Which are greener, real or artificial Christmas trees?

Are you still undecided regarding whether or not to buy a real tree this christmas?
An artificial tree will last but it lacks the smell that a lot of us associate with a Christmas tree.
The Irish Times put sentiment aside and had a look at this argument from a purely scientific point of view with a little help from Dr. Fionnuala Murphy at UCD's School of Biosystems and Food Engineering.

Full article (opens in a new window)here.