Get him his lil own baby Xmas tree that he’s allowed to play with. We had the big one that he didn’t really touch, and then he’s got his lil one I bought from Ikea and bought lil baubles to go with it. He loves it. Never really touched the big one. Or get a felt wall one where he can stick on and off felt Xmas decorations.
Put all decorations starting above where he can reach
I saw a video where they had the Christmas tree set up inside a travel cot. So LO couldn't get in! My LO is 20 months and I'll be putting up the tree this weekend so will be experimenting too!