We discuss the role of scaling the leaf scale processes to canopy and landscape, as is necessary for the land surface models. We present this discussion initially with the theoretical considerations for scaling; followed by analysis with a simplified photosynthesis based vegetation scheme embedded within SSiB, and the initial results of the simulations using this scheme over the Amazonian region. Results from a sensitivity analysis will be presented to show the effect of scaling on the model results. This discussion will be followed by a presentation of results for a coupled analysis with different level of complexity for the vegetation representation: Wesely's radiation based vegetation model; Jarvis type scheme; and a photosynthesis scheme. The effect of scaling on each of these vegetation schemes will also be presented for a summertime US simulation. Comparisons between model simulations, and observations will also be presented. The models show different significant nonlinear response in simulating the regional climate and weather patterns and a clear distinction is still not possible on whether complex schemes are better than simpler models for biosphere models.