It is very important to prevent the cat from licking sap, drinking tree water (from the container that we place to supply the water to the tree), or ingesting pine needles. Cats are also sensitive to pine oil (worth keeping in mind if you like using any essential oils in your house!).
Unfortunately, artificial trees come with their own potential hazards which have to be considered. Cats will still try to climb the tree and play with the decorations. Electric cables can be chewed, and your cat can become entangled in them.
Obviously, many cats will never climb the tree or even attempt to chew on the branches, but we should consider the worst-case scenario!