How many times have you tried to guess how tall a tree is in your yard or where your shool is? This is an easy way to find out, and you use math to do it!

You will need

• A strip of paper that is white or a very bright color
• A straight pin
• A ruler that measures in inches (at least 12 inches, and longer if you are going to measure a very tall tree
• A pencil and a piece of paper

Here's What You Do

1. Find out how tall you are.
2. Pin a piece of paper on the tree trunk at your height (at the top of your head).
3. Being very careful not to stumble, walk away from the tree while you hold the ruler at arms' length away from you.
4. Walk away until the 1 inch mark on the ruler is even with the strip of white paper AND the 0 mark on the ruler is even with the bottom of the tree trunk.
5. Write down the inch mark where the very top of the tree touches.
6. Now, multiply the inch mark the top of the tree touches by your height. The answer will be how many inches tall the tree is. To get find out the number of feet tall the tree is, divide your answer by 12 inches. Example: 11 inches x 50 inches = 550 inches. 550 divided by 12 = 45 feet, 10 inches.

Questions to Answer

• Do all trees grow at the same rate? Research the answer at the library or on the internet.

• Do you know how old the tree is that you measured? Ask people in the neighborhood or call local conservation or park organizations for help. (Get your parents or teacher to help you find out who to call, or check out the internet!)

• How long would it take for a new tree to grow as tall as the one you measured?

• What does that tell you about how long it takes a forest to grow and for new trees to take the place of old ones?

• How many trees does every person in the United States use every year? How many years do you think it would take for trees to grow to replace those trees?