A long-held belief about old trees has been uprooted. A recent study by the U.S. Geological Survey finds that trees’ growth rates do not slow as they get older and larger. Instead, they keep putting on mass along with their years.
According to the study’s lead author, Nate Stephenson, a forest ecologist with the USGS, if people did the same, we’d weigh well over a ton by retirement. For trees, the finding changes what we know about how they store carbon, and has implications for forest management.
“About for every pound of mass a tree puts on, it’s absorbing and sequestering about a half-pound of carbon,” he said, and added that old, large trees are better at storing and absorbing carbon from the atmosphere.
Stephenson pointed out that the rapid absorption rates mean old trees are the star players within forest carbon dynamics. And that’s also of interest in terms of the changing climate.
“Change is going to happen no matter what, and if we want to project how forests are going to respond to that, we really have to get some of these key pieces right.”
Trees around the world were studied for the report, more than 600,000 of them from 400 species, on six continents.