Real or artificial?
I haven’t been able to find a full lifecycle analysis of the environmental impacts. The real trees don’t release carbon when they’re growing, but it does take carbon to get a fresh tree to market every year. The artificial ones require carbon but only have to be shipped once. In addition, there are possible health effects from the artificial tree. And so on and so on. One site recommends the real tree primarily because it can be recycled and used for mulch. Wiki draws no explicit conclusion but seems to favor the real ones too. The American Christmas Tree Association cites a study saying that aartificial trees have a smaller carbon footprint.
If there’s a larger moral, I’m not sure what it is, except that life cycle analysis is really difficult to do right. And maybe — I know I’m going to get in trouble for saying this — you should rethink the whole Christmas tree idea — after all, it’s not a religious symbol unless you happen to be a Druid. (I’d suggest that to our Environmental President, but I’m afraid the resulting barrage from Fox News would torpedo the health care bill.)
By the way, there’s a similar debate over diapers. But giving them up probably isn’t an option.