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.
2015
Forfattere
Tuva Grytli Geoffrey Guest Carine Lausselet Francesco Cherubini Ryan Bright Per Kr. Rørstad Helmer Belbo Rasmus Astrup Øyvind Skreiberg Morten Seljeskog Franziska Goile Anders Hammer StrømmanSammendrag
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Forfattere
Tuva Grytli Geoffrey Guest Carine Lausselet Francesco Cherubini Ryan Bright Per Kr. Rørstad Helmer Belbo Rasmus Astrup Øyvind Skreiberg Morten Seljeskog Franziska Goile Anders Hammer StrømmanSammendrag
Det er ikke registrert sammendrag
Forfattere
Safaa Wasof Jonathan Lenoir Per Arild Aarrestad Inger Greve Alsos W. Scott Armbruster Gunnar Austrheim Vegar Bakkestuen Harry John Betteley Birks Kari Anne Bråthen Olivier Broennimann Jörg Brunet Hans Henrik Bruun Carl Johan Dahlberg Martin Diekmann Stefan Dullinger Mats Dynesius Rasmus Ejrnæs Jean-Claude Gegout Bente Jessen Graae John-Arvid Grytnes Antoine Guisan Kristoffer Hylander Ingibjørg Jonsdottir Jutta Kapfer Kari Klanderud Miska Luoto Ann Milbau Mari Moora Bettina Nygaard Arvid Odland Harald Pauli Virve Ravolainen Stefanie Reinhardt Sylvi Marlen Sandvik Fride Høistad Schei James David Mervyn Speed Jens-Christian Svenning Wilfried Thuiller Unn Tveraabak Vigdis Vandvik Liv Guri Velle Risto Virtanen Pascal Vittoz Wolfgang Willner Thomas Wohlgemuth Niklaus E Zimmermann Martin Zobel Guillaume DecocqSammendrag
Aim Previous research on how climatic niches vary across species ranges has focused on a limited number of species, mostly inv asive, and has not, to date, been very conclusive. Here we assess the degree of niche conservatism between distant populations of native alpine plant species that have been separated for thousands of years. Location European Alps and Fennoscandia. Methods Of the studied pool of 888 terrestr ial vascular plant species occurring in both the Alps and Fennoscandia, we used two complementary approaches to test and quantify climatic-niche shifts for 31 species having strictly disjunct populations and 358 species having either a contiguous or a patchy distribution with distant populations. First, we used species distr i- bution modelling to test for a region effect on each species’ climatic niche. Second, we quantified niche overlap and shifts in niche width (i.e. ecological amplitude) and position (i.e. ecological optimum) within a bi-dimensional climatic space. Results Only one species (3%) of the 31 species with str ictly disjunct populations and 58 species (16%) of the 358 species with distant popula- tions showed a region effect on their climatic niche. Niche overlap was higher for species with strictly disjunct populations than for species with distant populations and highest for arctic–alpine species. Climatic niches were, on average, wider and located towards warmer and wetter conditions in the Alps. Main conclusion Climatic niches seem to be generally conserved between populations that are separated between the Alps and Fennoscandia and have probably been so for 10,000–15,000 years. Therefore, the basic assumption of species distribution models that a species’ climatic niche is constant in space and time – at least on time scales 10 4 years or less – seems to be largely valid for arctic–alpine plants.
2014
Sammendrag
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Forfattere
Nils Egil SøvdeSammendrag
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Forfattere
Nils Egil SøvdeSammendrag
Ground based systems are the main approach used for off-road timber transportation throughout the world. Estimates of terrain transportation costs are required for several forest planning problems and for assessment of harvesting contracts and forest land values. Methods for these calculations can be categorized into two groups. Methods based on average transportation distance predate computers, are analytical, and based on manual calculations. Network methods are based on a digital raster representation and are solved with numerical computations. Here, the two categories are compared and linked. Analytical methods in the literature have been limited to flat terrain and including detail is difficult. The network method can be extended to include uneven terrain or detailed input data.
Sammendrag
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Sammendrag
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Sammendrag
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Sammendrag
Whole trees from energy thinnings constitute one of many forest fuel sources, yet ten widely applied supply chains could be defined for this feedstock alone. These ten represent only a subset of the real possibilities, as felling method was held constant and only a single market (combustion of whole tree chips) was considered. Stages included in-field, roadside landing, terminal, and conversion plant, and biomass states at each of these included loose whole trees, bundled whole trees or chipped material. Assumptions on prices, performances, and conversion rates were based on field trials and published literature in similar boreal forest conditions. The economic outcome was calculated on the basis of production, handling, treatment and storage costs and losses. Outcomes were tested for robustness on a range of object volumes (50–350 m3solid), extraction distances (50–550 m) and transport distances (10–70 km) using simulation across a set of discrete values. Transport was calculated for both a standard 19.5 m and an extended 24 m timber truck. Results showed that the most expensive chain (roadside bundling, roadside storage, terminal storage and delivery using a 19.5 m timber truck) at 158 € td−1 was 23% more costly than the cheapest chain (roadside chipping and direct transport to conversion plant with container truck), at 128 € td−1. Outcomes vary at specific object volumes and transport distances, highlighting the need to verify assumptions, although standard deviations around mean supply costs for each chain were small (6%–9%). Losses at all stages were modelled, with the largest losses (23 € td−1) occurring in the chains including bundles. The study makes all methods and assumptions explicit and can assist the procurement manager in understanding the mechanisms at work.