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.
2017
Forfattere
José Ramón González-Olabarria Jordi Garcia-Gonzalo Blas Mola-Yudego Timo PukkalaSammendrag
& Key message We generate flexible management rules for black pine stands, adaptable to alternative stand management situations and entailing thinnings, final-felling, and salvage cuts, based on the results on 270 stand level optimizations. & Context Forest management instructions often rely on the anticipated prediction of the stand development, which poses a challenge on variable economic and environmental conditions. Instead, an alternative approach to better adapt forest management decisions to changing conditions is defining flexible rules based on thresholds that trigger management operations. & Aims This article develops rules for the adaptive management of P. nigra stands in Catalonia (Spain) addressing the risk of fire and post-fire forest management. & Methods The stochastic version of the simulationoptimization system RODAL was used to optimize the management of forest stands in three sites under different fire probability levels. A total of 270 optimizations were done varying site fertility, fire probability, and economic factors. The results of the optimizations were used as the basis of flexible forest management rules for adaptive stand management. & Results The developed management rules defined the basal area limit for thinning, the thinning intensity, the mean tree diameter at which regeneration cuttings should start, and the basal area below which a salvage cutting should be done. Fire risk was not a significant predictor of the models for thinning and final cutting rules. & Conclusion The presented rules provide a flexible tool for forest management during the stand development and under changing conditions when the management objective is to maximize economic profitability of timber production.
Forfattere
Marek Marian Pierzchala Knut Kvaal Karl Stampfer Bruce TalbotSammendrag
Cable yarding is a semi-mechanized timber harvesting system that relies on human machine interaction where a considerable share of the work is done by forest workers. The system is used in mountain forests around the world. Automation of one or more functions could contribute to increased productivity, reduced physical workloads and improved safety conditions. This paper presents a method for sensor data fusion in order to automatically distinguish work phases using Partial Least Squares Discriminant Analysis (PLS-DA). The Robot Operation System (ROS) is implemented to allow for real-time data processing with a maximum latency of 0.16 s. Global Positioning System (GPS), Inertial Measurement Unit (IMU) and camera integration provided a robust solution for 78% correct process segmentation. These results provide a basis for further development from which there is a possibility of expanding this approach for semi-automation, remote control, and autonomous operation.
Sammendrag
The use of digital aerial photogrammetry (DAP) for forest inventory purposes has been widely studied and can produce comparable accuracy compared with airborne laser scanning (ALS) in small, homogeneous areas. However, the accuracy of DAP for large scale applications with heterogeneous terrain and forest vegetation has not yet been reported. In this study we examined the accuracy of timber volume, biomass and basal area prediction models based on DAP and national forest inventory (NFI) data on a large area in central Norway. Two separate point clouds were derived from aerial image acquisitions of 2010 and 2013. Vegetation heights were extracted by subtracting terrain elevation derived from ALS. A large number of NFI sample plots (483) measured between 2010 and 2014 were used as reference data to fit linear models for timber volume, biomass and basal area with height metrics derived from the DAP data as explanatory variables. Variables describing the heterogeneous environmental and image acquisition conditions were calculated and their influence on the model accuracy was tested. The results showed that forest parameter prediction using DAP works well when applied to a large area. The model fits of the timber volume, biomass and basal area models were good with R2 of 0.80, 0.81, 0.81 and RMSEs of 41.43 m3 ha−1 (55% of the mean observed value), 32.49 t ha−1 (47%), 5.19 m2 ha−1 (41%), respectively. Only a small proportion of the variation could be attributed to the heterogeneous conditions. The inclusion of the relative sun inclination led to an improvement of the model RMSEs by 2% of the mean observed values. The relatively low cost and stability across large areas make DAP an attractive source of auxiliary information for large scale forest inventories.
Sammendrag
Angiostoma norvegicum n. sp. (Angiostomatidae) is described from the oesophagus, crop and the buccal mass of five species of slugs of the family Arionidae, Arion vulgaris (Moquin-Tandon), Arion ater (L.), Arion fasciatus (Nilsson), Arion fuscus (Müller) and Arion rufus/Arion ater hybrid), collected throughout Norway. Angiostoma norvegicum n. sp. was found parasitising arionids at seven of the 30 sample sites examined (23.3%), and 9.9% of all Arion spp. were infected with this nematode. The new species is characterised by its large size (4.0–8.6 mm long) and in having: lateral alae; 6 + 6 papillae at the cephalic end; a large circular mouth aperture; a spacious stoma; a pharyngeal basal bulb without valvular apparatus; an excretory pore near the base of bulb; a distal part of posterior ovary always outstretched; an anterior ovary distally nearly always outstretched; a vulva situated anterior to mid-body; long, nearly straight spicules and a small gubernaculum; three circumcloacal papillae and caudal genital papillae (GP) arranged in a pattern 1+2/3+3 with GP 5 and GP 8 opened on dorsal side of narrow bursa not reaching tail tip; short conical tails in both sexes with tips supplied by 4 short, unequal denticles. Morphologically, A. norvegicum n. sp. is similar to Angiostoma limacis Dujardin, 1845, which diagnostic characteristics are given based on examination of specimens from Norway and the UK. Conversely, the phylogenetic analyses based on D2D3 large subunit (LSU) rRNA gene sequences performed in the present study did not support the morphological affinity of these two species. Phylogenetic analyses demonstrated that although Angiostoma spp. cluster together, A. norvegicum n. sp. forms a tight monophyletic clade with the milacid nematode parasites Angiostoma margaretae Ross, Malan & Ivanova, 2011 and Angiostoma milacis Ivanova & Wilson, 2009.
Forfattere
Ola Stedje Hanserud Kari-Anne Lyng Jerke W. de Vries Anne K. Falk Øgaard Helge BrattebøSammendrag
©2017 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open accessarticle distributed under the terms and conditions of the Creative Commons Attribution(CC BY) license (http://creativecommons.org/licenses/by/4.0/).
Forfattere
Monica Suarez Korsnes Reinert KorsnesSammendrag
Korsnes, Monica Suarez; Korsnes, Reinert. Mitotic catastrophe in BC3H1 cells following yessotoxin exposure. Frontiers in Cell and Developmental Biology 2017 ;Volum 5.(30)
Forfattere
Dionisio Andújar Xavier Rodriguez Victor Rueda-Ayala Carolina San Martín Angela Ribeiro César Fernández-Quintanilla José DoradoSammendrag
New technologies, such as Differential Global Positioning Systems (DGPS) and Geographic Information Systems (GIS), may be useful in order to create models to predict the spatio-temporal behaviour of weeds. The aim of this study was to generate a geometric model able to predict the patch expansion of S. halepense, a problematic perennial weed in maize crops in Central Spain. From previous infestation maps, the model describes new possible spreading areas for the upcoming growing season, and therefore, herbicide treatments can be planned on time. Two different experiments were implemented, in which initial patch density and size were examined. Patches of different size (1, 10 and 100 m2) and density (4, 20 and 100 shoots m−2), were established. These patches were visually identified, their perimeter defined and their density characterized, during three growing seasons (from 2008 to 2010 campaigns). According to this information different descriptors were built: (1) area and density of each patch; (2) the relative growth in width and length, according to space and time and compared with previous years; and (3) the increased density ratio, calculated in relation of patch size and distance to previous patch in the new infestation areas of expansion. All these descriptors were added to the model in order to predict the patch expansion in the last studied season (i. e., 2010) using previous maps (i. e., season 2008 and 2009). The model uses geometrical assimilation to predict, and two expansion assumptions were considered: (a) a conservative approach based on triangular geometry; and (b) a rectangular geometry which maximizes the simulated infested area. The results were compared with the ground truth map created in 2010. Each method showed weaknesses and strengths. The triangular approach minimized the infested area, mainly in the small patches, and therefore it could predict the expansion of previously established patches, but not the emergence of new ones. In contrast, the rectangular approach simulated the position of new foci, maximizing the infested area. Therefore, although a substantial reduction of herbicides is possible using both models, a final decision must be taken individually for each field.
Forfattere
Kine Svensson Oda Kjørlaug Svein Jarle Horn Jane Wittrup_AggerSammendrag
Bio-Methane Potential (BMP) tests are used to evaluate the suitability of a biomass for anaerobic digestion. BMP data are usually presented as the amount of methane produced from a kilogram of volatile solids (VS) or chemical oxygen demand (COD) of the substrate. However, the most used methods for determination of VS and COD are not always accurate. Oven drying may underestimate VS content due to loss of volatile organic compounds, and incomplete chemical oxidation may lead to underestimation of COD content. Bomb calorimetry is an attractive alternative to COD measurements, because the physical state of the biomass sample does not influence the measurement, and because sample preparation is limited. In this study, 11 biomass samples, wet and dry, were analyzed with different methods for organic content determination. COD (determined by bomb calorimetry and by wet chemistry) and VS (by Karl Fischer titration and loss on drying; LOD) were compared, and used for determination of BMP. In general, the BMP estimated on a VS basis were higher than those estimated on COD basis. For certain biomass samples the method for VS determination also greatly influenced the results; for fishery waste the BMP was estimated as 928 L kg−1 based on LOD-VS compared to 394 L kg−1 based on KF-LOD. Thus, this study shows that determination of organic content is not trivial and the method of choice strongly influences the estimation of bio-methane potentials. Bomb calorimetry offers a possibility to measure energy content directly, independent of biomass composition and physical state.
Sammendrag
Pine wood nematode (PWN), Bursaphelenchus xylophilus, is a threat for pine species (Pinus spp.) throughout the world. The nematode is native to North America, and invaded Japan, China, Korea, and Taiwan, and more recently Portugal and Spain. PWN enters new areas through trade in wood products. Once established, eradication is not practically feasible. Therefore, preventing entry of PWN into new areas is crucial. Entry risk analysis can assist in targeting management to reduce the probability of entry. Assessing the entry of PWN is challenging due to the complexity of the wood trade and the wood processing chain. In this paper, we develop a pathway model that describes the wood trade and wood processing chain to determine the structure of the entry process. We consider entry of PWN through imported coniferous wood from China, a possible origin of Portuguese populations, to Europe. We show that exposure increased over years due to an increase in imports of sawn wood. From 2000 to 2012, Europe received an estimated 84 PWN propagules from China, 88% of which arose from imported sawn wood and 12% from round wood. The region in Portugal where the PWN was first reported is among those with the highest PWN transfer per unit of imported wood due to a high host cover and vector activity. An estimated 62% of PWN is expected to enter in countries where PWN is not expected to cause the wilt of pine trees because of low summer temperatures (e.g., Belgium, Sweden, Norway). In these countries, PWN is not easily detected, and such countries can thus serve as potential reservoirs of PWN. The model identifies ports and regions with high exposure, which helps targeting monitoring and surveillance, even in areas where wilt disease is not expected to occur. In addition, we show that exposure is most efficiently reduced by additional treatments in the country of origin, and/or import wood from PWN-free zones. Pathway modelling assists plant health managers in analyzing risks along the pathway and planning measures for enhancing biosecurity.
Forfattere
Linda Meyer-Veltrup Christian Brischke Gry Alfredsen Miha Humar Per Otto Flæte Tord Isaksson Pia Larsson Brelid Mats Westin Jöran JermerSammendrag
Comprehensive approaches to predict performance of wood products are requested by international standards, and the first attempts have been made in the frame of European research projects. However, there is still an imminent need for a methodology to implement the durability and moisture performance of wood in an engineering design method and performance classification system. The aim of this study was therefore to establish an approach to predict service life of wood above ground taking into account the combined effect of wetting ability and durability data. A comprehensive data set was obtained from laboratory durability tests and still ongoing field trials in Norway, Germany and Sweden. In addition, four different wetting ability tests were performed with the same material. Based on a dose– response concept, decay rates for specimens exposed above ground were predicted implementing various indicating factors. A model was developed and optimised taking into account the resistance of wood against soft, white and brown rot as well as relevant types of water uptake and release. Decay rates from above-ground field tests at different test sites in Norway were predicted with the model. In a second step, the model was validated using data from laboratory and field tests performed in Germany and Sweden. The model was found to be fairly reliable, and it has the advantage to get implemented into existing engineering design guidelines. The approach at hand might furthermore be used for implementing wetting ability data into performance classification as requested by European standardisation bodies.