Northern Research Station News Releases

How Will Forests Grow as the Climate Changes?

Rhinelander, WI, March 3, 2010 - For more than a decade, researchers at Michigan Technological University (Michigan Tech) and the USDA Forest Service have worked together, along with scientists from across the nation and around the world, to determine how forests will respond to the higher carbon dioxide and ozone concentrations predicted in the future. In the global change research project known as Aspen FACE (Free Air Carbon dioxide Emission), researchers studied whether forests become more or less productive as greenhouse gas levels rise, altering their ability to sequester more carbon dioxide and help offset rising atmospheric carbon dioxide.

Now Michigan Tech and the Institute for Applied Ecosystem Studies (IAES) of the USDA Forest Service’s Northern Research Station have received another $1.1 million in USDA Forest Service funding to conduct new, related research at the IAES research farm in northern Wisconsin.  Approximately half of the funding will go to MTU.

The new project, called the Northern Forest Ecosystem Experiment, asks: How does a natural forest respond to harvesting under global change conditions?

“Forests grow differently when they are exposed to carbon dioxide, ozone and other pollutants,” explained Andrew Burton, a professor in Michigan Tech’s School of Forest Resources and Environmental Science. Burton is Michigan Tech’s lead investigator on the new research study. 

During the Aspen FACE project, scientists planted aspen and birch trees in 12 circular plots at the USDA Forest Service test site near Rhinelander, Wisconsin. They then exposed them to elevated levels of carbon dioxide, ozone and a combination of the two, and analyzed the impacts of varying amounts and mixtures of the greenhouse gases on the tree growth, roots, leaves, soil carbon and nutrients, insects and diseases and entire ecosystem carbon storage.

Their main findings were that carbon dioxide caused increased growth; ozone caused reduced growth, and in combination, the negative effects of ozone offset much of the positive effects of CO2.

The new study takes a step back, starting by cutting down all the trees planted during Aspen FACE and letting the forest resprout on its own.  Researchers then will use the Aspen FACE technology to expose the new growth to increased levels of carbon dioxide, ozone and a combination of the two.

Richard Norby, a corporate research fellow at the Oak Ridge National Laboratory and principal investigator of another US Department of Energy (DOE)-supported FACE experiment, is glad to see the research continue at Aspen FACE. "The effect of elevated CO2 on forest regeneration has not been well studied, but it could be a very important factor shaping the state of our future forests and the many services they provide. This new research at Aspen FACE will be an important contribution to the nation's global change research portfolio." 

“You might call this a prequel to Aspen FACE,” said USDA Forest Service researcher Mark Kubiske. “Last time we planted the trees. This time we are starting with trees that are regenerating of their own accord.”

Scientists will be studying what Burton called “the legacy effects” of new trees sprouting from the root system formed under the Aspen FACE treatments, as well as continuing effects of the treatments used on the new growth.   They will be simulating the carbon dioxide concentrations expected 50 years from now and ozone concentrations typical of a location closer to larger cities —80 to 100 parts per billion.

“Aspen forests play an incredibly important role in our lives,” Kubiske said. “They are extremely important for paper production and as a food source and cover for wildlife. Aspen ecosystems account for about half of the upland hardwood forests throughout the lake states, and they occur all across the US and Canada. We have to be able to predict what will happen to existing forests under global change conditions.” Kubiske is the Institute for Applied Ecosystem Studies’ lead investigator on the new study.   

Michigan Tech will be operating the test site, applying the treatments, and monitoring results. The USDA Forest Service will be operating the experiment, monitoring the growth and development of the forests, and coordinating research among visiting scientists from the University of Michigan, the University of Nevada-Reno, the University of Wisconsin, DOE’s Brookhaven National Laboratory, and other collaborators worldwide. More than 80 scientists are expected to participate in the experiment before it is completed. 

The U.S. Forest Service is an agency of the U.S. Department of Agriculture, a mission of sustaining the health, diversity and productivity of the nation’s forests and grasslands to meet the needs of present and future generations. The mission of the Forest Service's Northern Research Station is to improve people’s lives and help sustain the natural resources in the Northeast and Midwest through leading-edge science and effective information delivery.

The U.S. Forest Service manages 193 million acres of public land, provides assistance to state and private landowners, and maintains the largest forestry research organization in the world. Public lands the Forest Service manages contribute more than $13 billion to the economy each year through visitor spending alone. Those same lands provide 20 percent of the nation’s clean water supply, a value estimated at $7.2 billion per year. The agency has either a direct or indirect role in stewardship of about 80 percent of the 850 million forested acres within the U.S., of which 100 million acres are urban forests where most Americans live. For more information, visit


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Last modified: March 3, 2010