tailieunhanh - Báo cáo khoa học: "Tree canopy and herb layer transpiration in three Scots pine stands with different stand structures"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: Tree canopy and herb layer transpiration in three Scots pine stands with different stand structures. | 265 Ann. For. Sci. 56 1999 265-274 Inra Elsevier Paris Original article Tree canopy and herb layer transpiration in three Scots pine stands with different stand structures Dietmar Liittschwagera Steffen Rustb Monika Wulfd Jacqueline Forkertb Reinhard F. Hiittlb a Center for Agricultural Landscape and Land use Research Eberswalder StraBe 84 15374 Miincheberg Germany b Technical University of Brandenburg 03013 Cottbus Germany Received 30 March 1998 accepted 25 January 1999 Abstract - To evaluate the impact of herb layer structure on the transpiration of Scots pine ecosystems in north-eastern Germany we measured tree canopy and herb layer transpiration in three stands. Parameters of tree hydraulic architecture were measured and their drought stress monitored. Despite striking differences in ecosystem structure combined tree and herb layer transpiration was equal for all three sites. Transpiration rate per needle area and tree canopy transpiration were least at the site dominated by the tall grass species Calamagrostis epigeios. Pine pre-dawn water potential in the Calamagrostio-Cultopinetum sylvestris was never lower than in the Myrtillo-Cultopinetum sylvestris indicating that severity of competition of ground vegetation was not much different. Huber values xylem hydraulic conductance and leaf-specific conductance of pine were least in the Calamagrostio-Cultopinetum sylvestris. Thus pine transpiration rate might have been adjusted to lower tree hydraulic conductance and the herbaceous species used the water left by the trees. Inra Elsevier Paris. canopy herb layer transpiration hydraulic conductance Scots pine Resume - Transpiration des arbres et de la strate herbacée dans trois peuplements de pins Sylvestres de differentes structures. Dans le but d evaluer les effets de la strate herbacée sur la transpiration d ecosystemes de pins Sylvestres en Allemagne du nord-est la transpiration des houppiers et de la strate herbacée a été mesurée dans trois peuplements. Les .

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