Mark Rushdoony wrote this for the Chalcedon magazine in 2001, and it will serve us well today. It’s a little long, but stick with it: given the fallen world’s growing hostility to Christian faith, we want to hang on to Christmas–and reclaim it for Our Lord and for His people.
https://chalcedon.edu/magazine/the-christian-christmas-tree
Simply put, it’s okay for us to have a Christmas tree. Throughout the Bible, from Genesis to Revelation, the tree symbolizes the Tree of Life: and the Tree of Life is also Jesus Christ. That trees have been misused by pagans, unbelievers, and secularists does not invalidate it as a Christian symbol. It’s ours, God gave it to us, and we ought to keep it.