Could they be artificial candles -- small battery operated ones?
Yes. That's what the Swedes do now. When I was in Europe I saw a large choir of Swedish girls in white dresses and candles (electric) on their heads singing St. Lucy's day songs.
I just like to tease my daughter with the real candles bit.
We do, however, use real candles on our Christmas tree - a custom I picked up in Denmark. We are very careful not to leave the tree unsupervised.