Six sap flow sensors have been installed in the observed forest. The sensors give measurements of the rate at which moisture is transported up or down the stem. This gives an indication of when changes in water content in the tree can be expected, as well as how the tree responds to its environment.
A sap flow sensor produces a pulse of heat in a probe insterted in the stem. Temperature probes then monitor the change in heat up or down the stem, from which the flow rate of moisture in the tree can be inferred.
Along with the dendrometers and new soil moisture sensors, the effects of forest water dynamics on radar measurements can be revealed.