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.
2004
Authors
Risto Kasanen Jarkko Hantula M. Vourinen Jan Stenlid Halvor Solheim Timo KurkelaAbstract
Genetic variation in three multiallelic loci was analysed with Temperature Gradient Gel Electrophoresis in order to assess the genetic population structure of Venturia tremulae var. tremulae in order to understand the evolutionary potential of the pathogen against resistance breeding. Also the identification of the fungus was verified with molecular analysis of reference isolates. The Fst and Gst values were very low indicating no substructuring or restrictions to gene flow between Fennoscandian populations of V. tremulae. The results imply high epidemiological efficiency of the fungus and therefore continuous breeding programme should be implemented for Venturia resistance of aspen.
Abstract
No abstract has been registered
Abstract
Ecosystems as objects of natural sciences are often difficult to understand, as an object of traditional management they are sometimes easy to utilize. Computer-based modeling offers new tools to study this apparent paradox.We propose an interactive framework from which the traditional approach based on dynamic system theory can be challenged for living systems: Models derived on the basis of the state concept have not (yet?) allowed predictions that derive novel management competence relevant for the altered boundary conditions of ecosystems. Here a concept of interaction as currently used in information sciences serves as starting point for deriving models more appropriate for ecosystems.An application and test of this concept consists in a search for signatures of interaction in environmental and ecological time series. Confronted with the notorious lack of detailed process understanding, it is plausible to rely on time series analysis techniques. The intricate nature of typical multivariate data sets from ecosystems immediately suggests a preference for nonlinear techniques, and among them temporally local methods, able to detect even subtle changes in the underlying dynamics.We shortly introduce a couple of these methods, which have been demonstrated to be appropriate for time series exceeding minimal length requirements. This is exemplified by recurrence quantification analysis. In addition we present methods to quantify the memory content (Hurst analysis) and complexity of data sets (defined in an informationtheoretic context).Time series analysis of extended environmental and ecological data sets can give detailed structural insights, monitors subtle changes undetectable otherwise, forms the basis for further inferences and provides rigorous model testing on all scales. The success of dynamic system theory when applied to non-living environmental data is strikingly contrasted by the difficulties of the same method when dealing with ecological data We conjecture that this difference reflects the extent to which interaction has been disregarded for ecosystems.
Abstract
No abstract has been registered
Authors
Ken Olaf StoraunetAbstract
Number of years since death was estimated by dendrochronological cross-dating of 107 standing dead trees (snags) of Norway spruce [Picea abies (L.) Karst.] in a submountainous old-growth forest in south-central Norway. Snag characteristics (size, bark cover, branch order present and variables derived from tree-ring analyses) were used in stepwise linear regression procedures to identify variables that explained time since death.Number of branch orders present (where branches growing directly on the stem were branch order 1, branches growing on order 1 branches were order 2, and so on) explained two-thirds of the variation in time since death. Adding other significant variables, such as diameter, relative height of snags, percentage bark cover and average tree-ring width in the final years before death, increased model precision only moderately.The models were validated by the PRESS statistic, which showed that new observations were predicted fairly well with 65-69% of the variation explained.
Authors
Axel Schmidt K. Witzel Gazmend Zeneli D. Martin J. Bohlmann Paal Krokene Trygve Krekling Ari M. Hietala Carl Gunnar Fossdal Erik Christiansen Jonathan GershenzonAbstract
The study of conifer chemical defense has been dominated by investigations of oleoresin and its components. However, the actual function of resin components in plant defense and their mode of action is still uncertain, and the role of other defense compounds is relatively unexplored.We are studying the biochemical and molecular bases of chemical defenses, including terpenes, phenolics and chitinases, in Norway spruce (Picea abies) to learn more about how the accumulation of defense compounds is regulated, with the long-term goal of manipulating defense levels to test their function.Manipulation can be crudely accomplished by treatment with methyl jasmonate, which often mimics the general increases in defenses seen following herbivore or pathogen attack. Such treatment was shown to increase resistance to a fungal associate of bark beetles.To more conclusively test function, isolated genes of defense biosynthetic pathways are being transformed into Norway spruce to produce plants whose defense profiles are altered more precisely.
Authors
Sjur Spildo PrestegardAbstract
Norway, Switzerland, the European Union, Korea, Japan and some other countries place substantial emphasis on the so-called non-trade concerns in the ongoing WTO negotiations on further agricultural trade liberalisation. In addition to the production of food and fibre, agriculture also may provide national food security, environmental benefits, and viable rural areas. The term «multifunctional agriculture» has been increasingly applied to describe these additional functions. This working paper focuses on how to achieve the multifunctional goals that nations may have with minimal tradedistortion. In this study, the economic concepts of externalities and public goods are used to analyse non-trade concerns and multifunctional agriculture. It is argued that just as a tax is widely accepted as the optimum policy for a negative externality, so should the use of a production-tied subsidy or payment be accepted as optimum policy for a positive externality or public good that is produced jointly with or complementary to agricultural production. The study concludes with suggestions for international trade rules to prevent such policies from becoming a form of protectionism.
Authors
Sjur Spildo PrestegardAbstract
One of the questions debated in the ongoing WTO agricultural negotiations is whether ‘trade-distorting’ subsidies, or subsidies outside the ‘green box’, are needed in order to pursue non-trade concerns. The term ‘multifunctional agriculture’ is increasingly applied to describe non-trade concerns. This article focuses on how to achieve the multifunctional goals that nations may have with minimal trade-distortion. In the first part of the article, this is done by a literature review and a theoretical analysis. The findings are then converted into an analysis of possible policy formulations in a Norwegian context using a partial equilibrium model. The article argues that multifunctionality hardly can justify the use of market support, while it may justify production-related budget support if the positive externalities or public goods are produced jointly with or complementary to agricultural production. The article concludes with suggestions for WTO trade rules to prevent such policies from becoming a form of protectionism.
Authors
Per Otto Flæte Erlend Ystrøm HaartveitAbstract
In Scandinavia Scots pine (Pinus sylvestris L.) is an important commercial tree species. Its heartwood has traditionally been used in constructions exposed to risk of decay. In a laboratory experiment Scots pine wood specimens sampled from inner heartwood, outer heartwood and sapwood were exposed to the brown rot fungus Poria placenta.In general outer heartwood was more resistant than inner heartwood, but there were variations even within the same wood zone. NIR spectra obtained on solid wood prior to decay testing were used in multivariate calibrations to predict decay resistance of heartwood.Results from segmented cross validated partial least squares (PLS1) regression modelling showed that resistance to decay in Scots pine heartwood could be predicted with satisfying precision using NIR spectroscopy. As NIR spectra were collected on solid wood, development of the method for industrial use is potentially possible.
Authors
Live Semb Vestgarden Petter Nilsen Gunnar AbrahamsenAbstract
No abstract has been registered