My cats love the Christmas tree and we’ve never had a problem. However, for the extra safety conscious here are some suggested tips:
1. Replace ornament hooks with pretty ribbons.
2. Plastic and wood ornaments are the safest.
3. Presents that are placed under a tree early can be targets for cats to play with and they can ingest the paper and ribbon.
4. Clean up fallen pine needles because they can cause tummy problems.
5. Keep lights off when your aren’t home.
6. Spray the tree with bitter apple for the kitty that just won’t leave it alone.
Suggestions from: http://opcatchat.blogspot.com/2010/12/cats-and-christmas.html