Dovetail Partners provides great information on making your holiday habits environmentally-friendly
Research has shown that locally-sourced natural trees have less environmental impact than artificial ones. An independent Life Cycle Analysis (LCA) study released by the Montreal firm Elliposos  determined that real trees have less overall impact in terms of distribution, disposal, and average carbon emissions than their artificial counterparts. The LCA method allows for evaluation of potential environmental impacts of a product (or service) over its entire life cycle and takes raw material processing, manufacturing, transportation, distribution, use, reuse, recycling and disposal impacts into consideration. 
When it comes to artificial trees, the key to achieving environmental gains lies in the amount of time they are kept and reused. Average households replace an artificial tree about every six years. Evidence shows that, in general, artificial trees need to be reused for at least 20 years if they are to compare favorably with natural trees.
“It makes sense to choose the tradition that suits your needs while also considering the best environmental practices,” says Kathryn Fernholz, Executive Director of Dovetail Partners, a Minneapolis-based environmental group. “If you choose a real tree, you can get to know your local grower and recycle your tree at the end of the holiday season. If you choose an artificial tree, make sure to reuse it for as many years as possible. Whichever route you go, your goal can be to pass the tradition of selecting a tree – or even the tree itself – down to the next generation!”
Additional environmentally-friendly measures you can take during the holidays include use of recycled and recyclable wrapping paper and greeting cards, use of LED holiday bulbs; and reuse and recycling of real trees and other decorations at the end of the season such as through collection programs, composting, wood chipping or planting.