Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2022
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The three-dimensional structure of forest canopies is essential for light use efficiency, photosynthesis and thus carbon sequestration. Therefore, high-quality characterization of canopy structure is critical to improving our carbon cycle estimates by Earth system models and better understanding disturbance impacts on carbon sequestration in forested ecosystems. In this context, a widely used observable is the Leaf Area Density (LAD) and its integral over the vertical dimension, the Leaf Area Index (LAI). A multitude of methods exists to determine LAD and LAI in a forest stand. In this contribution, we use a mature Norway spruce forest surrounding an ICOS flux tower at Hurdal site (NO-Hur) to investigate LAD and LAI with six different methods: field campaigns using (1) the Plant Canopy Analyzer LAI-2000; (2) the LaiPen LP 110; (3) Digital Hemispheric Photography at a set of plots within the area; (4) a Lidar drone flight covering the footprint area of the tower; (5) an airborne Lidar campaign, and (6) a satellite LAI product (MODIS). The horizontal spatial structure of LAI values is investigated using marked point process statistics. Intercomparison of the methods focusses not only on biases and root mean squared errors, but also on the spatial patterns observed, quantifying to which extent a simple bias correction between the methods is sufficient to make the different approaches match to each other.
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As a way to estimate evapotranspiration (ET), Heat Field Deformation (HFD) is a widely used method to measure sap flow of trees based on empirical relationships between heat transfer within tree stems and the sap flow rates. As an alternative, the Linear Heat Balance (LHB) method implements the same instrumental configuration as HFD but calculates the sap flow rates using analytical equations that are derived from fundamental conduction-convection heat transfer equations.
Authors
Lucius Tamm Barbara Thuerig Stoilko Apostolov Hugh Blogg Esmeralda Borgo Paola Elisa Corneo Susanne Fittje Michelangelo de Palma Adam Donko Catherine Experton Évelyne Alcázar Marin Ángela Morell Pérez Ilaria Pertot Anton Rasmussen Håvard Steinshamn Airi Vetemaa Helga Willer Joëlle Herforth-RahméAbstract
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Authors
Eli Knispel Rueness Kjersti Sternang Kvie Erlend Birkeland Nilsen Hugo de Boer Katrine Eldegard Kjetil Hindar Lars Robert Hole Johanna Järnegren Kyrre Linné Kausrud Inger Elisabeth Måren Anders Nielsen Eva Bonsak Thorstad Gaute VelleAbstract
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Authors
Mladen Ognjenović Ivan Seletković Nenad Potočić Mia Marušić Melita Perčec Tadić Mathieu Jonard Pasi Rautio Volkmar Timmermann Lucija Lovreškov Damir UgarkovićAbstract
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Authors
Tore SkrøppaAbstract
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Authors
P.W. Barnes J.F. Bornman K.K. Pandey G.H. Bernhard R.E. Neale S.A. Robinson P.J. Neale R.G. Zepp S. Madronich C.C. White M.P.S. Andersen A.L. Andrady P.J. Aucamp A.F. Bais A.T. Banaszak M. Berwick L.S. Bruckman S.N. Byrne Bente Føreid D.-P. Häder A.M. Heikkilä L.M. Hollestein W.-C. Hou S. Hylander M.A.K. Jansen A.R. Klekociuk J.B. Liley J. Longstreth R.M. Lucas J. Martinez-Abaigar R.L. McKenzie K. McNeill C.M. Olsen R. Ossola N.D. Paul L.E. Rhodes T.M. Robson K.C. Rose T. Schikowski K.R. Solomon B. Sulzberger J.E. Ukpebor Q.-W. Wang S.-Å. Wängberg C.E. Williamson S.R. Wilson S. Yazar A.R. Young L. Zhu M. ZhuAbstract
No abstract has been registered