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.
2007
Authors
Cecil C. Konijnendijk Anders Busse Nielsen Jasper Schipperijn Yngve Rosenblad Heldur Sander Mikk Sarv Kirsi Mäkinen Liisa Tyrväinen Janis Donis Vegard Gundersen Ulrika Åkerlund Roland GustavssonAbstract
A review of research and research needs in urban forestry was carried out in Denmark, Estonia, Finland, Latvia, Norway and Sweden during 2005. A questionnaire addressing post-2000 and ongoing research was sent to 146 researchers and generated 76 completed questionnaires. Universities were found to lead urban forestry research, while municipalities headed funding organisations in terms of number of projects funded. Planning, ecological and management aspects were the most common research themes, but socially oriented research also played an important role. The research needs questionnaire was sent to 192 key research actors (assignors, users and researchers), resulting in 63 completed needs assessments. The research themes of ‘urban forest management\", ‘social and cultural values\" and ‘urban forest and green planning\" were prioritised for future research. Comparison of ongoing research and research needs showed discrepancies, as ongoing research does not always cover the same themes identified as primary research needs. Priorities for future research as identified by the research community respective those assigning and using research also differed. Economic assessment of benefits, for example, scored much higher as a need among researchers than other respondents. In terms of present weaknesses in the research ‘infrastructure\", research actors emphasised lack of funding, fragmentation of research and insufficient critical mass. The region\"s urban forestry research can be enhanced and made more meaningful by strengthening national and international networking within the research community, across disciplines, as well as between researchers and those commissioning and using research.
Authors
Kristoffer Segerholm Roger Rowell Pia Larsson-Brelid Magnus Wålinder Mats Westin Gry AlfredsenAbstract
No abstract has been registered
Authors
Svein Solberg Lars Eklundh Arnt Kristian Gjertsen Tomas Johansson Steve Joyce Holger Lange Erik Næsset Håkan Olsson Yong Pang Anne SolbergAbstract
The REMFOR project evaluates remote sensing data and methods for monitoring forest health using variation in leaf area index (LAI) as a primary measure of defoliation. A large-scale pine sawfly outbreak in Norway serves as a test case. An LAI map of the study area was derived from airborne LIDAR measurements before and after the insect attack to serve as ground truth for satellite image analysis. The method predicts LAI from laser penetration rates through the canopy layer in accordance with the Beer- Lambert law calibrated with point measurements of LAI with LICOR LAI-2000. Comparing two cloud-free SPOT scenes from September 2004 and September 2005 shows obvious visual patterns of defoliation in pine forests from the 2005 outbreak. Preliminary analysis shows that the insect defoliation caused an increase in middle-infrared (SPOT band4) reflectance and a decrease in SPOT NDVI, and both these responses may be used as a reasonable predictor of LAI loss as derived from laser scanning. MODIS NDVI data were gathered for the area over the period 2000-2006, and the Timesat algorithm is used to smooth the seasonal variation. The insect attack is evident from the smoothed NDVI data both as a reduction in the summer mean value, and as an alteration of the seasonal profile during the larvae feeding period in June and July. REMFOR also encompasses a range of other remote sensing data types, including GLAS LIDAR, SAR and hyperspectral data from both airborne and satellite platforms (e.g. Hyspex and Hyperion). Landsat TM is used to generate a tree species map.
Abstract
No abstract has been registered
Abstract
In the context of an ongoing project on REMote sensing of FORest health (REM-FOR), we analyze airborne high-resolution hyperspectral images of a pine-dominated region in southeast Norway heavily attacked by the Pine sawfly Neodiprion sertifer, leading to severe defoliation. Leaf Area Index (LAI) is used as a proxy of the crown density, and comparing LAI maps from before and after the attack lead to indicators for damage extent. We discuss the application of the Forest Reflectance Model (FRT) of Kuusk and Nilson, which was designed for the application to (managed) Northern European Forests, to model the spectral response from the canopy. It is based on conventional forest inventory data, species-dependent parametrized crown shapes, canopy LAI, needle clumping index, and needle optical properties. Here, however, we run the model in an inverse mode, by iteratively minimizing the discrepancy between measured and simulated reflectances, and predicting the LAI, keeping known parameters of the model fixed. The LAI values are then compared to those obtained with either ground-based Licor LAI2000 measurements, or with airborne laser-scanning. Some preliminary results of this modelling concept for the case study are discussed.
Authors
Isabelle Schülli-Maurer Daniela Sauer Karl Stahr Ragnhild Sperstad Rolf SørensenAbstract
We investigated the development of Albeluvisols and Podzols with time in southern Norway. The Vestfold region at the western shore of the Oslofjord was chosen because it is characterized by continuous glacio-isostatic uplift for the last 12,000 years. Due to the permanent elevation process, no distinct marine terraces have been built, and the age of the sediments continuously increases with distance from the modern coastline. Albeluvisol development was assessed in a soil chronosequence on loamy marine sediments with ages ranging from approximately 1,800 to 10,200 years. The most obvious change during soil development was that after 4,500 - 5,000 years light tongues intruded from the E horizon into the B horizon, and became more pronounced with time. The combined thickness of the A and E-horizons was constant at 40 ± 3 cm in 9 of the 12 profiles and did not change with age. The organic matter content of the A-horizons, the fine silt to coarse silt ratio of the Btg horizons and the Feo/Fed ratio all decreased with soil age, whereas the thickness of the organic surface horizon and B horizon, as well as the Fed/Fet ratio all increased. Podzol development was investigated in a chronosequence on sandy beach sediments, the ages of the soils ranging from 2,400 to 8,500 years. All soil properties investigated - the organic matter content of the B horizons, clay content, Feo, Alo, Sio, Feo/Fed and Fed/Fet - tend to increase with advancing podzolization, and are strongly correlated with soil age. Topsoil pH values decrease with age. The characteristic Bh and Bs horizons had developed after approximately 4,000 years.
Authors
Daniela Sauer Isabelle Schülli-Maurer Ragnhild Sperstad Rolf Sørensen Karl StahrAbstract
The coastal areas of Scandinavia provide suitable conditions for studying soil development with time, due to glacio-isostatic uplift. Our study area is located along both sides of the Oslofjord (Vestfold and stfold). The climate in this area is rather mild although it is located between 59 and 59 40 latitude. The mean annual temperature ranges from 5.4 to 6. 0 C. Precipitation is 9751094 mm year1 in Vestfold and 751829 mm year1 in stfold. Due to the steadiness of the uplift, no separate terraces were formed in the study area, but soils continuously get older from the coast inland. We established two soil chronosequences comprising six pedons each, one in Vestfold (1650 9000 years) and one in stfold (300011050 years). The ages were estimated by use of several sea level curves established for various locations in the area, based on calibrated radiocarbon datings. The parent material is loamy marine sediment. The geological basement below the sediment consists of basic magmatite (monzonite, latite) in Vestfold and predominantly acid magmatite (granite) in stfold. Higher precipitation in Vestfold leads to earlier beginning of clay illuviation. Clay coatings are perceptible in Vestfold already in the 1650 years old soil. In stfold they become visible for the first time in the 3500 years old soil. The E horizon becomes lighter with age, but its thickness stays constantly around 40 cm in both areas. The development of the characteristic albeluvic tonguing starts after 4000 to 5000 years. The tongues initially develop mainly along intersections of cracks. Due to ongoing leaching they increase in length and width, progressively consuming the prisms in between the cracks in the upper part of the Bt horizon. Base saturation in the upper 25 cm exhibits a decrease with time which can be best described by an exponential model, while pH (water) stays constantly at pH 4.4 0.4 in all soils covering a range of 1650 to 11050 years in age. These findings indicate that the soil pH is buffered by protonation of surface charges occupied by exchangeable base cations over a time span of more than 9000 years. The Fed/Fet ratio shows an increase with time which can be described by both, a linear or potential model, reflecting progressive iron release from mineral weathering. The Feo/Fed ratio shows a linear decrease indicating increasing degree of iron oxide crystallization.
Authors
Gerhard Weiss Suzanne Martin Anne Matilainen Birger Vennesland Carmen Nastase Erlend Nybakk Laura BouriaudAbstract
This article examines innovation processes in forest recreational services on the basis of case studies in five European countries with differing institutional backgrounds of forest ownership and access rights. The analysis reveals that forest-related recreation services are developed under varying institutional conditions and on public as well as private land. Ideas for innovations in recreational services may come from within but often outside the forestry sector. Financing is provided from public and private sources. Both public and private spheres have important roles in providing natural, human and financial resources and usually a network of public and private actors are involved in innovation processes. Of particular importance are cross-sectoral interactions between forestry and tourism. Greater institutional support is needed for the development of forest-related recreation services because the field is at an early stage of development. It is concluded that support should focus on providing ideas and financial resources for product development and on facilitating cross-sectoral interaction between forestry and tourism actors. A particular need is seen for development of models for durable interaction between land owners and tourism operators on a regional scale.
Authors
Jørn Kristian LilengAbstract
No abstract has been registered
Authors
O. Janne Kjønaas Richard Frederic WrightAbstract
To determine the source of dissolved inorganic nitrogen (N) in runoff, approx. 35 kg N enriched with the stable isotope 15N (2110‰ δ15N) was added to a mature coniferous forested catchment for one whole year. The total N input was approx. 50 kg ha-1 year-1. The enrichment study was part of a long-term whole-catchment ammonium nitrate addition experiment at Gårdsjön, Sweden. The 15N concentrations in precipitation, throughfall, runoff and upper forest floor were measured prior to, during, and 3-9 years following the 15N addition. During the year of the 15N addition the δ15N level in runoff largely reflected the level in incoming N, indicating that the leached NO3- came predominantly from precipitation. Only 1.1% of the incoming N was lost during the year of the tracer addition. The cumulative loss of tracer N over a 10-year period was only 3.9% as DIN and 1.1% as DON.