The direct dependency of σs on ua−uw allows the former to be considered
as a proxy to quantify the plant-soil hydrological reinforcement.
The matric suction increase derived from plant water uptake or evapotranspiration
processes is one of the most recognisable hydrological effects
provided by the vegetation on the soil (Rodriguez-Iturbe and
Porporato, 2004). However, it cannot be employed alone to quantify
the plant-soil hydrological reinforcement as the mechanisms occurring
within the unsaturated soil-pore space are complex (Lu and Likos,
2004). Hence, the soil hydro-mechanical properties (e.g. α and n)
must be regarded in combination with ua − uw for the quantificationsampling locations in Catterline Bay by collecting coupled measurements
of the matric suction (ua − uw; kPa) and the moisture content
(w; %) over time (Fredlund and Rahardjo, 1993). Then, van Genuchten's