Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2013
Forfattere
Mekjell Meland Eva Birken Clive KaiserSammendrag
Crop load adjustments in European plum trees (Prunus domestica L.) require thinning either by hand (mechanical) or chemical means to achieve marketable size, fruit quality and to overcome alternate bearing. Efficient tools for crop load management are highly desirable, since only a few chemical thinners are registered and hand thinning is labor intensive and costly. Gibberellic acid (GA3) was tested as a novel approach to regulate the crop load of the plum cultivar ‛Opal’ at Ullensvang, western Norway. The objective was to reduce flower bud induction in the “off-year” thus adjusting crop load the subsequent year. In 2008, an “off-year”, GA3 was applied to 9 year-old ‘Opal’ trees as a high volume spray to the point of run-off at 50 ppm or 100 ppm at either 5 weeks after full bloom or 10 weeks after full bloom, or on both dates and compared with untreated control trees. Trees were unthinned the first year but then thinned to commercial standard the following year. In the year of application, total yield was recorded and fruit quality evaluated. Return bloom, fruit set, yield and fruit quality were assessed the subsequent year. In general, there were no significant differences in crop load of all treated trees compared to untreated trees in the year of application (non-target crop) however, fruit weight increased slightly on those trees when GA3 was applied 5 weeks after full bloom compared to all other treatments and untreated trees. The following year (target crop) fruit set was significantly reduced for all GA3 treatments. The most effective application time was 5 weeks after full bloom. Before thinning, initial fruit set was greatest on untreated trees as well as on those trees treated with GA3 10 weeks after full bloom. Fruit weight and fruit colour were significantly better on trees with the least fruit set. GA3 applications had no effect on fruit firmness. It is concluded that GA3 is an effective tool for inhibiting flower bud induction in an “off-year” thus enabling crop load management the subsequent “on-year”.
Sammendrag
The distribution of Leiopus nebulosus (Linnaeus, 1758) and L. linnei Wallin, Nylander & Kvamme, 2009, in Norway is discussed and depicted. Observations of host trees as well as information of substrate qualities and phenology are included.
Forfattere
John A. Finn Laura Kirwan John Connolly Maria Teresa Sebastia Aslaug Helgadottir Ole Hans Baadshaug Gilles Bélanger Alistair Black Caroline Brophy Rosemary P. Collins Jure Cop Sigridur Dalmannsdottir Ignacio Delgado Anjo Elgersma Michael Fothergill Bodil Frankow-Lindberg An Ghesquiere Barbara Golinska Piotr Golinski Philippe Grieu Anne-Maj Gustavsson Mats Höglind Olivier Huguenin-Elie Marit Jørgensen Zydre Kadziuliene Päivi Kurki Rosa Llurba Tor Lunnan Claudio Porqueddu Matthias Suter Ulrich Thumm Andreas LüscherSammendrag
Det er ikke registrert sammendrag
Forfattere
Halvor SolheimSammendrag
Common juniper (Juniperus communis) hosts not many pests or pathogens, but recently increasing needle blight has been observed in Norway. During a survey the needle blight was recorded in many parts of southern Norway but not above 550 m a.s.l., and it has been found both in forests, pastures and gardens. Trees are affected differently; some trees seem to be unaffected, while other trees may be killed. The cause of the disease is a fungus in the family Mycosphaerellaceae hitherto not reported from Norway. In forest pathology literature it has been named Stigmina juniperina, but also Asperisporium juniperinum. However, based on results of molecular sequence analyses it is proposed here that a more appropriate name should be Passalora juniperina (Georgescu & Badea) H. Solheim comb. Nov.
Forfattere
Kerry O'Donnell Alejandro P. Rooney Robert Proctor Daren W. Brown Susan P. McCormick Todd J. Ward Rasmus J. N. Frandsen Erik Lysøe Stephen A. Rehner Takayuki Aoki Vincent A.R.G Robert Pedro W. Crous Johannes Z. Groenewald Seogchan Kang David M. GeiserSammendrag
Det er ikke registrert sammendrag
Forfattere
Aksel Bernhoft Gunnar Sundstøl Eriksen Leif Sundheim Marc Berntssen Anne Lise Brantsæter Guro Brodal Christiane Kruse Fæste Ingerd Skow Hofgaard Trond Rafoss Tore Sivertsen Anne Marte Tronsmo Heidi Amlund Augustine Arukwe Marit Aursand Margaretha Haugen Gro Ingunn Hemre Trond Hofsvang Helle Katrine Knutsen Åshild Krogdahl Jørgen Fredrik Lassen Christer Magnusson Audun Helge Nerland Live Lingaas Nesse Bjørn Næss Einar Ringø Anders Ruus Janneche Utne Skåre Halvor Solheim Arild Sletten Inger-Lise Steffensen Line Charlotte Sverdrup Birger Svihus Ole Torrissen Bente Elisabeth Torstensen Cathrine Thomsen Robin Ørnsrud Bjørn Økland Olav Østerås Jan AlexanderSammendrag
Det er ikke registrert sammendrag
Sammendrag
Old trees represent key features of old-growth forests and are important elements for maintaining biodiversity. Due to extensive human exploitation of Fennoscandian boreal forests during several centuries, old Norway spruce trees have become exceedingly rare. We analysed 91 spruce trees in Trillemarka Nature Reserve, southern Norway, to investigate (1) the maximum age of living trees, (2) growth rates of different-age trees and (3) growth trends in very old trees. Increment cores were taken from trees in selected old-growth stands located at 700–850 m a.s.l. Twelve spruce trees had an estimated total age of >400 years, the oldest one being 529 years and presumably the oldest known still living Norway spruce in northern Europe. A negative relationship between growth rate (basal area increment) and total age was observed, being most distinct for growth rates at 126–275 years and less marked for early stage growth (26–75 years). Thus, high age apparently was related more to low growth rates at adult and old stages of life rather than at the earlier stage. Among the trees >400 years, many of them did not show growth decrease with advancing age, indicating that ageing did not reduce growth. We conclude that the maximum age of stand-forming Fennoscandian Norway spruce trees would be in the range of 500–600 years.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
1. Whether plant competition grows stronger or weaker across a soil fertility gradient is an area of great debate in plant ecology. We examined the effects of competition and soil fertility and their interaction on growth rates of the four dominant tree species in the sub-boreal spruce forest of British Columbia. 2. We tested separate soil nutrient and moisture indices and found much stronger support for models that included the nutrient index as a measure of soil fertility. 3. Competition, soil fertility and their interaction affected radial growth rates for all species. 4. Each species supported a different alternate hypothesis for how competitive interactions changed with soil fertility and whether competition intensity was stronger or weaker overall as soil fertility increased depended on the context, specifically, species, neighbourhood composition and type of competition (shading vs. crowding). 5. The four species varied slightly in their growth response to soil fertility. 6. Individual species had some large variations in the shapes of their negative relationships between shading, crowding and tree growth, with one species experiencing no net negative effects of crowding at low soil fertility. 7. Goodness-of-fit was not substantially increased by models including competition–soil fertility interactions for any species. Tree size, soil fertility, shading and crowding predicted most of the variation in tree growth rates in the sub-boreal spruce forest. 8. Synthesis. The intensity of competition among trees across a fertility gradient was species- and context-specific and more complicated than that predicted by any one of the dominant existing theories in plant ecology.
Sammendrag
The mating system ofCapercaillie has been referred to as “exploded lek” because displaying males are spaced farther apart than on classical leks. However, inter-male distances and spacing behavior rarely have been quantified. In 2009–2011, we examined the spatial relationships of males on two leks in southeastern Norway by GPS satellite telemetry. Largely exclusive display territories (median 2 ha) surrounded the mating site, but the males spent most of the time displaying on smaller, well-defined display sites (median 182 m2) within their territories. When on their display sites, neighboring birds were spaced 64–212 m apart; decreasing to a minimum during the time of mating. Occasionally, males made long exploratory excursions (median 243 m) across the territories of neighbors, sometimes interacting with them at close distance (< 10m). During daytime, males resided solitarily in radially extending ranges within 1 km of the lek center, commuting to the lek either in the evening or morning by walking or flying, leaving in the morning mostly by walking. The distance from the lek center to night roosting trees and daytime resting areas decreased during the mating season. With interacting males and a spatial arrangement in-between that of classical leks and dispersed polygyny, the term “exploded lek” seems appropriate for the mating system of Capercaillie.