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.
2014
Abstract
This study presents the analysis of panel data on steep terrain logging productivity in Norway. Given the specification of a Cobb Douglas stochastic frontier production function in which the technical inefficiency is a function of six different environmental factors, it was found that only one (terrain hindrance) decreased the efficiency significantly. The estimated efficiencies for the sample crews ranged from 0.43 to 0.99. Because of the nature of the inefficiency factors, one way to improve the efficiency could be to train the crews for working on steep slopes. This would also improve the safety when exposing workers to these types of environmental hazards.
Authors
Maria Magdalena Estevez Roar Linjordet Svein Jarle Horn John MorkenAbstract
No abstract has been registered
Abstract
Variable retention harvesting is acknowledged as a cost-effective conservation measure, but previous studies have focused on the environmental value and planning cost. In this study, a model is presented for optimizing harvesting cost using a high resolution map generated from airborne laser scanning data. The harvesting cost optimization model is used to calculate the objective value of different scenarios. By comparing the objective values, better estimates of the opportunity cost of woodland key habitats are found. The model can be used by a forest manager when evaluating what silvicultural treatments to implement or as an input for improving the nature reserve selection problem for woodland key habitats or retention patches. The model was tested on four real-world cases, and the results indicate that terrain transportation costs vary more than reported in the literature and that it may be worthwhile to divide the opportunity cost into its direct and indirect components.
Authors
Nils Egil SøvdeAbstract
Ground based systems are the main approach used for off-road timber transportation throughout the world. Estimates of terrain transportation costs are required for several forest planning problems and for assessment of harvesting contracts and forest land values. Methods for these calculations can be categorized into two groups. Methods based on average transportation distance predate computers, are analytical, and based on manual calculations. Network methods are based on a digital raster representation and are solved with numerical computations. Here, the two categories are compared and linked. Analytical methods in the literature have been limited to flat terrain and including detail is difficult. The network method can be extended to include uneven terrain or detailed input data.
Abstract
No abstract has been registered
Authors
Gunvor Elise Nagel-Alne Leif Jarle Asheim J. Brian Hardaker Liv Sølverød Dag Lindheim Paul Steinar ValleAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Lynne Boddy Ulf Büntgen Simon Egli Alan C. Gange Einar Heegaard Paul M. Kirk Aqilah Mohammad Håvard KauserudAbstract
No abstract has been registered
Abstract
Since the late nineteenth century when high-cost equipment was introduced into forestry there has been a need to calculate the cost of this equipment in more detail with respect to, for example, cost of ownership, cost per hour of production, and cost per production unit. Machine cost calculations have been made using various standard economic methods, where costs have been subdivided into capital costs and operational costs. Because of differences between methods and between national egulations, mainly regarding tax rules and subsidies, inter-national comparisons of machine costs are difficult. To address this, one of the goals of the European Cooperation in Science and Technology (COST) Action FP0902 was to establish a simple format for transparent cost calculations for machines in the forest biomass procurement chain. A working group constructed a Microsoft Excel – based spreadsheet model which is easy to understand and use. Input parameters are easy to obtain or possible to estimate by provided rules of thumb. The model gives users a simultaneous view of the input parameters and the resulting cost outputs. This technical note presents the model, explains how the calculations are made, and provides future users with a guide on how to use the model. Prospective users can view the model in the Supplementary Material linked to this article online
Authors
Kari Marie Njåstad Steffen Adler Jens Hansen-Møller Erling Thuen Anne-Maj Gustavsson Håvard SteinshamnAbstract
Dietary phytoestrogens are metabolized or converted in the gastrointestinal tract of ruminants, only limited knowledge exists on the extent and location of this conversion in vivo. The objective of this study was to quantify the gastro-intestinal metabolism of phytoestrogens in lactating dairy cows fed silages with different botanical composition. Four lactating rumen cannulated Norwegian Red cattle were assigned to a 4 × 4 Latin square with 1 cow per treatment period of 3 wk. The 4 treatment silages were prepared from grasslands with different botanical compositions: organically managed short-term timothy (Phleum pratense L.) and red clover (Trifolium pratense L.) ley (2 yr old: ORG-SG); organically managed long-term grassland with a high proportion of unsown species (6 yr old; ORG-LG); conventionally managed perennial ryegrass (Lolium perenne L.) ley (CON-PR); and conventionally managed timothy ley (CON-TI). The herbages were cut, wilted, and preserved with additive in round bales, fed as a mix of the first and third cut at 90% of ad libitum intake, and contributed to 70% of the total dry matter intake. Milk, feed, omasal digesta, urine, and feces were collected at the end of each period and analyzed for the concentrations of phytoestrogens by using a liquid chromatography–tandem mass spectrometry technique. Concentration of total isoflavones was highest in ORG-SG and lowest in CON-TI silage, whereas the content of total lignans was highest in the grass silages. The isoflavones were extensively metabolized in the rumen on all diets, and the recovery of formononetin and daidzein in omasum, mainly as equol, averaged 0.11 mg/mg. The apparent intestinal metabolism was less severe as, on average, 0.29 mg/mg of the omasal flow was recovered in feces. The plant lignans were also strongly degraded in the rumen. However, the flow of lignans to omasum and excretion in feces were, on average, 7.2- and 5.2-fold higher, respectively, than the intake of the plant lignans matairesinol and secoisolariciresinol, known as precursors of mammalian lignans. Thus, excretion to milk could not be directly related to intake, implying that plant lignans other than matairesinol and secoisolariciresinol in forage are precursors for enterolactone production in the rumen and for its content in milk. Equol followed mainly the flow of large particles out of the rumen, whereas the mammalian lignans were distributed between phases proportional to dry matter flow. The main metabolism of phytoestrogens occurred in the rumen and the main route of excretion was through feces and urine, with only a small part being excreted in milk. The concentration of phytoestrogens in milk can be manipulated through intake but the intermediate transfer capacity to milk appears to be limited by saturation