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.
2004
Authors
Per Otto Flæte Erlend Ystrøm HaartveitAbstract
In Scandinavia Scots pine (Pinus sylvestris L.) is an important commercial tree species. Its heartwood has traditionally been used in constructions exposed to risk of decay. In a laboratory experiment Scots pine wood specimens sampled from inner heartwood, outer heartwood and sapwood were exposed to the brown rot fungus Poria placenta.In general outer heartwood was more resistant than inner heartwood, but there were variations even within the same wood zone. NIR spectra obtained on solid wood prior to decay testing were used in multivariate calibrations to predict decay resistance of heartwood.Results from segmented cross validated partial least squares (PLS1) regression modelling showed that resistance to decay in Scots pine heartwood could be predicted with satisfying precision using NIR spectroscopy. As NIR spectra were collected on solid wood, development of the method for industrial use is potentially possible.
Authors
Jørn Kristian Lileng Erlend Ystrøm HaartveitAbstract
Forest roads ensure access to standing timber and their standards may restrict the opportunity set for efficient logistical solutions. Traditionally, the objective of road investments has been maximisation of returns for the landowner.Investments in forest roads in Norway are subsidised by the Norwegian government. These subsidies should preferably be allocated to projects creating the best premises for efficient log supply. The total cost approach evaluates costs using a holistic perspective. In this paper we use this approach to evaluate the profitability of investments in forest roads so that the total costs for log supply to the industry are minimised.The distribution of standing timber in the catchment area of the forest road is also taken into account. The results show that the sum of costs for road construction, harvesting and forwarding account for more than 99% of the total costs, compared to less than 1% for the sum of log hauling costs. Differentiation of forest road standards is more appropriate in situations where the volume of standing timber decreases in remote areas of the forest road network.
Abstract
A method for determination of the climate gases CH4, CO2 and N2O in air samples and soil atmosphere was developed using GC-MS. The method uses straightforward gas chromatography (separation of the gases) with a mass spectrometric detector in single ion mode (specific determination).The gases were determined with high sensitivity and high sample throughput (18 samples h1). The LOD (3) for the gases were 0.10 L L1 for CH4, 20 L L1 for CO2 and 0.02 L L1 for N2O. The linear range (R2 = 0.999) was up to 500 L L1 for CH4, 4000 L L1 for CO2 and 80 L L1 for N2O. The samples were collected in 10 mL vials and a 5 L aliquot was injected on column.The method was tested against certified gas references, the analytical data gave an accuracy within 5% and a precision of 3%. The presence of 10% by volume of C2H2 (often used experimentally to prevent N2 formation from N2O) did not interfere with detection for the targeted trace gases.
– A method for evaluation of sustained low-level muscle activity
Kaj Bo Veiersted, Tove M. Østensvik
Authors
Kaj Bo Veiersted Tove M. ØstensvikAbstract
No abstract has been registered
Abstract
The forest stand growth simulator TRAGIC (tree response to acidification in groundwater in C) which has been developed to serve as a decision support system and a visualisation tool for scientists and forestry practitioners is introduced. TRAGIC places an emphasis upon visualisation techniques while at the same time providing detailed information on tree physiology and related parameters. The model is calibrated numerically to growth history data from two different European sites.Next, due to the importance of the visual component of the model, its ability to reproduce forest stand spatial structure is investigated, using an application of the theory of marked point processes. This analysis is applied to different experimental data sets for stands of different age, revealing information on planting schemes and the extent of significant spatial correlations.The spatial structure of the two model calibrations is then explored with the same methods. The point process analysis turns out to be a powerful diagnostic for model quality assessments, since spatial distribution is an indirect result of competition between trees for light.
Authors
Audun Øvrum Terje BirkelandAbstract
No abstract has been registered
Authors
Torild Wickstrøm Gunnar OgnerAbstract
A humus sample and a mineral soil sample were collected to investigate different sample pretreatments and their effects on the quality (mean value and uncertainty) of soil chemical data. Thirty-four humus subsamples and sixty mineral subsamples were prepared for chemical analysis. Diverse combinations of sieving, milling or grinding were utilized before the determination of Kjeldahl nitrogen (Kj-N), pH, extractable elements, and a few other chemical parameters.The humus subsamples were sieved, sieved and milled or sieved and ground. Relative to sieving, grinding improved the uncertainty in the determination by 210 times [highest for calcium (Ca), manganese (Mn), Kj-N, loss on ignition and volume weight].The mineral soil subsamples were either sieved or sieved and ground. The uncertainty was improved by 24 times for aluminum (Al), barium (Ba), Ca, hydrogen (H), potassium (K), sulphur (S), silicon (Si), zinc (Zn), and nitrogen (N) when grinding was applied.The result increased for almost all of the chemical parameters when the samples (humus and mineral) were ground in addition to sieving. The maximum increase in mean value was observed for Si (330%), iron (Fe) (200%) and carbon (C), K, magnesium (Mg), Mn, sodium (Na) (1734%).The determination of Kj-N was less influenced (016%) by different pretreatments but the uncertainty in the determination was improved up to 10 times when the sample was ground.Different sieving techniques were also utilized. It was shown that different sieving techniques altered the mean value for Ba, Fe, K, Mg, Si, Zn, pH, and loss on ignition, while the uncertainty was unaffected.All subsamples were reanalyzed after 15 months, without mixing in each sample before weighing. An increase in concentration was observed for C, Fe, phosphorus (P), S (up to 130%) and in volume weight (626%) while a decrease was observed for Ca, K, Mg, strontium (Sr), Zn (727%).
Abstract
Border cells from the seedling root tips were added to the conidium suspensions of two soilborne rootpathogens, Fusarium sp. and Cylindrocarpon sp. The presence of border cells in the suspension clearly stimulated germination of fungal conidia. Conidia of Fusarium sp. and Cylindrocarpon sp.started to germinate within 3 hours after inoculation.When border cells were washed off, the stimulating effect disappeared. Addition of malt extract caused similar stimulation as border cells. Germination of conidia was suppressed in Al-treated plants.
Abstract
Extensive monitoring of forest health in Europe has been carried out for two decades, based mainly on defoliation and discolouration. Together these two variables reflect chlorophyll amounts in the tree crown, i.e. as an indicator of foliar mass, and chlorophyll concentration in the foliage, respectively.In a current project we try to apply remote sensing techniques to estimate canopy chlorophyll mass, being a suitable forest health variable. So far, we limit this to Norway spruce only. LIDAR data here play an important role, together with optical and spectral data, either from survey flights or from satellites. We intend to model relationships between foliar mass and LIDAR data for sample trees, and then scale up this to foliar mass estimates for the entire LIDAR area.Similarly, we try to scale up chlorophyll concentrations in sample trees, by modelling a relationship between sample tree chlorophyll and hyper-spectral data. The estimates of foliar mass and chlorophyll concentrations are then aggregated to every 10x10 m pixel of a SPOT satellite scene which is also covered by airborne data, providing an up-scaled ground truth. If we are successful with this, it might be a starting point for developing a new nationwide forest health monitoring system in Norway.
Authors
Birger VenneslandAbstract
No abstract has been registered