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.
2003
Authors
Erlend Ystrøm Haartveit J. Chaseling Per Otto FlæteAbstract
The use of PLS as a tool for developing reliable models for predicting wood quality is demonstrated with two case studies, one involving Norwegian spruce as manufactured lumber, and the other involving decay resistance of Scots pine wood. It is concluded that a PLS model involving eight simple measurements taken on the trees standing in the forest and on their unprocessed logs, can be used to predict the bending stiffness and bending strength of subsequent manufactured lumber.This approach can be used to provide a non-destructive way of predicting wood strength before processing, thus enabling more efficient use of raw materials. The use of different levels of segmental cross validation, with units being tree, forest stand, growing environment or country, did not change the predictive outcome of the models.More complicated models involving additional variables and their interactions did not provide an improved prediction. In the second case study, all but one of the wood samples were successfully classified into their correct class of heartwood or sapwood using PLS dummy regression models based on 926 wavelength variables in the NIR and visual regions.Models including the visual region as well as the NIR region proved to be superior even when there was no observable colour difference between the two wood types. Satisfactory models were obtained for predicting the resistance to decay of heartwood by using PLS on the non-destructive NIR data. As for the classification models, better predictions were achieved when the visual region of the spectra was included.
Abstract
A multiplex real-time PCR assay was developed to monitor the dynamics of the Picea abies-Heterobasidion annosum pathosystem. Tissue cultures and 32-year-old trees with low or high resistance to this pathogen were used as the host material. Probes and primers were based on a laccase gene for the pathogen and a polyubiquitin gene for the host.The real-time PCR procedure was compared to an ergosterol-based quantification method in a tissue culture experiment, and there was a strong correlation product moment correlation coefficient, 0.908) between the data sets. The multiplex real-time PCR procedure had higher resolution and sensitivity during the early stages of colonization and also could be used to monitor the host.In the tissue culture experiment, host DNA was degraded more rapidly in the clone with low resistance than in the clone with high resistance. In the field experiment, the lesions elicited were not strictly proportional to the area colonized by the pathogen.Fungal colonization was more restricted and localized in the lesion in the clone with high resistance, hereas in the clone with low resistance, the fungus could be detected until the visible end of the lesion. Thus, the real-time PCR assay gives better resolution than does the traditionally used lesion length measurement when screening host clones for resistance.
Authors
Morten NittebergAbstract
The Norwegian Forest Research Institute (Skogforsk) is conducting a study of mechanised harvesting in cable operations.The activity of cable crane systems is heavily reduced the last years in Norway. There are different reasons for this:Low price on wood High direct logging cost Relative low technical development Hard to recruit workers General scepticism to logging in steep terrain, due to environmental influences The positive environmental effect by use of cable crane systems is not well known, and is overshadowed by the negative publicity. Use of cable crane systems may among other things contribute to reduce technical encroachment in the terrain, road building, and wheeled terrain transport.When the harvesting operation in steep terrain is mechanised the safety will increase and the working load will be easier. We hope this will have a positive effect on recruiting workers to this kind of work.The use of harvester inn logging operation will probably also increase the productivity of the cable crane system, and will hopefully give better economy for steep terrain harvesting. A harvester (Menzi Muck A71) is developed in Switzerland for use in steep and difficult terrain. The harvester is based on a Menzi Muck excavator. The machine is mainly build for operations in steep terrain up to 60 %, but with a safety winch it may operate in steepness up to 100%.The Menzi Muck harvester is now working together with a Owren 400 cable crane system in steep terrain (30 70 % steepness), and Skogforsk will during the project period study the productivity and the operating cost of the cable crane system in cooperation with Menzi Muck harvester, and compare the result with ordinary manual felling. This will be done time study and operational statistics.The project started up 1 July 2002, so at this moment we do not have much data, but within March 2003 we will have data enough to present some results.
Authors
Halvor SolheimAbstract
No abstract has been registered
Authors
Arne Sandnes Toril Drabløs EldhusetAbstract
With small seedlings and dilute nutrient solutions, the use of glass beads as growth medium alters pH, conductivity and elemental composition of the solution to an extent that may affect the glass beads\" suitability as growth medium in plant cultivation experiments.
Authors
Staffan JacobsonAbstract
No abstract has been registered
Authors
Risto Seppälä Thomas RimmlerAbstract
No abstract has been registered
Authors
Erik Jautris Joner C. LeyvalAbstract
Phytoremediation as a means of cleaning up polluted soils has gained popularity during the last decade due to its convenience and low costs of installation and maintenance. When the target pollutant is biodegradable, this technology exploits the stimulating effect that roots have on microbial processes and physical/chemical modifications in the rhizosphere.Among the microorganisms that affect rhizosphere processes, symbiotic fungi forming mycorrhizas induce a series of changes in plant physiology, nutrient availability and microbial composition that may determine the outcome of a phytoremediation attempt. Beyond the rhizosphere, mycorrhizal hyphae act as the roots of the roots, and may thus extend the rhizosphere into the bulk soil by creating a new interface of soil-plant interactions: the hyphosphere.We here discuss some of the recent results on phytoremediation of organic pollutants with emphasis on processes in the mycorrhizosphere, and highlight future research priorities
Abstract
Modern information technology allows the investigation of the characteristic properties of living systems from a new perspective. Which of the ecosystem features are necessary conditions resulting from their constraints, which are accidental, constituting contingent facts of their respective histories?As long as we know of a single phylogenetic tree in nature, the difference is hard to tell, rendering the reconstruction and realisation of artificial ecologies a major challenge. It has been taken up by the high technology of the time since decades; since two decades, IT is leading in this respect.Are there life forms that can be created in contemporary computers, and which ones? Successes and failures of a number of virtualizations are forming de facto constraints for theoretical ecosystem research. Artificial Life (AL) research appears to be not just another attempt towards realistic models for ecological systems, but undermines the basic assumptions of most of conventional modeling in this area: in AL, behavior is in general irreducible to internal mechanisms; behavior results rather from interactive and intentional usage of the simulation.We try to elucidate and demonstrate the crucial role of interaction in these simulations, drawing from current developments in theoretical computer science as well as a number of examples. We propose a new classification of ecosystem models according to its degree of interactivity.
Abstract
In this study of 130 sites with different management we investigated whether vascular plant species richness is significantly reduced when traditionally managed hay meadows are abandoned and reforested. We also compared the effects of reforestation with those of intensified land-use to see which have the largest effects on species richness. Finally, we investigated the relative importance of relevant ecological factors for species richness.While the use of artificial fertilizers in traditionally managed hay meadows has resulted in significantly lower species richness, and intensive cultivation in even lower species richness, abandonment with reforestation has not decreased the species richness significantly.Productivity and habitat diversity have determined the species richness of meadows on the scale (0.035.1 ha) of this study. Low productivity is a prerequisite for high species richness in meadows. Maximum species richness was observed in unproductive, old, traditionally managed hay meadows with a high soil pH and high habitat diversity. The high species richness of these meadows suggests that they are in urgent need of conservation.