Always fake. We are highly allergic to the mold that comes with fresh trees
Found it out the hard way one year when the Ron and I were both so sick that we had a huge fuss about WHO would drive us and our three sick babies to the emergency room for treatment.
The Doc on duty asked us if we had a live tree -- told us to toss it, we did and within a few days we were feeling much better -- with the aid of some high priced meds, of course.