The manuscript submitted by MW Malone at al. is potentially a good one, enhancing knowledge on a broad spectrum of scientific interest. However, it lacks totally of organization and balancing in its parts. It must be rewritten by separating arguments in sub-chapters headed and organized in order to drive readers in the two different experimental goals: i) testing the apparatus and ii) characterizing changes in the water status of trees over long time periods.

In parallel with a convincing physical description of the experimental setup, biological evidence is very weak and/or weakly described, controlled and referenced.

I appreciated a lot the control of putative deuterium (negative?) involvement and its control in the experimental setup, but many other basic aspects that have to be controlled in order to have reliabilty in the trial have been neglected.

The most limiting factor to realize that i) methods and ii) results are reliable is a total absence of experimental reference out of the proposed technique. At least ponderal measurements in fresh versus dry samples must be provided to reference water quantities and putative flows.

Stomatal conductance trends should be showed, and water potential measurements should be performend, as water content and water availabilty for tissues can be characterized in the range of NMR outputs.