Older, wiser and better at accumulating carbon?

by Meghan Beamish

The other morning, while listening to NPR, I came across this story: “An Old Tree Doesn’t Get Taller, But Bulks Up Like a Bodybuilder.” It highlights a recent Nature paper that was published last week by U.S. Geologic Survey forest ecologist Nate Stephenson. The paper addresses some blank spots in our knowledge of how tree growth rates change with age, and it concludes (after a global analysis of about 400 temperate and tropical tree species) that a tree’s growth rate actually increases with age. This means that large trees increase the amount of carbon they store each year; in an extreme case, a single large tree can add as much carbon into the forest in a single year as is contained in an entire mid-sized tree, trunk, branches and all!

This new study has some pretty interesting implications for how we think about the forest carbon cycle, and how we use trees as resources (for wood and carbon sequestration).