"Transpiration and the Emergence of Vegetation Hydrodynamics Models"
Dr. Ashley M. Matheny
Assistant Professor, UT Department of Geological Sciences
Feedbacks between vegetation and climate are critical to the function of the Earth system, with strong controls over water, carbon, and energy. Vegetation provides a critical pathway for water transport from the land surface to the atmosphere. The ability of vegetation to actively modulate water uptake and release makes this a challenging process to model, with divergent hydrodynamic behaviors occurring frequently among species in the same ecosystem. Recently, a number of mechanistic process models of water flow through vegetation have come to the fore. These models draw a parallel between vegetation’s conductive tissues and porous media, and are poised to replace the current empirical representation of stomatal conductance in hydrologic and land-surface models. The FETCH2 scalable vegetation model uses a simplified form of the Richards equation to simulate water movement within trees while allowing for dynamic changes in hydraulic conductance and capacitance. FETCH2 and other mechanistic plant hydraulics models stand to promote significant improvements to our ability to model transpiration at local to global scales.