Mine are pretty good with the christmas tree. They don't bother it on purpose for the most part. If they are playing or a cat is under there, then its a whole new ball game. I find that ornaments that look like balls should be higher up on the tree.
Misty- Samoyed Mix, Tannor- Golden Retriever CGC
Robyn- GSD CGC, TC, Midnite-GSD CGC,TC, Brennan-Golden Retriever CGC, Batman-Husky/Greyhound , Apollo-GSD