Scientists at Marine Biological Laboratory say trees in a mini-forest where they simulated future global warming stored more carbon, a bonus offset for expected higher CO2 releases from the faster decay of organic matter in soil as Earth heats up.
The MBL researchers artificially warmed about one acre of Harvard Forest in Massachusetts by 9 degrees Fahrenheit (or by about 12.7 degrees Celsius) for seven years, simulating the global warming they expect by the end of this century, if nothing is done between now and then to curb carbon dioxide (CO2) and other greenhouse gas emissions, ScienceDaily reports.
According to the ScienceDaily article about the study:
Humans cause extra CO2 emissions worldwide, by burning fossil fuels to generate energy.
The scientists wanted to find out how a hotter environment would affect the capacity of trees to store carbon as woody tissue, keeping it from entering Earth's atmosphere as the greenhouse gas CO2, offsetting human CO2 production.
Hotter temperatures increase CO2 emissions from the ground, because buried organic matter rots faster as soil gets warmer, previous studies have shown.
But project leader Jerry Melillo of MBL said this study demonstrates for the first time that global warming would also be likely to increase the carbon storing potential of trees, by speeding up nitrogen cycling in the forest -- more matter decomposing frees up more inorganic nitrogen compounds, such as ammonium (also known as garden fertilizer), causing greater tree growth and more tree tissue available to store carbon.
The increased carbon storage capacity of the trees in MBL's Harvard Forest experiment was enough to outpace atmospheric CO2 gain resulting from the warmer soil, Melillo concluded.
A summary of these results was published May 23 in the online early edition of the Proceedings of the National Academy of Sciences (PNAS).
While environmental advocacy groups and the U.S. Environmental Protection Agency emphasize the influence of carbon capture (or sequestration) by trees and plants on global warming, and encourage planting trees and protecting forests, some scientists maintain, based upon computer simulations, that in the bigger picture, factoring in multiple tree functions at all Earth's latitudes, more trees would not necessarily mean less global warming.
Will the results of the Harvard Forest experiment change the simulation game again, and lead to scientific proof that planting trees and preserving forests can indeed reduce warming?