The watering of tall trees - Embolization and recovery

Henri Gouin (1)

1 IUSTI - Institut universitaire des systèmes thermiques industriels

We can propound a thermo-mechanical understanding of the ascent of sap to the top of tall trees thanks to a comparison between experiments associated with the cohesion-tension theory and the disjoining pressure concept for liquid thin-films. When a segment of xylem is tight-filled with crude sap, the liquid pressure can be negative although the pressure in embolized vessels remains positive. Examples are given that illustrate how embolized vessels can be refilled and why the ascent of sap is possible even in the tallest trees avoiding the problem due to cavitation. However, the maximum height of trees is limited by the stability domain of liquid thin-films.

Mots clés: disjoining pressure; sap ascent; tree recovery; cohesion-tension theory; van der Waals forces; high trees.

Domaines: Biologie végétale; Chimie-Physique [physics.chem-ph]; Mécanique des fluides [physics.class-ph]

Henri Gouin. The watering of tall trees - Embolization and recovery: Crude sap ascent and tree recovery. Journal of Theoretical Biology, 2015, 369, pp.42 - 50. ⟨10.1016/j.jtbi.2015.01.009⟩. ⟨hal-00979793v2⟩