A long-held belief about trees is apparently wrong. A new study shows tree growth rates do not slow as the tree gets older and that instead, trees continue to put on mass along with the years. 

The study’s lead author Nate Stephenson, a forest ecologist with the United States Geological Survey, says if people did the same thing they would weigh well over a ton by retirement. He says the finding changes what we know about how trees store carbon, which 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,” Stephenson said.

He also says old, large trees are better at both storing and absorbing carbon from the atmosphere, which means the older trees are the star players in forest carbon dynamics. Forests cover about 27 percent of Arizona, or nearly 20 million acres.