Smaller stars lower down on the tree symbolize the heavens or God creation of the entire universe by representing other stars. The light of the world. Light of God in all creation. Different colors symbolize that we are all different individuals but all can contain the light of God. Candles Candles symbolize stars and lights, therefore they carry the symbolism of lights and of lamps.
Candles also symbolize waiting, especially for the second comming.
Don't light any real candles on your tree, plastic ornaments with fake flames are fine. Lamps Christ talked of oil lamps and lamp under a bushel etc. Christ is the light of the world. We should put our lamps on a stand and not under a bushel. The disciples fishermen.