I may be a little late coming into this topic but I thought I'd join in anyway! My kitty is 9 months old and I thought I was going to end up with a destroyed tree! I have an artificial tree but my secret was to put little containers of vinegar spaced out around the tree. Cats hate the smell of vinegar. My vet also suggested mixing water and vinegar together to spray them with... as long as you avoid accidently squirting them in the eyes! Yikes!

So far my kitty has pretty much left the tree alone. He does get squirted once in a while when he ventures too close! I think he is getting the hint that the pretty lit up thingy is not his toy!

Hope this helps a bit!
Tracy