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
Authors
Rastislav Solár Frantiek Kaík Ladislav Reinprecht Marta Laurová Jarmila Geffertová Janka DibdiakovaAbstract
A series of comparable specimens of hornbeam wood were submitted to fungal and chemical pretreatments. Two strains of erosive white-rot fungi (P. chrysosporium and T. versicolor) and a lignin-selective fungus C. subvermispora were used. Chemical pretreatments were carried out with diluted sodium hydroxide, or sodium hydroxide and then by hydrogen peroxide, or per-acetic acid. Both biotic and abiotic pre-treatments modified the chemical composition of wood and were accompanied by its weight loss. The applied fungi apparently delignified the specimens, however at the expense of cellulose, especially when the erosive strains of fungi were used. The chemical pretreatments caused deep deacetylation, and milder delignification of wood and did not cause an apparent loss of cellulose. Biotic pretreatments of hornbeam wood, despite their marked delignification effect, led to unexpected increase in the contents of residual lignin in the resulting kraft pulps. On the other hand, pulping of the chemically pre-treated chips yielded pulps with low contents of residual lignin and much higher brightness.
Abstract
Extensive timber imports represent potential introduction pathways for exotic bark beetles (Col: Scolytidae) that may pose ecological hazards and economical risks to native forests. One such species, Ips amitinus Eichh., has been intercepted several times at Norwegian ports of entry in the years since 2002, the year of the first Scandinavian record. Detection of overwintering individuals of I. amitinus at the timber storage site of import timber and preliminary results of a stepwise import model may suggest a high risk of establishment and spread in Norway spruce forests in Scandinavia.Using various modeling approaches, our goal is to reduce the risk of introduction, establishment, and spread of introduced bark beetles. Our objectives are to:model the processes of dispersal and establishment of arriving bark beetlesexplore to what extent an introduced species interacting with native Ips typographus L., the most dominant species in Norway spruce, will lead to stronger and more frequent outbreaks of I. typographusassess potential patterns of spread of newly established bark beetle species and the spatiotemporal outbreak dynamics resulting from interactions between native and introduced species; andadvise on the implications for forest industry and management.Here we present current efforts to model dispersal (objective 1). Dispersal patterns, and hence rates of establishment and spread, may vary considerably depending on dispersal behaviors of insects, such as directionality of movement and aggregation propensity. To assess underlying assumptions of dispersal models, we are using an individual-based model where traits governing dispersal are inherited with random mutations. Individual reproductive success is determined by resource availability and density-dependence in a simulated landscape governed by external forces (e.g., windfellings) and beetle activity (consumption of resources). Evolvable traits include straight line vs. random-walk flight paths and aggregation propensity.Model simulations show that the chance of successful reproduction is greatest for intermediate to high levels of directionality, and that directionality increases over time up to a certain point determined by the landscape features as well as other traits of the species. Assuming limited (local) information in a stochastic landscape, intermediate to high degree of flight directionality is selected for.
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
Bjørn ØklandAbstract
In recent years several forest insects have been recorded as newcomers or as more abundant than before towards northern latitudes and higher elevations in Norway. Such observations are from different groups of forest insect, including herbivorous geometrids, phloeophagous bark beetles and insects in cone seed .......
Authors
Peder GjerdrumAbstract
Moisture content, volatile in nature, is an important trait for any timber customer. Commercial board samples were observed to yield formulas for EMC reduction by kiln temperature, for hysteresis by board length, and for MC sorption dynamics by temperature. Industrial kiln practice lowers the EMC to approximately 95% of tabulated values. In this work, hysteresis was verified, and the most significant impact in natural ambient is that moisture migration to the board center appears to catch up with surface adsorption, reducing the influence of temperature and surface resistance. A concluding procedure for estimating MC dynamics for timber boards on stickers is outlined.
Abstract
Rural communities in Norway have been under great economic stress in recent years. There has been an increasing debate about how to utilize the large potential in a growing tourism industry to promote rural employment and income. This study is based on the institutional view of innovation with a focus on institutions that are important for stimulating innovations. The objectives are: 1) to determine if networking is positively related to innovativeness and if innovativeness is positively related to performance in the nature-based tourism industry in Norway and 2) to develop an in-depth understanding of how different actors trigger a member of the industry to change, create, or otherwise innovate. An email survey was conducted of companies across the country followed by a qualitative study in one Norwegian municipality. Results indicate that there is a positive connection between networking and innovativeness, and between innovativeness and performance. A qualitative case example illustrates the interaction among actors and the resulting impacts on the innovation process.
Authors
Tor MykingAbstract
An international EU/Interreg III Kolarctic project `Development and implementation of an environmental monitoring and assessment program in the joint Finnish, Norwegian and Russian border area`, was carried out during 2003–2006 as a joint undertaking between Norwegian, Finnish and Russian research institutes and environmental authorities. The aim of the terrestrial ecosystem sub-project of the Pasvik project was to develop and implement a monitoring and assessment programme for terrestrial ecosystems in the joint Finnish, Norwegian and Russian border area...
Authors
Peder GjerdrumAbstract
Cost and revenue related to kiln drying are described. A calculation model compatible with a sawmill\"s profit and loss account is suggested. Typical cost items for a Scandinavian sawmill and from European litterature are reported. Cost for shrinkage/distortion/quality losses and investment/depriciation and maintenance for kilns and other technical equipment. It is claimed that better models and intensified calculation will improve sawmill profitability.
Abstract
In Norway, exterior wood structures have traditionally, nearly exclusively been made of untreated Norway spruce (Picea abies (L.) Karst) and pressure treated Scots pine (Pinus sylvestris L.). In recent years there has been a tendency that other wood species, like various Norwegian hardwoods or imported species, have been used in exterior above ground applications, often not surface treated. For several wood species, especially hardwoods, information regarding the durability in use class 3 is limited. Most information given in EN 350 part 2 is based on testing of the heartwood in ground contact. The test procedures for above ground test prescribed in European standards, both laboratory and field tests, have some weaknesses regarding natural durability testing. Hence, some new methods for accelerated above ground testing have been put forward. The main objectives of this project are to evaluate natural durability of Norwegian and some imported wood species for above ground applications, and to study various methods for assessing decay in wood. The project material and methods used in the project, and the results from double layer tests after one year of exposure has earlier been described, Flæte et al. (2006). This paper presents the results of the weight and MOE loss in small samples after about 3 years exposure above ground.
Authors
Peder Gjerdrum Olav Albert HøibøAbstract
A huge effort has been put into modelling wood quality the last few decades. Predicting knot size has been the centre of interest, either for timber quality, for tree growth models, or related purposes. The main objective of this paper is to analyse the stochastic features connected to knot distribution inside the three-dimensional volume of a tree\"s trunk. Four large Alpine spruce trees were sampled; age 150 years, DBH 30 to 70 cm, total volume 14.5 m3. To open a possibly large part of the stems, they were cross-cut to 31 logs and sawn to 193 unedged boards. On each unique board surface all perceptible knots were observed and localised in polar coordinates; origin in the stem base, along the pith and in the north direction. A total of 6200 knot intersections were observed in the 283 m2 sawn surfaces; however, most knots were observed several times in consecutive sawn surfaces. In order to obtain stationary variable, knot size was transformed by dividing by the square root of radial distance, and radial distance was transformed by dividing by log radius at the given location. Relative size, knot quality and spatial distribution were largely random and not correlated to each other in a tree. Thus, knots demonstrate a double nature, one part obeying the physiological laws, and another part stochastic.