Contrary to popular belief, a new study indicates that old trees actually grow faster than their younger counterparts. As a tree matures and gets larger, its growth rate actually increases. Moreover, a tree's ability to store carbon also grows as it ages.
Before the recent study was conducted, scientists used to believe that a tree's growth rate slows down as it ages. Scientists also previously thought that older trees store less carbon compared to younger trees. However, the new study provides new evidence showing that older trees may actually be more valuable for trapping carbon compared to younger ones.
The new study was published in the online journal Nature and the study was spearheaded by lead researcher Nate Stephenson. Stephenson is a forest ecologist from the U.S. Geological Survey. Along with Stephenson, the team was comprised of close to 40 researchers from different academic institutions, government agencies and NGO's from all over the world.
"This finding contradicts the usual assumption that tree growth eventually declines as trees get older and bigger," says Stephenson. "It also means that big, old trees are better at absorbing carbon from the atmosphere than has been commonly assumed."
To get enough data for the study, the researchers involved took measurements from a total of 673,046 trees. The researchers also took data from over 400 species of trees from all over the world. According to the data they gathered, almost all of the trees involved showed accelerated growth as they aged. Some older and larger trees could also store more carbon in a single year than the entire carbon collected by a younger tree.
"In human terms, it is as if our growth just keeps accelerating after adolescence, instead of slowing down," explains Stephenson. "By that measure, humans could weigh half a ton by middle age, and well over a ton at retirement."
In light of the new research, scientists are growing more concerned over current logging practices. Given that older trees are more adept at storing carbon, the practice of cutting down older trees with the intent of replacing them with new plantings may need to be revisited.
