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.
2006
Abstract
In this study, forest treated with different strengths of selective cutting (2570 % of volume removed) was remeasured after twelve years in 2005. At each of the sixteen 0.2 ha plots, including four repeats of each treatment, all trees larger than dbh 2.5 cm were calipered. We investigated growth, changes in stand structure, tree age, tree damage and crown condition.The diameter distribution displayed a reverse J-curve at all plots both before and after the cuttings. Twelve years later the curve is only slightly changed. Increment cores from 300 trees were taken to analyse annual growth reactions in different diameter classes. Most trees reacted with increased growth from the second or third year after the cutting.This improved growth accelerated the following six or seven years with 20-80% increase. Both small and large trees reacted, including severely suppressed trees. The initial crown volume and crown vitality after cutting is essential for the increased growth since several years are necessary to build up a larger and better crown. The relationship between increased growth and reduced volume per hectare indicates less competition between trees regarding nutrients and light after the cutting.
Authors
Håkan Broman Mikael Frisk Mikael Rönnqvist Mikael RönnqvistAbstract
The storm Gudrun hit southern Sweden in January 2005 and approximately 70 million cubic meters of forest was wind felled. The existing logistic planning at forest companies in the damaged area had to be changed over night. There was a direct shortage of both harvest and transportation capacities. Key questions that arised were which terminals to use, where to harvest, where to store, which transportation modes (truck, train, ship) to use. In this paper we describe how the forest company Sveaskog made use of Operations Research (OR) as an important decision support in their supply chain planning in the aftermath of the storm.
Abstract
No abstract has been registered
Abstract
The effect of plant age and cold hardening on resistance to pink snow mould caused by Microdochium nivale was studied in perennial ryegrass. Resistance to M. nivale was estimated as relative regrowth after inoculation and incubation under artificial snow cover at 2 degrees C. Resistance increased with increasing plant age. Cold hardened and unhardened plants of the same age displayed identical resistance. Preliminary studies indicate that expression of genes coding for the PR proteins chitinase and PR-1a increased during incubation of inoculated perennial ryegrass, but no clear difference in expression of these genes was found between plants of different ages, or in hardened versus unhardened plants.
Authors
Steffen Adler Åshild T. RandbyAbstract
Feed fatty acid (FA) composition influences the FA composition of cow milk. In a continuous production experiment with 32 Norwegian red dairy cows fishmeal (FM) was compared to peameal (PM) as protein supplement to home-grown cereals and grass silage in organic farming. The protein supplements were together with cereals formulated to be isonitrogeneous and isoenergetic (NEL) and were compared at high (HC) and low concentrate (LC) level. The concentrate rations did not affect the intake of silage. Fishmeal resulted in significantly higher milk yield (kg) with a lower fat concentration (HC) compared to PM. Lower concentrations of urea and FFA were found in milk produced with FM compared to PM. Milk flavour and odour was equal or better when FM rather than PM was fed. Fishmeal diets increased significantly the proportions of several long-chain FAs: oleic acid (C18:1c9), vaccenic acid (C18:1c11), CLA (C18:2c9,t11, not significant at HC), C20:0, C18:1t10, and DHA (C22:6 n-3) in milk fat compared to PM. DHA, which is found in high concentrations in FM (14 g/100g FAME), had the most significant increase. The proportion of C18:3 n-3 (ALA) was significantly lower when FM was fed compared to PM. The percentage of saturated FA was significantly lower and the percentage of monounsaturated FA was higher when FM rather than PM was fed. For cows on HC the n-6/n-3 ratio was lower in the FM group than in the PM group, and the ratio was lower at LC than at HC (p = 0.006, interaction p = 0.02). Fishmeal diets included higher proportions of oats than PM diets. Oats have high content of oleic acid and may therefore have influenced the composition of FAs in milk fat as well as the protein supplements. Fishmeal increased the proportion of beneficial FAs without reducing the sensoric quality of milk. It remains unclear whether this is an effect of protein source or an effect of the higher oat proportions in FM diets.
Authors
Kjersti Holt Hanssen M. LiuAbstract
The use of partial cuttings in spruce (Picea abies L. Karst.) stands is increasing in Norway, especially at sites where special consideration must be taken regarding biodiversity or the recreational value of the forest. However, obtaining sufficient numbers of vital natural regeneration using partial cuttings can be challenging in the Nordic countries, due to harsh climatic conditions and tough competition.We wanted to relate the establishment and growth of natural spruce regeneration to soil conditions and understorey light levels using a thirteen year old field trial with different types of partial cuttings. The field trial was established in a Norway spruce forest on a hillside with varying soil conditions in Oslo, SE Norway. The harvesting treatments included thinning from above, single-tree selection, group felling, shelterwood cuttings and small clear cuts, resulting in a range of cutting intensities and gap sizes.In 2005, spruce seedling establishment as well as growth variables of the tallest seedlings were registered in circular plots of 50 m2 in the different treatments, and soil thickness and moisture class were registered in the same plots. Samples of seedling needles were tested for nitrogen content. Light levels (diffuse, direct and total radiation) below the canopy were measured for each circular plot using hemispherical photography.A covariance analysis with light level as the continuous variable was used to test whether seedling establishment or growth was dependent of soil depth, moisture class or light levels. Diffuse light values corresponded best with seedling growth. The levels of diffuse light in the partial cuttings varied from 19 to 30 % of above canopy values, with the shelterwoods and the group fellings having the highest levels. Still, the clear cuts had light levels more than twice as high as the shelterwoods.The number of spruce regeneration varied substantially between plots with the same harvesting treatment. Seedling numbers were dependent on soil conditions, and were highest on sites with good moisture conditions and soil thickness 20 cm. The covariance analysis did not give a significant effect of light values on spruce seedling number, but there was a tendency to better regeneration at medium light levels.However, the growth of the seedlings was strongly dependent on light levels, with taller leader length and total growth as well as a higher number of annual shoots under good light conditions.Soil depth was insignificant for seedling growth, but moisture class affected annual height growth. Nitrogen concentration in seedling needles was positively correlated with light conditions and negatively with stand density in the vicinity of the seedling, which indicates that the positive effect of large gaps on seedling growth may be caused by decreased competition for nutrients as well as increased radiation levels. Soil depth did not influence the nitrogen concentration.
Authors
Steffen Adler Åshild T. RandbyAbstract
Three continuous production experiments and three short term cross over experiments were carried out in Northern Norway to investigate different feeding strategies for dairy cows in organic farming. This paper focuses on the effects on sensoric milk quality. Half of the 32 Norwegian red dairy cows in the production experiments were fed 40% (HC) concentrates (on energy basis per year) and the other half 10% (LC). Twelve cows (HC) participated in the short term cross over experiments. The experimental factors in the continuous production experiments were barley preservation method (P1), grass silage maturity (P2) and type of protein supplement (P3), and in the short term cross over experiments barley preservation method (C1), type of protein supplement (C2) and time for fishmeal feeding (C3). In all experiments the cows were offered grass silage ad libitum, restricted amounts of cereals and protein feeds, and mineral and vitamin supplements. The sensoric quality of milk was in general high. In the production experiments, milk from cows in HC had slightly higher quality than from cows in LC (significant in P2, p = 0.04). Neither the preservation method of barley (dried or ensiled with molasses), maturity of grass silage or type of protein supplement (fishmeal or peameal) influenced the sensoric milk quality significantly. Also in the cross over experiments no effect of the studied factors was found in milk flavour and odour. Early harvested grass silage gave significantly lower FFA contents than grass silage cut at normal time (P2) and FM gave significantly lower FFA concentrations than peameal (P3). These results indicate that organic farmers with different feeding regimes can produce milk of first class sensoric quality. Also the content of FFA has been low in all experiments (except C1). However, feeding regimes containing low levels of concentrates may reduce milk taste slightly.
Abstract
Three multiparous cannulated dairy cows were used to test the effect of including 0, 23 % and 46 % red clover (RC) on dry matter (DM) basis in timothy (T) silage on nitrogen (N) intake, utilization and excretion. The cows were offered a fixed ration; 13 kg silage and 7 kg concentrate DM. The N intake and urine N excretion increased with increasing silage clover proportion. Milk yield was higher in the clover containing silages than in the pure grass silage, probably due to higher organic matter digestibility in RC containing silages. The efficiency in converting feed N into milk N, however, was higher in cows fed the timothy silage than in cows offered grass/clover silages. The efficiency in microbial protein synthesis in the rumen and the proportion of microbial N of the total N flow to duodenum was higher on the T diet than on the RC containing diets. However, the clover diets gave a slightly higher proportion of bypass N originating from the feed. So, the total flow of N to duodenum was the same for all three diets. In conclusion, increased proportion of RC in T silage did not improve the N utilization.
Authors
Clemens Reimann Arnold Arnoldussen Rognvald Boyd Tor Erik Finne Øystein Nordgulen Tore Volden Peter EnglmaierAbstract
Forty terrestrial moss (Hylocomium splendens) samples were collected along a 120-km-long south–north transect running through Norway\"s largest city Oslo. Concentrations of 29 chemical elements (Ag, Al, Au, Ba, Bi, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, La, Mg, Mn, Mo, Na, Ni, P, Pb, Pt, S, Sb, Sr, Th, Ti, and Zn) and values for loss on ignition (475 °C) are reported. Silver (Ag), Al, Au, Bi, Cd, Co, Cr, Cu, Fe, Mo, Ni, Pb, Pt, Sb, Th, Ti, and Zn all show a characteristic Oslo peak when element concentrations are plotted against location of the sample site along the transect. Gold (Au) and Pt show the greatest relative enrichment of all elements in the city (ca. 10× “background”). Titanium (Ti), which is related to local minerogenic dust rather than anthropogenic emissions, shows a significant peak in Oslo. Loss on ignition, a measure of the amount of organic material in a sample, shows a negative peak in Oslo and at sites close to a known dust source. Input of fine dust thus appears to dominate many of the observed element concentrations in moss. The concentrations of Na are clearly influenced by the input of marine aerosols and show decreasing concentrations from south (near Oslo Fjord) to north (inland). The major plant nutrients Ca, K, Mg, P and S, as well as Hg, are the few elements displaying no spatial dependency along the transect. Element concentrations reach background variation levels at a distance of 20–40 km from the city centre.
Authors
Ingjerd Solfjeld Øystein JohnsenAbstract
We have examined shoot and root growth and the concentration of carbohydrates in seedlings of a northern (67 degrees N) and a southern (61 degrees N) ecotype of Betula pendula Roth. cultivated at root-zone temperatures of 2, 6, 12 and 17 degrees C. Three hydroponic experiments were conducted in controlled environments. We used three different pretreatments before seedlings were subjected to the experimental temperature treatments. Actively growing seedlings that were acclimated to the hydroponic solution for 3 weeks at a root temperature of 17 degrees C, continued to grow at all the experimental temperatures, with an expected increase in growth from 2 to 17 degrees C. However, if we started with ecodormant cold stored plants or used seedlings grown actively in perlite, no growth was observed at 2 degrees C and only minor growth was found at 6 degrees C. The highest root temperature always produced the best growth. The concentration of nonstructural carbohydrates was higher in seedlings grown at 2 degrees C than at 17 degrees C, and this is probably due to extensive incorporation of carbohydrates into cell walls and other structural elements at 17 degrees C. We found no evidence for differences between the two ecotypes in root growth, in timing of bud burst, but shoot growth terminated in the northern ecotype in the first experiment because the natural photoperiod was below the critical value. Our study highlights the importance of post-transplantation stress (planting check) related to root growth, and that root threshold temperatures may change according to the way plants are pretreated. Abstract: We have examined shoot and root growth and the concentration of carbohydrates in seedlings of a northern (67 degrees N) and a southern (61 degrees N) ecotype of Betula pendula Roth. cultivated at root-zone temperatures of 2, 6, 12 and 17 degrees C. Three hydroponic experiments were conducted in controlled environments. We used three different pretreatments before seedlings were subjected to the experimental temperature treatments. Actively growing seedlings that were acclimated to the hydroponic solution for 3 weeks at a root temperature of 17 degrees C, continued to grow at all the experimental temperatures, with an expected increase in growth from 2 to 17 degrees C. However, if we started with ecodormant cold stored plants or used seedlings grown actively in perlite, no growth was observed at 2 degrees C and only minor growth was found at 6 degrees C. The highest root temperature always produced the best growth. The concentration of nonstructural carbohydrates was higher in seedlings grown at 2 degrees C than at 17 degrees C, and this is probably due to extensive incorporation of carbohydrates into cell walls and other structural elements at 17 degrees C. We found no evidence for differences between the two ecotypes in root growth, in timing of bud burst, but shoot growth terminated in the northern ecotype in the first experiment because the natural photoperiod was below the critical value. Our study highlights the importance of post-transplantation stress (planting check) related to root growth, and that root threshold temperatures may change according to the way plants are pretreated.