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The Aspen FACE (Free-Air Carbon Dioxide Enrichment) Experiment is a multidisciplinary study to assess the effects of increasing tropospheric ozone and carbon dioxide levels on the structure and function of northern forest ecosystems.

The Aspen FACE experiment consists of twelve 30m rings 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, and soil carbon.

Each ring consists of a series of vertical ventpipes which disperse carbon dioxide, ozone or normal air 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 and/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.

Research Questions

  • Where is the missing carbon from global carbon models?
  • Is it being sequestered by forests?
  • Will more or less CO2 be sequestered by forest trees as CO2 levels rise?
  • Are forests net carbon sources or sinks? Do they change over time?
  • Is carbon sequestered by trees stored for long time periods in the soil?
  • Will elevated CO2 alleviate other stresses (e.g. ozone, drought, low fertility)?
  • Will our forests become more or less productive over time under elevated CO2?
  • How will elevated CO2 affect insect and disease interactions with trees?
  • How do CO2 and the greenhouse gas ozone interact?