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.
2019
Abstract
No abstract has been registered
Authors
Olalla Díaz-Yáñez Blas Mola-Yudego José Ramón González-OlabarriaAbstract
Snow and wind damages are one of the major abiotic disturbances playing a major role in forest ecosystems and affecting both stand dynamics and forest management decisions. This study analyses the occurrence of wind and snow damage on Norwegian forests, based on data from four consecutive forest inventories (1995–2014). The methodological approach is based on boosted regression trees, a machine learning method aiming to demonstrate the effects of different variables on damage probability and their interactions as well as to spatialize damage occurrence to make predictions. In total, 313 models are fitted to detect trends, interactions and effects among the variables. The main variables associated with damage occurrence are consistent across all the models and include: latitude, altitude and slope (related to site and location), and tree density, mean diameter and height (related to forest characteristics). The results show that stand dominant height is a key variable in explaining damage probability, whereas stand slenderness has a limited effect. More heterogeneous forest structures make birch dominated stands more resistant to damage. Finally, the models are translated into occurrence maps, to provide landscape-level information on snow and wind damage hazard. Further application of the models can be oriented towards assessing the probability of damage for alternate stand management scenarios.
Abstract
Assessing redox conditions in soil and groundwater is challenging because redox reactions are oxygen sensitive, hence, destructive sampling methods may provide contact with air and influence the redox state. Furthermore, commonly used redox potential sensors provide only point measurements and are prone to error. This paper assesses whether combining electrical resistivity (ER) and self-potential (SP) measurements can allow the mapping of zones affected by anaerobic degradation. We use ER imaging because anaerobic degradation can release iron and manganese ions, which decreases pore water resistivity, and produces gas, which increases resistivity. Also, electrochemical differences between anaerobic and aerobic zones may create an electron flow, forming a self-potential anomaly. In this laboratory study, with four sand tanks with constant water table heights, time-lapse ER and SP mapped changes in electrical/electron flow properties due to organic contaminant (propylene glycol) degradation. Sampled pore water mapped degradation and water chemistry. When iron and manganese oxides were available, degradation reduced resistivity, because of cation release in pore water. When iron and manganese oxides were unavailable, resistivity increased, plausibly from methane production, which reduced water saturation. To bypass the reactions producing methane and release of metallic cations, a metal pipe was installed in the sand tanks between anaerobic and aerobic zones. The degradation creates an electron surplus at the anaerobic degradation site. The metal pipe allowed electron flow from the anaerobic degradation site to the oxygen-rich near surface. The electrical current sent through the metal pipe formed an SP anomaly observable on the surface of the sand tank. Time-lapse ER demonstrates potential for mapping degradation zones under anaerobic conditions. When an electrical conductor bridges the anaerobic zone with the near surface, the electron flow causes an SP anomaly on the surface. However, electrochemical differences between anaerobic and aerobic zones alone produced no SP signal. Despite their limitations, ER and SP are promising tools for monitoring redox sensitive conditions in unsaturated sandy soils but should not be used in isolation.
Authors
Hilde Margrethe Helgesen Marije Oostindjer Erik K. Arnesen Laila Dufseth Ellen-Margrethe HovlandAbstract
No abstract has been registered
Authors
Bjørn Egil FløAbstract
No abstract has been registered
Authors
Ivar PettersenAbstract
A grand societal challenge arises from an ageing population. Central governments respond by issuing an innovation imperative targeted at local municipalities as a major instrument to form a sustainable welfare sector policy. The presentation studies policies relating to one particular form of care innovation in the field of dementia care, in particular day care services provided by farmers – Farm Based Dementia Care – FBDC. The intention is to explore potential barriers to increased use of FBDC and the relevance of the current policy mix. Barriers are derived from innovation theory, theory of transaction costs, regulation and societal transformation. Observations from municipalities applying FBDC are used to understand the relevance of potential barriers. Relevant barriers are compared with the diversity of policies aiming to impact dementia care directly or indirectly, e.g. through general innovativeness at municipal level. Empirical observations are based on in-depth, semi-structured interviews with seven municipalities, complemented by contributions at workshops and previous analysis. When compared with the panel of policy measures and initiatives taken in order to make elderly care match future challenges from shifting demographics, we may identify strengths and weaknesses of policy aimed to manage the grand challenges arising from an ageing population.
Abstract
No abstract has been registered
Authors
Kjersti Holt HanssenAbstract
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Authors
Samuel Wilkinson Melissa Magerøy Ana López Sánchez Lisa M. Smith Leonardo Furci T. E. Anne Cotton Paal Krokene Jurriaan TonAbstract
No abstract has been registered
Authors
Márk Rékási Nikolett Mazsu Eszter Draskovits Botond Bernhardt Anita Szabó Pierre-Adrien Rivier Csilla Farkas Barbara Borsányi Béla Pirkó Sándor Molnár György Kátay Nikolett UzingerAbstract
The aim of this work was to investigate whether the agronomic traits of vermicompost prepared from partially stabilised sewage sludge digestate after thermophilic composting were more favourable than those of conventional compost. The effects of various additives (green waste, spent mushroom compost, wheat straw, biochar) were also tested after 1.5 months precomposting followed by 3 months vermicomposting with Eisenia fetida or by compost maturing. Vermicomposting did not result in significantly more intensive mineralisation than composting; the average organic carbon contents were 21.2 and 22.2% in vermicomposts and composts, respectively. Hence, the average total (N: 2.4%; P: 1.9%; K: 0.9%) and available (N: 160 mg/kg; P: 161 mg/kg; K: 0.8%) macronutrient concentrations were the same in both treatments. The processing method did not influence the organic matter quality (E4/E6) either. However, on average the concentration of the plant growth regulator kinetin was more than twice as high in vermicomposts.