1989/04/01 by C. Valancogne, Charles Valancogne, Z. Nasr +1 · 1 citation
Agricultural and Biological Sciences · Environmental Science · Mathematics · #Biology #Botany #Calibration #Composite material #Environmental science #Flow (mathematics) #Forest ecology and management #Greenhouse #Heat flow #Materials science #Mathematics #Mechanics #Physics #Plant Surface Properties and Treatments #Plant Water Relations and Carbon Dynamics #Thermal #Thermocouple #Thermodynamics #Volume (thermodynamics)
paper · pdf · doi:10.21273/hortsci.24.2.383
openalex publication_date 1989/04/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/25
Abstract A heat balance method has been developed that directly estimates sap volume flow rate (m 3 s -1 ). The measuring device involves: a) a heating jacket wound around the stem that delivers constant heat, and b) four thermal sensors (copper-constantan thermocouples) used to measure temperature changes in the sap and thermal gradients at the upstream and downstream ends of the heating jacket. Lateral heat losses, minimized by surrounding the heat jacket with good insulation, are ignored. This method requires no previous calibration since empirical coefficients can be computed when the sap flow is zero. The method has been tested under laboratory conditions on stem segments and in a greenhouse on small potted fruit trees. The results appear satisfactory, especially under high flow conditions.