Christmas trees are pagan, and should be avoided by Christians.
They are basically a repeat of what was described in the book of Jeremiah.
For the customs of the people are vain: for one cutteth a tree out of the forest, the work of the hands of the workman, with the axe. They deck it with silver and with gold; they fasten it with nails and with hammers, that it move not.
- Jeremiah 10:3-4 (KJV)
Decorated with silver and gold.
Jesus was born around August/September, so I have honestly no idea what Christmas is anymore...