North Central Research Station

Global Change Research

The FACE (Free-Air Carbon Dioxide Enrichment) Experiment is a multidisciplinary study assessing the effects of increasing tropospheric ozone and carbon dioxide levels on forest ecosystems.  Located at the Harshaw Experimental Forest near Rhinelander, Wisconsin, the FACE Experiment is a collaborative multinational effort, involving scientists from the United States, Canada, Slovakia, Finland, and Estonia.  Brookhaven National Laboratory is a major partner in this research.

The FACE simulated environment is created by 12 rings of gas-emitter tubes surrounding stands of aspen, maple, and birch, in which the concentrations of carbon dioxide and tropospheric ozone can be controlled.  The design provides the ability to assess the effects of these gasses alone and in combination on many ecosystem attributes, including growth, leaf development, root characteristics, soil carbon, and plant-insect-environment interactions.

Each ring consists of a series of vertical vent pipes which disperse carbon dioxide and/or ozone into the center of the ring.  This computer controlled system uses signal feedback technology to adjust gas release each second in order to maintain a stable, elevated concentration of carbon dioxide or ozone throughout the experimental plot.  Because there is no confinement, there is no significant change in the natural, ambient environment other than elevating these trace gas concentrations.

North Central Researchers have a number of studies underway, focusing in several areas, including tree physiology effects (eg, plant productivity, carbon balance and allocation, and photosynthesis responses to elevated CO₂ and O₃) and the effects on insects and microbes (eg, how changes in the nutrient quality of leaves, grown in the presence of elevated greenhouse gases, will impact organisms that feed on and decompose those leaves).  Scientists from Research Work Unit 4401 are studying the meteorological effects of global change, characterizing the microclimate inside and outside the FACE rings.