Premium
A single‐probe heat pulse method for estimating sap velocity in trees
Author(s) -
LópezBernal Álvaro,
Testi Luca,
Villalobos Francisco J.
Publication year - 2017
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.14694
Subject(s) - instrumentation (computer programming) , convection , thermal conduction , compensation (psychology) , mechanics , pulse (music) , heat flow , flow (mathematics) , convective heat transfer , environmental science , materials science , nuclear engineering , biological system , process engineering , computer science , thermodynamics , thermal , physics , electrical engineering , voltage , engineering , composite material , psychology , biology , psychoanalysis , operating system
Summary Available sap flow methods are still far from being simple, cheap and reliable enough to be used beyond very specific research purposes. This study presents and tests a new single‐probe heat pulse ( SPHP ) method for monitoring sap velocity in trees using a single‐probe sensor, rather than the multi‐probe arrangements used up to now. Based on the fundamental conduction−convection principles of heat transport in sapwood, convective velocity ( V h ) is estimated from the temperature increase in the heater after the application of a heat pulse (Δ T ). The method was validated against measurements performed with the compensation heat pulse ( CHP ) technique in field trees of six different species. To do so, a dedicated three‐probe sensor capable of simultaneously applying both methods was produced and used. Experimental measurements in the six species showed an excellent agreement between SPHP and CHP outputs for moderate to high flow rates, confirming the applicability of the method. In relation to other sap flow methods, SPHP presents several significant advantages: it requires low power inputs, it uses technically simpler and potentially cheaper instrumentation, the physical damage to the tree is minimal and artefacts caused by incorrect probe spacing and alignment are removed.