Inclusion of a cold hardening scheme to represent frost tolerance is essential to model realistic plant hydraulics in the Arctic–boreal zone in CLM5.0-FATES-Hydro

Abstract. As temperatures decrease in autumn, vegetation of temperate and boreal ecosystems increases its tolerance to freezing. This process, known as hardening, results a set physiological changes at the molecular level that initiate modifications cell membrane composition synthesis anti-freeze proteins. Together with freezing extracellular water, proteins reduce plant water potentials xylem conductivity. To represent responses climate change, land surface schemes increasingly employ “hydrodynamic” models explicit fluxes from soil through plants. The functioning such under frozen conditions, however, is poorly understood. Nonetheless, hydraulic processes are major importance dynamics these systems, which can suffer from, e.g., winter “frost drought” events. In this study, we implement scheme represents hardening into CLM5.0-FATES-Hydro. FATES-Hydro hydrodynamics module FATES, cohort model physiology, growth, hosted CLM5.0. We find that, it necessary introduce reductions loss associated prevent desiccation. work makes possible use CLM5.0-FATES-Hydro realistic impacts frost droughts on growth photosynthesis, leading more reliable projections how northern respond change.