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.
2008
Authors
Mari Mette TollefsrudAbstract
Norway spruce (Picea abies), a conifer of the boreal forest, is one of the ecologically and economically most important forest tree species in Europe. It is naturally distributed into two disjunct ranges, one northern and one southern. In this thesis, genetic variation in Norway spruce populations has been investigated to obtain a comprehensive understanding of how its genetic structure has been shaped by Quaternary climate changes, hybridization with Siberian spruce (P. obovata), present-day ecological marginality and adaptive changes. Recently compiled fossil records of Norway spruce have moreover been used for inference of glacial refugia and the direction of migration routes. In Paper I, we combine fossil pollen data with a dataset of the maternally inherited, seed-dispersed mitochondrial (mt) marker nad1 obtained from 369 populations (4876 trees) to infer glacial refugia, postglacial colonization routes and the genetic consequences of range contractions and expansions. The combined data suggest that Norway spruce survived in at least seven refugial areas from which it expanded in the Holocene. These were the Russian plains, south-eastern Alps, southern Bohemian Massif including its southern foreland, northern Dinaric Alps, northern Carpathians, southern Carpathians and south-west Bulgarian mountains. Siberian spruce survived the last glacial maximum east of the Ural Mountains, separated from the refugia of Norway spruce (Paper III). Genetic diversity in Norway spruce showed an overall decrease from the oldest regions towards the younger regions. The different refugia had, however, contrasting genetic structuring and there were large differences in the genetic patterns along the different colonization routes. In the Alps, for example, diversity decreased over very short distances, whereas diversity in northern Europe was maintained over large distances. In Paper II we obtained a deeper insight into the genetic structuring of the northern European populations by analyzing nuclear microsatellite variation. Very little differentiation was revealed across the northern European range, manifesting high levels of past and present gene flow. Despite little differentiation, the microsatellite structure corroborated the mtDNA-based hypothesis of expansion out of one large Russian refugium along two separate migration routes, one northwestern route through Finland into northern Scandinavia and one southwestern route across the Baltic Sea to southern Scandinavia. In the south, microsatellite diversity was largely maintained from east to west, suggesting that pollen flow has efficiently counteracted the loss of diversity following colonization. Towards the northern climatic margin, nuclear microsatellite diversity decreased and inbreeding increased, probably due to smaller effective population size and more limited pollen production in the north, promoting mating among relatives. In Paper III, we investigated genetic differentiation between Norway spruce and Siberian spruce with mtDNA and chloroplast (cp) DNA markers. Chloroplast DNA is paternally inherited and spread with both seeds and pollen. We found two main genetic groups with both types of markers, corresponding to the two species and associated with separate refugia west (Norway spruce) and east (Siberian spruce) of the Ural Mountains. The Ural Mountains do not constitute a major barrier to gene flow. mtDNA haplotypes of Norway spruce were found east of the Ural Mountains, and extensive paternal introgression from Siberian spruce to Norway spruce was suggested across the Ural Mountains. Extensive pollen flow is in agreement with the homogenization observed in both the chloroplast (Paper III) and the nuclear (Paper II) gene pool of northern European Norway spruce. Pollen flow mainly occurs from Siberian spruce to Norway spruce, and Siberian spruce thus disperses westwards through paternal introgression. With the mtDNA marker nad1, it is possible to trace the origin of central European and northern European trees with a simple assay. In Paper IV, we determined the origin of trees in Norway spruce plantations. This was done prior to a greenhouse experiment recording the timing of terminal bud set of seedlings of different origins. We found that seedlings of central European origin from seeds produced in Norway had on average a bud set more similar to local Norwegian seedlings than to central European seedlings from seeds produced in central Europe. This suggests that the progenies of trees of central European provenances growing in Norway may have a rapid adaptation to the northern climate. Norway spruce thus not only has a fast and extensive migratory capacity but also a fast adaptative capacity, which may facilitate its altitudinal migration as climate warming proceeds.
Abstract
In a pilot field study conducted in an apple orchard in Hardanger (Western Norway) in two succesive years both Beauveria bassiana and Metarhizium anisopliae were applied to apple trees just after hatching of mirid nymphs in spring. Both predatory, omnivorous and principally plant-pathogenic species of mirids were collected, and all groups of species were infected by B. bassiana or M. ansiopliae in treated plots. B. bassiana and M. anisopliae were also found on some individuals in non treated control plots the second year. M. anisopliae was more predominant in 2006, B. bassiana in 2007. Mirids were also observed for natural occurrence of parasitoids, and parasitoids were found both years.
Authors
Erik ChristiansenAbstract
Hylobius abietis L. feed on the stem bark of conifer seedlings. In the absence of appropriate control measures, the damage may reach a level that rules out planting as a means of conifer regeneration. It is distributed throughout the coniferous forests of northern Eurasia, including the British Isles and Japan. Other Hylobius species cause damage of a similar type, both within this area, and in North America. Soon after the introduction of clear felling systems in Central Europe, damage by H. abietis became wide-spread.
Abstract
Forsøk har synt at det mest vanlege dekkesystemet over søtkirsebær i Noreg kan nyttast både som eit alternativ og eit supplement til sprøytingar med kjemiske middel mot rotesoppar som angrip søtkirsebærfrukter.
Abstract
The coastal areas of SE Norway provide suitable conditions for studying soil development with time, because unweathered land surfaces have continuously been raised above sea level by glacio-isostatic uplift since the termination of the last ice age. We investigated Podzol development in a chronosequence of six soils on sandy beach deposits with ages ranging from 2,300 to 9,650 y at the W coast of the Oslofjord. The climate in this area is rather mild with a mean annual temperature of 6 degrees C and an annual precipitation of 975mm (Sandefjord). The youngest soil showed no evidence of pocizolization, while slight lightening of the A horizon of the second soil (3,800 years) indicated initial leaching of organic matter (OM). In the 4,300 y-old soil also Fe and humus accumulation in the B horizon were perceptible, but only the 6,600 y-old and older soils exhibited spodic horizons. Accumulation of OM in the A horizons reached a steady state in <2,300 y, while in the B horizons OM accumulated at increasing rates. pH dropped from 6.6 (H2O)/5-9 (KCI) in the recent beach sand to 4.5 (H2O)/3.8 (KCl) within approx. 4,500 y (pH(H2O))/2,500 y (pH(KCl)) and stayed constant thereafter, which was attributed to sesquioxide buffering. Base saturation showed an exponential decrease with time. Progressive weathering was reflected by increasing Fe-d and Al-d contents, and proceeding podzolization by increasing amounts of pyrophophate- and oxalate-soluble Fe and Al with soil age. These increases could be best described for most Fe and Al fractions by exponential models. Only the increasing amounts of Fe-p could be better described by a power function and those of Fe-o by a linear model.
Authors
Anders Lunnan Lelde Vilkriste Gunnar Wilhelmsen Diana Mizaraite Antti Asikainen Dominik RöserAbstract
Bioenergy projects must be economically viable for the different actors in the value chain. Economic studies can contribute to the understanding of the competitive situation of bioenergy. Sustainability aspects, supply and demand aspects, regional cooperation and impacts and external effects are discussed. Recommendations for bioenergy policy to promote a more integrated market for biofuels in the Baltic Sea region is given
Authors
Hallvard Jensen Kimmo K. Kahilainen Per-Arne Amundsen Karl øystein Gjelland Anti Tuomaala Tommy Malinen Thomas BøhnAbstract
No abstract has been registered
Authors
Per Otto Flæte Kjell VadlaAbstract
Concern about environmental impacts of chemical wood preservatives has resulted in increased interest for natural wood durability. The natural durability of sapwood of most species is generally low, while heartwood can be more resistant to biodeterioration. For the sawmill industry various lumber products require certain diameters and lengths of the logs in addition to requirements for wood properties. When utilising the heartwood, it is therefore important to acquire information already in the forest about which trees that can be suitable for logs with a predefined heartwood diameter and length. The main objectives of this work was to study the variation in heartwood diameter along the stem of Scots pines (Pinus sylvestris L.), and to develop a model for predicting heartwood diameter profiles based on variables that can easily be measured in the forest.....
Abstract
No abstract has been registered
Authors
Peder GjerdrumAbstract
Cost and revenue related to kiln drying are described. A calculation model compatible with a sawmill\"s profit and loss account is suggested. Typical cost items for a Scandinavian sawmill and from European litterature are reported. Cost for shrinkage/distortion/quality losses and investment/depriciation and maintenance for kilns and other technical equipment. It is claimed that better models and intensified calculation will improve sawmill profitability.