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.
2012
Abstract
The paper focuses on the use of thermogravimetric analysis (TGA) as a fast method for estimating the change of lignocellulosic materials during fungal degradation in laboratory trials. Traditionally, evaluations of durability tests are based on mass loss. However, to gain more knowledge of the reasons for differences in durability and strength between wooden materials, information on the chemical changes is needed. Pinus sylvestris sapwood was incubated with the brown rot fungus Gloeophyllum trabeum and the white rot fungus Trametes versicolor. The TGA approach used was found to be reproducible between laboratories. The TGA method did not prove useful for wood deteriorated by white rot, but the TGA showed to be a convenient tool for fast estimation of lignocellulosic components both in sound wood and wood decayed by brown rot.
Abstract
Brown-rot fungi such as Postia placenta are common inhabitants of forest ecosystems and brown rot fungi are also largely responsible for the destructive decay of wooden structures. The aim of this study was to compare two commonly used strains of Postia placenta MAD-698-R and FPRL 280. Scots pine sapwood samples were exposed for two and eight weeks to both fungal strains. The following was investigated: mass loss, fungal gDNA content and gene expression.A significant difference was found in mass loss after eight weeks between the P. placenta strains MAD-698-R and FPRL 280. MAD-698-R gave higher mass loss than FPRL 280. However, MAD-698-R seems to have a slightly slower growth rate than FPRL 280, reflected in lower gDNA content after two weeks.After eight weeks of exposure the gDNA content dropped and no significant difference was found between MAD-698-R and FPRL 280. We observed differences in mass loss, colonization-rate and gene expression between the two Postia strains. Results suggest significant differences in the regulation of key lignocellulose degrading enzymes between MAD-698-R and FPRL 280.
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Authors
Richard Bischof Leif Egil Loe Erling Meisingset Barbara Zimmermann Bram F. A. Van Moorter Atle MysterudAbstract
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Anders Skonhoft Vebjørn Veiberg Asle Årthun Gauteplass Jon Olaf Olaussen Erling Meisingset Atle MysterudAbstract
This paper presents a bioeconomic analysis of a red deer population within a Norwegian institutional context. This population is managed by a well-defined manager, typically consisting of many landowners operating in a cooperative manner, with the goal of maximizing the present-value hunting related income while taking browsing and grazing damages into account. The red deer population is structured in five categories of animals (calves, female and male yearlings, adult females and adult males). It is shown that differences in the per-animal meat values and survival rates (‘biological discounted’ values) are instrumental in determining the optimal harvest composition. Fertility plays no direct role. It is argued that this is a general result working in stage-structured models with harvest values. In the numerical illustration it is shown that the optimal harvest pattern stays quite stable under various parameter changes. It is revealed which parameters and harvest restrictions that is most important. We also show that the current harvest pattern involves too much yearling harvest compared with the economically efficient level.
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Erling MeisingsetAbstract
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Authors
Terje Gobakken Erik Næsset Ross F. Nelson Ole Martin Bollandsås Timothy G. Gregoire Göran Ståhl Sören Holm Hans Ole Ørka Rasmus AstrupAbstract
In this paper two sampling and estimation strategies for regional forestinventory were investigated in detail and results were presented for various geographical scales. Airbornelaser scanner (ALS) data were acquired to augment data from a systematic sample of NationalForestInventory (NFI) ground plots in HedmarkCounty, Norway (27,390 km2). Approximately 50% of the NFI fieldplots were covered by the systematic ALS sample of 53 parallel flight lines spaced 6 km apart. The area was stratified into eight cover classes and independent log-transformed regression models were developed for each class to predict total above-ground dry biomass (AGB). The two laser-ground estimation strategies tested were a model-dependent (MD), two-phase approach that rests on the assumption that the predictive models are correctly specified, and a model-assisted (MA) approach with a two-stage probability sampling design which utilizes design-unbiased estimators. ALS AGB estimates were reported by land cover class and compared to the NFI ground estimates. The ALS-based MA and MD mean estimates differed from the NFI AGB estimates by about 2% and 8%, respectively, for the entire County. At the county level the smallest estimated standard error (SE) for the estimates was obtained using the field data alone. However, the SEs calculated from field and ALS data were based on unequal numbers of ground plots. When considering only the NFI plots in the ALS strips, the smallest SEs were obtained using the MD framework. However, we also illustrated the sensitivity of the estimates of applying different plausible models. All the applied estimators assumed simple random sampling while the selection of flight lines as well as ground plots followed a systematic design. Thus, the estimates of SE were most likely conservative. Simulated sampling undertaken in a parallel research effort suggests that the overestimation of the SEs was probably much larger for the ALS-based estimates compared to the NFI estimates. ALS-based estimates were also derived for sub-county political units and thereby demonstrated how limited sample sizes affect the standard error of the biomass estimates.
Abstract
No abstract has been registered