NASA Proposal Selected for Funding

How will Climate, Urbanization, & Forest Change affect Ecosystem Productivity?

land cover
Population has grown tremendously since the 1980s, causing major changes to land use and land cover. Photo by tpsdave, courtesy of Pixabay.

Forests – and other plant communities – pull carbon dioxide gas out of the air and store it, or convert it into forms the rest of life on earth can use. “The conversion of carbon dioxide gas into other carbon-containing forms is called primary productivity,” says U.S. Forest Service scientist Jim Vose.

Productivity in the southeastern U.S. is high – we have plenty of sun, plenty of rain, and lots of plant growth. However, productivity could change in the future. The southeast is currently in the midst of many changes – changes in forest cover and species composition, land use, and increased variability in the amount and timing of rain and snow.

A collaborative, interdisciplinary research project will explore how these changes could affect primary productivity in the southeast. The project is funded by NASA, and Conghe Song, a professor at the University of North Carolina-Chapel Hill, is the principal investigator. Indiana University scientists Kimberly Novick and Taehee Hwang are participating as is Vose and U.S. Forest Service scientist John Coulston.

Vose and his colleagues plan to use multiple types of remote sensing data – from historical air photos to advanced satellite images – to reconstruct the history of land use and cover since the 1980s.

The reconstruction will show how land use has shifted from forests to agriculture to housing developments – or back to forest.  The reconstruction will also capture the changes in species composition over time.

Changes in forest species are driven by ecological succession and management activities and could affect how forests cycle carbon and water. “We are focusing on how plants use water, especially during droughts,” says Vose.

loblolly
In 1952, pine plantations covered less than 1 percent of the southeast, but by 2060 are expected to cover as much as 36 percent. Photo by David Stephens, courtesy of Bugwood.org.

The scientists will integrate the reconstruction with a model of ecosystem productivity, and will also use data from the U.S. Forest Service’s Forest Inventory and Analysis Program, as well as the AmeriFlux network.

Vose and his colleagues plan to estimate how productivity has changed since the 1980s, especially in light of urbanization and forest change. The scientists also want to show how the combination of changes in climate, land use, and forest composition could affect productivity and water use in the future.

Droughts, ice storms, and other severe weather events are expected to become more common. For example, unprecedented droughts in 2001 and 2007 significantly reduced net primary productivity, as did a major ice storm in 2002. If such events become more common, ecosystem productivity and carbon storage could be affected.

“Forests play a critical role in providing services such as timber products, carbon sequestration, and clean water,” says Vose. “Understanding how climate and land use change could affect ecosystem productivity and water use in the southeast is critical.”

For more information, email Jim Vose at jvose@fs.fed.us.

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