Stochastic dynamics of plant-water interactions

Describing water flow from soil through plants to the atmosphere remains a formidable scientific challenge despite years of research. This challenge is not surprising given the high dimensionality and degree of nonlinearity of the soil-plant system, which evolves in space and time according to complex internal physical, chemical, and biological laws forced by external hydroclimatic variability. Although rigorous microscopic laws for this system still await development, some progress can be made on the formulation of macroscopic laws that upscale known submacroscopic processes and use surrogate stochasticity to preserve the probabilistic and spectral information content of the high dimensional system. The external hydroclimatic forcing is inherently intermittent with variability across all scales, thereby precluding the use of standard approximations employed in analysis of stochastic processes (e.g., small noise perturbations). Examples are provided to show how superposition of stochasticity at multiple space-time scales shapes plant-water interactions.