Free-Air Concentration Enrichment

Free-Air Carbon dioxide Enrichment (FACE) is a method employed by ecologists and plant biologists that allows for an elevation of [CO₂] in a specified area of forest or other biomass filled area. It has been used to study the response of tree growth in an environment with elevated CO₂ levels. The projection of carbon dioxide levels often used are based on a variety of climate change models all predicting a definite elevation in carbon dioxide levels due to anthropogenic emissions.

FACE circles have been used across in parts of the United States in temperate forests and also in stands of aspen in Italy. The method is also utilized for agricultural research. For example, FACE circles have been used to measure the reactions of soybean plants to increased levels of ozone and carbon dioxide at research facilities at the University of Illinois at Urbana-Champaign. FACE technologies have yet to be implemented in old growth forests, tropical forests, or boreal forests. Future research projects will probably include these areas.

Concerns about FACE Circle Emissions

FACE circles used to test increased levels of CO₂ have been a matter of concern for some environmentalists who wonder how much the release of the enhanced amount of CO₂ contributes to the gas's emissions. However, the amount released is negligible and does not even come close to the 6 Gigatons of anthropogenic carbon dioxide created annually at the current rates of emission. Further, much of the CO₂ emitted in FACE rings is captured gas that would have been emitted anyway; the FACE experiments simply release move the gas to be released in a controlled way in a certain place.

Varieties of FACE Experiments

FACE implementations are utilized in crop experiments such as the soyFACE [http://www.soyface.uiuc.edu/] experiments at the University of Illinois at Urbana-Champaign.

FACE experiments in Australia

TasFACE [http://www.utas.edu.au/docs/plant_science/ps/ps/face.html] is investigating elevated [CO₂] effects on a native grassland in Tasmania, Australia. The National Wheat FACE array is presently being established in Horsham, Victoria, Australia as a joint project of the Victorian Department of Primary Industries and the University of Melbourne.