As a tree grows, it produces new layers of wood around the trunk, just under the bark. If a tree is cut down, the layers are visible in a cross section. The layers appear as a set of concentric circles known as tree rings.
In general, one layer of wood grows each year. Each
layer consists of two colors of wood: light-colored
"earlywood" that grows in the spring and summer plus
darker, denser "latewood" from the fall and winter.
! Examine this cross section of a tree. Identify the earlywood and latewood in several rings. Count or estimate the total number of tree rings.