title: The response of plants to elevated CO2: IV. Two deciduous-forest tree communities.
abstract: Tree saplings, two groups of three species from each of two deciduous tree communities, were grown in competition at three CO2concentrations and two light levels. After one growing season, biomass was measured to assess the effect of CO2on community structure, and nitrogen and phosphorus concentrations were measured for leaves, stems, and roots of all trees. Gas-exchange measurements were made on the same species grown under the same CO2concentrations.Photosynthetic capacity (rate of photosynthesis at saturating CO2and light) tended to decline as CO2concentration increased, but differences were not statistically significant. Stomatal conductance declined significantly as CO2increased. Nitrogen and phosphorus concentrations generally declined as CO2increased, but there were some unexpected patterns in roots and stems. CO2concentration did not significantly affect the overall growth of either community after one season, but the relative biomass of each species changed in a complex way, depending on CO2light level, and community.
authors.affiliation: Department of Organismic and Evolutionary Biology, Harvard University, 02138, Cambridge, MA, USA.
authors.forename: William E
authors.initials: WE
authors.lastname: Williams
authors.affiliation: Department of Organismic and Evolutionary Biology, Harvard University, 02138, Cambridge, MA, USA.
authors.forename: K
authors.initials: K
authors.lastname: Garbutt
authors.affiliation: Department of Organismic and Evolutionary Biology, Harvard University, 02138, Cambridge, MA, USA.
authors.forename: F A
authors.initials: FA
authors.lastname: Bazzaz
authors.affiliation: Department of Biological Sciences, Stanford University, 94305, Stanford, CA, USA.
authors.forename: P M
authors.initials: PM
authors.lastname: Vitousek