Regrown forests can thrive

Research has found that newly grown forests consume carbon from the air faster than thought.

In the face of rising environmental concerns, scientists have found carbon-reducing benefits from newly grown forests that were previously considered pointless.
Researchers from around the world, with help from the University of Minnesota, published a study last week in the journal Nature about the potential for secondary forests — forests that are regrowing — to take carbon out of the air. 
The team found that secondary forests suck carbon from the air faster than grown forests while regrowing nearly twice as fast as previously thought, said Jennifer Powers, a College of Biological Sciences professor and co-author on the study.
The study measured chrono-sequences — groups of trees of varying ages — to compare the qualities in tropical forests as they grow, Powers said.
Previously, secondary forests were thought of as sort of “useless,” Powers said, adding that scientists believed they didn’t draw much carbon from the atmosphere and had less biodiversity than older forests.
The results of the study were surprising, she said. They found the secondary forests removed carbon nearly 11 times faster than existing forests.
“The value of these young forests was low from a biodiversity perspective,” said Justin Becknell, who worked on the study during his graduate studies. “These young forests are super valuable, and in fact are more valuable [than existing ones] while they are growing from a carbon perspective.”
The forests also grow back much more rapidly than researchers previously thought, taking about 60 years to fully grow instead of the 100 or more years, Powers said.
“Once you cut down these forests, they can regrow, and they do store lots of carbon,” she said.
Taking carbon out of the atmosphere with secondary forests has a direct effect on climate change, she said.
Forests are also one of the best ways to fight climate change, said Matthew Russell, assistant professor at the University’s Department of Forest Resources. 
“Plants are the opposite of humans. They take in carbon dioxide and release oxygen,” Russell said. “A lot of that carbon dioxide goes into plant growth. About 15 percent of carbon emissions we emit, those get sucked back into forests through carbon sequestration.”
Powers said although these younger forests are better at removing carbon from the air, the researchers say that old forests shouldn’t be cut down and replaced with new growing forests because older forests have more biodiversity and biomass, which is good for the earth long-term.
Now, the researchers want to know how regrowth of forests affects the large-scale ecology of the planet and how this regrowth affects land use policies worldwide.