When I was asked to contribute I asked for today's date as it's the names day of Sinterklaas, the original Santa Claus. In the netherlands we still celebrate it, and there is no mention of Santa or christmas trees until after the 5th of December.
However for this painting I wanted to create a Santa that is a bit of a mix of everything: father winter, father christmas, russian Santa, Dutch Santa, American Santa, forest spirit. So yes, that's why he does have antlers.
If you are interested I kept a log of the work in progress, you can find it on [link]