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.
2012
Authors
Marie L. Davey Einar Heegaard Rune Halvorsen Mikael Ohlson Håvard KauserudAbstract
Bryophytes are a dominant vegetation component of the boreal forest, but little is known about their associated fungal communities, including seasonal variation within them.Seasonal variation in the fungal biomass and composition of fungal communities associated with three widespread boreal bryophytes was investigated using HPLC assays of ergosterol and amplicon pyrosequencing of the internal transcribed spacer 2 (ITS2) region of rDNA.The bryophyte phyllosphere community was dominated by Ascomycota. Fungal biomass did not decline appreciably in winter (P = 0.272). Significant host-specific patterns in seasonal variation of biomass were detected (P = 0.003). Although seasonal effects were not the primary factors structuring community composition, collection date significantly explained (P = 0.001) variation not attributed to locality, host, and tissue. Community homogenization and a reduction in turnover occurred with the onset of frost events and subzero air and soil temperatures. Fluctuations in the relative abundance of particular fungal groups seem to reflect the nature of their association with mosses, although conclusions are drawn with caution because of potential methodological bias.The moss-associated fungal community is dynamic, exhibiting seasonal turnover in composition and relative abundance of different fungal groups, and significant fungal biomass is present year-round, suggesting a winter-active fungal community.
Authors
Casper Claudi Rasmussen Erlend NybakkAbstract
This study examines the relationship between customer orientation, innovativeness, autonomy, risk taking, growth willingness and growth in low technology micro-firms. A survey was sent to 3000 CEOs in the Norwegian wood industry and resulted in 514 usable respondents. Customer orientation, innovativeness, risk taking, autonomy and growth were conceptualized and analyzed as first order constructs using confirmatory factor analysis and OLS regression. The findings showed that customer orientation, innovativeness and autonomy have a significant impact on growth in micro-firms. The study found no support for interaction effects between innovativeness, autonomy, risk taking and customer orientation, however the interaction effect between customer orientation and autonomy was significant at the 10% level.
Authors
Carl Gunnar Fossdal Ari M. Hietala Igor A. Yakovlev Gustav Vaaje-Kolstad Emil Stefaczyk Halvor SolheimAbstract
The GH61 represents the most enigmatic Glycoside Hydrolase Family (GH) regarding putative enzymatic activity and importance in cellulose degradation. Heterobasidion irregulare is a necrotizing pathogen and white rot fungus, causing enormous damages in conifer forests.The genome of H. irregulare allowed identification of ten HiGH61 genes. qRT-PCR analysis separate the HiGH61 members into two groups; one that show up regulation on lignocellulosic substrates and another that show either down regulation or constitutive expression. This grouping suggests that the fungus relates different sets of GH61s for different substrates, like in the various stages of necrotizing and saprophytic growth on the host.One HiGH61 showed up to 17000 fold increase on spruce heartwood suggesting a pivotal role in cellulose decomposition during saprophytic growth. Sequence analysis of these genes reveals that all GH61s but one possess the conserved metal binding motif predicted to be essential for activity.The sequences also divide into groups having either an insert near the N-terminus or an insert near the second catalytic histidine, which both may represent extensions of the substrate binding surface. Three HiGH61s encode cellulose-binding modules (CBM1), indicating direct targeting of crystalline cellulose, two being up regulated on pure cellulose.There was a common substrate-specific induction patterns of the HiGH61s with several reference cellulolytic and hemicellulolytic GHs, this taken together with their low levels on media lacking lignocellulose, reflect the concerted nature of cell wall polymer degradation.
Authors
Lone Ross Gobakken Olav Albert HøibøAbstract
The aesthetic service life of outdoor exposed wooden surfaces are often decided by growth of moulds and blue stain fungi, but also other visual changes caused by weathering such as colour changes, abrasion or wear, blistering, flaking, and even cracks in the wood or coating will contribute. When developing models that describe changes in the wood material and aim to predict the service life, it is essential to understand the impact of different climatic factors, the effect of variation in the wooden product itself and in the quality of craftsmanship and building design. The objective of this presentation is to gather knowledge about which factors influence surface mould growth on wood substrates in an outdoor environment. The analysis and the model development are based on data from evaluation of mould growth coverage on outdoors exposed wood panels consisting of different combinations of wood substrates and surface finishes from a number of field studies performed over the last years [1, 2, 3, 4, 5, 6 and 7].
Authors
Peder GjerdrumAbstract
Sawmillers want to have predictable and homogeneous timber outcome from their industry. This paper analyses and discusses how well timber quality of boards from the same log, and in particular pairs of sister boards, correspond to each other, i.e. the limit for quality homogeneity.Observations from three different sawn timber outcome experiments were analysed. Varying quality traits were observed: appearance and machine strength grading, knot size and number, and board value.The results showed that 80% and 53% respectively, for two different samples, of the boards had different quality grade from their sister boards, and less homogeneity when more boards are sawn from the same log. The correlation between observations made in sister boards were modestly 0.42 for biggest green knot diameter, and almost absent for dry knots and other traits. Board value and machine strength are better correlated, 0.76 and 0.69, respectively.Relative pairwise difference for these parameters was found to follow the exponential distribution with mean 0.169 and 0.068, respectively. The results clearly indicate that there is no easy way achieving a consistent and pre-requested quality, at the same time avoiding an inherent portion of diverted quality boards.
Authors
Igor A. Yakovlev YeonKyeong Lee Adam Vivian-Smith Jorunn Elisabeth Olsen Carl Gunnar FossdalAbstract
In Norway spruce there is an enigmatic epigenetic memory of the temperature conditions during embryogenesis affecting vital phenological traits (Yakovlev et al. 2012). Adaptive phenological traits such as bud burst and bud set, observed as clinal variation in nature, are the ones affected.The epigenetic memory is establishment exclusively during embryogenesis in response to environmental impact. The epitype fixated by the time the embryo is fully developed without any change in the primary DNA sequence and is mitotically propogated. The epigenetic mechanism influence the phenotype through altered regulation of gene expression and is propagated throughout every growth cycle for the entire lifespan of this long lived species.The epigenetic memory may be realized through several molecular mechanisms including DNA methylation, and histone modifications affecting chromatin, as well as by small non-coding RNAs, and may also be related to the mechanisms silencing transposable or repetitive elements in the genome. MicroRNAs (miRNAs), endogenous small regulatory RNAs, are shown to be differentially expressed in genetically identically but epigenetically different progenies, in regards to the timing of bud burst and bud set (Yakovlev et al. 2010).We have started large scale studies using next regeneration sequencing approaches to identify and characterize the genes and regulatory elements involved in the initiation, maintenance, and heritability of the epigenetic memory. Epigenetic related changes in miRNA regulation during the establishment of the epigenetic memory are now studied in in vitro derived somatic embryos developing under cold (18C) and warm (30C) environmental conditions (that induce epitypes).We have constructed and sequenced 10 small RNA libraries during proliferation, maturation stage 1, 2 3 and the mature stage of embryo formation in the contrasted temperatures, in two control libraries during proliferation at 22C, as well as their mRNA transcriptomes using the Ion Torrent PGMTM (Life technologies) platform.We are expecting to determine at what stage(s) during embryogenesis the epigenetic memory marks are being laid down by identifying when the transcriptomic differences, of small RNA and mRNAs, between the epitypes are the most prominent during embryogenesis. The identification of novel miRNA candidates and the confirmation of conserved and novel miRNAs will be presented.
Abstract
No abstract has been registered
Abstract
The combined effects of light, soil fertility, and ontogenetic changes on plant growth rates are poorly understood, yet these three factors play fundamental roles in structuring plant communities. We sought to determine how lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia), interior spruce (Picea glauca engelmanii (Moench) Voss), and subalpine fir (Abies lasiocarpa (Hook.) Nutt.) sapling growth responds to the combination of light, soil fertility, and ontogeny and how these three dominant conifer species in sub-boreal forests of British Columbia differ in their responses.Using maximum likelihood methods, we found that 0.204 m tall sapling growth rates changed during ontogeny and were limited by both light and soil resources. The strongest differences among species growth rates were due to tree size, with smaller differences due to soil fertility, and there were no differences among species in the shape of their growth responses to light. Rank order in growth rates for small saplings (pine spruce fir) inversely corresponded to classic shade-tolerance ratings, thus supporting the carbon balance theory. Interior spruce height growth rates increased relative to lodgepole pine with increasing soil fertility, clearly matching the landscape-scale increase in canopy dominance of interior spruce over lodgepole pine with increasing soil fertility.
Authors
Bengt Gunnar Jonsson Juha Siitonen Jogeir N. StoklandAbstract
No abstract has been registered
Abstract
This study examines already existing guidelines for the sustainable removal of slash from forests for bioenergy use. Existing guidelines from some countries, states and provinces with forest ecosystems comparable to Norways (Sweden, Finland, the U.K., Ireland, Minnesota, New Hampshire and British Columbia) are compared with the Norwegian Living Forests (LF) and Debio (ecological forestry) guidelines. The aim is to identify areas where the Norwegian guidelines could be further developed.