One more reason to go with a live tree, other than the fact that it makes the house smell like Christmas, is carbon fixing. If you live in a community like mine in So. Cal. where the local waste management turns your real tree into mulch at the end of the holiday you are removing green house gasses from the environment and putting the carbon into the ground.

The trees convert CO2 into wood thus removing it from the atmosphere. Since these trees are farmed and therefore planted for maximum growth, not crowded, provided optimal growing conditions, ect. One would expect plantation-raised trees to remove greenhouse gasses faster than natural forest grown trees.

And they make my house smell like Christmas.