There have been hints before that mature trees grow faster than they age, but the idea had been controversial, he says. So he got together with 37 scientists from 16 nations to answer the question on a global scale.
They examined nearly 700,000 trees that have been the subject of long-term studies. Their conclusion, published in this week’s issue of the journal Nature: While trees did stop getting taller, they continued to get wider — packing on more and more mass the older they got. And we’re not talking about the tree-equivalent of an aging crowd with beer guts — old trees are more like active, healthy bodybuilders.
The world’s biggest trees, such as this large Scots pine in Spain’s Sierra de Baza range, are also the world’s fastest-growing trees, according to an analysis of 403 tree species spanning six continents.
Like other animals and many living things, we humans grow when we’re young and then stop growing once we mature. But trees, it turns out, are an exception to this general rule. In fact, scientists have discovered that trees grow faster the older they get.
Once trees reach a certain height, they do stop getting taller. So many foresters figured that tree growth — and girth — also slowed with age.
“What we found was the exact opposite,” says Nate Stephenson, a forest ecologist with the U.S. Geological Survey, based in California’s Sequoia and Kings Canyon national parks. “Tree growth rate increases continuously as trees get bigger and bigger,” Stephenson says.