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.
2014
Abstract
National Forest Inventories (NFIs) provide estimates of forest parameters for national and regional scales. Many key variables of interest, such as biomass and timber volume, cannot be measured directly in the field. Instead, models are used to predict those variables from measurements of other field variables. Therefore, the uncertainty or variability of NFI estimates results not only from selecting a sample of the population but also from uncertainties in the models used to predict the variables of interest. The aim of this study was to quantify the model-related variability of Norway spruce (Picea abies [L.] Karst) biomass stock and change estimates for the Norwegian NFI. The model-related variability of the estimates stems from uncertainty in parameter estimates of biomass models as well as residual variability and was quantified using a Monte Carlo simulation technique. Uncertainties in model parameter estimates, which are often not available for published biomass models, had considerable influence on the model-related variability of biomass stock and change estimates. The assumption that the residual variability is larger than documented for the models and the correlation of within-plot model residuals influenced the model-related variability of biomass stock change estimates much more than estimates of the biomass stock. The larger influence on the stock change resulted from the large influence of harvests on the stock change, although harvests were observed rarely on the NFI sample plots in the 5-year period that was considered. In addition, the temporal correlation between model residuals due to changes in the allometry had considerable influence on the model-related variability of the biomass stock change estimate. The allometry may, however, be assumed to be rather stable over a 5-year period. Because the effects of model-related variability of the biomass stock and change estimates were much smaller than those of the sampling-related variability, efforts to increase the precision of estimates should focus on reducing the sampling variability. If the model-related variability is to be decreased, the focus should be on the tree fractions of living branches as well as stump and roots.
Abstract
No abstract has been registered
Authors
Christian Brischke Christian R. Welzbacher Antje Gellerich Susanne Bollmus Miha Humar Katharina Plaschkies Wolfram Scheiding Gry Alfredsen Joris Van Acker Imke De WindtAbstract
No abstract has been registered
Authors
Fredrik Wulff Christoph Humborg Hans Estrup Andersen Gitte Blicher-Mathiesen Mikołaj Czajkowski Katarina Elofsson Anders Fonnesbech-Wulff Berit Hasler Bongghi Hong Viesturs Jansons Carl-Magnus Mörth James C.R. Smart Erik Smedberg Per Stålnacke Dennis P. Swaney Hans Thodsen Adam Was Tomasz ZyliczAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Marta Camino-Serrano Bert Gielen Sebastiaan Luyssaert Philippe Ciais Sara Vicca Bertrand Guenet Bruno de Vos Nathalie Cools Bernhard Ahrens M. Altaf Arain Werner Borken Nicholas Clarke Beverley Clarkson Thomas Cummins Axel Don Elisabeth Graf Pannatier Hjalmar Laudon Tim Moore Tiina M. Nieminen Mats B. Nilsson Matthias Peichl Luitgard Schwendenmann Jan Siemens Ivan A. JanssensAbstract
No abstract has been registered
Authors
Lisbeth Schnug John Jensen Janeck J Scott-Fordsmand Hans Petter LeinaasAbstract
No abstract has been registered
Authors
Atle Mysterud Yngve Rekdal Leif Egil Loe Michael Angeloff Ragnhild Mobæk Øystein Holand Geir-Harald StrandAbstract
No abstract has been registered
Authors
Steffen Adler Stig Purup Jens Hansen-Møller Erling Thuen Anne-Maj Gustavsson Håvard SteinshamnAbstract
Phyto-oestrogens are a group of secondary plant metabolites that may bind to oestrogen receptors and exert oestrogenic or anti-oestrogenic effects in humans and can protect against cancer diseases. When ingested by dairy cows, phyto-oestrogens can be metabolised and transferred to the milk. The objective of this study was to assess the effects of grazing a recently established pasture containing red clover (Trifolium pratense L.) and an older pasture containing a variety of sown and unsown plant species on milk concentrations of phyto-oestrogens. Sixteen Norwegian Red dairy cows [mean (standard deviation); body weight 599 (45.1) kg, stage of lactation 73 (15.0) d in milk, milk yield 29.9 (2.90) kg/d at the start of the experiment] were divided into two groups and grazed either a short-term pasture (SP) or a long-term pasture (LP). The SP was representative of organically managed leys in Norway, which are frequently, approximately every third year, renewed by soil tillage and seeding, whereas LP was representative of organically managed grasslands that are less frequently renewed. The SP contained meadow fescue (Festuca pratensis Huds.) (mean 34%), timothy (Phleum pratense L.) (mean 19%), red clover (mean 28%), shepherd׳s-purse (Capsella bursa-pastoris (L.) Medik.) (mean 6%), pineappleweed (Matricaria matricarioides Porter ex Britton) (mean 5%) and scentless mayweed (Tripleurospermum perforatum (Mérat) Laínz) (mean 4%), and LP contained mainly white clover (Trifolium repens L.) (mean 21%), smooth meadowgrass (Poa pratensis L.) (mean 19%), timothy (mean 17%), meadow fescue (mean 15%), perennial ryegrass (Lolium perenne L.) (mean 6%), tufted hairgrass (Deschampsia cespitosa (L.) P. Beauv.) (mean 5%), northern dock (Rumex longifolius DC.) (mean 4%), common couch (Elytrigia repens (L.) Desv. Ex Nevski) (mean 4%), red clover (mean 3%) and dandelion (Taraxacum spp.) (mean 3%). In addition to a daily pasture allowance of 20 kg dry matter per cow, supplements of 3.0 kg barley (Hordeum vulgare L.) concentrate were fed. Herbage, concentrates and milk was sampled during the last week of three experimental periods and analysed for phyto-oestrogens using LC-MS/MS technology. Herbage from SP had 19 times higher concentration of isoflavones than herbage from LP, whereas only small differences were found for lignans. Milk produced on SP had 14 times higher concentrations of the mammalian isoflavonoid equol, and the concentrations of equol were higher than found in most other studies. This study confirms that grazing pastures containing red clover increases concentrations of isoflavones and especially equol in bovine milk compared to grazing pastures with other botanical composition. The higher milk concentrations of the lignan metabolite enterodiol in milk from SP compared to LP could not be related to differences in intake of the analysed lignans and may therefore be related to unidentified lignans.
Abstract
Treatability of wood is a function of anatomical properties developed under certain growing conditions. While Scots pine sapwood material normally is considered as easy to impregnate, great variations in treatability can be observed. In order to study anatomical differences in the structural elements of transverse fluid passage, wood material with contrasting treatability has been compared. Ray composition and resin canal network, membrane areas of fenestriform pits in the cross-field as well as dimension and properties of bordered pits were investigated. The results showed large anatomical differences between the two contrasting treatability groups. Refractory Scots pine sapwood samples developed more rays per mm2 tangential section, while they were on average lower in cell numbers than rays found in easily treatable material. Easily treatable material had more parenchyma cells in rays than refractory material. At the same time, a larger membrane area in fenestriform pits in the cross-field was observed in the easily treatable sample fraction. Differences in the composition of resin canal network were not observed. Refractory samples developed on average smaller bordered pit features, with relatively small formed pit apertures compared to the easily treatable samples. In refractory Scots pine sapwood material, the structural elements of fluid passage such as bordered pit dimensions, fenestriform pits in the cross-field and parenchyma cells were altogether developed in smaller dimensions or number. Wood samples from better growing conditions and sufficient water supply showed a better treatability in this study.