How are tree rings formed? What's the role? How are trees formed?

The formation of tree rings is mainly related to the climatic conditions, water and inorganic salts when cambium cells divide. In spring, the climate is warm and nutritious. At this time, the division of cambium cells is accelerated, xylem cells become larger and cell walls become thinner. So the wood is light in color and loose in texture. This part of wood is called Chunmu.

In autumn, the temperature drops and the nutrients decrease. At this time, cambium cells divide slowly, xylem cells become smaller and cell walls become thicker. Therefore, the wood is dark in color and dense in texture. This part of wood is called autumn wood. In the same year, the color of spring and autumn wood changes gradually, and there is no obvious boundary between them.

The boundary between autumn wood in the previous year and spring wood in the next year is very obvious, forming a remarkable annual ring, called annual ring.

Usually, the age of a tree can be inferred from the number of rings on the trunk. But for tropical trees, this method is not feasible, because tropical trees grow in middle age, and most of them have no obvious annual rings.

Extended data

Trees growing in temperate and tropical areas with alternating rainy and dry seasons have annual rings, while trees growing in areas with little climate change in four seasons have no obvious annual rings. Tree rings contain a lot of historical information about climate, astronomy, medicine and environment. At the same time, tree rings also play an important role in historical archaeology, forestry research, geology and public security.

In history, tree rings are often used to calculate the specific age of some historical events. For example, in the vast sea, there are large and small ships that have sunk in past dynasties, and the tree species of shipbuilding can be determined according to the patterns (annual rings) of wooden ships; According to the corrosion of materials, the age of the sunken ship and some historical events related to this age are determined.

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