annual rings

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annual rings

a series of concentric circles found in the heartwood of trees, indicating the approximate age of the tree. Each ring is formed by the contrast in texture between spring wood and autumn wood. Spring wood in ANGIOSPERMS contains a high proportion of large, thin-walled XYLEM vessels and few fibres, for maximum water transport when the leaves are newly formed. Autumn wood contains fewer, smaller, thicker-walled vessels with many fibres for greater mechanical support. GYMNOSPERMS show similar contrasting structures in spring wood and autumn wood, although their water-conducting tissues contain TRACHEIDS, not vessels. Microscopic examination of annual rings (a science called DENDROCHRONOLOGY) has revealed many interesting facts about past climates and also allows wooden structures (e.g. building timbers) to be accurately dated.
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Hoibo (1991) did not analyze annual ring width patterns, but his results indicate likely relationships between annual ring width patterns at breast height and vertical knot diameter profiles.
Axial parenchyma cells consist of band of cell rows at the border of each annual ring (apotracheal terminal).
Radionuclide specific activities in each annual ring are determined according to formula (2), evaluating a specific activity decrease due to radioactive decay:
The approximate size (diameter) of the first annual ring can be easily estimated using the relationship between flounder's total length (L) and the length of otoliths ([L.
Damage due to fire, landslide, insects, and other natural occurrences can be seen in the patterns of annual ring formation.
Dendroecology is the study of the ecological and environmental changes depicted in the annual rings of trees.
Each annual ring in that tree represents one year of the tree's memory.
The North East Wrestling Club stages its second annual Ring of Faith Tournament in St Joseph's Hall, Gateshead, this Saturday at 7pm.
We measured the distances (mm) along the anterior--posterior scale axis from the focus (F) to the last circulus of the freshwater zone (ocean entry, OE), to the outside edge of the winter annual ring (the "winter annulus," A) when present, and to the margin (M), and also determined the total numbers and average spacing of circuli in the ocean growth zone (Fig.
The infected potatoes were detected by the Central Science Laboratory during Defra's annual ring rot survey.
An annual ring, seen in a cross-section of a tree trunk, represents a years growth.
A new event - The Annual Ring of Kerry/Celtic Club Challenge Tournament - will be part of the fixture list at the club as a result of the link-up with Celtic.

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