[Below is the original script. But a few changes may have been made during the recording of this audio podcast.]

Christmas trees are certainly green under all those baubles, lights and tinsel. But are they environmentally green? After all, cutting down a living tree for a few weeks of glory robs the planet of years worth of carbon dioxide absorbed within its growing trunk and needles.

But the alternative is a plastic tree made from oil and typically shipped from halfway around the world.

So which is better: wood or plastic?

Adding up all the carbon dioxide emitted in the manufacture of the fake tree and shipping it from China to the U.S. contributes only slightly more of the greenhouse gas than is absorbed in a year by the slowest growing trees. Fast-growing firs and pines suck up several times that amount of CO2 so cutting them down is bad.

But that's not the whole story. Real trees can be turned to mulch and when continuously grown and harvested sequester even more CO2 than a single tree living its full natural life in the wild. Plus, real trees are carbon neutral--cutting them down and disposing of them emits no more CO2 than they absorbed while growing--unlike the artificial trees that rely on fossil plankton.

Ultimately, a potted living tree is the greenest solution. They won't dry out in your living room and rather than spending an eternity in the local landfill, they can happily absorb planet-warming CO2 in your backyard.

—David Biello

60-Second Earth is a weekly podcast from Scientific American. Subscribe to this Podcast: RSS | iTunes