growth ring

In a cross section of the stem of a woody plant, the amount of wood added during a single growth period.

In temperate regions this period is usually one year, in which case the growth ring may be called an annual ring. In tropical regions growth rings may not be discernible or are not annual. Even in temperate regions growth rings are occasionally missing; and sometimes a second, or "false," ring may be deposited during a single year (e.g., following defoliation by insects). Nevertheless, annual rings have been used in dating ancient wooden structures, especially those of American Indians in the dry U.S. Southwest. Changes in ring width are a source of information about ancient climates.

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▪ plant anatomy
 in a cross section of the stem of a woody plant, the increment of wood added during a single growth period. In temperate regions the growth period is usually one year, in which case the growth ring may be called an “annual ring.” In tropical regions growth rings may not be discernible or are not annual. Even in temperate regions growth rings are occasionally missing, or a second, or “false,” ring may be deposited during a single year, for example, following insect defoliation. Growth rings are distinct if conducting cells produced early in the growth period are larger (spring, or early, wood) than those produced later (summer, or late, wood) or if growth is terminated by a layer of relatively thick-walled fibres or by parenchyma. In temperate or cold climates the age of a tree may be determined by counting the number of annual rings at the base of the trunk or, if the trunk is hollow, at the base of a large root. Annual rings have been used in dating ancient wooden structures, especially those of the American Indians in the dry southwestern regions of the United States; fluctuation in ring width is a source of information about ancient climates.

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Universalium. 2010.

Look at other dictionaries:

  • growth ring — ► NOUN ▪ a concentric layer of wood, shell, or bone developed during a regular period of growth …   English terms dictionary

  • growth ring — noun an annual formation of wood in plants as they grow • Syn: ↑annual ring • Hypernyms: ↑organic phenomenon * * * noun : a layer of wood developed during any one continuous growth period; usually : annual ring …   Useful english dictionary

  • growth ring — noun Any of the concentric rings formed in the trunk of a tree by the annual growth of wood Syn: tree ring, annual ring …   Wiktionary

  • growth ring — noun Date: 1907 a layer of wood (as an annual ring) produced during a single period of growth …   New Collegiate Dictionary

  • growth ring — a layer of material deposited on a scale or bone which reflects the growth of a fish. Also called growth mark or growth zone …   Dictionary of ichthyology

  • growth ring — /ˈgroʊθ rɪŋ/ (say grohth ring) noun → tree ring …   Australian English dictionary

  • growth ring. — See annual ring. [1905 10] * * * …   Universalium

  • growth ring — rings that form in the wood of a tree during seasonal growth (can be viewed in a cross sectional slice and used to estimate the age of the tree) …   English contemporary dictionary

  • growth ring — noun a concentric layer of wood, shell, or bone developed during an annual or other regular period of growth …   English new terms dictionary

  • growth ring — Rings visible in a cross section of a woody stem, such as a tree trunk. Each ring represents the xylem formed in one year as a result of fluctuating activity of the vascular cambium …   Glossary of Biotechnology

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