Tree rings are formed by seasonal variations in the growth rate and cell density of a tree's wood tissue throughout the year. This lateral growth, known as secondary growth, occurs in a microscopic, active layer of cells located just beneath the bark called the vascular cambium. As the cambium produces new wood cells internally, changes in weather and resources alter how these cells look, creating distinct bands. Tree rings are a direct product of seasonal conditions, they act as environmental diaries.
Read more