Mapping forest age using National Forest Inventory, airborne laser scanning, and Sentinel-2 data

The age of forest stands is critical information for many aspects of forest management and conservation but area-wide information about forest stand age often does not exist. In this study, we developed regression models for large-scale area-wide prediction of age in Norwegian forests. For model development we used more than 4800 plots of the Norwegian National Forest Inventory (NFI) distributed over Norway between 58{\deg} and 65{\deg} northern latitude in a 181,773 km2 study area. Predictor variables were based on airborne laser scanning (ALS), Sentinel-2, and existing public map data. We performed model validation on an independent data set consisting of 63 spruce stands with known age. The best modelling strategy was to fit independent linear regression models to each observed site index (SI) level and using a SI prediction map in the application of the models. The most important predictor variable was an upper percentile of the ALS heights, and root-mean-squared-errors (RMSE) ranged between 3 and 31 years (6% to 26%) for SI-specific models, and 21 years (25%) on average. Mean deviance (MD) ranged between -1 and 3 years. The models improved with increasing SI and the RMSE were largest for low SI stands older than 100 years. Using a mapped SI, which is required for practical applications, RMSE and MD on plot-level ranged from 19 to 56 years (29% to 53%), and 5 to 37 years (5% to 31%), respectively. For the validation stands, the RMSE and MD were 12 (22%) and 2 years (3%). Tree height estimated from airborne laser scanning and predicted site index were the most important variables in the models describing age. Overall, we obtained good results, especially for stands with high SI, that could be considered for practical applications but see considerable potential for improvements, if better SI maps were available

Single vortices observed as they enter NbSe2_2

We observe single vortices as they penetrate the edge of a superconductor using a high-sensitivity magneto-optical microscope. The vortices leap across a gap near the edge, a distance that decreases with increasing applied field and sample thickness. This behaviour can be explained by the combined effect of the geometrical barrier and bulk pinning.Comment: 2 pages, 1 figure, M2S-Rio proceeding

Fiscal policy in United States and value added tax

Die vorliegende Arbeit befasst sich mit dem Thema der Fiskalpolitik in den USA. Als einziges Mitglied der Organisation für wirtschaftliche Zusammenarbeit und Entwicklung (OECD) haben die Vereinigten Staaten keine federale Umsatzsteuer (bzw. Mehrwertsteuer). Wie ist es dazu gekommen, dass es gerade in den USA die weltweit populäre Steuer nicht gibt? Wäre es nicht vorteilhaft für die USA diese Steuer somit einzuführen? Was hat die Einführung von Mehrwertsteuer bis jetzt verhindert und welche Hürden würden ihr im Wege stehen - das sind die Kernfragen dieser Magisterarbeit. Um die Fragen zu beant- worten wird zuerst Fiskalpolitik und Mehrwertsteuer erläutert - und das unter Berücksichtigung von relevanten Gegebenheiten politischer Natur.This thesis discusses the idea of introducing Value Added Tax in United States. As the only OECD member, the US has not adopted VAT yet, a tax which since its introduction in late 1950s/ early 1960s can be found in nearly 160 countries. Does United States need a (federal) VAT, could it possibly benefit from its introduction? These questions gain in importance when paired with current economic stance of the US and future fiscal obligation on the horizon. In order to answer these and other questions fiscal policy and consumption taxes are discussed together with relevant political circumstances

Building a high-resolution site index map using boosted regression trees: The Norwegian case

Accurate estimation of site productivity is essential for forest projections and scenario modelling. We present and evaluate models to predict site index (SI) and whether a site is productive (potential total stem volume production ≥ 1 m3·ha−1·year−1) in a wall-to-wall high-resolution (16 m × 16 m) SI map for Norway. We investigate whether remotely sensed data improve predictions. We also study the advantages and disadvantages of using boosted regression trees (BRT), a machine-learning algorithm, to create high-accuracy SI maps. We use climatic and topographical data, soil parent material, a land resource map, and depth to water, together with Sentinel-2 satellite images and airborne laser scanning metrics, as predictor variables. We use the SI observed at more than 10 000 National Forest Inventory (NFI) sample plots throughout Norway to fit BRT models and validate the models using 5822 independent temporary plots from the NFI. We benchmark our results against SI estimates from forest monitoring inventories. We find that the SI from BRT has root mean squared error (RMSE) ranging from 2.3 m (hardwoods) to 3.6 m (spruce) when tested against independent validation data from the NFI temporary plots. These RMSEs are similar or marginally better than an evaluation of SI estimates from operational forest management plans where SI normally stems from manual photo interpretation.publishedVersio

Real time magneto-optical imaging of vortices in superconductors

We demonstrate here real-time imaging of individual vortices in a NbSe2 single crystal using polarized light microscopy. A new high-sensitivity magneto-optical (MO) imaging system enables observation of the static vortex lattice as well as single vortex motion at low flux densities.Comment: 3 pages, 1 figur

Sentral organisering og prosjektledelse

Delrapport 2 analyserer og vurderer den sentrale organisering og prosjektledelse av Trosopplæringsreformen. Rapporten tar for seg perioden fra Stortingsbehandlingen våren 2003 til våren 2005