I've had cats and/or dogs in my household for 40+ years, and never had a problem with them climbing in or peeing on the tree. I stopped using tinsel when one of my RB Meezers used to slurp it up like spaghetti, and still only put non breakable decorations toward the bottom part of the tree. If the kitties just can't resist playing with them and knocking them down, at least there is no harm done - to ornaments or kitties!