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.
2003
Authors
Peder GjerdrumAbstract
Knowledge about the transformation of sapwood into heartwood contributes to the understanding of the nature of pine trees and should be considered prior to the conversion of sawlogs to produce timber of prescribed properties and optimal revenue. In this study, heartwood formation was ascribed to the joint effect of ageing and growth rate. Observations of heart- and sapwood in 1656 trees and sawlogs of Scots pine (Pinus sylvestris L.), sampled throughout Scandinavia, were analysed using mixed models. The most important finding was expressed in the pine heartwood age rule: heartwood age equals the square root of cambial age less three, to the second power. This global formula was valid irrespective of environmental factors and location within the tree, and described 93 per cent of the variance in the sample. Transition rate increases from 0.6 rings a−1 at 50 years to 0.8 rings a−1 at 200 years. The spatial amount of heartwood might be influenced by the silviculture through the annual ring width pattern. For samples missing sapwood, e.g. archaeological wood, the results might be combined with dendrochronology in specimen dating. When the diameter and the heartwood diameter of sawlogs were known, the mean annual ring width could be estimated with a standard deviation of 0.5 mm a−1. The simplicity, consistency and high correlation of the pine heartwood age rule confirms the importance of age as the main factor in heartwood formation.
Abstract
Areas near the Norwegian-Russian border are being strongly contaminated by heavy metal emissions from copper-nickel smelters in the Kola peninsula. The present report presents data for the four elements arsenic, chromium, cobalt, and selenium in vegetation sampled in eastern Finmark, obtained by neutron activation analysis. It is no doubt that the smelters in Nikel and Zapolyarny, constitute the main source of these elements in this area. Some chromium comes from local domestic sources. Still, however, the concentration of these elements in soil and vegetation are probably too low as such to represent any harm to the ecosystem.
Authors
Peder GjerdrumAbstract
The timber industry in Norway is quite fragmented. Several small-scale and a few medium-sized sawmill add up to an annual production of 2.5 mill. m3. Since three decades, most of the timber is kiln dried. Modern kilns and enhanced modelling contribute to improved drying quality and increased drying speed. However, due to harsh competition, fast dried, inferior drying quality timber is continually being offered and accepted for trade in the European area. This might put the overall goodwill for timber at hazard in the long run. Unfortunately, the detection of drying quality properties is quite complex. In this situation, industry and RTD-bodies like the Norwegian Forest Research Institute co-operate to offer competence-building activities. Seminars in wood drying and related topics are offered mainly on a corporate basis, thereby introducing an intimate atmosphere for dealing with these cautious topics. A fixed number of participants meet regularly for two day\"s of intensive work over a period of two or three years. The seminars typically include persons from all levels of the factory organisation, incorporating salesmen, mill operators and maintenance together with kiln operators, sometimes also bringing inn external customers. Work alternate between practical experiments, presentations and training. The activity is continued in working groups between the meetings. All seminars are adequately reported with respect to findings, thereby enhancing the business value of the achievements. The seminars also provide an invaluable basis for research projects and for recruiting fresh candidates. For the institute, this symbiosis with industry helps keeping focus on factors influencing profitability in the timber business.
Authors
Morten Ingerslev Inge Stupak Møller Karsten Raulund-Rasmussen Ingeborg Callesen Vivian Kvist JohannsenAbstract
No abstract has been registered
Authors
Bjørn ØklandAbstract
No abstract has been registered
Authors
Øystein Johnsen Carl Gunnar Fossdal Rüdiger Baumann Jørgen A. Mølmann Ola Gram Dæhlen David Clapham Tore SkrøppaAbstract
No abstract has been registered
Authors
Petter Nilsen Gunnar AbrahamsenAbstract
Results from two fertilizer experiments in coniferous forest in south and southeast Norway with applications of nitrogen (N), magnesium (Mg) and phosphorous (P) are presented. A Scots pine stand has been fertilized annually for 9 years and one Norway spruce stand has been fertilized annually for 4 years. The aim of the study has been to investigate to what extent N fertilization in middle-aged stands of Scots pine and Norway spruce stimulates tree growth, and whether Mg and P counteract possible induced nutrient imbalances caused by high N doses. Both stands responded strongly to N addition and application of 30 and 90kgNha-1yr-1 resulted in a relative volume increment of 150 and 250%, respectively, compared to control. The increment effect in the pine experiment ceased after 4 years, but the difference between the two N doses was still significant after 9 years. The application of 1.5kgMgha-1yr-1 had just a slight significant positive effect on volume increment in two of the 9 years in the pine experiment, while no effect of 5.3kgPha-1yr-1 on volume increment was found. Needle nutrient concentrations were mainly affected by the N treatment and concentrations above 30mgg-1 was detected in the pine experiment. The concentration of P, Mg and K was negatively affected by the highest N dose in the spruce experiment, but not in the pine experiment. The imbalanced nutritional status created by N application was partly reduced by the P and Mg addition, but no substantial effect on tree growth has been detected so far. The stands have a large potential for accumulating N in the standing biomass and judged from the effect on nutrient concentrations and growth, Mg might be the next element that could limit tree growth by a continued high N atmospheric input.
Authors
Live S. Vestgarden O. Janne KjønaasAbstract
The objective of this study was to quantify the net potential N mineralisation and nitrification rates in mineral soils of two coniferous forest soils subjected to different N additions. One study site was located at Åmli (Pinus sylvestris L. forest), southern Norway and another at Gårdsjön (Picea abies forest), southwestern Sweden. Mineral soil was collected from 14 to 19 and 24 to 29 cm depth in May at Gårdsjön and in May, July, September and November at Åmli. The soil was incubated in the dark at 15 °C for 2 months in the laboratory, and the NH4+ and NO3- content were compared relative to pre-incubated values. The initial contents of NO3- and NH4+ in the soil at the two sites were of about the same magnitude, but the potential net N mineralisation, ammonification and nitrification rates differed significantly. At Gårdsjön, the net N mineralistion ranged from 6 to 29 mg N kg-1 per 2 months, whereas a net N immobilisation generally occurred at Åmli. Additions of 0–50 kg N ha-1 per year had no effect on the transformation rates at the two sites. Applications of large single doses of 90 kg N ha-1 per year during the last 8 years have significantly increased the net nitrification rate in the soil at Åmli. However, a net N mineralisation was only observed in the soil 1 month after the N addition. At low N input levels, site-specific factors, such as the content of organic matter, clay, and moisture, seemed to a large degree to determine the transformation rates. Large spatial variability both within catchments and between catchments at Gårdsjön may have obscured the effects of small N inputs.
Authors
Erlend Ystrøm Haartveit J. Chaseling Per Otto FlæteAbstract
The use of PLS as a tool for developing reliable models for predicting wood quality is demonstrated with two case studies, one involving Norwegian spruce as manufactured lumber, and the other involving decay resistance of Scots pine wood. It is concluded that a PLS model involving eight simple measurements taken on the trees standing in the forest and on their unprocessed logs, can be used to predict the bending stiffness and bending strength of subsequent manufactured lumber.This approach can be used to provide a non-destructive way of predicting wood strength before processing, thus enabling more efficient use of raw materials. The use of different levels of segmental cross validation, with units being tree, forest stand, growing environment or country, did not change the predictive outcome of the models.More complicated models involving additional variables and their interactions did not provide an improved prediction. In the second case study, all but one of the wood samples were successfully classified into their correct class of heartwood or sapwood using PLS dummy regression models based on 926 wavelength variables in the NIR and visual regions.Models including the visual region as well as the NIR region proved to be superior even when there was no observable colour difference between the two wood types. Satisfactory models were obtained for predicting the resistance to decay of heartwood by using PLS on the non-destructive NIR data. As for the classification models, better predictions were achieved when the visual region of the spectra was included.
Abstract
A multiplex real-time PCR assay was developed to monitor the dynamics of the Picea abies-Heterobasidion annosum pathosystem. Tissue cultures and 32-year-old trees with low or high resistance to this pathogen were used as the host material. Probes and primers were based on a laccase gene for the pathogen and a polyubiquitin gene for the host.The real-time PCR procedure was compared to an ergosterol-based quantification method in a tissue culture experiment, and there was a strong correlation product moment correlation coefficient, 0.908) between the data sets. The multiplex real-time PCR procedure had higher resolution and sensitivity during the early stages of colonization and also could be used to monitor the host.In the tissue culture experiment, host DNA was degraded more rapidly in the clone with low resistance than in the clone with high resistance. In the field experiment, the lesions elicited were not strictly proportional to the area colonized by the pathogen.Fungal colonization was more restricted and localized in the lesion in the clone with high resistance, hereas in the clone with low resistance, the fungus could be detected until the visible end of the lesion. Thus, the real-time PCR assay gives better resolution than does the traditionally used lesion length measurement when screening host clones for resistance.