%0 Research article
%T Comparison of an optimal stomatal regulation model and a biochemical model in explaining CO2 exchange in field conditions
%A Aalto, Tuula
%A Hari, Pertti
%A Vesala, Timo
%D 2002
%J Silva Fennica
%V 36
%N 3
%R doi:10.14214/sf.529
%U https://silvafennica.fi/article/529
%X Gas exchange of Pinus sylvestris L. was studied in subarctic field  conditions. Aspects on optimal control of the gas exchange were examined  using approach by Hari et al. (Tree Phys. 2: 169–175, 1986).  Biochemical model by Farquhar et al. (Planta 149: 78–90, 1980) was  utilized to describe the photosynthetic production rate of needles. The  model parameters were determined from field measurements. The results  from the optimization approach and biochemical model were compared and  their performance was found quite similar in terms of R2 calculated  using measured exchange rates (0.89 for optimization model and 0.85 for  biochemical model). Minor differences were found in relation to  responses to intercellular carbon dioxide concentration and temperature.