Predicting Transpiration Response to Climate Change: Insights On Physiological and Morphological Interactions That Modulate Water Exchange From Leaves to Canopies

Leaves are key factors in the global water exchange cycle.  For leaves, stomata is assumed to be the primary control of transpiration, however, when ascending beyond the single-leaf scale to that of the crown and canopy, the dominant transpiration control can become the thickness of the boundary layer – a consequence of environment and canopy structure interactions.   Here we separate the morphological and physiological interactions and assess their contributions to transpiration along the leaf-to-atmosphere gas exchange continuum.  Multi-scale analyses illustrate the quantitative importance of leaf-to-atmosphere microclimate interactions at interlocking scales of observation.