Archive for May, 2010

Phyto-IT co-authors a paper comparing several sap flow sensors

Friday, May 7th, 2010

A paper about the comparison of several sap flow sensors, co-authored by Dirk De Pauw (Phyto-IT), was published in Agriculture and Forest Meteorology. A laboratory test and field evaluation were conducted to determine the accuracy of the three commonly used techniques for measuring sap flux density in trees: heat pulse velocity, thermal dissipation and heat field deformation. In the laboratory test a constant flow rate of water was maintained through freshly cut stem segments of diffuse-porous Fagus grandifolia trees. The three sensor types were measured simultaneously and compared against gravimetric measurements. All three techniques substantially underestimated sap flux density. It is concluded that a species-specific calibration is necessary when using any of these techniques to insure that accurate estimates of sap flux density are obtained, at least until a physical basis for an error correction can be proposed.

Full reference details:

    Steppe K., De Pauw D.J.W., Doody T.M. and Teskey R.O. (2010). A comparison of sap flux density using thermal dissipation, heat pulse velocity and heat field deformation methodsAgricultural and Forest Meteorology150(7-8), 1046-1056. 
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