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.
2007
Abstract
No abstract has been registered
Abstract
In Norway exterior wood structures have traditionally nearly exclusively been made of treated and untreated Picea abies and Pinus sylvestris. In recent years there has been a tendency that other tree species, like various domestic hardwoods and imported species have been used in exterior above ground applications, often unfinished. For several wood species, especially hardwoods, information regarding the durability in use class 3 is lacking. The main objective of this paper is to evaluate natural durability of Norwegian wood species for above ground applications comparing two non-standard above ground tests with the European standard tests for soil contact (EN 252) and lab performance against basidiomycetes (EN 113). The European standard tests EN 113 and EN 252 gave quite similar results, and they also corresponded well with the natural durability classification in EN 350-2. The two non-standard above ground tests differed to some extend from EN 113, EN 252 and EN 350-2. The results indicate that natural durability classification for one single wood species can change depending on use class. However, the field trials need a longer period of time before a final classification can be performed. Four species not included in EN 350-2 were classified in this study: Juniperus communis (1), Salix caprea (5), Sorbus aucuparia (5) and Populus tremula (5).
Abstract
City planners need practical methods to assess and compare the sustainability of different alternatives for urban infrastructure. This article presents the consequences of selecting different methods to normalize the values of sustainability indicators, and the influence of selecting different indicators and different weighting techniques. A nature based sewerage system is compared to a conventional system. The article demonstrates that the method used to normalize the indicators, the choice of relevant indicators and the weighting technique have considerable influence on which system is found to be the most sustainable. By selecting particular indicators, weighting and normalization methods, it is possible to prove that virtually any infrastructure system is more sustainable than any other alternative system. Such a biased approach is difficult to reveal unless the most careful, expert scrutiny is applied. Because of this fact, it is of paramount importance that the consequences of different evaluation methods are discussed and sensitivity analyses are carried out honestly and objectively on the critical parameters. An evaluation process made in this way will enable those parts of the analysis that generate disagreement to be identified, and decisions taken on what is important and unimportant.
Abstract
Forest stands are the basic planning units of managed forest landscapes, and the structural composition of these units is important for conservation of biodiversity. We present a methodological approach for identification and mapping of important structural and environmental features of forest stands. Based on an analysis of habitats of red-listed species and a synthesis of results from research on spatial distribution of forest species, we developed a habitat inventory approach (Complementary Hotspot Inventory, CHI) that is currently used in forestry planning in Norway. The CHI maps fine-scale hotspots for 12 habitat types that are further classified according to positions along main environmental gradients (productivity and humidity). Consisting of different substrates in different environments, these habitats to a large degree support different species assemblages. By incorporating both the hotspot and the complementary approach, the CHI produces data tuned for later conservation measures. The high spatial resolution of data facilitates the use of conservation measures at different spatial scales, from single-tree retention to forest reserves. Avalidation test of habitats identified by CHI showed that the density of red-listed species was four times that of randomly selected old forests.
Abstract
The control of Alopecurus geniculatus, Poa annua and Poa trivialis using iodosulfuron (Hussar/Hussar OD) was investigated in field experiments in the seed harvest year in timothy (Phleum pratense), and in the sowing year and seed harvest year in smooth meadow-grass (Poa pratensis) and red fescue (Festuca rubra). Iodosulfuron (10 g a.i. ha-1) usually had good effect on Poa trivialis and Alopecurus geniculatus. As for Poa annua the effect on seed contamination was better than on weed coverage in the field. Early application improved weed control in the seed harvest years, and iodosulfuron was shown to perform well at low temperatures. The herbicide often delayed timothy development, but caused seed yield reduction only in two out of eight experiments, both with moist soil at treatment. The visual damage increased with increasing rates and use of additives (alcoholetoxylate or rape oil). A questionnaire investigation among timothy growers in 2004 showed that farmers using Hussar had 43% lower contamination of P. trivialis in cleaned seed yield and 20% lower yield than the farmers not using Hussar. In some trials in timothy and smooth meadow-grass, the new formulation Hussar OD gave slightly more damage than the old formulation Hussar. While well-established timothy crops seem to tolerate some visual damage without seed yield reduction, the risk of yield reduction in first year crops can usually be avoided by splitting the application into 5 g a.i. ha-1 at 14 days intervals. In smooth meadow-grass and red fescue established without cover crop, repeated applications of 5 g a.i. ha-1 in the sowing year resulted in better control of P. annua and significant seed yield improvements compared to application only in the seed harvest year. Both Hussar and Hussar OD have off-label approvals for members of the Norwegian Seed Growers Association.
Authors
Mikael Frisk Maud Göthe-Lundgren Kurt Jörnsten Mikael Rönnqvist Mikael RönnqvistAbstract
No abstract has been registered
Authors
Mikael Rönnqvist Mikael Frisk Maud Göthe-Lundgren Kurt Jörnsten Mikael RönnqvistAbstract
No abstract has been registered
Abstract
During 2002-2005, Norwegian seed yields of meadow fescue (Festuca pratensis Huds.) were 52% lower in organic than in conventional seed production. The difference was most conspicuous in ley year 1, suggesting that seed crop establishment is a limiting factor in organic seed production. Meadow fescue is usually underseeded in a cover crop of spring wheat or spring barley, and many organic growers delay the underseeding until after harrowing for weed control. Our objectives were (1) to determine whether organic seed crops of meadow fescue should be underseeded in the same operation as, or immediately after, the cover crop (implying no harrowing for weed control); or if they should be underseeded in conjunction with, or just after, weed harrowing (on average nine days after the cover crop); and (2) to compare the establishment of meadow fescue seed crops without cover crop or in cover crops of spring barley, spring wheat, peas or green fodder (barley + peas). On average for all cover crops and four trials, first year’s seed yields of meadow fescue were 11 % lower for crops seeded after weed harrowing than for crop seeded immediately after the cover crop. Weed harrowing combined with delayed seeding also resulted in more scentless mayweed (Tripleurospérmum inodórum) and other weeds in ley year 1. Despite less plant-available nitrogen in spring, seed crops underseeded just after the cover crop were more lodged than crops underseeded after weed harrowing. On average for the two seeding dates, the highest seed yield were produced from crops seeded in pure stand and from crops that had been underseeded in green fodder and received an extra 30 kg N ha-1 in manure shortly after green fodder harvest in late July. The results suggest that seed crops of meadow fescue need ample supply of light, water and nutrients in August to produce a good seed yield in ley year 1.
Abstract
No abstract has been registered
Authors
Mikael Frisk Mikael Rönnqvist Mikael RönnqvistAbstract
No abstract has been registered