Age estimation of tree from rings

Question

How the age of a tree can be calculated from the analysis of rings present on the cross section of its stem?

Answer 1

For growth of the tree it is essential to have the formation of new vessels inside the stem, a task which is performed by the vascular cambium. The vascular cambium is more active in the hot seasons (summer and spring) producing the lighter band formed of the large calibered vessels. During winter and fall the vascular cambium generates the opposite, so small calibered vessels and a darker band emerge outside the previous lighter band. Thus, two ring bands are formed yearly, one lighter and other darker. Through direct counting of these band pairs one may estimate how old the tree is.