There are a few things you can do to protect your Christmas tree from cats. First, try placing some aluminum foil around the base of the tree. This will help deter them from climbing it. You can also try placing some cat-safe deterrents around the tree, like citrus scents or motion-activated alarms. Additionally, make sure you have plenty of cat toys available for them to play with, so they're less likely to be interested in the tree. Finally, you can try using a cat-repelling spray or essential oils to keep them away.