The cells and ducts in the tree repeat once a year, from large to small, and the material changes from loose to dense, thus forming rings with different color and texture. Concentric rings on the cross section of the stems of perennial woody plants. Common in temperate trees and shrubs, usually once a year. The boundary of Tree rings is obvious in temperate regions. In tropical areas, the Tree ring is not obvious due to the small climate change in a year.

Tree rings are produced by the annual activities of the cambium. In spring, the mild climate and abundant rainfall are beneficial to the growth of trees. This is the vigorous division of cambium cells. The newly generated cells are large and obvious, and the ducts are large and many. Therefore, the wood appears light in color and soft in texture. After summer, as the temperature increases.

The first rings of trees are generally wide, which means that they were young and strong and had strong vitality at that time; Sometimes, after a tree has many narrow rings, a wide ring suddenly appears. This shows that in the years when the ring is wide next year, the environment and climate are suitable and conducive to the growth of trees. Eccentric ring indicates that the environment on both sides of the tree is different. Generally, the south facing side of the northern hemisphere is warmer than the north facing side, so the south facing side is wider.

Source: @amarahollowbones