January 16, 1998 - Kids, Uncategorized

sagar: Author=’Deborah Byrd, Marc Airhart’ program=” video=”Regina Budden, St. Marys, KS
Age: 9. Description: “Mostly brown” Using: “paper, colored pencils and most important – imagination.”.Trees can’t speak, but they can tell a story about Earth’s past.

Some trees grow an extra layer of wood every year as the seasons change. It grows just inside the bark of a tree. The thickness and appearance of this new wood depends on that year’s weather and other conditions.

So these extra layers of wood are like clues to the riddle of Earth’s weather from long ago. If you cut down a tree, you’d see a series of tree rings nestled inside each other. Each ring is made from the wood that grows every year. Scientists call the study of tree rings dendrochronology. It’s a word whose ancient roots mean tree and time.

Scientists don’t have to cut down trees to study tree rings. They can drill into trees from the side – and take out thin cores – that look like long, striped straws. The study of tree rings can tell us about droughts and floods. It can tell us about prehistoric disasters – like volcanos.

Tree ring studies are one reason some scientists believe that Earth has been warming up. Studies have shown that this century has had higher temperatures than in any other period in the tree ring record – that’s going back more than 500 years.

Written by earthsky