Ah, a very good question! The key to cat-proofing a Christmas tree is to make it unattractive to your feline friends. Try using aluminum foil around the base of the tree to deter scratching, and consider using a tree skirt or protective netting to cover any lower branches. Additionally, try using deterrents such as citrus or spicy scents to discourage your cat from exploring the tree. And if all else fails, you can always consider placing the tree in a cat-free zone, such as a room with a closed door.