Free Air CO2 Enrichment Model-Data Synthesis (FACE-MDS) project

Prior Free Air CO2 Enrichment (FACE) experiments were designed to determine if increasing atmospheric CO2 concentrations can lead to increased photosynthesis and forest biomass. Recognizing that higher photosynthesis can, in turn, stimulate plant growth, increase carbon storage, and potentially remove CO2 from the atmosphere as a negative feedback, the experiments were also designed to improve predictions of the governing processes. However, representation of these processes and their uncertainties in Earth system models to allow for upscaling of the results to the whole planet remains a challenge.

The broad, motivating question of the FACE Model Data Synthesis (FACE- MDS) project is 'Does rising atmospheric CO2 stimulate terrestrial carbon uptake and storage, and can we predict this process using terrestrial ecosystem models?' To answer this question we aim to extract further value from the investments of the DOE FACE experiment program by: 1) synthesizing data from FACE experiments, 2) evaluating model performance and behavior, 3) using model and experiment synthesis to gain a greater mechanistic understanding of ecosystem responses to elevated CO2, and 4) making the synthesized data more open-access.

In this final phase of the FACE-MDS project we will: 1) investigate processes associated with tree competition for nitrogen in even aged stands and how that influences elevated CO2 responses, 2) standardize, analyze, and publish as yet unpublished soils data that are unprecedented in detail and use them to investigate mechanistic soil responses to elevated CO2, and 3) develop FACE-MDS data sets to facilitate open access to the community and public.