Empirical and optimal stomatal controls on leaf and ecosystem level CO2 and H2O exchange rates

► Two semi-empirical and two optimal stomatal control models were coupled with a multi-layer canopy model. ► All models were parameterized against same shoot-scale dataset from a Scots pine site and compared against canopy-scale fluxes and concentration profiles. ► Different shoot-scale stomatal control model can have as large as 25% effect on ecosystem-scale CO2 and H2O fluxes. ► Ecosystem-scale canopy conductance appears to be more sensitive to vapor pressure deficit than shoot-scale stomatal conductance.