: Canadian Journal of Forest Research; 9/1/2009