Real or artificial? A forestry scientist explains how to choose the most sustainable Christmas tree, no matter what it's made of

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Curtis VanderSchaaf, Mississippi State University

(THE CONVERSATION) Every year, Americans buy somewhere between 35 million and 50 million Christmas trees, and many more pull an artificial tree out of storage for the season. In all, about three-quarters of U.S. households typically have some kind of Christmas tree, surveys show.

People often ask which is more sustainable – a real tree or an artificial one? It’s a big debate, and the answer depends on who you ask and which factors you consider.

A more useful question is: How do I find the most sustainable tree of the kind I want to get?

I’m a forestry professor who works on issues of sustainability. There are advantages and disadvantages to both cut trees and artificial trees. Here are some tips to consider for each.

If you’re buying a live Christmas tree

When Christmas trees are alive and growing, they pull carbon dioxide from the air and use it as the building blocks of their wood. That keeps the greenhouse gas out of the atmosphere, where too much carbon dioxide contributes to global warming.

This process stops once the tree is harvested. And at some point, the cut tree begins to decompose and releases that...