Supported sensors
Currently Sap Flow Tool supports two sensor type: HRM-sensors (Heat Ratio Method) and HFD-sensors (Heat Field Deformation).
HRM-sensor (Heat Ratio Method)
The Heat Ratio Method (HRM) is a modification of the Compensation Heat Pulse Method (CHPM). The HRM improves on the CHPM by allowing very slow flow rates and even reverse sap flow to be measured. This allows water flows to be monitored in stems and roots of a wide range of different species, sizes and environmental conditions, including drought.
Developed by the University of Western Australia and partner organisations, ICRAF and CSIRO, the HRM sensor has been validated against gravimetric measurements of transpiration and used in published sapflow research since 1998. Burgess, S.S.O., et.al. 2001 "An improved heat pulse method to measure low and reverse rates of sapflow in woody plants", Tree Physiology 21, 589-598.
For more detailed information click here.
HFD-sensor (Heat Field Deformation)
The Heat Field Deformation (HFD) technique is a radically new method for measuring sapflow. It is ideally suited to sapflow research projects that require the measurement of extended radial sapflow profiles to accurately map hydraulic architecture of trees.
Similar to the HRM sap flow sensor the HFD sensor can measure high sapflow rates as well as low to zero and reverse sapflow. Hence as both sensors can measure in the same range the HFD sensor provides an extension of the HRM method making both sensors highly complimentary to each other in most sapflow measurement applications.
For more detailed information click here.
