In autumn, the leaves on many trees change color. This happens before the leaves fall off the trees. The leaves can turn red, orange, yellow, or brown. 

A leaf is green because of something called chlorophyll. Chlorophyll helps plants make food with sunlight. When autumn comes, there is less sunlight each day. 

Trees start to stop making chlorophyll in the fall. That is when the green color fades away. Then we can see the other colors in the leaves. 

These colors were in the leaves all along. They were just covered up by the green. Autumn is a great time to enjoy the beautiful leaves.