How Do Trees Record Time?
ES2905  Tree Ring Widths Vary from Year to Year

Tree rings—also known as annual growth rings—vary in size each year depending upon the environmental conditions that the tree experiences. For most locations, tree rings will be wider during years of abundant rainfall and narrower during times of drought. A slice from the cross section of a tree is shown in the photo below.

  !   Observe the tree rings. Compare the relative widths of the
rings marked 1 through 5.

Courtesy of Laboratory of Tree-Ring Research, University of Arizona

2. Which rings indicate years of relatively abundant water? Which rings might indicate years of drought?

 Step:   1   2   3   4   5   6   7   8   9   10