Rings

the co-hearted erraprises on the stem cross-section of the woody plant stem. Trees and shrubs commonly found in temperage areas. The formation of the annual wheel is due to the influence of plants by the growing season. When in spring and summer, the climate is warm, the formation layer cells divide quickly, grow fast, the resulting wood cells are large, thin walls, more catheters, larger diameter, less wood fibers, loose wood, light and generous, called early or spring. From late summer to autumn, the formation layer activity gradually weakens, the cell division is slower, the volume is smaller, the wall is thicker, the catheter is small, the diameter is small, the wood fiber is more, the wood is dense, the color is dark and narrow, called late or autumn material. The early and late materials formed in that year, representing the
that were produced in the first two years of the year, formed a round. Between the late material formed in that year and the early material formed the next year, the line is very obvious, showing a ring-shaped wheel pattern, that is, the annual wheel. In temper zone areas, the age of trees can be calculated according to the number of annual wheels of the trunk base. The formation of the annual wheel, vulnerable to external environmental influences, each due to climate, pests or other reasons,
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years can produce a number of rotations, which is called a false annual wheel. Tropical trees grow all year round, mostly without obvious annual rounds.