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.
2005
Authors
Per Gundersen Jan-Olov Weslien Bjarni D. Sigurdsson Magne Sætersdal Leena Finér Ingeborg CallesenAbstract
Forest ecosystems provide many deliverables or benefits to society. The most obvious one is wood for the forest industry. Other benefits include berries, hunting, and recreation. More recently recognised benefits are environmental services such as carbon sequestration, water protection and biodiversity, which are without an immediate market value.On the other hand, there are pressures (e.g. climate change, air pollution, exploitation, and costs) on the ecosystem that may hamper the wood production or other benefits......
Authors
M. van der Sluijs Bent Christen Braskerud Ivan Digernes Inggard BlakarAbstract
No abstract has been registered
Authors
M. van der Sluijs Bent Christen Braskerud Ivan Digernes Inggard Blakar Anne Grete BlankenbergAbstract
No abstract has been registered
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No abstract has been registered
Authors
Svein SolbergAbstract
Forest damage will result in two general effects: defoliation and/or discolouration. The two available techniques in remote sensing of forests today, LiDAR and spectroscopy, are promising tools for monitoring these two, respectively. Merging data on foliar mass, estimated by LiDAR, with data on chlorophyll concentrations, estimated by spectroscopy, can provide data on chlorophyll mass pr area unit. Monitoring the temporal changes of this is likely to be a very good measure for variations in forest health.In order to check out the possibilities for this, we are now working on building relationships between foliar mass data and LiDAR data for single spruce trees. In total we have measurements of position and stem diameter on about 2000 trees distributed on 16 plots, where 64 trees are intensively sampled for estimating foliar mass, as well as crown size.We need to parameterize a relationship between the LiDAR data for each of these trees and their foliar mass (or leaf area). If we succeed to build this relationship, we will scale it up to provide foliar mass (or leaf area) estimates for every 10x10 m pixels in two SPOT images of the area.Together with a similar up-scaling of chlorophyll concentrations, based on spectroscopy, we will test the possibility of estimating chlorophyll mass per area from SPOT or other satellites. In addition, we have visually assessed data on crown density for all the trees, being a rough, but valuable data-set for validating the relationship.The work, being in progress now, includes several tasks:a) finding an appropriate canopy surface modelb) segmentation of treesc) estimating crown volume, and evt d) handling of smaller trees standing below (this is a heterogenous canopy layer forest) and e) handling of the relative influence of stem and branches.Additionally, we see some other benefits from using LiDAR together with airborne hyperspectral data and satellite data in general. Firstly, the combination of high resolution LiDAR and hyper-spectral data, is a good basis for separating the signals from ground vegetation and from the tree canopy. Secondly, LiDAR provides both a DTM and a canopy surface model, and they are two alternative surface models for the geo-referencing of other data, and for appropriate handling of effects of shadowing and obstacles from tall trees.
Authors
Kåre Lye Halvor B. Gjærum Mary NamagandaAbstract
No abstract has been registered
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No abstract has been registered
Authors
J. Brian Hardaker Gudbrand LienAbstract
Because the analysis of risky choice in agriculture and rural resource management is important but difficult, we argue that there is a need for some agreed principles on how to proceed. This paper is intended as a first step to this end. We start with the proposition that the importance of risk aversion has generally been exaggerated relative to the task of finding better ways to deduce relevant and reliable probabilities. Getting better probabilities demands careful thought, drawing on what is know about the pitfalls and on evolving insights into better ways of proceeding. Our aim is to stimulate a debate leading to a clearer consensus about better practice in these matters.
Authors
Nina Jøhnk Ari M. Hietala Carl Gunnar Fossdal Mari-Anne Newman David B. Collinge Harald KvaalenAbstract
Stilbene synthases make the backbone of stilbenes in a single enzymatic step. Many stilbenes are stressinduced antimicrobial phenolics, believed to work in disease resistance. In conifers, stilbenes are found in pine (Pinus), spruce (Picea) and a few other genera.Stilbene synthase isoforms in pine use cinnamyl-CoA to form pinosylvin, these are termed pinosylvin synthases, whereas stilbene synthases in spruce use pcoumaryl- CoA to form resveratrol and are sometimes termed resveratrol synthases.Pinosylvin has been found to be more effective than resveratrol in inhibiting fungal growth and wood decay (Seppnen et al. 2004), and pathogens of non-pinosylvin producing species have been found to be less tolerant of pinosylvin than pine pathogens (Seppnen et al. 2004). In the present study, Norway spruce (Transformation of Norway spruce with the pinosylvin synthase gene, PSS1) was transformed using the biolistic technique with a gene encoding pinosylvin synthase, PSS1, from Scots pine and the E. coli nptII antibiotic resistance gene.Vector constructs carrying PSS1 in sense and antisense, as well as control vectors without PSS1 were transferred into two embryogenic cell lines of Norway spruce, 11703-B63 and 186-3C. Selection condition for transgenic tissue was conferred by nptII in combination with the antibiotic geneticin. Geneticin resistant lines were recovered from all transformation events, a total of 55 lines.NptII was detected by PCR analysis in many of these lines, the majority derived from the cell line 11703 B63. However, nptII protein was detected in just five lines, and several lines of evidence indicate that the transgenic lines obtained in this study might be chimaeras.Fifty-six seedlings were successfully regenerated from antibiotic resistant lines, 50 of these were derived from cell line 11703 B63. All seedlings died during cold storage before further testing could be carried out.
Abstract
The uptake of chitosan based impregnation solutions were tested on Scots pine (Pinus sylvestris L), Beech (Fagus sylvatica L.), Downy birch (Betula pubescens Ehrh.) and Norway spruce (Picea abies L. Karst.) in longitudinal, radial and tangential directions separately. The four chitosans tested had a fraction of acetylated residues (FA) of 0.198 and average molecular weights ranging from 18 to 129kDalton. The kinetic viscosity of the 2.4% (weight/volume) solutions at pH 5.0 was in the range of 2.95 to 28.8mm2s-1. The general trend showed that there was an increase in uptake of chitosan based impregnation solutions with decreasing viscosity, and the chitosan solution with the lowest viscosity had almost comparable uptake with water for Pine and Beech in the longitudinal direction. In general, the lower the ability for uptake of impregnation solution, the more the viscosity influences the uptake.