title: Model-data synthesis for the next generation of forest free-air CO2 enrichment (FACE) experiments.
abstract: The first generation of forest free-air CO2 enrichment (FACE) experiments has successfully provided deeper understanding about how forests respond to an increasing CO2 concentration in the atmosphere. Located in aggrading stands in the temperate zone, they have provided a strong foundation for testing critical assumptions in terrestrial biosphere models that are being used to project future interactions between forest productivity and the atmosphere, despite the limited inference space of these experiments with regards to the range of global ecosystems. Now, a new generation of FACE experiments in mature forests in different biomes and over a wide range of climate space and biodiversity will significantly expand the inference space. These new experiments are: EucFACE in a mature Eucalyptus stand on highly weathered soil in subtropical Australia; AmazonFACE in a highly diverse, primary rainforest in Brazil; BIFoR-FACE in a 150-yr-old deciduous woodland stand in central England; and SwedFACE proposed in a hemiboreal, Pinus sylvestris stand in Sweden. We now have a unique opportunity to initiate a model-data interaction as an integral part of experimental design and to address a set of cross-site science questions on topics including responses of mature forests; interactions with temperature, water stress, and phosphorus limitation; and the influence of biodiversity.
authors.affiliation: Environmental Sciences Division and Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge, TN, 37831-6301, USA.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Norby
authors.affiliation: Department of Biological Sciences, Macquarie University, North Ryde, NSW, 2109, Australia.
authors.forename: Martin G
authors.initials: MG
authors.lastname: De Kauwe
authors.affiliation: Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, São Paulo, 14040-901, Brasil.
authors.forename: Tomas F
authors.initials: TF
authors.lastname: Domingues
authors.affiliation: Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, NSW, 2751, Australia.
authors.forename: Remko A
authors.initials: RA
authors.lastname: Duursma
authors.affiliation: Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, NSW, 2751, Australia.
authors.forename: David S
authors.initials: DS
authors.lastname: Ellsworth
authors.affiliation: Laboratoire de Sciences de Climat et de l'Environnement, IPSL, Gif-sur-Yvette, F-91198, France.
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Goll
authors.affiliation: Laboratório de Ciência do Sistema Terrestre, Departamento de Ecologia, Universidade Estadual Paulista, Rio Claro, São Paulo, 14800-850, Brasil.
authors.forename: David M
authors.initials: DM
authors.lastname: Lapola
authors.affiliation: Biogeochemical Integration Department, Max Planck Institute for Biogeochemistry, Jena, D-07701, Germany.
authors.forename: Kristina A
authors.initials: KA
authors.lastname: Luus
authors.affiliation: Birmingham Institute of Forest Research, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
authors.forename: A Rob
authors.initials: AR
authors.lastname: MacKenzie
authors.affiliation: Department of Biological Sciences, Macquarie University, North Ryde, NSW, 2109, Australia.|Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, NSW, 2751, Australia.
authors.forename: Belinda E
authors.initials: BE
authors.lastname: Medlyn
authors.affiliation: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, 91109, USA.
authors.forename: Ryan
authors.initials: R
authors.lastname: Pavlick
authors.affiliation: Potsdam Institute for Climate Impact Research, Potsdam, 14473, Germany.|TUM School of Life Sciences Weihenstephan, Technische Universität München, Freising, 85354, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Rammig
authors.affiliation: Department of Physical Geography and Ecosystem Science, Lund University, Geocentrum II, Lund, 22362, Sweden.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Smith
authors.affiliation: Birmingham Institute of Forest Research, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
authors.forename: Rick
authors.initials: R
authors.lastname: Thomas
authors.affiliation: Potsdam Institute for Climate Impact Research, Potsdam, 14473, Germany.
authors.forename: Kirsten
authors.initials: K
authors.lastname: Thonicke
authors.affiliation: Environmental Sciences Division and Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge, TN, 37831-6301, USA.
authors.forename: Anthony P
authors.initials: AP
authors.lastname: Walker
authors.affiliation: Environmental Sciences Division and Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge, TN, 37831-6301, USA.
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Yang
authors.affiliation: Biogeochemical Integration Department, Max Planck Institute for Biogeochemistry, Jena, D-07701, Germany.
authors.forename: Sönke
authors.identifier: http://orcid.org/0000-0001-5602-7956
authors.initials: S
authors.lastname: Zaehle
mesh_terms: D001272:Atmosphere; D001315:Australia; D044822:Biodiversity; D001938:Brazil; D002245:Carbon Dioxide / Q000494:pharmacology*; D002980:Climate; D003681:Dehydration; D004739:England; D005052:Eucalyptus / Q000187:drug effects / Q000502:physiology*; D065928:Forests; D008962:Models, Theoretical; D010758:Phosphorus / Q000172:deficiency; D065947:Rainforest; D012987:Soil; D014197:Trees / Q000187:drug effects / Q000502:physiology*
chemical_list: D012987:Soil; D002245:Carbon Dioxide; D010758:Phosphorus
keywords: biodiversity; climate; elevated CO2; forest; free-air CO2 enrichment (FACE); model-data synthesis; nitrogen (N); phosphorus (P)