Christmas can pose a threat for some cats. Kittens and young cats are most likely to tackle scaling a Christmas tree. Some common-sense precautions are in order.
Secure the tree to the wall with a tether if a sturdy base is not available. Fasten all ornaments to the branches by pinching the wire hooks. Eliminate decorating with tinsel. Keep furniture from being placed too close to the tree which might encourage a daring leap. It may be wise to avoid adding any valuable ornaments to the tree until your cat is more mature.
For live trees, vacuum fallen needles frequently. Keep the tree well-watered but cover the reservoir with tin foil to avoid any water ingestion.
Have a safe and joyous Christmas season.