I got a Styrofoam tree shape. folded 2 in squares like prairie points, stuck two small pins in to hold them, went all the way around the bottom of the shape. Next row I cover about half of the first row, but off set them, so no Styrofoam showed. Jest keep going till you reach the top, I covered it with one of the squares, then put a bow or a star on it.
very easy, foam comes in all sizes, makes a great centerpiece. Have fun
PS can do the same thing with foam egg shapes, start at the pointy part of the egg, end with a loop of ribbon to hang them, looks like pine cones!