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
Authors
Kjell Andreassen Birger Solberg Øyvind JacobsenAbstract
Four forest management systems, clear cutting, mountain forest selective cutting (50-90 % of volume removed), group system and single tree selection system (20-50 % of volume removed) were compared in two Norway spruce mountain forest stands. The sites are located 650 m.a.s.l., which is about 100 meter below the alpine tree line in this region. The background for this experiment was that the forest owner wanted to examine alternatives to clear cutting with silvicultural methods where some trees were left in the stand to protect regenerating against frost, to maintain biodiversity, and for recreational reasons in such areas close to the tree line. In twenty 400 m2 systematically sampled plots we assessed or measured vegetation type, regeneration, diameter of all trees > 2.5 dbh, tree heights, annual growth from increment cores, tree quality, old stumps and windthrows. In addition, time studies of the four harvesting methods were performed close to each other in the area. The following mean values were estimated in the two stands before cutting: Area 7 hectares, volume 170 m3/ha, mean diameter 23 cm, mean height 18 m, stems 550/ha, seedlings 150/ha, productivity 3 m3/ha/yr. The diameter distribution of the two stands was almost similar to a reverse J-shaped curve, but a larger amount of trees in some medium and large diameter classes were observed. However, most of the 230 m3 harvested trees were medium and large sized. Annual increment indicated growth reactions 3 years after harvesting. The operational costs were estimated according to time studies of the harvesting and extraction of 580 trees. Analyses of net present value, where bare land value and all future revenues and expenses were estimated and discounted backwards to the harvesting year, indicates less profitability for group selection and selection system than clear cutting and mountain forest selective cutting.
Abstract
Modification of wood with furfuryl alcohol or furfuryl alcohol prepolymer leads to a wood product with increased decay resistance, hardness and dimensional stability. In normal application, i.e. under Use Class 3 conditions, furfurylated wood can be regarded as non-toxic. This has earlier been demonstrated by toxic hazard tests on water leachates using relevant leaching procedures, e.g. the OECD Guideline 313 or the Dutch shower test procedure. These leachates showed slight to no toxicity towards standard aquatic test organisms. However, when using forced leaching procedures with limited amount of water such as the EN 84 procedure, slight to moderate toxicity to the same test organisms was observed, depending on furfurylation process. Furthermore, earlier studies have shown that leachates from wood treated with furfuryl alcohol pre-polymers have higher toxicity to Vibrio fischeri (luminescent marine bacterium) than leachates from wood treated with furfuryl alcohol monomers and that this probably is attributed to differences in leaching of chemical compounds. The ambition of the present study, was to investigate which chemical compounds in the leachates causes toxicity to the aquatic organisms V. fischeri and Daphnia magna (water flea). In this study five different wood species, both hardwoods and softwoods, treated with three different furfurylation processes, were leached according to two different leaching methods. The study shows that this difference in toxicity of leachates towards V. fischeri most likely cannot be attributed to maleic acid, furan, furfural, furfuryl alcohol or 2-furoic acid. However, the difference in toxicity might be caused by the substance 2,5-furandimethanol. Leachates from furfurylated wood still need to be investigated further in order to identify the chemical differences between wood furfurylated with furfuryl alcohol monomers and furfuryl alcohol prepolymer causing differences in toxicity to different organisms.
Authors
Peder Gjerdrum Bjarne HamarAbstract
Commercial timber sawing is always done in trade-off between yield and capacity, between cost of raw material and of production. Accurate knowledge of the dimensions for every single log is needed for successful breakdown. Traditionally, mills sawing to customers\" order, i.e. timber lots of given dimension and quality, start the breakdown process by scaling and sorting unbarked logs. However, accuracy can be greatly improved if scaled after barking. Scaling barked logs to adapt sawing pattern to each log inevitably slows down production speed, and also produces a variety of sawn boards besides the ordered one. The goal of the project described in this paper was to optimise the yield while maintaining high capacity and sawing to order. A modern, medium-sized sawmill producing ca. 60 000 m3 spruce timber annually was about to renew the sawlog intake. A two-stage log scaling/sorting and sawing twin mini-series was concluded. The first stage is the traditional sorting of unbarked logs. In the new intake, when the order is to be produced, logs are debarked before a second scaling with a 3D scanner based on laser beams reflected from the smooth and bright log surface. Logs are directed to either of two log decks, or buffers, each of ca. 25 logs, and sawn in twin mini-series alternating between the two. Sorting criteria might be purely diameter, log length, quality prediction generated from log geometry, or a combination. The sawn timber yield was increased by up to 3 000 m3 annually, corresponding to the contribution margin improved by 3 mill. NOK or more. Production speed is increased by ca. 4%, but producing two orders simultaneously increases planning complexity, requiring additional training for involved personnel. It can be concluded that the chosen set-up: Two-stage log sorting with accurate scaling in the final sorting and sawing twin orders in alternating twin mini-series, has proved successful with respect to sawn timber recovery and production capacity.
Abstract
Measurements of heat production rate have been made on wood samples with the brown rot fungus Postia placenta at different moisture contents. The results clearly indicate that the heat production rate (a measure of respiration rate and activity) is moisture dependent. When the moisture content is decreased, less heat is produced, and when the moisture content is increased, more heat is produced. Isothermal calorimetry seems to be a measurement technique well suited to the study of rot fungal activity as a function of temperature and moisture content.
Authors
Peder GjerdrumAbstract
A number of presentations were given at the GlueLam Study Tour in Trøndelag arranged by The Norwegian Forest and Landscape Institute April 2010 within the Developing the Scots Pine Resource project. The editor wishes to express his gratitude to all those who contributed to the outcome of the study tour: To the host businesses, to the participants and those giving presentations, and to Northern Periphery Program for contributing to the funding. The presentations listed in this report has been collected, trimmed and otherwise slightly modified by the editor. However, the content as well as the layout have been the choice and responsibility of each author. The report is intended for publication in electronic format on the project\"s web page and distribution to the participants. However, the report is public and free to use for anybody, provided a proper citation is given.
Abstract
Plants use an array of responses to pathogenic infection. Understanding of the underlying defence mechanisms may lead to new strategies for reducing the damage. Our objective here was to study histological and cytological responses in Norway spruce of different ages (from seedlings to mature trees) to infection with several pathogenic organisms (Pythium dimorphum, Ceratocystis polonica and Heterobasidion annosum) and compared them to effects of mechanical wounding. To visualize the reaction on infection/wounding we used different histological staining techniques followed by laser confocal microscopy and TEM. Primary roots of Norway spruce seedlings were infected with P. dimorphum, while mature trees (about 30 years old) were infected with C. polonica, H. annosum and wounded. In seedling roots the hyphae of P. dimorphum penetrated the tissue rapidly and colonized the root within 24 hours. In the infected tissue the lignin concentration doubled within 6 days compared to non infected roots. General response to infection by C. polonica and H. annosum in mature trees was the production of lignosuberised wound periderm, accumulation of polyphenolic aggregates in living parenchyma cells in the phloem and development of traumatic resin ducts in the xylem. Upon wounding, we observed a similar, but less intense response. In conclusion, although we tested fungi belonging to different taxonomical and ecological groups, the responses were similar, differing in intensity and timing of the defence response mainly. The response seems to be similar but dependent on the degree of susceptibility in the individual trees and clones.
Authors
Peder GjerdrumAbstract
This presentation describes the Conifer Heartwood rule, i.e. the constant difference between the square root of the cambial age and the number of heartwood rings. This difference seems to be an inherent property of each species, irrespective of stand or site characteristics, or for location in the tree. When needed, heartwood can be identified by means of IR ecposures or chemical indicators.
Authors
Igor A. Yakovlev Carl Gunnar Fossdal Øystein JohnsenAbstract
Norway spruce (Picea abies (L.) H. Karst.) displays a temperature-dependent epigenetic memory from the time of embryo development, which thereafter influences the timing of bud phenology. As a first step toward unravelling the molecular mechanism behind an epigenetic memory, transcriptional analysis was performed on seedlings from seeds of six full-sib families produced under cold (CE) and warm (WE) embryogenesis temperature regimes. We prepared two suppressive subtracted cDNA libraries, representing genes predominantly expressed after bud set induction in plants from seeds obtained after CE and WE embryogenesis. Sequencing and annotation revealed considerable differences in the transcriptome of WE and CE seedlings. We studied the expression patterns of 32 selected candidate genes using qRT-PCR. Five genes, two transposon-related genes and three with no matching sequence in databases showed differential expression in progeny from CE and WE correlated with family differences. Another step was to study microRNAs (miRNAs), which are endogenous small RNAs exerting epigenetic gene regulatory effects. We tested for their presence and differential expression. We then prepared concatemerized small RNA libraries from seedlings of two fullsib families, originated from seeds developed in a cold or a warm environment. One family showed distinct epigenetic effects whilst the other did not. Sequencing identified 24 novel and 4 conserved miRNAs. Further search and screening of the conserved miRNAs confirmed the presence of 17 additional miRNAs. Most of the miRNAs were targeted to unknown genes. The expression of seven conserved and nine novel miRNAs showed significant differences in transcript levels in the full-sib family showing distinct epigenetic difference in bud set, but not in the non-responding full-sib family. The differential expression of specific miRNAs indicates their putative participation in epigenetic regulation. Putative miRNA targets were studied. These findings may contribute to our understanding of the epigenetic mechanisms underlying adaptive changes acquired during embryogenesis in Norway spruce.
Authors
Harald Bratli Per Magnus Jørgensen Reidar Haugan John Inge JohnsenAbstract
Catapyrenium psoromoides has been discovered in three localities in southern Norway, in Aust-Agder (Åmli), Hedmark (Ringsaker) and Rogaland (Rennesøy). In Aust-Agder and Rogaland it occurred on Ulmus glabra in a wood pasture and an open deciduous forest. In Hedmark the species was found on a calcareous rock outcrop. These finds fill in the distribution gap between Scotland and Sweden and confirm that the species is nemoral to southern boreal with oceanic tendencies. The preference for big, broad-leaved trees in the Atlantic-Mediterranean part of the distribution area is pointed out.
Authors
Nadeem Yaqoob Jan Karlsson Benedicte Riber Albrectsen Halvor Solheim Carl Gunnar FossdalAbstract
Plants are exposed to a variety of pathogens in their natural habitats. To understand the key processes of defense responses in aspen (Populus tremulae) at the transcript level two clones C72 and C23 with differential level of resistance from the SwAsp collection were inoculated with a foliar rust (Melampsora magnusiana Wagnar). Leaf samples were collected from adjacent areas of the inoculation site to examine the long distance (systemic) defense responses at day1, day3 and day14 post treatments. We performed microarray experiments on the biothrophic interaction, on comparison with the healthy controls we found that the two clones respond in a widely different fashion to the rust. Clone C23 showed almost no response to biotroph after 24 hours while clone 72 gave a clear defense response to the pathogen. Quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) showed a significant differential expression patterns in susceptible and resistant colnes. Chitinase, cinnamic acid reductase and the iaa genes showed signification up-regulation in resistant clone. The level of expression was 5.9 delta threshold cycles in chitinase gene at day14. Data analysis from extracted total phenolics and condensed tannins verify the results of cDNA arrays and qRT-PCR.