Modeling tree water flow as an unsaturated flow through a porous medium

Area of Science:

• Plant Physiology
• Biophysics
• Hydrology

Background:

• The electric circuit analogy is widely used in tree water flow modeling.
• This analogy has limitations in accurately representing changes in saturation over time.
• Capacitance, as defined by the analogy, implies unrealistic saturation changes.

Purpose of the Study:

• To identify the inadequacies of the electric circuit analogy in tree water flow.
• To propose a new theory for tree water flow.
• To develop new models for saturated and unsaturated water flow in trees.

Main Methods:

• Developing a new theory combining Cohesion theory with multiphase flow in porous media.
• Presenting mathematical models for both saturated and unsaturated tree water flow.
• Demonstrating the mathematical equivalence of previous models to saturated porous flow.

Main Results:

• The electric circuit analogy is insufficient for predicting changes in saturation.
• The new theory accurately models saturated and unsaturated flow.
• The unsaturated model explicitly accounts for pressure, saturation changes, and interfacial area.

Conclusions:

• A new theory is needed to accurately model tree water flow.
• The proposed theory provides a more robust framework for understanding water transport.
• Higher spatial and temporal resolution measurements are crucial for understanding tree water dynamics.