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.
2025
Abstract
In terrestrial ecosystems, forest stands are the primary drivers of atmospheric moisture and local climate regulation, making the quantification of transpiration (T) at the stand level both highly relevant and scientifically important. Stand-level T quantification complements evapotranspiration monitoring by eddy-covariance systems, providing valuable insight into the water use efficiency of forested ecosystems in addition to serving as important inputs for the calibration and validation of global transpiration monitoring products based on satellite observations. Stand level T estimates are typically obtained by scaling up individual tree estimates of water movement within the xylem – or sap flow. This movement affects the radius of a tree stem, whose fluctuations over the diel cycle provide pertinent information about tree water relations which can be readily detected by point (or precision) dendrometers. While sap flow measurements have greatly advanced our understanding of water consumption (T) at the level of individual trees, deploying conventional sap flow monitoring equipment to quantify T at the level of entire forested stands (or ecosystems) can quickly become costly since sap flow measurements from many trees are required to reduce the uncertainty of the upscaling. Using a boreal old-growth Norway spruce stand at an ICOS site in Southern Norway as a case study, we assess the potential of augmenting conventional sap flow monitoring systems with sap flow modeling informed by point dendrometer measurements to reduce the uncertainty of stand level T estimation at the daily resolution. We test the hypothesis that the uncertainty reduction afforded by a boosted tree sample size more than offsets the propagation of uncertainty originating from the point dendrometer-based sap flow estimates.
Authors
Lathika Y. Hitige Rashmi N.J.K. Arachchi Nimal Ratnayake Miyuru Gunathilake Upaka RathnayakeAbstract
No abstract has been registered
Abstract
Climatic drought and changes in precipitation patterns are key features of the ongoing and predicted climatic changes in northern latitudes such as the boreal forest of Norway. Recent droughts highlight on the possible difficult future of spruce forests in southern Norway. To better understand and monitor these forests under a more extreme climate, it is crucial to gain a better understanding of the water relations of spruce trees across forest stands. Sap flow sensors are typically used for directly measuring the water demands for transpiration in individual trees. There are however limitations to their use in examining the hydraulic and physiological responses to extreme water supply variability: i) manufactured high-resolution sensors such as those following the Heat Ratio Method (HRM) or Heat Field Deformation (HFD) are expensive, limiting their deployment to a few trees in a stand, and ii) the sap flow sensors only measure the movement of water within the active sapwood, not accessing other physiological mechanisms and responses (radial growth, water storage) associated with stress response. Point dendrometers have become increasingly used, monitoring sub-daily stem size fluctuations resulting from both seasonal patterns of radial growth increment and the dynamics of plant tissue water balance. Manufactured point dendrometers are much cheaper to buy and easier to install and maintain than manufactured sap flow sensors. They can therefore be much more extensively deployed across forest stands. We aimed to analyse the relationship between sub-daily stem diameter changes and sap flow using point dendrometers and HRM sap flow sensors installed in a Norway spruce forest located 50 km north of Oslo, Norway. We linked these relationships with individual tree physical attributes, meteorology and soil climate over two growing seasons in 2022 and 2023. Our goal was to assess whether a predictive model of sap flow could be built from measured diameter changes, tree properties and climate, to ultimately reduce the uncertainty of stand level transpiration estimation at the daily resolution across entire forest stands.
Authors
Gunhild Bødtker Claire Coutris Eva Marie-Louise Denison Åsa Frostegård Erik J. Joner Bjørn Tore Lunestad Elisabeth Henie Madslien Kaare Magne Nielsen Pål TrosvikAbstract
In this self-tasking scoping review, VKM will map research about the environmental impacts of biodegradable plastics, including biodegradation rates and material persistence in different environments and geographical regions, the influence on microbial ecology and activity, and ecotoxicological effects of materials and associated chemical substances. Related to this is also research associated with the development of methodology, standards, environmental risk assessment, life cycle impact analyses, material sources and properties of biodegradable plastics and products. The aim is to 1) determine the extent of evidence summarised in reviews and original research papers within this emerging research area and 2) map the evidence according to the materials and chemicals studied, types of environments and geographical regions covered, the hypotheses addressed, the type of endpoints assessed and the reported key findings. Systematic literature searches will be performed to identify the summarised evidence, applying APRIO to develop a tailored search protocol that addresses the multi- and cross-disciplinary nature of the research area. We will select and map the identified publications applying Rayyan and sort them into three categories based on their main scientific focus and aim of study: 1) material properties and application, 2) biodegradation and microbial ecology, and 3) ecotoxicology. There will be no geographical restrictions on the search and study selection, but in the data charting process we will highlight findings relevant to Norway and other Nordic countries. The current project adheres to the “Preferred Reporting Items for Systematic Reviews and MetaAnalyses extension for Scoping Reviews (PRISMA-ScR) Checklist” for protocol development and reporting. We will address uncertainties associated with research studies applying EFSA guidelines and their generic list of common types of uncertainty affecting scientific studies and assessments.
Authors
Mikolaj Lula Kjersti Holt Hanssen Martin Goude Hannu Hökka Sauli Valkonen Andreas Brunner Pasi Rautio Charlotta Erefur Aksel GranhusAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Daniel Flø Johan A. Stenberg Lawrence Richard Kirkendall Anders Nielsen Selamawit Tekle Gobena Jorunn Børve Paal Krokene Christer Magnusson Mogens Nicolaisen Line Nybakken Iben Magrete Thomsen May-Guri Sæthre Sandra A.I. WrightAbstract
It is highly unlikely that Anagyrus vladimiri will be able to establish or spread in Norway. There are no native host organisms, and winter temperatures are too low. Therefore, it is likely that the parasitic wasp will not affect local biodiversity. Thus concludes the Norwegian Scientific Committee for Food and Environment (VKM). Background VKM has assessed the environmental risk of using the product Citripar in Norway. The risk assessment was carried out at the request of the Norwegian Food Safety Authority. Citripar, a product for biological control, is being sought for approval for use in Norway. The product contains the parasitic wasp Anagyrus vladimiri and is intended to be used against mealybugs, especially the species Planococcus citri and P. ficus, on fruits, berries, vegetables, and herbs in greenhouses and plastic tunnels, as well as on indoor plants. Conclusions There have been no reported observations of Anagyrus vladimiri in Norway. VKM assesses that Anagyrus vladimiri will not be able to establish and spread in Norway under current conditions. Anagyrus vladimiri will have no effect on biological diversity in Norway, as there are no known native host organisms that the wasp can parasitize. Individuals of what is now known as Anagyrus vladimiri were for many years identified as belonging to the species Anagyrus pseudococci. Anagyrus pseudococci and A. vladimiri belong to a complex of species that are almost impossible to distinguish from each other and are informally referred to as the Anagyrus pseudococci complex. The risk assessment is approved by VKM's Panel on Plant Health.
Authors
Eystein Skjerve Erik Georg Granquist Tone Kristin Bjordal Johansen Ingrid Olsen Truls Nesbakken Amin Sayyari Kristin Opdal Seljetun Morten Tryland Åsa Maria Olofsdotter Espmark Grete H. M. Jørgensen Janicke Nordgreen Ingrid Olesen Sonal Jayesh Patel Sokratis Ptochos Marco A. Vindas Tor Atle MoAbstract
VKM has assessed the risk of introduction and spread of bovine tuberculosis in Norway and cannot rule out that the disease still exists in Norway. There is a low risk of the disease being reintroduced with imported cattle, but the import of llamas and alpacas poses a greater risk. If the disease were to establish in Norway, there is a high risk of spread both among domestic animals and to wildlife. These are the main conclusions The Norwegian Scientific Committee for Food and Environment (VKM) has made in a risk assessment commissioned by the Norwegian Food Safety Authority. Background Following the outbreak of bovine tuberculosis in 2022, VKM was asked to investigate the risk of introduction as well as the risk of spread and establishment of the disease in Norway. The disease primarily affects cattle, but other animals and humans can also be affected. Bovine tuberculosis is a chronic disease that is difficult to diagnose. Therefore, it may take months or years before infected animals are detected. This makes it challenging to eradicate the disease. Conclusions With today's very limited import, VKM concludes it is unlikely that bovine tuberculosis will be introduced to Norway with cattle. Since neighboring countries Sweden and Finland are free from the disease, migration of wildlife will not pose a risk of introduction. However, as the source of the 2022 outbreak has not been identified, it cannot be determined if the disease is still present in Norway. “Alpacas and llamas pose a greater risk. These species are particularly susceptible to the disease, and animals have been imported to Norway, also from countries where the bacterium is common in the cattle population. It is therefore likely that the bacterium could be introduced to Norway with these species if imports continue”, says Eystein Skjerve, Scientific leader of the project team. There is significant trade and transportation of live animals (cattle, alpacas, and llamas) within Norway. If bovine tuberculosis were to establish here, such movements would pose a significant risk of spreading the bacterium. Furthermore, manure from infected herds could pose a risk of spreading to livestock and wild animals. Additionally, contact between livestock and wild animals, such as badgers, wild boars, and various deer species, could lead to the spread of the disease to the wild population. If bovine tuberculosis is established in Norway, a control and eradication strategy would require considerable time and resources. If the disease is introduced to-, and established in wild animal populations, experience from other countries indicates that it will be very challenging to eradicate the disease. “The risk of transmission of bovine tuberculosis to humans is generally low. Veterinarians, farmers, and slaughterhouse workers have an increased risk of infection. If the disease is established in Norway, the greatest risk of transmission to humans is through the consumption of both unpasteurised milk and dairy products”, Skjerve says. Risk-Reducing Measures VKM was also asked to identify several measures that could reduce the risk of introduction and establishment of bovine tuberculosis in Norway: Avoid importing animals from countries and regions where bovine tuberculosis is present in livestock. Avoid importing roughage to Norway from countries and regions with bovine tuberculosis. Increase testing requirements for the trade and movement of alpacas and llamas inside Norway. In the event of an outbreak of bovine tuberculosis, reduce contact between livestock and wild animals and routinely test wild animals (badgers, wild boars, and deer species). (...)
Authors
G. Brundu S. Follak J. Pergl D. Chapman E. Branquart S. Buholzer Inger Sundheim Fløistad G. Fried M. Herbst E. Marchante Valkenburg van Valkenburg R. TannerAbstract
No abstract has been registered
Abstract
No abstract has been registered