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Build a Tree-Ring Timeline

The activity below allows you to build a tree-ring chronology. Each horizontal bar represents the tree-ring pattern for one tree. By looking for matches in the patterns, you should be able to build an overlapping sequence that stretches back in time. You can move the chronology to the right and left using the arrows. Afterwards, go on to the next feature (see below).

The technique used here to create a chronology of tree-ring patterns is similar to the one that dendrochronologists use. Called crossdating, the process has established tree-ring chronologies for many areas around the world.

Some of these chronologies extend back thousands of years. In the American Southwest, using both living and dead samples from the long-lived bristlecone pine, scientists have constructed a continuous history of tree rings that stretches back almost 9,000 years, to about the year 6700 B.C.

Note: This activity is meant simply to illustrate the principles involved in creating a tree-ring chronology. In creating actual chronologies, dendrochronologists make use of skeleton plots, which are graphical representations of tree-ring patterns.

Next: Anatomy of a Tree Ring
Growth and Sensitivity
Skeleton Plots

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Explore the Methuselah Grove | A Tree's Secret to Living Long
Build a Tree-Ring Timeline | Illuminating Photosynthesis
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