I have a few strategies for keeping cats out of a Christmas tree. First, it's important to secure the tree to a wall or other surface so it can't be easily knocked over. You can also use scents that cats dislike, such as citrus or peppermint, to deter them from the tree. Additionally, you can provide alternative places for cats to play and climb, such as cat trees or scratching posts. Finally, if all else fails, you can try using a fence or barrier around the tree to keep cats out.