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.
2011
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Abstract
The Norwegian National Forest Inventory (NNFI) provides estimates of forest parameters on national and regional scales by means of a systematic network of permanent sample plots. One of the biggest challenges for the NNFI is the interest in forest attribute information for small subpopulations such as municipalities or protected areas. Frequently, too few sampled observations are available for those small areas to allow an estimate with acceptable precision. However, if an auxiliary variable exists that is correlated with the variable of interest, small area estimation (SAE) techniques may provide means to improve the precision of estimates.
Authors
Arnstein ØvrumAbstract
No abstract has been registered
Authors
Peder GjerdrumAbstract
Scaling accuracy is of utmost importance to obtain optimal yield in log breakdown. In this paper we have combined sawmill experience, a review of available publications and supplementary observations to analyse the accuracy of roundwood scaling for Norway spruce and Scots pine. The influence of ovality, bark thickness variation and bark damage were analysed for scaling in one-directional and two- directional shadow scanners, and for three-dimensional (3D) reflected beam scanners. The overall accuracy for diameter under bark can be calculated by adding the variances for each independent term. For unbarked logs, shadow scanners with two perpendicular directions are most accurate. Results show that 3D scanners are most accurate, provided used for barked logs. For a case study, transferring from scaling unbarked logs in a two-dimensional shadow scanner to a full 3D scan of barked logs reduced annual roundwood consumption by 2.0%.
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No abstract has been registered
Authors
Arnold ArnoldussenAbstract
Publiced earlier in English in 2006. In 2011 revised and translated into Chinese.
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No abstract has been registered
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Current risk assessment procedures for contaminated land and for pesticides often fail to properly characterize the risk of chemicals for environment or human health and provide only a rough estimate of the potential risk of chemicals. Chemicals often occur in mixtures in the environment, while regulatory agencies often use a chemical-by-chemical approach, focusing on a single media, a single source, and a single toxic endpoint. Further, the importance of soil microbes and their activity in the functioning of soils impose a need to include microorganisms in soil quality assessments including terrestrial ecotoxicological studies. Numerous papers have been published on the effects of different contaminants on soil microbes, establishing changes in soil microbial diversity as an indicator of soil pollution. However, only a limited number of molecular studies focus on changes in fungal species when investigating soil microbial diversity. The main objective of the study presented here, is to assess the applicability of changes in soil microbial diversity and activity levels as indicators of ecologically relevant effects of chemicals contamination. We will achieve this through studies of effects of the fungicide picoxystrobin and the chemical 4-n-nonylphenol on the microbial biodiversity in a Norwegian sandy loam, with focus both on prokaryotes and the fungal species. Laboratory incubation experiments at 20°C with soil samples treated with the single chemicals or mixtures, with continuous monitoring of respiration activity as well as occasional destructive sampling for extraction of soil DNA, RNA, and chemical residues, was performed through a 70 d period. Results from amplification of soil bacterial and fungal DNA followed by T-RFLP (terminal restriction fragment length) analyses to assess chemicals effects on soil microbial diversity, indicate significant effects of the studied chemicals on soil microbial community structure. To identify specific bacterial or fungal groups that are affected, an assessment of the effects of the chemicals on the soil microbial metagenome by high throughput shot-gun sequencing (454 sequencing) is in progress This work is part of the research project ‘Bioavailability and biological effects of chemicals - Novel tools in risk assessment of mixtures in agricultural and contaminated soils’ funded by the Norwegian research council.
Abstract
Wood as a hygroscopic material gains or loses moisture with changes in climate of the surrounding air. The moisture content influences strength properties, hardness, durability and machinability. Therefore the hygroscopicity is a very important property, last but not least for economic factors. Below fibre saturation, a change in moisture content causes shrinkage or swelling and anisotropic behaviour can be seen in the different growth directions. For a better understanding of the sorption behaviour of Scots pine (Pinus sylvestris L.) the variation between different adsorption and desorption curves has been investigated. Trees from 25 different sites in Northern Europe were collected and 3651 samples (1510 heartwood- and 2141 sapwood-samples) measuring 5 (T) x 10 (R) x 30 (L) mm were obtained. The sorption isotherms for all specimens were measured at 25 °C at relative humidities of 15, 35, 55, 75 and 95 % for both desorption and adsorption. The aim of this study is to investigate the influence of raw material variability on the sorption behaviour of Scots pine. Due to the different growing conditions, densities and wooden material (heart or sapwood) variations within the sample groups have been found. Correlations between moisture and density respectively latitude were investigated.