[Insert Fig. 11 here]
5 Conclusions
We present a new heat-pulse-based method, the Double-Ratio Method (DRM),
to calculate sap velocity in woody plants. We demonstrate both
theoretically and experimentally that the DRM can effectively measure a
broader range of sap velocities than other common heat-pulse based
methods. Like an earlier approach that combined the HRM and CHPM, the
DRM computes two distinct estimates of sap velocity at each time point;
however, the DRM has several advantages over the combination of the HRM
and CHPM, including a theoretical basis for selecting between the two
velocity estimates and identifying the optimal times for averaging data,
and a reduced sensitivity to noise at high velocities.
Acknowledgements
This work was supported by the Australian Research Council
(LP130100183), the International Wheat Yield Partnership (IWYP, project
89) through a grant from the Grains Research and Development Corporation
(GRDC, US00082), the National Science Foundation (Awards #1557906 and
1951244), Almond Board of California and the USDA National Institute of
Food and Agriculture, Hatch project 1016439.