Sap flux in pure aspen and mixed aspen-birch forests exposed to elevated concentrations of carbon dioxide and ozone

Abstract

Elevated concentrations of atmospheric carbon dioxide ([CO₂]) and tropospheric ozone ([O₃]) have the potential to affect tree physiology and structure and hence forest water use, which has implications for climate feedbacks. We investigated how a 40% increase above ambient values in [CO₂] and [O₃], alone and in combination, affect tree water use of pure aspen and mixed aspen?birch forests in the free air CO₂-O₃ enrichment experiment near Rhinelander, Wisconsin (Aspen FACE). Measurements of sap flux and canopy leaf area index (L) were made during two growing seasons, when steady-state L had been reached after more than 6 years of exposure to elevated [CO₂] and [O₃].

Citation

Uddling, Johan; Teclaw, Ronald M.; Kubiske, Mark E.; Pregitzer, Kurt S.; Ellsworth, David S. 2008. Sap flux in pure aspen and mixed aspen-birch forests exposed to elevated concentrations of carbon dioxide and ozone. Tree Physiology 28: 1231-1243.