I found this lesson in an Usborne Art book. I talked to the students about perspective before we tackled this one. They VERY LIGHTLY sketched a tree to one side of their paper and divided the paper between land and sky. Then they tried to paint in leaves that were smaller on the tree and bigger as the got closer to the bottom of the paper. This gave the impression of leaves blowing toward the viewer.
I love how the fall-colored leaves "pop" off the page with color. They worked hard using the watercolor paints ,which are not the easiest of mediums to control.
Here are some of the final results: