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
Abstract
In this study, the effect of two boric acid concentrations (1% and 2%) and four derivates of tall oil with varying chemical composition were tested separately and in combination. The tall oil derivates were chosen in a way that they consist of different amounts of free fatty, resin acids and neutral compounds. Decay tests using two brown rot fungi (Postia placenta and Coniophora puteana) were performed on both unleached and leached test samples. Boric acid showed a low weight loss in test samples when exposed to fungal decay before leaching, but no effect after leaching...
Abstract
Wood for outdoor decking has a high marked share in the Nordic and Baltic countries among private house owners. Important issues for the consumer are maintenance intervals and aesthetic appearance as well as decay resistance. Knowledge and consumer information about these aspects are required to ensure that wood can compete with alternative decking materials. In this paper an accelerated testing of decking, “stapelbäddsmetoden”, was evaluated after six years of exposure at Ås, Norway, and compared with earlier reported results after three years. Twelve different preservatives and wood modification treatments were used in addition to untreated Scots pine (sapwood and heartwood) and larch (heartwood). The samples were treated with two different surface treatments. In addition there was one set without any surface treatment. In this method for accelerated testing, discolouration and decay was evaluated. This provided new information about performance both on and above ground for a range of different combinations of preservative/modified systems and surface treatments of wood in decking for outdoor use. For example, no clear differences were found between the surface treatments and no surface treatment. The wood modifications with styrene and furfurylalcohol performed just as good, or better, than the copper containing treatments.
Authors
I. A. Yakolev Daniel Kwaku Addo Asante Carl Gunnar Fossdal Jouni Partanen Olavi Junttila Øystein JohnsenAbstract
No abstract has been registered
Authors
Audun KorsæthAbstract
No abstract has been registered
Abstract
Over the last decades the forestry sciences have been opened for new topics and methods. In addition to traditional forestry topics they have participated in environmental and ecosystem research. So far this type of research has been perceived as “applied”. From the modelling perspective there has been a misunderstanding among the participating disciplines of the character of knowledge being applied. Here we introduce two types of models of forest utilization and discuss their possibilities and limits for forestry sciences. The first perspective of forests is the one dominating in modelling today and in forestry sciences. It has been adopted from physics. The second perspective of forests has implicitly been adopted in the past for pragmatic reasons.
Authors
Nina Hovden Sæther Øystein Havrevoll Odd VangenAbstract
Possible differences in gross and net feed balance and feed efficiency between two cattle breeds were studied. The “old” Black Sided Trønderfe and Nordlandsfe (STN) breed has hardly been selected for production traits the last decades due to a small population (800) while and the modern Norwegian Red (NR) breed (230 000) has been bred according to a modern breeding programme with genetic improvements in milk, growth, health and fertility. The study was done on lactating cows in three indoor feeding periods; ten cows in each breed group, fed roughage ad-lib and an adjusted level of concentrates. Feed intake, milk yield and -quality were recorded every week, and live weight was recorded every month. The gross energy balance was defined as energy intake subtracted by energy in produced milk, while the gross energy efficiency was computed by dividing energy in produced milk by energy intake. At the net energy level it was adjusted for energy loss or release from body tissue gain or loss. The results show that in spite of the large difference in production level, there were no breed differences in energy balance, neither at the gross nor at the net level. However, the NR was significantly more efficient when comparing gross feed efficiency, but there were no breed differences in net feed efficiency.
Abstract
No abstract has been registered
Authors
Øystein Johnsen Igor A. Yakovlev Daniel Kwaku A. Asante Anne Eskild Nilsen Harald Kvaalen Carl Gunnar FossdalAbstract
In forest trees, environmental conditions during the reproduction can greatly influence progeny performance. We here suggest that temperature during zygotic embryogenesis and seed maturation regulates an “epigenetic memory” in the progeny, involving differential expression of genes that may regulate bud phenology, cold acclimation and embryogenesis in Norway spruce. Conditions colder than normal advance the timing whilst temperatures above normal delay the onset of these processes. The altered performance lasts for many years. The seedlings actually remember the temperatures and photoperiod prevailing during zygotic embryogenesis and seed maturation. We show for the first time that regenerated plants, cloned through somatic embryogenesis, express a memory of the temperatures applied during embryo development whilst growing in a common greenhouse environment. The warmer the in vitro temperature applied, the later the regenerated plants formed terminal buds in the common environment the second growth season. The differences were very large, and similar in size to a provenance separation of 4 – 6 degrees of latitude. To study a molecular mechanisms of a memory from embryo development identical crosses were performed, seed were produced in different temperature regimes (cold and warm embryonic history) and seedling were grown under long day (LD = continuous light) and short day (SD = 12 h night) conditions. We have prepared two subtracted cDNA libraries, forward and revers, representing genes predominantly expressed in plants growing from seeds obtained after embryogenesis in cold environment (CE) and warm environment (WE) after short day treatment (going to bud set). Annotation reveals considerable differences in studied transcriptomes. More than 50% of contigs were unknown. So obtained subtracted libraries is a good source of candidate genes. We used quantitative RT–PCR to study the expression patterns of 34 chosen candidate genes. Just two putative genes among them with no matching in the Database and one reverse transcriptase show constitutively differential expression in progeny from CE and WE
Authors
Igor A. Yakovlev Daniel Kwaku A. Asante Carl Gunnar Fossdal Jouni Partanen Olavi Junttila Øystein JohnsenAbstract
The initiation of growth and dormancy represents critical ecological and evolutionary trade-offs between survival and growth in most perennial plants and represents one of the most basic adaptations of trees to their environment. It is likely that they regulates differently: apical bud set and dormancy induction regulates by perception of short-day signal, but bud burst regulates mostly by temperature signals. We tried to dissect these processes on phenotypical and molecular levels. Seedlings for dormancy analysis were grown under long day (LD = continuous light) and short day (SD = 12 h night) conditions. We have prepared two SSH cDNA libraries, forward and reverse, representing genes predominantly expressed in plants after short day (SD) treatment (going to bud set) and continue growing at LD. Subtracted libraries had been partially sequenced for candidate genes seeking. Annotation reveals considerable differences in studied transcriptomes. More than 50% of contigs in LD library were represented by photosynthesis related genes and just nearly 6% in SD library. High differences were found in RNA synthesis and RNA processing, protein degradation, defense and transporting genes and also in transposable elements. Each library contains large number of unknown genes (mostly in SD). So obtained subtracted libraries is a good source of candidate genes, differently expressed during regulation of bud set. Bud burst initiation was studied on grafts from 15- and 30-year old Norway spruce within 3 time-points during autumn in natural (outdoor) and “forcing” (1 week, 12 h light and 20°C constant) conditions using earlier developed candidate genes (Yakovlev et al., 2007). We used quantitative RT–PCR to study the expression patterns of 58 chosen genes related for bud set and 34 genes – for bud burst. By the experiment conditions we could study only delayed genes and constitutively expressed early genes. Among the candidate genes found, the most interesting ones were the transcription factors, calcium censors, signaling, cold- and water stress related genes. The putative role of the studied genes in development regulation bud set and bud burst is discussed.
Authors
Vidar Selås Ronny Steen Sverre Kobro Terje Lislevand Ingvar StenbergAbstract
In Norway, a positive relationship between spring numbers of lesser spotted woodpecker (Dendrocopos minor) and previous June temperatures has been interpreted as an effect of temperatures on woodpecker survival and reproduction during the breeding season. This article considers the possibility that woodpecker numbers are related to the abundance of the moth Argyresthia goedartella in the current year. Larvae and pupae of A. goedartella are important food for lesser spotted woodpeckers in early spring when few other surface-living invertebrates are available. The occurrence of this moth depends on the flowering of birch (Betula spp.) and alder (Alnus glutinosa), which in turn is influenced by June temperatures in the preceding year. Spring numbers of the lesser spotted woodpecker in two regions of Norway were compared with a trapping index of A. goedartella and weather variables assumed to influence the woodpeckers' breeding success and adult survival. The best multiple regression model included December temperatures and moth indices, supporting the hypothesis of a strong impact of A. goedartella on spring survival. Conservation strategies for the lesser spotted woodpecker should therefore focus not only on minimum areas of deciduous forests with decaying wood, but also on the availability of the moths' host trees, birch and alder.