Cats in my Christmas tree

I have three cats that I absolutely love. The problem is that they keep climbing up in my Christmas tree, and trying to take naps underneath it. They have actually knocked it over several times (it's a small tree). Is there any way to convince them that the tree is not a place to play? Or do I have to give up my Christmas tree forever?

One of our members discovered that misting the tree with vinegar has kept her wild kitties out of the tree. You can also try hanging a few citrus-scented car air fresheners from the lower limbs.

Rose I just posted to this same question in New Cats for you and left a link to an article for you.