DUUHHH, cats OR trees, cats OR trees. Not both, never.
that doesnt really apply here.
I have 2 cats, a tree and glass bulbs on it.
I make a spray of vinegar + cayenne pepper.
I spray the bottom of the tree with it. They both get one good taste.. and never ever bother it again
Though, my cats are not climbers , nor are they very destructive ( she says while knocking on wood)