Tulle is a delicate, net-like material that is often used to make dresses, veils, and other elegant garments. To put tulle on a Christmas tree, start by cutting a long strip of tulle. Then, wrap the strip of tulle around the tree, starting at the base and working your way up. Secure the tulle in place with a small piece of tape, or tie it in a knot at the top of the tree. You can also add ornaments or decorations to the tulle to make it look even more festive.