Stars make a great choice for tree skirts because they are already in a circular shape, so no need to find curved edges to use to trim down your square. There are of course 6 point stars, 8 point stars and really I see no reason why a version of a Mariners Compass wouldn't work out very well, just let your holiday fabrics make it festive.
Several years ago I created a ebook pattern that is available for sale of a Christmas Tree Skirt that uses the lone star quilt block. Diamonds and Y seams are challenging, especially for a new quilter, but it's worth it to add another skill to your quilting tool box. For me, the hardest part of making this tree skirt was actually cutting the slit to make it fit around the tree base.
Time to dig out that holiday fabric!