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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.

2017

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Abstract

Different sowing methods and sowing rates were evaluated in organic seed production of timothy (two trials), meadow fescue (two trials) and red clover (one trial) in Southeast Norway, during 2010–2013. The plan included: (1) broadcast sowing of grass/clover, cover crop sown at 12 cm row distance; (2) sowing of cover and seed crop in crossed rows, both at 12 cm row distance; and (3) sowing of cover crop and seed crop in every other row. The three sowing rates were 5, 10 and 15 kg ha−1 in timothy and meadow fescue and 3, 6 and 9 kg ha−1 in red clover. On average for sowing rates and all trials with timothy, meadow fescue and red clover, first year’s seed yields were 5–6%, 20–25% and 19–25% higher on plots sown with cover crop and seed crop in every other row than on plots where seed crop had been broadcast or sown perpendicularly to the cover crop. The different sowing methods had no effect on weed coverage or weed contamination in the cleaned seed. Increasing sowing rate usually had a negative influence on seed yield, while weed coverage/contamination was not significantly affected. It is concluded that organic seed crops should be established with cover crop and seed crop in every other row at a low sowing rate. However, in an organic production system, even this favorable method will not always be sufficient to meet the requirement for seed crop purity.

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Abstract

Wood biomass for energy can be largely produced in northern Europe from forest land resulting from silvicultural practices and from agricultural land in the form of fast-growing plantations. The present paper estimates and compares the current regional potentials for wood biomass production attending to these sources. The data are based on spatialized estimates from previous models, largely based on empirical records concerning forest and plantation's productivity. The results show that 8.5 Mm3 of wood biomass can be produced annually from plantations when using 5% of the total available agricultural land, and 58.5 Mm3 from forest lands using current estimates of forest production. However, the results also show that a strategy for wood biomass resource management should be local rather than general: wood biomass potential from fast-growing plantations was larger in 19 regions than from forest resources (10 in Denmark, 6 in Norway and 3 in Lithuania) out of the 91 regions in the area included to this study. When considered together, northern Europe presents significant potential for wood biomass production for energy uses, and each country - and even region - should develop independent policy strategies of biomass generation in order to most efficiently realize their own potential for wood-based bioenergy.

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Abstract

The risk of snow and wind damage should be considered when deciding forest management actions, as it can greatly change forest development and its accompanying services. In this study, we develop models that predict snow and wind damage using management related variables as predictors. The plot level models are based on the extensive data available for Norwegian forests from four consecutive measurements of the national forest inventory along the period 1995–2014. The snow and wind risk is assessed in pure stands (pine, spruce and birch) as well as for mixed stands. Separate models are constructed for predicting the probability of a tree to be damaged, broken or uprooted. The models’ descriptors include: mean diameter, mean tree slenderness, mean height, basal area and a portfolio of variables related to stand structure and composition. The models are based on generalized linear models assuming binomial or quasi-binomial distributions resulting in nine models. Mixed stands are the stands most commonly affected by snow and wind damage followed by spruce dominated stands. Spruce stands with more heterogeneous structures are less prone to suffer breakage of trees, and increasing stand height have a big impact on the risk of tree breakage. The models presented in this study can be used to create management prescriptions considering the risk of snow and wind damage. These models also help to better understand which variables make a forest more vulnerable to snow and wind damage.