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.
2010
Abstract
Wood protection is mainly based on chemical protection of wood. The disposal of wood preservative treated material causes restrictions in its later use or recirculation into the eco-cycle. A new protective system, electro-osmotic pulsing technology on wood, called PLEOT, is tested in a fungi test and in soil contact. Mass loss and moisture content of Scots pine sapwood samples was calculated after testing and an element analysis was performed on the sample powder. The results show that PLEOT- protected samples have nearly no mass loss after 4, 8 and 12 weeks of exposure to Coniophora puteana in laboratory trials. The samples protected with PLEOT showed lower moisture content but trace elements of metals in the samples after basidiomycete test compared to untreated samples. It is concluded, that neither the resulted wood moisture content nor the transferred metal ions in the PLEOT samples contribute to large amounts to the wood protection effect. Furthermore, the PLEOT system might give a protection for wood in soil contact. Further research on the mode of action as well as further tests including field tests are under planning.
Abstract
Understanding the feedback between terrestrial biosphere processes and meteorological drivers is crucial to ecosystem research as well as management. For example, remote sensing of the activity of vegetation in relation to environmental conditions provides an invaluable basis for investigating the spatiotemporal dynamics and patterns of variability. We investigate the Fraction of Absorbed Photosynthetically Active Radiation (fAPAR) using SeaWiFS satellite observations from 1998 to 2005 and ancillary meteorological variables from the CRU-PIK dataset. To what extent do precipitation and temperature dominate the terrestrial photosynthetic activity on monthly to interannual time scales? A spectral decomposition using Singular System Analysis leads to a global ‘classification’ of the terrestrial biosphere according to prevalent time-scale dependent dynamics of fAPAR and its relation to the meteorology. A complexity analysis and a combined subsignal extraction and dimensionality reduction reveals a series of dominant geographical gradients, separately for different time scales. Here, we differentiate between three time scales: on short time scales (compared to the annual cycle), variations in fAPAR coincide with corresponding precipitation dynamics. At the annual scale, which explains around 50% of the fAPAR variability as a global average, patterns largely resemble the biomes of the world as mapped by biogeographic methods.At longer time scales, spatially coherent patterns emerge which are induced by precipitation and temperature fluctuations combined. However, we can also identify regions where the variability of fAPAR on specific time scales cannot be traced back to climate and is apparently shaped by other geoecological or anthropogenic drivers. http://uregina.ca/prairies/assets/Prairie_Summit_Final_Program.pdf
Authors
Mari Mette Tollefsrud Christian Brochmann Christoph SperisenAbstract
Norway spruce (Picea abies L. Karst) and Siberian spruce (Picea obovata Lebed.) are closely related and occupy a large parapatric area across the entire northern Eurasia. They have been suggested to be connected by a wide zone of hybridization along the Ural Mountains, separating the European Norway spruce from the Siberian spruce. This introgressive zone is believed to be formed by secondary contact after the last glaciation. Based on macrofossils, P. obovata has been suggested to have survived the LGM in refugia both on the eastern and the western side of the Urals. Previous genetic isozyme studies have indicated that the two spruce taxa are genetically poorly differentiated.
Authors
Stein Tomter Gro Hylen Jan-Erik Ørnelund NilsenAbstract
No abstract has been registered
Abstract
Determining the feedbacks between terrestrial biosphere processes and the meteorological drivers (here precipitation and temperature) is crucial to ecosystem research. In this context, the continuous monitoring of the earth surface provides an invaluable basis for investigating the spatiotemporal dynamics in the activity of vegetation in relation to environmental conditions. Here, we seek to identify which patterns of variability in the meteorological drivers dominate the terrestrial photosynthetic activity from monthly to interannual time scales (resp. fluctuation frequencies). We investigate the Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) using SeaWiFS observations from 1998 to 2005 and ancillary meteorological variables. A spectralanalysis leads to a global `classification` of the terrestrial biosphere according to prevalent scale dependent dynamics of fAPAR and its relation to the meteorology. A combined subsignal extraction and dimensionality reduction reveals a series of dominant geographical gradients on specific time scales. E.g. we uncover spatially coherent patterns at low frequencies and show where these are induced by precipitation or temperature fluctuations. We also show where high frequency variations (relative to the annual cycle) in fAPAR coincide with corresponding precipitation dynamics. However, we can also identify regions where the variability of fAPAR on specific time scales cannot be traced back to climate and is apparently shaped by other geoecological or anthropogenic drivers. http://www.terrabites.net/fileadmin/user_upload/terrabites/PDFs/Programme_Book_TERRABITES.pdf
Authors
Antti Asikainen Karl Stampfer Bruce TalbotAbstract
Large volumes of spruce-dominated forests established on steep terrain are maturing in western Norway. The level of harvesting needed in utilising these forests calls for investments in cable yarding, processing and transport systems, and updated knowledge on the appropriate technology for Norwegian conditions. In the yarding-processing-truck transport operation, the processor cannot operate if the cable yarding system does not supply trees at a sufficient rate or when the buffer storage becomes full. As a result, the productivity of the whole system is often substantially lower than those of the individual parts in the system. Discrete-event simulation has been applied successfully in the analysis of a wide variety of wood harvesting and transport systems, where the productivities of different parts in the supply chain are interlinked .....
Authors
Lone Ross Gobakken Patricia K. LebowAbstract
Mould growth on coated wood is today a genuine challenge for house owners. Environmentally sound wooden facades with long service lives and acceptable appearance are desired. The objective in this study was to investigate the accumulated mould growth on 13 different wood substrates with 3 surface coating systems by identifying the factors that contribute to the variation and to predict future performance. A generalized linear mixed model was fit to the data with the analysis showing that coating and exposure time both had highly significant influences on mould growth. Further, wood substrate was significant, but comparatively less than coating and exposure time. A smaller coefficient for mould coverage in the beginning of the exposure period gave the panels with one of the coating systems, BAP, a delay in mould growth, and the extrapolated values for years 6-12 indicate a longer aesthetic service life than panels with the two other coating systems. Coated heartwood as wood type was less susceptible to mould growth than coated mixed wood and coated sapwood. Acetylated pine as wood substrate and aspen as wood species had lower resistance to mould growth than the other wood substrates and wood species, respectively.
Authors
Bruce Talbot Nils Egil Søvde H. Fridén Lars WilhelmssonAbstract
This paper builds on findings from the recently finalised work package 3.9 of the EU Indisputable Key project. Three institutes cooperated in developing intricate models spanning from the standing tree to the dispatch yard of a Swedish window manufacturer. Numerous timber properties were assigned to RFID tags, applied to the log at felling by a specially adapted harvester head. Logs were allocated to each of seven sawmills according to their timber properties using an LP based optimisation procedure. Simulation was then used to compare the fate of traced timber throughout the production lines of one of the sawmills and its downstream manufacturers.....
Authors
Peder GjerdrumAbstract
Building, maintaining and operating drying kilns is a heavy economic burden for most sawmills. As a consequence, drying capacity is often a bottleneck. Kilns are generally operated 24 h a day, 7 days a week, so there is no spare time to increase the production. Good planning routines are a prerequisite for short as well as long term operational planning. Most established sawmills have a mixture of batch and progressive kilns, some older, possibly upgraded, others more modern. This offers some flexibility in choosing the right kiln for drying a timber lot of defined quality, but also represents operational challenges. Through the years working in and for the sawmill industry, a spreadsheet model tool was made for analysing kiln capacity. The model is put together to examine the available-to-needed capacity balance in each of thirteen four-week periods of a year. Input values are information about the drying kilns and their operations, the sawmill production plans and the requested drying quality. Capacity is given in volume-hours (calculated in the same way as man-hours). The operational plans, i.e. the input values, can and should be adjusted until a reasonable balance for all periods, summed up in a graph, is achieved. A description of the model with a specified sawmill example will be given, illustrating the process from the initial stage to the final plans.
Authors
Igor A. Yakovlev Carl Gunnar Fossdal Øystein JohnsenAbstract
The temperature level experienced during zygotic embryogenesis in the conifer Norway spruce effects an epigenetic memory and vital phenological traits in the progeny (Kvaalen & Johnsen, 2008). MicroRNAs (miRNAs) are endogenous small RNAs having large-scale regulatory effects on plant development and could participate in epigenetic regulation of expression in plants. To unravel the possible molecular mechanisms behind this epigenetic phenomenon we prepared two concatemerized small RNA libraries representing smallRNAs expressed in plants from seeds obtained after embryogenesis in cold environment and in a warm environment and made a search of conserved miRNAs found in other plant species. Partial sequencing of the libraries allowed identifying of 199 different small RNAs, with predominant length of 21-nt. Among them were 24 novel candidate miRNAs and 4 conserved. Screening of conserved miRNAs allowed confirming additional 17 miRNAs belonged to 11 miRNA families. Most of the miRNA obtained were related to unknown and “no-hit” genes. The expression of 8 conserved miRNAs (pab-miR156c, 159a, 396a,b, 535, 947, 951 and 858) and 9 predicted miRNAs (miR080, 100, 105, 119, 122, 132, 144a,b and 157) showed significant differences in transcript levels between epigenetically distinct plants. Additionally we confirmed that four selected genes PaLPT4, PaGaMYB, PaMYB10 and PaSPB13 regulated by miRNAs pab-miR100, 858, 159a and 156c, may also be involved in epigenetic memory regulation. Our results suggest that Norway spruce miRNAs are composed of a set of conserved miRNAs and a large proportion of novel non-conserved miRNAs with relatively low expression levels. These findings imply that both kinds of miRNAs might be involved or at least affected by the molecular mechanisms underlying the temperature sensitive epigenetic memory in Norway spruce.