Can I buy a Christmas tree and be Green?

http://www.guardian.co.uk/environment/2010/dec/12/christmas-tree-green-fairtrade-fair-tree

I bow to Lucy Siegle on ecological/green matters and I love her weekly column in the Observer; she seems to answer all those little niggling questions about ecology and it's great to have her detailed research for us 'trying our best to be green' public, so here's what she has to say about buying a Christmas tree.