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.
2005
Authors
Bjørn ØklandAbstract
Ips typographus is considered the most destructive of the bark beetles in the coniferous forests of the Palaearctic region. At low population densities this species breeds in fresh windfalls or dying trees of Norway spruce. At high densities, in contrast, the beetles may show tree-killing outbreaks at regional scales. Spatio-temporal analyses based on pheromone trap data indicated that large windfall events may be a major instigator and synchronizer of beetle outbreaks in areas subjected to regionalized weather systems. The general dominance of lag 1 density dependence of the time series indicated that the beetle populations are constrained by intraspecific competition for breeding substrates. The time series sequence before the large windfelling of 1987 was however declining without significant density dependence. We suggest this to be a transition period, reflecting a drop in carrying capacity due to depletion of susceptible trees during the preceding outbreak period (1970s) and a drop in beetle number to below the density required to kill trees. A variety of organisms exhibit episodes of explosive population growth, triggered by disturbance events. A new general model is constructed to capture the coupling of disturbance events with resource accumulation / depletion. The model is refined and parameterized using the dynamics of the Ips typographus in Scandinavia as a model system. The waiting times between outbreaks of simulated time series were generally longer and more variable than the outbreak lengths, which agree well with the historical records in the last 250 years. Spectral analysis and logspline density plots of waiting times suggest that the transition from aperiodic to periodic population dynamics should be regarded as a continuum.
Authors
Inge Stupak Møller Karsten Raulund-Rasmussen Antti Asikainen Dominik Röser Anders Lunnan Erik Karltun M. Jonsell M. Schröder R. Ozolincius M. Mandre Talis Gaitnieks Ingeborg Callesen Nicholas Clarke Heljä-Sisko Helmisaari A. Indriksons Morten Ingerslev L. KairiukstisAbstract
The substitution of biomass for fossil fuels in energy consumption is a measure to mitigate global warming, and political action plans at European and national levels exist for an increased use. The use of forest biomass for energy can imply different economic and environmental advantages and disadvantages for the society, the energy sector and forestry. For the achievement of an increased and sustainable use of forest biomass for energy, the WOOD-EN-MAN project aimed at synthesis and creation of new knowledge within the field.
Authors
D. Tønnesen Tor Myking Ingvald Røsberg Nicholas Clarke Brit Lisa Skjelkvåle Øyvind Kaste Thorbjørn LarssenAbstract
Impact assessment for a proposed LNG plant has been carried out for three potential locations in northwest Russia. The impact from the plant is small, and the critical loads for terrestrial ecosystems and aquatic ecosystems will not be exceeded at any of the 3 locations.
Authors
Vegard GundersenAbstract
Det overordna målet med avhandlingen er å frembringe relevant kunnskap om urbane skoger i Norge. Artikkel I og II undersøker tilstand og forvaltningspraksis i urbane skoger. Jeg undersøker to faktorer som har vært viktig for forvaltningen av urbane skoger, folks preferanser for skog (Artikkel III) og naturskogens kontinuitet (Artikkel IV, V). Til slutt diskuterer jeg disse resultatene i forhold til Aldo Leopold ideer om hvordan estetikk og økologi kan integreres i forvaltningen (Artikkel VI, VII). Skog dekker dominerende arealer rundt de vel 900 byer og tettsteder i Norge, og urban skog dekker anslagsvis 2 % av det totale skogarealet. Selv om nesten 80 % av befolkningen har de urbane skogene som nærområde, angir avhandlingen at tilstand og forvaltning er ganske lik det øvrige skogarealet, og det fremkommer heller ingen vesentlig forskjell mellom byer og tettsteder. Tradisjonell forvaltningspraksis utviklet for landlige forhold dominerer også de urbane skogene. Avhandlingen diskuterer hvordan forvaltningen kan videreutvikles i urbane skoger, inkludert fokus på langsiktige visjoner for utvikling av urbane skoger ved bruk av en aktiv og dynamisk forvaltningstilnærming. Kunnskap fra preferanseundersøkelser kan brukes til å innarbeide generelle hensyn i skogskjøtselen. Folks preferanser for tilstander i naturskog er lite studert, men de studiene som finnes indikerer lav preferanseverdi. Avhandlingen diskuterer noen utfordringer i skogskjøtselen knyttet til konflikter mellom økologi og estetikk, der også forhold mellom skogens dynamikk og forvaltningen inngår. En konklusjon fra avhandlingen er at forvaltningen av urbane skoger bør videreutvikles på to nivåer: 1) generell soningsmodell for tilpasninger i forvaltningen til spekteret av verdier og funksjoner i urbane skoger, 2) stedstilpasset forvaltning, der skogeiere, forvaltere og lokalbefolkningen motiveres til en aktiv forvaltningspraksis som avtegner en signatur som klart viser at de bryr seg om stedet.
Authors
Anssi Niskanen Anders LunnanAbstract
Entrepreneurship can be defined as the process of transformation of new economic opportunities into values in the markets. It has become the engine of economic and social development throughout the world. Rural areas have some fundamental disadvantages for enterprises and entrepreneurship: they provide less skilled labor, less non-traded inputs to industry and at a higher cost, and finally but perhaps most importantly, rural areas are less attractive in terms of access to knowledge and information than concentrations of industries and population.Often the actions for new entrepreneurship in rural areas are targeted to the production and use of natural resources e.g. in agriculture, fishery, forestry, processing and nature-based tourism. Rural areas also have some fundamental advantages for enterprises and entrepreneurship as they provide cheap location for the enterprises, good quality of life for the employees and reliable unskilled labor.Entrepreneurship policies can be divided into policies that support the demand or supply for entrepreneurial activities.The (i) demand side policies aim to elaborate the opportunities to engage actors in entrepreneurial activity. They include, for example, deregulation of entry in the markets, privatization of public services and promotion of firm linkages or clustering. The (ii) supply side policies focus on promoting the capabilities of individuals and firms and facilitating access to resources, for example, via education and training, incubators, micro-credits and other financial incentives and various promo-campaigns. Entrepreneurship policy can also (iii) change the risk-reward profile of an entrepreneur by shaping taxes, subsidies, labor market rules and bankruptcy regulations. The aim of this paper is to consolidate the knowledge on the applied entrepreneurship policies (i-iii) in forestry in Finland, Norway, Japan, Australia, the Philippines and the United States. Aside this, the paper aims for identifying research needs and gaps of knowledge on forest sector entrepreneurship to suggest approaches for future research.
Authors
Karin Jacobs Brenda D. Wingfield Halvor Solheim Michael J. WingfieldAbstract
No abstract has been registered
Editors
Kåre HobbelstadAbstract
SNS-meeting 2004 in Nordic Forest Inventory was held at Sjusjøen, Norway, September 6-8, 2004. This publication is a collection of all the subjects dealt with at the meeting. The articles are written by the speakers on the meeting. The subjects were country and team reports, lidar measurements in forest inventory, national forest inventory, remote sensing studies, forest planning and current topics in forest modelling.
Abstract
We investigate ecosystem dynamics by analyzing time series of measured variables. The information content and the complexity of these data are quantifed by methods from information theory.When applied to runoff (stream discharge) from catchments, the information/complexity relation reveals a simple non-trivial property for a large ensemble (more than 1800) of time series. This behaviour is so far not understood in hydrology.Using a multi-agent network receiving input resembling rainfall and producing output, we are able to reproduce the observed behaviour for the first time. The reconstruction is based on the identification and subsequent replacement of general patterns in the input. We thus consider runoff dynamics as the expression of an interactive learning problem of agents in an ecosystem.
Authors
Jolanda Roux Halvor Solheim Michael J. WingfieldAbstract
No abstract has been registered
Authors
Lisbeth Mehli Trygve D. Kjellsen Frances M. Dewey Ari M. HietalaAbstract
Strawberry Fragariax ananassa (cv. Korona) was inoculated with Botrytis cinerea by dipping berries in a conidial suspension. The colonization of the pathogen was monitored with real-time PCR, ELISA and ergosterol assays, the first showing the highest sensitivity. The expression of pathogen -tubulin and six polygalacturonases (Bcpg1-6) and three host defense genes (polygalacturonase inhibiting protein (FaPGIP) and two class II chitinases) were monitored with real-time RT-PCR. The maximum transcript levels of the host defense genes occurred at 16 hours post inoculation (hpi), at the presumed initial penetration stage.The unique transcript profile of Bcpg2 over the 96-hour-long incubation time and its high transcript levels relative to those of the other Bcpgs at 8 to 24 hpi suggest that the gene has a specific role in the penetration stage.Bcpg1 was constitutively expressed at a relatively high level in actively growing mycelia throughout the experimental period. Comparison of the transcript profiles indicated that Bcpg1 and Bcpg3-6 were co-ordinately regulated.