Christmas Cat?

Does anyone know how to keep a cat from tearing up a Christmas tree? Dinah is obsessed with our tree. The other day, we had 12+ ornaments strung all over the house. We even went to Petsmart and bought some spray that is supposed to keep animals away. All she did was blink her eyes and act a little annoyed that something stunk up her playground. Then, she got after it again. HELP!