Linkage between the leaf-level stomatal conductance (g s ) response to environmental stimuli and canopy-level mass exchange processes remains an important research problem to be confronted. How various formulations of g s influence canopy-scale mean scalar concentration and flux profiles of CO 2 and H 2 O within the canopy and how to derive ‘effective’ properties of a ‘big-leaf’ that represents the eco-system mass exchange rates starting from leaf-level parameters were explored. Four widely used formulations for leaf-level g s were combined with a leaf-level photosynthetic demand function, a layer-resolving light attenuation model, and a turbulent closure scheme for scalar fluxes within the canopy air space. The four g s models were the widely used semi-empirical Ball-Berry approach, and its modification, and two solutions to the stomatal optimization theory for autonomous leaves. One of the two solutions to the optimization theory is based on a linearized CO 2 -demand function while the other does not invoke such simplification. The four stomatal control models were then parameterized against the same shoot-scale gas exchange data collected in a Scots pine forest located at the SMEAR II-station in Hyytiälä, Southern Finland. The predicted CO 2 (F c ) and H 2 O fluxes (F e ) and mean concentration profiles were compared against multi-level eddy-covariance measurements and mean scalar concentration data within and above the canopy. It was shown that F c comparisons agreed to within 10% and F e comparisons to within 25%. The optimality approach derived from a linearized photosynthetic demand function predicted the largest CO 2 uptake and transpiration rates when compared to eddy-covariance measurements and the other three models. Moreover, within each g s model, the CO 2 fluxes were insensitive to g s model parameter variability whereas the transpiration rate estimates were notably more affected. Vertical integration of the layer-averaged results as derived from each g s model was carried out. The sensitivities of the up-scaled bulk canopy conductances were compared against the eddy-covariance derived canopy conductance counterpart. It was shown that canopy level g s appear more sensitive to vapor-pressure deficit than shoot-level g s .