You might even join a listserv and post a message asking teachers in other regions to join in a leaf exchange. You're bound to meet up with a teacher willing to share native leaves. Collect samples of colorful leaves and place the leaves between sheets of wax paper. Set the iron to a hot setting. Cover the layers of wax paper with a couple sheets of newspaper and iron them.
Students can observe the effects of light on the color of leaves.
When leaves on a tree are still green, invite each student to cover part of a leaf with aluminum foil. Use masking tape to tape the foil to the leaf. Students can sign their name on the masking tape. Wait until the leaves on the tree change color. Let students work in teams to take a census of the trees in your school yard, an area of a nearby park, or another defined area.