Impacts of Elevated CO2 and O3, Alone and in Combination, on the Structure and Functioning of a Northern Forest Ecosystem: Operating the Aspen FACE User Facility

Emphasis Area: Atmosphere-Biosphere Interactions

Principal Investigator(s): David F. Karnosky1, Kurt Pregitzer1, Kevin Percy2, Neil Nelson3, George Hendrey4, John Nagy5, Mark Kubiske3, Rick Lindroth6, and Don Zak7

Sponsor:  US Department of Energy

Amount:  $5,197,336.00

Duration: 4/1/05 – 3/31/08

Summary:

Human activity has caused CO2 and O3 to accumulate in the Earth’s troposphere, a trend that will likely continue over the 21st century. The increase in atmospheric [CO2] is ubiquitous, whereas [O3] is a more regional pollutant; nonetheless, [O3] is predicted to affect large areas of forests in coming decades.  The individual effects of these atmospheric gases on terrestrial vegetation have been widely studied at the individual plant level.  Alone, these two atmospheric gases affect trees in diametrically opposite ways.  Yet, very little is known about their interactive effects, largely due to the fact that long-term, mixed species, ecosystem-level studies are more difficult and extremely rare.  Consequently, it is currently impossible to predict how forest trees, and forest ecosystems, will respond as both [CO2] and [O3] concentrations continue to increase and their interactions occur over broader land areas. 

To address this problem, the FACTS (Forest Atmospheric Carbon Transfer and Storage) II Free-Air CO2 and O3 Enrichment (Aspen FACE) experiment was established in 1997 near Rhinelander, Wisconsin.  In this experiment, we have been examining the impacts of elevated [CO2] and [O3], alone and in combination, on the structure and functioning of aggrading aspen (Populus tremuloides Michx.), birch (Betula papyrifera Marsh.) and maple (Acer saccharum Marsh.) forest ecosystems.  The Rhinelander area is ideal for this experiment because its background O3 concentrations rarely exceed 45 ppb.
The Aspen FACE project was designated a component of a distributed DOE FACE User Facility in 2003.  Currently, we have some 75 scientists from 20 universities, national labs, and agencies as active users of the Aspen FACE User Facility.  During the past three-year grant cycle, this user group published some 38 journal articles and two books based on Aspen FACE research.

In this proposal, we discuss new research opportunities at the Aspen FACE User Facility.  While this proposal is strictly for operations, research at our site is supported by DOE PER, NSF, USFS North Central Research Station, USFS Northern Global Change Program, USDA National Research Initiative, McIntire Stennis, NRCAN Canadian Forest Service, the Wisconsin Focus on Energy Program, DOE GREF, and Michigan Technological University.  The Aspen FACE project is a key experiment within the International Biosphere Geosphere Programme and the only open-air site in the world to study the combined effects of [CO2] and [O3] on forest ecosystems. 

This proposal seeks continued operational support (driven largely by costs associated with dispensing CO2), and infrastructure improvement costs to allow continued dispensing and monitoring of CO2 and O3, as well as continued canopy access, as our forest trees have nearly outgrown our existing infrastructure.

1Michigan Technological University, School of Forest Resources and Environmental Science, 1400 Townsend Drive, Houghton, Michigan 49931
2Natural Resources Canada, Canadian Forest Service, P.O. Box 4000, Fredericton, New Brunswick, Canada E3B 5P7
3USDA Forest Service, Forestry Sciences Laboratory, 5985 Highway K, Rhinelander, Wisconsin 54501
4School of Earth and Environmental Sciences, CUNY/Queens, 65-30 Kissena Blvd., Flushing, NY 11367
5Brookhaven National Laboratory, 30 Bell Avenue, Upton, New York 11973
6University of Wisconsin, Dept. of Entomology, 1630 Linden Drive, Madison, Wisconsin 53706
7The University of Michigan, School of Natural Resources & Environment, 430 E.University, Ann Arbor, Michigan  48109