How does a tree without green foliage keep itself alive?
Dr Martin Bader and Assoc. Prof. Sebastian Leuzinger from Auckland University of Technology have found that when two trees of the same species are close to one another, they are able to undertake Hydraulic Coupling – that is share water, carbon, minerals and microorganisms.
From the data that these instruments captured, Bader and Leuzinger were able to observe the movement of the sap between the stump and the tree.
The SFM1 Sap Flow Meter can measure very low sap flow and reverse sap flow. This enabled measurement of sap flow toward the tree in day time and reversal of flow toward the stump at night. The hydraulic gradient as measured by the PSY1 Stem Psychrometer reversed from day to night and hence the direction of flow reversed from day to night in relationship to this measured hydraulic gradient.
Bader, M. K.-F., & Leuzinger, S. (2019). Hydraulic Coupling of a Leafless Kauri Tree Remnant to Conspecific Hosts. iScience, 19, 1238–1247.
Figure (above, right) shows SFM1 Sap Flow Meters monitoring sap flow through the stump at different times of day. (Supplied by Assoc. Prof. Sebastian Leuzinger)
Figure (above, top) is a combined diagram of Daytime & Nightime Shared Sap Flow, Based on the Scientific Paper’s Diagrams (Original Photo Supplied: Assoc. Prof. Sebastian Leuzinger).