Sap flow sensors: construction, quality control and comparison

Sensors (Basel). 2012;12(1):954-71. doi: 10.3390/s120100954. Epub 2012 Jan 16.


This work provides a design for two types of sensors, based on the thermal dissipation and heat ratio methods of sap flow calculation, for moderate to large scale deployments for the purpose of monitoring tree transpiration. These designs include a procedure for making these sensors, a quality control method for the final products, and a complete list of components with vendors and pricing information. Both sensor designs were field tested alongside a commercial sap flow sensor to assess their performance and show the importance for quality controlling the sensor outputs. Results show that for roughly 2% of the cost of commercial sensors, self-made sap flow sensors can provide acceptable estimates of the sap flow measurements compared to the commercial sensors.

Keywords: environmental sensors; heat ratio method; sap flow; thermal dissipation method.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Acer / physiology
  • Biosensing Techniques / economics
  • Biosensing Techniques / instrumentation*
  • Biosensing Techniques / standards*
  • Calibration
  • Electricity
  • Equipment Design / economics
  • Linear Models
  • Plant Exudates / physiology*
  • Quality Control
  • Temperature


  • Plant Exudates