Soil nutrition affects carbon sequestration in forests

Dec 13, 2006
Aerial View of Free-Air Carbon Dioxide Enrichment
Aerial view of free-air carbon dioxide enrichment (FACE) rings at Duke Forest, Durham, NC. Credit: Will Owens

On December 11, USDA Forest Service (FS) scientists from the FS Southern Research Station (SRS) unit in Research Triangle Park, NC, along with colleagues from Duke University, published two papers in The Proceedings of the National Academy of Science that provide a more precise understanding of how forests respond to increasing atmospheric concentrations of carbon dioxide, the major greenhouse gas driving climate change.

Building on preliminary studies reported in Nature, the researchers found that trees can only increase wood growth from elevated CO2 if there is enough leaf area to support that growth. Leaf area, in turn, is limited by soil nutrition; without adequate soil nutrition, trees respond to elevated CO2 by transferring carbon below ground, then recycling it back to the atmospheric through respiration.

"With sufficient soil nutrition, forests increase their ability to tie up, or sequester carbon in woody biomass under increasing atmospheric CO2 concentrations," says Kurt Johnsen, SRS researcher involved in the project. "With lower soil nutrition, forests still sequester carbon, but cannot take full advantage increasing CO2 levels. Due to land use history, many forests are deficient in soil nutrition, but forest management -- including fertilizing with nitrogen -- can greatly increase growth rate and wood growth responses to elevated atmospheric CO2."

The studies took place at a Free Air Carbon Enrichment (FACE) study established by the U.S. Department of Energy on the Duke Forest in Durham, NC. In FACE studies, groups of trees are circled by rings of towers that provide CO2 to increase atmospheric concentrations of the gas around the selected trees. At the Duke FACE experiment, half of each ring was fertilized with nitrogen to study the effect of added soil nutrients on tree growth under elevated CO2.

The researchers further tested their hypotheses using data from FACE sites in Wisconsin, Colorado, and Italy. In the articles, the scientists identify critical areas needing further study, but the overall consistency they found across these diverse forests bodes well for developing accurate models to predict the ability of the world's forests to sequester carbon.

"Forests play a critical part in sequestering carbon, and may play a role in mitigating the elevated levels of carbon dioxide associated with climate change," says Johnsen. "To predict how much forests can sequester, we need accurate ways to predict what happens to carbon within forest systems and how this partitioning is affected by environmental conditions."

Source: Southern Research Station - USDA Forest Service

Explore further: Earthquakes occur in 4 parts of Alaska

add to favorites email to friend print save as pdf

Related Stories

Microsoft CEO sees 'bold' plan as 4Q tops Street

28 minutes ago

(AP)—Microsoft Corp. CEO Satya Nadella painted an upbeat vision of the future Tuesday, saying that the next version of Windows will be unified across screens of all sizes and that two money-losing units—Nokia ...

Thieves got into 1K StubHub accounts

9 minutes ago

(AP)—Cyber thieves got into more than 1,000 StubHub customers' accounts and fraudulently bought tickets for events through the online ticket reseller, a law enforcement official and the company said Tuesday.

Recommended for you

Tropical Storm Genevieve forms in Eastern Pacific

Jul 25, 2014

The seventh tropical depression of the Eastern Pacific Ocean formed and quickly ramped up to a tropical storm named "Genevieve." NOAA's GOES-West satellite captured an infrared image of the newborn storm ...

NASA maps Typhoon Matmo's Taiwan deluge

Jul 25, 2014

When Typhoon Matmo crossed over the island nation of Taiwan it left tremendous amounts of rainfall in its wake. NASA used data from the TRMM satellite to calculate just how much rain fell over the nation.

User comments : 0