Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí lâm nghiệp đề tài: Infra-red images of heat field around a linear heater and sap flow in stems of lime trees under natural and experimental conditions. | Ann. For. Sci. 61 2004 203-213 INRA EDP Sciences 2004 DOI forest 2004014 203 Original article Infra-red images of heat field around a linear heater and sap flow in stems of lime trees under natural and experimental conditions Nadezhda NADEZHDINAa Helmut TRIBUTSCHb Jan CERMÁKa a Institute of Forest Ecology Mendel University of Agriculture and Forestry Zemedelska 3 Brno 61300 Czech Republic b Hahn-Meitner Institute Dept. Solare Energetik 14109 Berlin Germany Received 26 February 2003 accepted 20 August 2003 Abstract - The heat field deformation method HFD for sap flow measurements was applied under field conditions simultaneously with the infra-red imaging of the smoothed stem surface in two lime Tilia cordata Mill. trees. Deformation of the heat field generated in the stems by the linear heater was measured by thermocouples installed in axial and tangential directions around the heater in different xylem depths. The frontal and radial views of the heat field were visualized at the same time by the infra-red IR camera under conditions of zero-flow and moving sap. The IR-technique basically underlines the established interpretation of sap flow dynamics but contributes by a more complex and visualized picture. The IR also shows directly the xylem anisotropy. The ability of HFD-method for measurements of bi-directional sap flow rates and flows approaching zero was confirmed by simultaneous comparing with IR-images. Fast responding and capabilities of HFD-method for studying tree architecture and function were demonstrated. cutting bi-directional low and zero -flow flow redistribution heat field deformation method Résumé - Images infra-rouges du champ calorifique autour d un appareil de chauffage linéaire et flux de sève dans des troncs de tilleul en conditions naturelles et expérimentales. La méthode de déformation du champ calorifique HFD a été appliquée à des mesures du flux de sève en conditions naturelles simultanément avec la photographie infra-rouge de la
