Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: Radial distribution of sap flux density in trunks of a mature beech stand. | Ann. For. Sci. 64 2007 431-438 INRA EDP Sciences 2007 DOI forest 2007020 Available online at Original article Radial distribution of sap flux density in trunks of a mature beech stand Dietmar LUttschwager Rainer REMUS Leibniz Centre for Agricultural Landscape Research 15374 Muncheberg Germany Received 11 July 2006 accepted 13 December 2006 Abstract - In a mature beech stand located in north-eastern Germany xylem sap flux measurements were continuously performed during the 2002-2004 growing seasons. Ten representative trunks were studied using heated thermal dissipation probes. The measurements aimed at identifying principles governing radial profiles of xylem flux in beech trunks. The measurements were taken up to a trunk depth of 132 mm. The sap flow density in the pericambial xylem was found to vary among trees of different diameters but was not considerably smaller in suppressed trees. A model for the radial distribution of sap flux density was formulated relating trunk radius and sap flow density. The model takes into account different trunk diameter. About 90 of the sap flux was found to occur in the outer two fifths of the trunk. Using this model an adequate estimate of transpiration can be achieved at tree and stand level even when the sap flux measurements are restricted to the outer trunk sectors. sap flow density radial model beech Résumé - Distribution radiale du flux de sève dans les troncs d un peuplement de hêtres. Nous avons mesuré les densités de flux de xylème dans le tronc de 10 individus représentatifs d un peuplement de hêtres du nord-est de l Allemagne. Ces mesures ont été conduites pendant les périodes de végétation de 2002 à 2004 en utilisant des sondes à dissipation de chaleur. Le but était de décrire les gradients radiaux de flux de sève dans le tronc des hêtres. Les mesures ont été réalisées jusqu à une profondeur de 132 mm. La densité de flux de sève du xylème de la zone cambiale variait d arbre en arbre en .
