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.
2010
Authors
Anders BrynAbstract
Extensive landscape and vegetation changes are apparent within southern Norway, specifically the expansion of forests into new areas and to higher altitudes. Two main processes are believed to cause these changes: regrowth after abandoned human utilisation and recent climate changes. The purpose of this article is to elucidate ways of separating the effects of these two processes on spatiotemporal changes in the upper forest limits using examples from southern Norway. Examples from two spatial scales are implemented, a vegetation map study of a mountain region in south-east Norway and a national map-based study of south Norway. The findings show that multiple methods are necessary to understand the forest limit changes and that the research focus should be on the separation of potential drivers, specifically climate improvements and land-use changes.
Authors
Svein Solberg Rasmus Astrup Dan Johan Weydahl Erik Næsset Terje Gobakken Ole Martin BollandsåsAbstract
There is an increasing need for forest resource monitoring methods, as more attention is paid to deforestation, bio-energy and forests as habitats. Most national forest inventories are based on networks of field inventory plots, sometimes together with satellite data, and airborne laser scanning (ALS) is increasingly used for local forest mapping. These methods are expensive to establish or carry out, and many countries, including some severely affected by deforestation, do not apply such methods.Satellite based remote sensing methods in use today are hampered by problems caused by clouds and saturation at moderate biomass levels. Satellite SAR is not hampered by cloud problems, and monitoring of canopy surface elevation, which is correlated to key forest resource variables, might be a future method in forest monitoring.We here present the main findings of three studies (Solberg et al. 2010, a, b, c) investigating the potential of interferometric SAR (InSAR) for forest monitoring, by describing the relationship between InSAR height above ground and key forest variables. We based this study on InSAR data from the Shuttle Radar Topographic Mission (SRTM) with its acquisition in February 2000. We obtained SRTM InSAR DEM data from DLR for two forest areas in Norway, and built a ground-truth from the combination of field inventory and ALS.The forest areas were dominated by Norway spruce and Scots pine. In each forest area we laid out a number of field inventory plots, where we recorded standard forest variables such as Dbh and tree height, and from this derived plot aggregated variables of top height, mean height, stand density (mean tree height divided by the mean tree spacing), volume and biomass. We used this to calibrate and validate ALS based models, from which we derived estimates of the same variables for each SRTM pixel. This served as reference data for the SRTM data.From the X-band SRTM digital surface model (DSM) image we subtracted a high quality digital terrain model (DTM) derived from the ALS data. This was based on an extraction of ground echoes from the data provider, and the elevations of these echoes were interpolated into a grid fitting the SRTM grid.This produced data on the RADAR echo height above ground (InSAR height), which we related to the forest variables. With digital stand maps we aggregated the variables to the stand level. The X-band microwaves penetrate a little into the canopy, and the InSAR height was on average about 1.2 m below the mean tree height. InSAR height was strongly related to all forest variables, most strongly to top height.Particularly valuable was that stem volume and biomass, ranging up to 400 m3/ha and 200 t/ha, respectively, were linearly related to InSAR height with an accuracy, RMSE, of 19% at the stand level. However, these relationships had an intercept, which represents the microwave penetration into the vegetation, and due to this the relationships were non-linear for forest stands having heights and biomass values close to zero.With a lower quality DTM derived from topographic maps, the relationships were weaker. However, as long as a forest variable is within the ranges of the linear relationship, any change in InSAR elevation would be proportional to a change in forest height, volume or biomass. And, any logging should be detectable as a sudden decrease in InSAR elevation.Hence, a forest monitoring based on X-band InSAR might be suitable even without a DTM. An application of space borne InSAR for forest monitoring would be feasible for large areas at low cost, whereas an ALS acquisition for a part of the area would serve as reference data for calibration.
Editors
Helmer BelboAbstract
The OSCAR network was formed in 2005 and includes five Nordic forest research institutes Metla (Finland), Mesäteho (Finland), Skogforsk (Sweden), Skov & Landskab (Denmark) and Skog og Landskap (Norway) and SILAVA (Latvia). The network is open for all relevant research bodies in the Nordic and Baltic countries. OSCAR is one of five virtual centres of advanced research financed by the Nordic Forest Research Cooperation Committee (SNS). The main target of OSCAR is increasing the excellence and critical mass of R&D within the field of forest operations research by integrating research resources and expertise, besides promoting and developing efficient, competitive and environmentally friendly forest operation systems on a joint Nordic basis....
Authors
John Marshall BrydenAbstract
No abstract has been registered
Authors
Lars Sekse Ursula WermundAbstract
No abstract has been registered
Authors
Chuan Li Heidi Rudi Jihong Liu Clarke Robert Wilson Robert Wilson M Cao Odd Arne RognliAbstract
No abstract has been registered
Authors
Rebekka ØvstegårdAbstract
Gender analysis is an important component of the Climarice project in order to better understand the ways in which women and men are differently affected by climate change and how they are adapting. During the current year, a preliminary analysis has been carried out on gender issues. This will be followed by a detailed study in 2011 in selected areas in Andhra Pradesh and Tamil Nadu. The expected outputs will provide more detailed analysis on gender differences and a better understanding of men and women’s vulnerabilities to climate change and clarify the special needs of men and women to adapt. The overall goal is to contribute towards developing appropriate strategies and policy to address gender issues in climate change.
Authors
Rebekka ØvstegårdAbstract
Gender analysis is an important component of the Climarice project in order to better understand the ways in which women and men are differently affected by climate change and how they are adapting. During the current year, a preliminary analysis has been carried out on gender issues. This will be followed by a detailed study in 2011 in selected areas in Andhra Pradesh and Tamil Nadu. The expected outputs will provide more detailed analysis on gender differences and a better understanding of men and women’s vulnerabilities to climate change and clarify the special needs of men and women to adapt. The overall goal is to contribute towards developing appropriate strategies and policy to address gender issues in climate change.
Abstract
No abstract has been registered
Authors
Hans Geir Eiken Rune Andreassen Alexander Kopatz I WartiainenAbstract
The use of non-invasive sampling of hairs and scats in wildlife genetics opens the possibility for sampling and analyzing living populations of brown bears (Ursus arctos). The aims of this study have been to develop a quality assured approach for genetic assignment of individual identity of brown bears and to generate a population database that can be used for research, conservation management and forensics. Non-invasive genetic sampling was performed by collection of scats and hairs in the field during the time period from 2004 to 2008. Hair traps were applied to collect hairs from bears in selected geographical areas in 2007 and 2008. Genotypes from 13 STR loci were determined for 232 Norwegian bears. Initial analysis of the entire sample indicated a high level of substructure, and the sample was divided in four geographically different populations consisting of 206 individuals for further validation of the markers. Ten STRs (G1D, G10L, Mu05, Mu09, Mu10, Mu15, Mu23, Mu50, Mu51 and Mu59) conformed to Hardy-Weinberg equilibrium expectations with only minor deviations, while the remaining three STR loci (G1A, Mu26 and G10B) were subjected to further molecular analysis. The average estimate of population substructure for Norwegian bears using 10 STRs (FST) was determined to be 0.1, while the estimate for inbreeding (FIS) was -0.02. Accounting for the FST-value, the average probability of identity (PIave) was 5.67 x 10-10 and the average probability of sibling identity (PIsib) was 1.68 x 10-4. Accreditation in accordance with the international standard ISO17025 was achieved for the described laboratory approach in 2009. We suggest that this approach and STR markers should also be considered to be used for other populations of brown bears in Northern Europe in order to ensure a common quality of the data as well as to facilitate exchange of information in conservation genetics.