Because a tree trunk adds a ring each year, the rings can be counted to determine the age of the tree. The rings can also tell scientists other important information.

To learn more about what tree rings tell scientists:

1. Visit these Web sites.
    Picture of Tree Rings
    Tree Ring Growth

2. Visit this Web site. Read the seventh paragraph.
    History in the Core of a Tree

3. For more information, visit these Web sites.
    Practice Reading Tree Rings
    Reading Between the Rings

4. Then return to this page and click the Go on arrow.