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
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Juha Heikkinen Erkki Tomppo Alexandra Freudenschuss Peter Weiss Gro Hylen Gal Kusar Ronald McRoberts Gerald Kändler Emil Cienciala Hans Petersson Göran StahlAbstract
National forest inventories (NFIs) are an important source of data for reporting greenhouse gas emissions and removals for the Land Use, Land-Use Change, and Forestry sector as required by the United Nations Framework Convention on Climate Change and its Kyoto Protocol. A major limitation is that NFI resources are generally not sufficient for producing reliable information on year-to-year variation. Interpolation, extrapolation, smoothing, and/or aggregation of data from several years are therefore needed to comply with the reporting requirements for a specific year. Various methods for accomplishing this task are illustrated and evaluated based on data and experiences from the NFIs of six countries, concentrating on the estimation of the stem volume of living trees as a surrogate for tree biomass. Six main conclusions were drawn: (1) NFI data from the target years only were not sufficient for reliable estimation of annual stock change; (2) changes between whole inventory cycles (typically 5 years) could be estimated with reasonable precision; (3) simple moving average estimators of stock are problematic in the estimation of changes; (4) interpenetrating panel designs with permanent sample plots are desirable from the point of view of inter/extrapolating and change estimation; (5) data on annual growth variation and harvests are important and can be used directly in the default method, which is based on differences between increment and drain; and (6) time gaps between NFI surveys may lead to significant errors in the estimation of stock changes.
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Arne StensvandAbstract
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Aruppillai Suthaparan Sissel Torre Leiv M. Mortensen Hans Ragnar Gislerød Knut Asbjørn Solhaug Arne Stensvand David M. GadouryAbstract
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Peder GjerdrumAbstract
Sawmillers want to have predictable and homogeneous timber outcome from their industry. This paper analyses and discusses how well timber quality of boards from the same log, and in particular pairs of sister boards, correspond to each other, i.e. the limit for quality homogeneity.Observations from three different sawn timber outcome experiments were analysed. Varying quality traits were observed: appearance and machine strength grading, knot size and number, and board value.The results showed that 80% and 53% respectively, for two different samples, of the boards had different quality grade from their sister boards, and less homogeneity when more boards are sawn from the same log. The correlation between observations made in sister boards were modestly 0.42 for biggest green knot diameter, and almost absent for dry knots and other traits. Board value and machine strength are better correlated, 0.76 and 0.69, respectively.Relative pairwise difference for these parameters was found to follow the exponential distribution with mean 0.169 and 0.068, respectively. The results clearly indicate that there is no easy way achieving a consistent and pre-requested quality, at the same time avoiding an inherent portion of diverted quality boards.
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Marte Meland Celine ReboursAbstract
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Marte Meland Celine ReboursAbstract
In Norway, regulations for harvesting seaweed apply to seabed algae such as Laminaria hyperborea. Harvest of foreshore algae such as Ascophyllum nodosum is not regulated, but is regulated by private owner rights because the species grow in the tidal zone. Environmental protection laws and other regulations can restrict areas for harvesting. Regulations of aquaculture of seaweed are under development.