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
Authors
Inge Dox Tore Skrøppa Mieke Decoster Peter Prislan Aina Gascó Jožica Gričar Holger Lange Matteo CampioliAbstract
Historically, the autumn dynamics of deciduous forest trees have not been investigated in detail. However, autumn phenological events, like onset of loss of canopy greenness (OLCG), onset of foliar senescence (OFS) and cessation of wood growth (CWG), have an important impact on tree radial growth and the entire ecosystem's seasonal dynamics. Here, we monitored the leaf and wood phenological events of silver birch (Betula pendula) at four different sites in Ås, southeastern Norway: (a) a natural mature stand, (b) a plantation on former agricultural ground, (c) young natural trees, and (d) young trees in pots under different fertilization levels. The study took place over four consecutive years (from 2017 to 2020), with a particular focus on 2018, a year in which there was a severe summer drought, and the next year, 2019, which featured more normal conditions. First, we provided a description of birch phenology within its mid-north distributional. Second, we showed that drought advanced CWG by about 5 to 6 weeks and it delayed OLCG and OFS up to 30 days. Third, we observed an unexpected advance in OLCG in 2019 compared to 2018 (30 days) and 2020 (14 days). OFS presented similar dynamics as OLCG, whereas CWG was advanced only in 2018. These findings might indicate lag-effects of severe drought on the next year autumn leaf phenology but not on wood growth. On the other hand, the comparison between the natural stand and the plantation showed that, under drought conditions, wood growth is more sensitive to site fertility than autumn leaf phenology. In summary, our study elucidated the autumn dynamics of an important deciduous forest species in the northern temperate zone and showed unexpected impacts of a severely dry and warm summer on the current and next year leaf phenology.
Authors
Ulrike BayrAbstract
No abstract has been registered
Authors
Ritter Atoundem Guimapi Saliou Niassy Bester Tawona Mudereri Elfatih M. Abdel-Rahman Ghislain T. Tepa-Yotto Sevgan Subramanian Samira A. Mohamed Karl Thunes Emily Kimathi Komi Mensah Agboka Manuele Tamò Jean Claude Rwaburindi Buyung Hadi Maged Elkahky May-Guri Sæthre Yeneneh Belayneh Sunday Ekesi Segenet Kelemu Henri E. Z. TonnangAbstract
No abstract has been registered
Authors
P.W. Barnes T.M. Robson P.J. Neale C.E. Williamson R.G. Zepp S. Madronich S.R. Wilson A.L. Andrady A.M. Heikkilä G.H. Bernhard A.F. Bais R.E. Neale J.F. Bornman M.A.K. Jansen A.R. Klekociuk J. Martinez-Abaigar S.A. Robinson Q.-W. Wang A.T. Banaszak D.-P. Häder S. Hylander K.C. Rose S.-Å. Wängberg Bente Føreid W.-C. Hou R. Ossola N.D. Paul J.E. Ukpebor M. P. S. Andersen J. Longstreth T. Schikowski K.R. Solomon B. Sulzberger L.S. Bruckman K.K. Pandey C.C. White L. Zhu M. Zhu P.J. Aucamp J.B. Liley R.L. McKenzie M. Berwick S.N. Byrne L.M. Hollestein R.M. Lucas C.M. Olsen L.E. Rhodes S. Yazar A.R. YoungAbstract
No abstract has been registered
Authors
Kristin Hamre Giulia Micallef Marie Hillestad Johan Johansen Sofie c Remø Wuxiao Zhang Elisabeth Rasmussen Ødegård Hernandez Pedro W Araujo P. Antony Jesu Prabhu Rune WaagbøAbstract
No abstract has been registered
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No abstract has been registered
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No abstract has been registered
Abstract
Tomato greenhouses at high latitudes (≥58°North) require supplemental light to enable high yields and year-round production. Supplemental light systems can differ in lamp type, high-pressure sodium (HPS) or light emitting diode (LED), and also vary in lamp capacity. Based on a combined greenhouse climate, tomato yield, and greenhouse economics model, a methodology was developed, for determining the optimal supplemental light system, dependent on local climate and economic conditions. Two optimisation objectives were considered separately, maximal energy use efficiency (EUE) and maximal net financial result (NFR). The developed methodology was applied to four different greenhouse locations in Norway. At each location, both optimisation objectives were reached with LEDs. The optimal lamp capacities range from 256 to 341 μmol m−2 s−1 (maximal EUE) and 302–323 μmol m−2 s−1 (maximal NFR). The economically optimal lamp capacity is little sensitive to climate conditions. At the lamp type respective NFR maxima, LEDs resulted, on average, in 10% higher tomato yield, 102.2 NOK m−2 year−1 higher NFR, and 35% higher EUE. Consequently, switching from HPS lamps to LEDs enables increasing productivity, energy efficiency and profitability of greenhouse tomato production. Furthermore, the difference between EUE and NFR optima was, on average, 24% lower in terms of EUE and 56% lower in terms of NFR, when using LEDs instead of HPS lamps. On farm-scale, the proposed methodology can be used as decision-support-tool for selecting an efficient and profitable supplemental light system for greenhouse tomato production, dependent on local climate and economic conditions.
Authors
Bertold Mariën Dimitri Papadimitriou Titta Kotilainen Paolo Zuccarini Inge Dox Melanie Verlinden Thilo Heinecke Joachim Mariën Patrick Willems Mieke Decoster Aina Gascó Holger Lange Josep Peñuelas Matteo CampioliAbstract
Accurate estimations of phenophases in deciduous trees are important to understand forest ecosystems and their feedback on the climate. In particular, the timing of leaf senescence is of fundamental importance to trees’ nutrient stoichiometry and drought tolerance and therefore to trees’ vigor and fecundity. Nevertheless, there is no integrated view on the significance, and direction, of seasonal trends in leaf senescence, especially for years characterized by extreme weather events. Difficulties in the acquisition and analyses of hierarchical data can account for this. We collected four years of chlorophyll content index (CCI) measurements in thirty-eight individuals of four deciduous tree species (Betula pendula, Fagus sylvatica, Populus tremula and Quercus robur) in Belgium, Norway and Spain, and analyzed these data using generalized additive models for location, scale and shape (GAMLSS). As a result, (I) the phenological strategy and seasonal trend of leaf senescence in these tree species could be clarified for exceptionally dry and warm years, and (II) the daily average (air) temperature, global radiation, and vapor pressure deficit could be established as main drivers behind the variation in the timing of the senescence transition date. Our results show that the onset of the re-organization phase in the leaf senescence, which we approximated and defined as local minima in the second derivative of a CCI graph, was in all species mainly negatively affected by the average temperature, global radiation and vapor pressure deficit. All together the variables explained 89 to 98% of the variability in the leaf senescence timing. An additional finding is that the generalized beta type 2 and generalized gamma distributions are well suited to model the chlorophyll content index, while the senescence transition date can be modeled using the normal-exponential-student-t, generalized gamma and zero-inflated Box-Cox Cole and Green distributions for beech, oak and birch, and poplar, respectively.
Authors
Marleen Pallandt Bernhard Ahrens Sujan Koirala Holger Lange Markus Reichstein Marion Schrumpf Sönke ZaehleAbstract
No abstract has been registered