Leaf Gas Exchange Responses to Short-term elevated CO₂ Concentration in Trees

Abstract

Evaluation of tree CO₂ uptake responses to elevated CO₂ concentration is necessary to determining the carbon fixation capacity of forest ecosystems for future. In order to estimate the characteristic of gas exchange in the leaves of temperate tree species, we measured net photosynthetic rates and transpiration rates under ambient CO₂ (350 μmol mol^-1) and elevated CO₂ (700 μmol mol^-1) concentrations with tenty emperate tree species. Then we conducted classification using cluster analysis from obtained gas schange rates under two CO₂ concentration conditions. As a result, net photosynthetic rates were stimulated 10-120% under elevated CO₂ in twenty tree species. All species were classified into five groups by the characteristic of gas exchange responses to elevated CO₂, so it was possible to obtain an index for spicies selection of afforestaion.