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Sap flow measurement by a single thermal dissipation probe in transient regime: implementation of the method and test under field conditions
- Source :
- Annals of Forest Science, Annals of Forest Science, Springer Nature (since 2011)/EDP Science (until 2010), 2012, 69 (7), pp.773-781. ⟨10.1007/s13595-012-0194-3⟩
- Publication Year :
- 2012
- Publisher :
- HAL CCSD, 2012.
-
Abstract
- Recent works have showed the possibility of measuring sap flow density (u) by a single heated probe using the transient regime just after the heating current is switched off. The method (SP-T) is based on a thermal index (I) which involves the temperature of the probe at three different times of the cooling kinetics (beginning, intermediate time, and end), the latter representing wood temperature at equilibrium. The present paper re-examines the method to better estimate wood temperature and to account for possible variations in probe-wood thermal properties. After a recalibration of the method on an olive branch with a hydraulic bench, the SP-T method is used to measure sap flow on two olive trees under field conditions. Estimated flow densities are compared to those obtained with the transient thermal dissipation-dual probe method (TTD-DP) of Do and Rocheteau. Obtained results show that: (1) wood reference temperature is better estimated when using the probe temperatures just before heating and at the end of the cooling phase; (2) calibration relationships based on a “normalized” thermal index K t = (I − I o )/I o, where I o represents the value of I under zero flow conditions, better account for differences in the wood-probe thermal properties; (3) I o, taken as the lowest I over a 24-h span, has shown consistent stability for a given probe-tree complex; (4) the SP-T method used in its normalized form appears to be in good agreement with the TTD-DP method.
- Subjects :
- 0106 biological sciences
Materials science
010504 meteorology & atmospheric sciences
Ecology
Flow (psychology)
Forestry
Mechanics
Sap flow measurement
01 natural sciences
Flow measurement
Olive trees
Flow conditions
[SDV.SA.SF]Life Sciences [q-bio]/Agricultural sciences/Silviculture, forestry
Phase (matter)
Thermal
Calibration
Transient (oscillation)
Thermal dissipation
Olive tree
Transient regime
ComputingMilieux_MISCELLANEOUS
010606 plant biology & botany
0105 earth and related environmental sciences
Single probe
Subjects
Details
- Language :
- English
- ISSN :
- 12864560 and 1297966X
- Database :
- OpenAIRE
- Journal :
- Annals of Forest Science, Annals of Forest Science, Springer Nature (since 2011)/EDP Science (until 2010), 2012, 69 (7), pp.773-781. ⟨10.1007/s13595-012-0194-3⟩
- Accession number :
- edsair.doi.dedup.....f3c9548f7641b751cb4345b2ed84c49f