Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2022
Forfattere
Joyce Machado Nunes Romeiro Tron Haakon Eid Clara Antón Fernández Annika Kangas Erik TrømborgSammendrag
It is expected that European Boreal and Temperate forests will be greatly affected by climate change, causing natural disturbances to increase in frequency and severity. To detangle how, through forest management, we can make forests less vulnerable to the impact of natural disturbances, we need to include the risks of such disturbances in our decision-making tools. The present review investigates: i) how the most important forestry-related natural disturbances are linked to climate change, and ii) different modelling approaches that assess the risks of natural disturbances and their applicability for large-scale forest management planning. Global warming will decrease frozen soil periods, which increases root rot, snow, ice and wind damage, cascading into an increment of bark beetle damage. Central Europe will experience a decrease in precipitation and increase in temperature, which lowers tree defenses against bark beetles and increases root rot infestations. Ice and wet snow damages are expected to increase in Northern Boreal forests, and to reduce in Temperate and Southern Boreal forests. However, lack of snow cover may increase cases of frost-damaged seedlings. The increased temperatures and drought periods, together with a fuel increment from other disturbances, likely enhance wildfire risk, especially for Temperate forests. For the review of European modelling approaches, thirty-nine disturbance models were assessed and categorized according to their required input variables and to the models’ outputs. Probability models are usually common for all disturbance model approaches, however, models that predict disturbance effects seem to be scarce.
Forfattere
Vilde Lytskjold Haukenes Lisa Åsgård Johan Asplund Line Nybakken Jørund Rolstad Ken Olaf Storaunet Mikael OhlsonSammendrag
Knowledge about the spatial variation of boreal forest soil carbon (C) stocks is limited, but crucial for establishing management practices that prevent losses of soil C. Here, we quantified the surface soil C stocks across small spatial scales, and aim to contribute to an improved understanding of the drivers involved in boreal forest soil C accumulation. Our study is based on C analyses of 192 soil cores, positioned and recorded systematically within a forest area of 11 ha. The study area is a south-central Norwegian boreal forest landscape, where the fire history for the past 650 years has been reconstructed. Soil C stocks ranged from 1.3 to 96.7 kg m−2 and were related to fire frequency, ecosystem productivity, vegetation attributes, and hydro-topography. Soil C stocks increased with soil nitrogen concentration, soil water content, Sphagnum- and litter-dominated forest floor vegetation, and proportion of silt in the mineral soil, and decreased with fire frequency in site 1, feathermoss- and lichen-dominated forest floor vegetation and increasing slope. Our results emphasize that boreal forest surface soil C stocks are highly variable in size across fine spatial scales, shaped by an interplay between historical forest fires, ecosystem productivity, forest floor vegetation, and hydro-topography.
Forfattere
Helani Perera Miyuru Gunathilake Ravindu Panditharathne Najib Al-mahbashi Upaka RathnayakeSammendrag
Satellite-based precipitation products, (SbPPs) have piqued the interest of a number of researchers as a reliable replacement for observed rainfall data which often have limited time spans and missing days. The SbPPs possess certain uncertainties, thus, they cannot be directly used without comparing against observed rainfall data prior to use. The Kelani river basin is Sri Lanka’s fourth longest river and the main source of water for almost 5 million people. Therefore, this research study aims to identify the potential of using SbPPs as a different method to measure rain besides using a rain gauge. Furthermore, the aim of the work is to examine the trends in precipitation products in the Kelani river basin. Three SbPPs, precipitation estimation using remotely sensed information using artificial neural networks (PERSIANN), PERSIANN-cloud classification system (CCS), and PERSIANN-climate data record (CDR) and ground observed rain gauge daily rainfall data at nine locations were used for the analysis. Four continuous evaluation indices, namely, root mean square error (RMSE), (percent bias) PBias, correlation coefficient (CC), and Nash‒Sutcliffe efficiency (NSE) were used to determine the accuracy by comparing against observed rainfall data. Four categorical indices including probability of detection (POD), false alarm ratio (FAR), critical success index (CSI), and proportional constant (PC) were used to evaluate the rainfall detection capability of SbPPs. Mann‒Kendall test and Sen’s slope estimator were used to identifying whether a trend was present while the magnitudes of these were calculated by Sen’s slope. PERSIANN-CDR performed well by showing better performance in both POD and CSI. When compared to observed rainfall data, the PERSIANN product had the lowest RMSE value, while all products indicated underestimations. The CC and NSE of all three products with observed rainfall data were also low. Mixed results were obtained for the trend analysis as well. The overall results showed that all three products are not a better choice for the chosen study area.
Forfattere
Jorge Aldea Ricardo Ruiz-Peinado Miren del Río Hans Pretzsch Michael Heym Gediminas Brazaitis Aris Jansons Marek Metslaid Ignacio Barbeito Kamil Bielak Gro Hylen Stig-Olof Holm Arne Nothdurft Roman Sitko Magnus LöfSammendrag
1. Climate change is increasing the severity and frequency of droughts around the globe, leading to tree mortality that reduces production and provision of other ecosystem services. Recent studies show that growth of mixed stands may be more resilient to drought than pure stands. The two most economically important and widely distributed tree species in Europe are Norway spruce (Picea abies (L.) Karst) and Scots pine (Pinus sylvestris L.), but little is known about their susceptibility to drought when coexist. 2. This paper analyses the resilience (resistance, recovery rate and recovery time) at individual-tree level using a network of tree-ring collections from 22 sites along a climatic gradient from central Europe to Scandinavia. We aimed to identify differences in growth following drought between the two species and between mixed and pure stands, and how environmental variables (climate, topography and site location) and tree characteristics influence them. 3. We found that both the timing and duration of drought drive the different responses between species and compositions. Norway spruce showed higher vulnerability to summer drought, with both lower resistance and a longer recovery time than Scots pine. Mixtures provided higher drought resistance for both species compared to pure stands, but the benefit decreases with the duration of the drought. Especially climate sensitive and old trees in climatically marginal sites were more affected by drought stress. 4. Synthesis. Promoting Scots pine and mixed forests is a promising strategy for adapting European forests to climate change. However, if future droughts become longer, the advantage of mixed stands could disappear which would be especially negative for Norway spruce.
Forfattere
Ercan Yildiz Mehmet Yaman Sezai Ercisli Ahmet Sumbul Osman Sonmez Adem Gunes Mehmet Ramazan Bozhuyuk Darius KviklysSammendrag
The plant pomological characteristics and physiological behaviors of genotypes in modern apple cultivation could be different depending on the use of rootstock, changing growth ecology and application of biological control agents. The aim of this research was to determine the effects of rhizobacteria application on leaf and fruit nutrient contents in different apple scion–rootstock combinations. This study was carried out with seven standard cultivars (Scarlet Spur, Red Chief, Fuji, Jeromine, Galaxy Gala, Granny Smith, and Golden Reinders) budded on M.9 and MM.106 rootstocks. In the experiment, trees were sprayed by a nitrogen + phosphorus solvent rhizobacteria three times, with an interval of 15 days in the spring period. The effect of rhizobacteria application on leaf and fruit nutrient contents was statistically significant and provided generally significant positive contributions, except for leaf Mg content. Comparing both rootstocks, the positive effect of bacterial application was higher on the M.9 rootstock for leaf N and B content and fruit N and Fe content, and on the MM.106 rootstock for other nutrient content. While the effects of bacterial application on the basis of cultivars were generally positive, the highest positive contribution was made in leaf P content (10.7%) and fruit Mn content (32.1%) of the Fuji cultivar. Considering the total increase in nutrients in scion–rootstocks combination, rhizobacteria application had a positive effect on the leaf nutrient contents in Golden Reinders/MM.106, but not leaf K content. The highest increases in leaves of scion-rootstock combinations were determined as 4.0% in N content in Granny Smith/M.9, 14.1% in P content in Scarlet Spur/MM.106, 7.1% in K content in Fuji/MM.106, 4.4% in Ca content in Jeromine/M.9, and 14.0% in Mg content in Granny Smith/MM.106. The highest increase in fruit nutrient contents was between 4.9% (N content) and 13.5% (Ca content) for macro elements, and between 9.5% (Cu content) and 41.8% (Mn content) for microelements. The results of the present study may provide significant leads for further studies on this subject.
Forfattere
Ali Hosseini Hans-Christian Teien Till Seehusen Merete Myromslien Marit Nandrup Pettersen Justin Brown Brit Salbu Deborah Helen OughtonSammendrag
A series of 131I tracer experiments have been conducted at two research stations in Norway, one coastal and one inland to study radioiodine transfer and dynamics in boreal, agricultural ecosystems. The hypothesis tested was that site specific and climatological factors, along with growth stage, would influence foliar uptake of 131I by grass and its subsequent loss. Results showed that the interception fraction varied widely, ranging from 0.007 to 0.83 over all experiments, and showing a strong positive correlation with biomass and stage of growth. The experimental results were compared to various models currently used to predict interception fractions and weathering loss. Results provided by interception models varied in the range of 0.5–2 times of the observed values. Regarding weathering loss, it was demonstrated that double exponential models provided a better fit with the experimental results than single exponential models. Normalising the data activity per unit area to remove bio-dilution effects, and assuming a constant single loss rate gave weathering half-times of 22.8 ± 38.3 and 10.2 ± 8.2 days for the inland and coastal site, respectively. Whilst stable iodine concentrations in grass and soil were significantly higher (by approximately a factor of 5 and 7 times for grass and soil respectively) at the coastal compared to the inland site, it was not possible to deconvolute the influence of this factor on the temporal behaviour of 131I. Nonetheless, stable iodine data allowed us to establish an upper bound on the soil to plant transfer of radioiodine via root uptake and to establish that the pathway was of minor importance in defining 131I activity concentrations in grass compared to direct contamination via interception. Climatological factors (precipitation, wind-speed and temperature) appeared to affect the dynamics of 131I in the system, however the decomposition of these collective influences into specific contributions from each factor remains unresolved and requires further study. The newly acquired data on the interception and weathering of radioiodine in boreal, agricultural ecosystems and the reparametrized models developed from this, substantially improve the toolbox available for Norwegian emergency preparedness in the event of a nuclear accident.
Sammendrag
Enhancing carbon storage in managed soils through increased use of cover and catch crops in cereal cropping is at the heart of a carbon-negative agriculture. However, increased C storage by additional biomass production has a nitrogen cost, both in form of increased N fertilizer use and by potentially increasing nitrous oxide (N2O) emissions when cover crops decay. Frost-sensitive, N-rich aboveground biomass may be a particular problem during wintertime, as it may fuel off season N2O emissions during freezing-thawing cycles, which have been shown to dominate the annual N2O budget of many temperate and boreal sites. Here we report growing season and winter N2O emissions in a plot experiment in SE Norway, testing a barley production system with seven different catch and cover crops (perennial and Italian ryegrass, oilseed radish, summer and winter vetch, phacelia and an herb mixture) against a control without cover crops. Cover crops where either undersown in spring or established after harvesting barley. While ryegrass undersown to barley marginally reduced N2O emissions during the growing season, freeze-thaw cycles in winter resulted in significantly larger N2O emissions in treatments with N-rich cover crops (oilseed reddish, vetch) and Italian ryegrass. N2O budgets will be presented relative to aboveground yield and quality of cover crops and compared to potential souil organic carbon gains.
Sammendrag
The study was performed with apple cultivar ‘Rubin’ grafted onto dwarf ‘P60’ rootstock at the experimental orchard of the Institute of Horticulture, Lithuanian Research Centre for Agriculture and Forestry, between 2016 and 2020. The orchard was planted in 2010. Planting distances were 1.25×3.5 m. Seven treatments of tree vigour control were established, including combinations of mechanical pruning, tree trunk incision and application of prohexadione-calcium (Pro-Ca). The strongest growth was recorded for the control treatment, where slender spindle trees were maintained manually. Significantly, the shortest shoots grew where mechanical pruning was applied. A tendency for higher yield was recorded for mechanical pruning treatments. Trunk incision and summer pruning exhibited significantly lower fruit mean weight and diameter. Multiple applications of Pro-Ca increased fruit weight. Less colored fruits were obtained for mechanical pruning treatments
Forfattere
Frank Maas Tore Krogstad Milica Fotiric Akšic Mekjell MelandSammendrag
Denne rapporten omhandlar resultat frå kartlegging av næringsstatusen i norske eplehagar. Jord,- blad og fruktprøvar vart samla inn frå ulike eplehagar på Aust- og Vestlandet med variasjon i jordart, innhald og type organisk materiale i åra 2018-2020. Føremålet var å studera samanhengane mellom plantefysiologiske sider i epletreet relatert til jorda, treveksten, avling og fruktkvalitet. Resultat frå det treårige studiet om verknaden av gjødselpraksisar på opptak av mineral i blada, avling og fruktkvallitet hjå ulike eplesortar frå fire regionar er samla i denne rapporten. This report is summarizing results from a survey analyzing the nutrient levels in fruit trees and soil in four fruit growing regions in Norway during the seasons 2018-2020. The aim was to study the relationship between main plant physiological principles in the tree, related to the soil, tree growth, yield, fruit quality, and fruit storage. The results of a three-year study of apple tree fertilization practices on orchard soil fertility, leaf mineral composition, apple tree yields and fruit quality of several apple cultivars in four main apple producing regions in Norway are compiled in this report.
Forfattere
Camilla Svendsen Heidi Amlund Monica Hauger Carlsen Gunnar Sundstøl Eriksen Trine Husøy Inger Therese Laugsand Lillegaard Gro Haarklou Mathisen Anine Christine Medin Robin Ørnsrud Angelika Agdestein Øivind Bergh Johanna Eva Bodin Ellen Merete Bruzell Edel O. Elvevoll Dag Olav Hessen Merete Hofshagen Helle Katrine Knutsen Åshild Krogdahl Asbjørn Magne Nilsen Trond Rafoss Olaug Taran Skjerdal Inger-Lise Karin Steffensen Tor Arne Strand Gaute Velle Gro Ingunn Hemre Vigdis Vandvik Jan AlexanderSammendrag
At request from the Norwegian Food Safety Authority (NFSA), VKM has identified food groups and food items consumed by the Norwegian population that are relevant for monitoring regarding content of one or more undesirable chemical substances (Figure 1). Undesirable chemical substances were defined as chemical substances in food that may constitute a potential health risk. VKM has created a knowledge base (an Excel file) as a tool for planning and prioritising monitoring of foods and undesirable chemical substances. The substance groups included in the knowledge base are flavourings, food additives, metals and metalloids, natural toxins, persistent organic pollutants, process-induced contaminants, substances in food contact materials, substances in food supplements, and trace elements. More than 40 different substances were included. Food items that are known contributors to exposure to an undesirable chemical substance were identified from quantitative and qualitative data, mainly from EFSA opinions and VKM risk assessments. Four national dietary surveys were used for identification of food items and food groups habitually eaten by the Norwegian population. The habitual diet was used to identify potential unknown sources of the substances. The information on known and unknown sources was compiled in a knowledge base comprised of 456 “undesirable chemical substance/food item” pairs that were identified to be relevant for monitoring. For each “undesirable chemical substance/food item” pair, the following information are included in the knowledge base: - Food category - Contribution to total exposure, including degree of contribution - Origin of occurrence data, and availability of Norwegian occurrence data - Remarks regarding sampling - Sources of the undesirable chemical substances in food - Risk (a combined score for hazard and exposure) Sampling of food is a complex area. Careful planning of the sampling strategy is needed and several parameters should be taken into consideration, depending on the properties of the chemical substance and the food item. Generic guidelines on sampling strategy, including sample number and frequency, have been provided in the report. Key words: VKM, health risk, monitoring, Norwegian Scientific Committee for Food and Environment, Norwegian Food Safety Authority, undesirable chemical substance.