I was inspired for this project by a stock art illustration. I really like how it turned out as it lets students focus on how detailed tree shapes can be. And it makes a good Halloween project too.
1. Give the students a 9" x 12" piece of watercolor paper, and some yellow and blue watercolor paint. Ask them to paint one large yellow moon circle in the middle of the paper, and then a blue sky all the way around it. Let the paint dry.
2. With wide, medium and thin-tipped Sharpie permanent markers, demonstrate how the students can draw thick tree trunks from the top to the bottom, and gradually add branches growing up and out from both sides, using lots of variation in line weight.