Activity

How Old is That Tree?

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Every year on our birthday we have a reminder of how old we are. And if we ever forget, we can always ask our parents! How do you think you find out how old a tree is? When a tree has been cut down, you can count its "rings" in order to tell how old it is, but what about when it is alive? We can't ask a tree how old it is. But there is a way! This activity will teach you and your child a way to estimate the age of a tree without cutting it down. It doesn't work with every tree but it will with a lot of them.

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Grade

Third Grade

Subject

Science

Math

Measurement
- Units of Measurement
  - Measuring in Inches

What You Need:

Tree
Measuring tape
Marker
Pen
Paper
Helper

What You Do:

Help your child find a tree that is at least as tall as a grown up and have your child wrap the measuring tape around the widest part of the trunk. (A grown up might need to help with this part!) The distance around the trunk of a tree is called the circumference. Write this measurement down on a piece of paper.
The measurement of the circumference in inches is also the approximate age of the tree in years!

Did You Know?

Every year a new layer of growth occurs just under the bark. Some trees like firs and redwoods may grow more than this in a year, while others like cedars may grow less. This method is a good rule of thumb to estimate the age of a tree.