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
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.
Abstract
We studied four south-facing and three north-facing boreal spruce forest stands (ca. 0.1ha each) in SE Norway with the aim of testing the hypothesis that former logging has long-term effects on boreal forest-floor vegetation. The stand series comprised unlogged natural forests and forests that were selectively or clear cut 6070 years prior to our study. Each stand was described with respect to history of forestry impact and tree-stand structure.Environmental, species number, species abundance and species composition (vegetation gradients obtained as ordination axes) variables obtained for 25 m1m plots in each stand were tested for among-stand differences. Significant among-stand differences were found, partly related to former forest management and partly due to among-stand differences in topography.Differences among stands related to management were found for tree stand density, highest in managed stands, and for Dryopteris expansa agg. and Luzula pilosa abundances, peaking in formerly clear-cut stands. Species number (at plot or stand scales) was weakly related to former management.On southerly as well as northerly aspects, gradients in species composition were found that separated plots according to former management. Differences among stand conditioned on topography resulted in opposite patterns in the two series of stands because among southerly stands the clear cut was the least while among northerly the clear cut was the most strongly sloping. Low-inclination sites tended more strongly to be paludified and to have high Sphagnum cover, and to have low abundance of specific microsites with small mosses and hepatics. Vegetation gradients related to soil moisture and microtopography were found for both aspects.A strong gradient in species composition related to tree influence at within-stand scales was found, with variation in species number. Existence of such a gradient should provide for significant biotic effects (of short or long duration) of the environmental changes that take place during forest re-growth: (1) the immediate creation of small or large tree-layer gaps by tree felling; and (2) the closing of the tree layer during the regeneration phase.Most notably, the phases at which the tree layer reaches minimum and maximum cover, respectively, may act as `bottlenecks\" for survival of forest-floor species. We conclude that forestry impacts understorey vegetation by way of changes in tree-layer structure and, to a lesser extent, substrate availability and the local environment, during forest regrowth. The extent and duration of this impact will depend on a complex set of factors.Our results are consistent with the view that if maintenance of species diversity is aimed at, environmental considerations should be built into forest management practices, preferably by mimicking the natural structural dynamics of the tree layer.
Abstract
No abstract has been registered