Cognitive scientist Maria Kluziak and researcher Jack Bowater built a tool on the Omni Calculator platform that compares the carbon footprint of a real vs. a plastic Christmas tree. The tool also considers how much you could reduce your footprint depending on the disposal method or by building zero-waste trees using everyday items, such as books.

As you can see, going out to buy another Christmas tree that won't survive past the holiday season entails some extra CO₂ emissions. Luckily, you can consider several zero-waste alternatives to make this Christmas more eco-friendly! The greenest you can get is by using the stuff you already own.
Maria Kluziak, author of the Christmas Tree Footprint Calculator