Since it is a tree and it is typically green, Christmas trees are considered the Wood element (even if they are not a real tree). The best placement is in the check marked areas (Prosperity and Family) in this bagua image. Because of the triangular shape of the tree it is also the Fire element and therefore not recommended near the front door. If you have your tree in any of the other areas of your home, decorate it in the color associated with that area. Be sure not to clutter your Christmas tree and only use ornaments you like. Wishing you a guilt free and Merry Christmas!