01757nam a2200157 a 450000100080000000500110000800800410001910000170006024500730007726002140015030000140036452011590037865300240153770000210156170000170158210170962015-03-12       2004    bl uuuu     u00u1 u    #d1 aMARIN, F. R.  aPreliminary evaluation of sap flow data by stem heat balance method.  aIn: REUNIÓN ARGENTINA Y LATINOAMERICANA DE AGROMETEOROLOGIA, 10., 4., 2004, Mar del Plata, Argentina. [Anais]: Agrometeorologia y Seguridad Alimentaria en América Latina. Mar del Plata, Argentina: AADAc2004  c1 CD-ROM.  aCermak et al. (1973) developed the first version of the heat balance method (HBM), which involves continuous application of heat in a stem segment and quantifying losses by axial and radial wood conduction. The heat flow carried out by the sap is determined from the difference between input power and axial and radial heat losses from the heated stem segment. Currently, this method follows Sakuratani (1981) and Baker & Van Bavel (1987), who modified the first HBM version by applying a constant power on the gauge, so reducing the electronic requirements for the measurements. The HBM is an absolute method that requires simple equipment and some basic procedures in order to minimize errors (Baker & Nieber, 1989; Steinberg et al., 1990; Valancogne & Nasr, 1993; Weibel & de Vos, 1994). However, it is difficult to evaluate sap flow measurements in field conditions since reference methods, such as lysimeters, soil water balance and other techniques are normally difficult to apply, especially for big plants. This paper focuses on this problem and considers some procedures to evaluate data supplied by HBM when reference methods are not available.  aHeat Balance Method1 aANGELOCCI, L. R.1 aRIGHI, E. Z.