Southern Research Station (SRS) scientists recently added two new eddy covariance towers to the Ameriflux network, setting the instruments up at the Coweeta Hydrologic Laboratory in Otto, North Carolina, and the Crossett Experimental Forest in southern Arkansas.
Established in 1996 and currently made up of sites throughout the Western Hemisphere, the Ameriflux network provides continuous observations of ecosystem-level exchanges of carbon dioxide, water, energy and momentum across multiple time-scales.
Rising levels of carbon dioxide in the atmosphere contribute to warming temperatures and other effects of climate change. Forests and other vegetation play an important role in sequestering—temporarily storing—carbon, reducing the concentration of carbon dioxide in the atmosphere. In a given area, the net exchange of carbon dioxide is closely related to the water use of plants, which in turn affects how much water makes it the streams of the forested watersheds that provide high-quality drinking water to millions.
“It’s critical to keep increasing our understanding of the different components of the carbon and water cycles and their interactions at various space and time scales,” says SRS research ecologist Kim Novick, who leads the effort to manage and analyze data from the SRS towers. “The eddy flux technique allows us to continuously measure the flow of carbon dioxide, water vapor, and other gases just above the forest canopy.”
The eddy flux technique essentially allows scientists to observe and compare the movement of carbon dioxide and water at a micro-climate level. Since the development of high-efficiency carbon dioxide analyzers in the 1990s, regional flux monitoring networks have expanded to include more than 500 research sites in a wide range of ecosystems and biomes.
The Coweeta tower, located in a cove hardwood forest in the southern Appalachians, sits on one of the most topographically complex sites in the Ameriflux network, while the Crossett tower, located in a 75-year-old loblolly and shortleaf pine forest managed for old-growth stand characteristics, provides unique information about the effects of prescribed burning.
“The Crossett tower is one of the only eddy covariance research sites where prescribed burning takes place,” says Jim Guldin, project leader of the SRS Southern Pine Ecology unit and Crossett Experimental Forest. “Our scientists are eager to assess the impact of the next prescribed burn (scheduled for spring 2013) on ecosystem fluxes.”
Adapted from feature article by Kim Novick and Jim Guldin in Summer 2012 issue of the Quarterly Newsletter of the EFR Network.