Tree Rings
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Dendroclimatology. Now that's a word you can wrap yourself around! Hi, I'm Bryan Yeaton and this is the Weather Notebook.

Dendroclimatology is, in fact, the term for studying tree rings to learn about past weather events, most notably severe droughts and periods of unusually wet weather. The National Oceanic and Atmospheric Administration‹known as NOAA - is supporting the research.

Right now, science's understanding of how extreme events occur is still limited to instrument-based meteorlogical records that go back only about 100 years. The NOAA study could change that. But tree rings?

Well, the rings you see in a cross section of a tree tell you the tree's age. The more rings, the older it is. By using this method, you can determine that trees are several hundreds of years old. But the width of the rings and how close those rings are to each other can tell you about the weather during those years of the tree's life, and that's what has the NOAA scientists so excited.

When the rings are narrow and the space between concentric rings is narrow, scientists know that the corresponding years of that tree's life were marked by a lack of rain. When the bands are thicker and there's more space between them, then scientists know that those years were good ones.

The period covered in the study is from 1700 to 1978. By knowing more about what happened in the past and putting that information in the computer, weather scientists will make better predictions for extreme droughts and very wet weather.

Thanks today to writer Duncan McKee. The Weather Notebook is a production of the Mount Washington Observatory and is supported by Subaru, the beauty of all-wheel drive. For more on trees and weather, go to our website at www.weathernotebook.org.