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
Anna Martha Elgersma Arnold Arnoldussen Shivcharn S. DhillionAbstract
No abstract has been registered
Authors
Erlend Ystrøm Haartveit Dag FjeldAbstract
Efforts to improve efficiencies in the forest industries have mainly focused on problems within the borders of the company. Thus, there is an unexploited potential for increased efficiency through integrating and coordinating activities between companies. This poster presents games that mimic the forest industry and demonstrate to...
Authors
Rolf Arnt Olsen Grete RasmussenAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Tonje Økland Knut Rydgren Rune H. Økland Ken Olaf Storaunet Jørund RolstadAbstract
No abstract has been registered
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
Wintering ability in the field and resistance to different winter-stress factors under controlled environmental conditions were studied in a full-sib family of perennial ryegrass (Lolium perenne L.). Significant variation in tolerance to freezing and ice encasement, resistance to pink snow mould (Microdochium nivale) and also in winter survival and spring growth were found between the different genotypes. No strong correlations were found between the resistances to the different stress factors. These results indicate that resistance to different winter-stress factors is controlled by separate genes in perennial ryegrass. A low but significant positive correlation was found between spring growth of plants in the field after the first winter and both freezing tolerance and M. nivale resistance measured in controlled environments. Cold hardening seemed to influence freezing tolerance and M. nivale resistance differently in the different genotypes, since no distinct correlation in tolerance to freezing or resistance to M. nivale was found between unhardened and hardened plants. Tolerance or resistance to most of the winter stress factors measured was positively correlated with plant size.
Authors
Trond Knapp Haraldsen Per Anker Pedersen Roald SørheimAbstract
No abstract has been registered
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.
Authors
A. Indriksons Talis Gaitnieks P. ZalitisAbstract
No abstract has been registered