If necessary, you can send them to me, just to keep them out of your pets' reach. Live and artificial Christmas tree needles are sharp and indigestible. Ingested pine needles can puncture your pet's intestines if sharp enough. Just look at your hands and arms after you struggle with the tree to get it standing straight up. Keep your tree away from your pet by fencing off the room it's in.
Some people use a playpen as a barrier.
With cats, you may need to only let them in the same room under your direct supervision. I know it kind of makes you feel like a warden, but you may save your kitty's life. Also, make sure your tree is well secured. If you have a tree-climbing cat or large dog with a happy tail, anchor the top of the tree to the wall, using strong cord or rope. Preservatives often used in the water in a tree stand can cause gastric upsets, so be sure it is inaccessible or not used.