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
Abstract
A crucial process of the terrestrial carbon cycle is photosynthetic uptake through plants. This may be quantified by calculating the fraction of absorbed photosynthetic active radiation (fapar), based on multispectral reflectance properties of the earth surface. The fapar index is available with global coverage from satellite sensors.Here, we combine two satellite missions, SeaWifs on board OrbView2 and MERIS on board Envisat, to produce time series with 10 days resolution for a period of 14 years (19982011) at a spatial resolution of 0.5 latitude x 0.5 longitude. These more than 50000 individual time series represent a huge range of dynamical behavior with respect to variability, periodicities and correlation structure.To characterize differences as a function of spatial location or distance, we employ Recurrence Quantification Analysis (RQA) and Recurrence Network Analysis (RNA). Two strategies are followed. On one hand, RQA and network variables are calculated for individual time series using identical recurrence parameters, and compared to see whether differences between them resemble different climate regimes, biomes, plant functional types or landuse classes. On the other hand, a multivariate extension of RNA will be exploited to see whether networks within networks occur, i.e. whether RNA provides sufficient contrasts to discern different clusters of pixels on the globe.Taken together, the recurrence analysis might lead to a new classification of the terrestrial biosphere which in turn can be compared to existing partitioning based on climate and/or vegetation properties. A number of technical issues will be addressed as well, such as the impact of the finite length of the series (504 values each), the necessity to gapfill parts of the data, the stability of network variables against changes in the recurrence parameters, or the computational challenges involved in the multinetwork analysis of many series. http://dames.pik-potsdam.de/Abstracts.pdf
Authors
Isabella Børja Jan Svtlík Toril Drabløs Eldhuset Holger Lange Frank Newell Kidder Douglas Lawrence GodboldAbstract
No abstract has been registered
Abstract
Damage by cone and seed insects is a severe impediment to those producing conifer seeds in seed orchards. The SNS-supported network `Nordic cone and seed insects` has been cooperating to address this problem since 2007. One of the outcomes is the coordinated monitoring of the most important insect species. The data collected form a basis for establishing strategies for pest management.
Authors
Andreas TreuAbstract
Improving wood preservation techniques can contribute substantially to reducing waste and avoiding negative environmental impacts. Dr Andreas Treu outlines a promising technique to dramatically reduce or even stop wood degradation altogether by using electro-osmosis. International Innovation is the leading global dissemination resource for the wider scientific, technology and research communities, dedicated to disseminating the latest science, research and technological innovations on a global level. More information and a complimentary subscription offer to the publication can be found at: www.researchmedia.eu
Authors
Severin WoxholttAbstract
No abstract has been registered
Authors
Lone Ross Gobakken Mats WestinAbstract
Environmentally sound wooden facades with long service lives and acceptable appearance are desired. Several types of modified wood are used in building applications to fulfil those requirements, but there is a potential for using more modified wood material. In facades modified wood are often used without any surface treatment or coating, but some sort of coating are desired and requested in a segment of the potential marked. Finding suitable coating systems for modified wood can be a challenge, and the objective of this study was to evaluate the long time performance of modified wood substrates in combinations with different coating systems after 8 years of outdoors exposure. Furthermore, evaluations at 4 and 8 years were compared to study the quantitative mould growth in a very late stage of the test period to capture any deviant behaviour from the traditional growth curve. Three coating systems were applied on furfurylated Scots pine, acetylated Scots pine, thermally modified Scots pine, oil/thermally modified Scots pine, thermally modified Norway spruce, and three reference wood substrates, and exposed outdoors for 8 years to evaluate their ability to resist surface moulds and blue stain fungi, cracking and flaking. The test was carried out according to EN 927-3. After 8 years mould growth, cracking and flaking mainly varied with type of coating where the tendency was that a waterborne system had the lowest rating for both mould growth, cracking and flaking. Oil/thermally modified treated pine had the lowest mould rating of the modified substrates. Acetylated pine had a decrease in mould rating from year 4 to year 8 when coated with the best coating system and a very small increase when coated with the second best system. Acetylated pine tended to have less flaking than the other modified substrates. Furthermore, acetylated pine, thermally modified pine and thermally modified spruce tended to have the least cracking of the modified wood substrates.
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].