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.
2012
Abstract
In South-east Norway, several scattered observations of reduced growth and dieback symptoms were observed over the last 20 years in 40-60 years old Norway spruce (Picea abies) trees. Typical symptoms start with yellowing in the top and subsequent dieback downwards from the top. These symptoms are often combined with bark beetle (Ips typographus), honey fungus (Armillaria spp.) infections, and a sudden decrease in diameter and height growth. After about 1-5 years, most of the symptomatic trees are dead.We selected 11 representative stands in six counties. In each stand all trees in ten 250 m2 plots were evaluated, in total about 4000 trees. In each of these 110 plots, one symptomatic and one non-symptomatic tree were investigated in more detail. We measured tree diameter, height, took increment cores and assessed crown condition, wounds, resin flow, stem cracks, bark beetle infection and Armillaria presence. In addition, internode lengths of the last 20 years were measured in two of the stands.Preliminary results of internode lengths and increment cores showed a sudden decrease of height and diameter growth in the symptomatic trees. Many of these trees had a secondary infection of bark beetles and Armillaria. Some years appear to be typical problem years for many of the trees. These years also correspond with summer drought, i.e. negative Palmer drought severity indexes which were estimated for each stand. In comparison, the non-symptomatic trees, growing close to the symptomatic ones, showed none or minor growth reductions and discolouration.Climate change and increased summer drought may worsen spruce dieback problems. Management adaptions are uncertain. We conclude that Norway spruce is sensitive to drought, which reduce the growth and weaken the health, and probably reduce the defence against secondary infections.
Authors
Nicholas ClarkeAbstract
This report presents preliminary results from investigations on changes in soil water chemistry after stem-only and whole-tree harvesting at a site in eastern Norway, with emphasis on major nutrients, pH and dissolved organic carbon. For stem-only harvesting (SOH) and whole-tree harvesting where slash had been piled (WTH pile), concentrations of nitrate, calcium, magnesium, and potassium peaked in the second year after harvesting and again, but lower, in the third. Ammonium concentrations peaked in the year after harvesting. There was slight acidification after harvesting. No increased concentrations of dissolved organic carbon were observed. In general, trends were similar between SOH and WTH piles, compared to where slash had been removed to form the piles. Peaks in concentrations were higher for WTH piles compared to SOH. The results agree well with results from other field measurements reported in the scientific literature.
Authors
Nicholas ClarkeAbstract
This report aims to summarise briefly the findings in the scientific literature concerning the effect of both stem-only and whole-tree harvesting on soil carbon stocks. Although the findings reported by previous authors vary, it is possible to draw some general conclusions about the effect of harvesting on soil carbon, and on whether whole-tree harvesting has a greater effect than stem-only harvesting. In general it appears that the organic C content in the soil’s organic layer is reduced after stem-only harvesting, sometimes by as much as 50%. This reduction has been explained in several ways. After a period of maybe 20 years, the carbon content of the organic layer starts to increase again. In the mineral soil a reduction is not always apparent and the C content can even increase, probably because of the incorporation of residues into the soil. Some studies have shown that this increase is short-lived, while others have found a longer-term increase. Unsurprisingly, thinning appears to affect the soil carbon content much less than clear-cutting; the effect tends to be proportional to the thinning intensity. The soil carbon content appears to be higher after selection cutting than after clear-cutting. Studies comparing effects of whole-tree harvest with those of stem-only harvest have tended to show smaller carbon contents in the mineral soil after whole-tree harvest than after stem-only harvest, although once again results vary greatly. There are many factors affecting soil C content and thus accounting for the observed differences, including temperature, moisture content, and harvesting type. Variation in the results obtained may depend on site-specific factors such as site nutrient status, especially with regard to the most common limiting nutrient nitrogen, which will affect growth in the next rotation. Making sure there are enough nutrients available, if necessary by compensatory fertilisation, will improve carbon sequestration in both trees and soil.
Abstract
A proposal for a web-based platform for scientific exchange of test data in the field of wood durability and wood protection has been made. The overall aim of the durability data base is to improve the usability of existing test data and to create an added value for durability research and service life prediction. The database allows for test results from standardized and non-standardized laboratory and field tests. Natural durable timber, preservative and water-repellent treated timber, chemically and thermally modified timber as well as composites have been considered. Finally all types of decay organisms and other degrading agents are regarded.
Abstract
During the last decade wood modification has become a recognized method for delivery of enhanced timber. Hence, a range of studies have been performed to evaluate the decay resistance of modified wood. High resistance of modified wood against fungal decay is assumed to be due to changes in the wood properties rather than a toxic effect on fungal physiology. This is an advantage due to the concern from the European Union, national movements and society in general about the environmental impact of wood protection is increasing. In this paper we aimed to quantitatively summarise the performance of the different types of modified wood. However, this turned out only to be possible for acetylation. This was due to the format of the published data, variation in treatment processes and wood species used for the other treatments. For acetylated wood statistical analyses based on previously published data were performed to quantify what factors contribute most to the performance (calculated as test sample/control). The results showed that WPG can explain approximately 50 % of the performance, measured as test sample/control (T/C), for acetic anhydride treated wood. Other of the applied variables, like wood species or type of fungus can reduce the variance in T/C by additional 15 %. In addition, the paper highlight future research opportunities related to fungal deterioration of modified wood.
Abstract
This report has been prepared in the frame of Work Package 3 (Policy) of the Interreg IVB project Bioenergy Promotion. The main rationale of this work package is to support the development of coherent national and (sub)regional policies promoting the sustainable production and consumption of bioenergy. The purpose of the country policy assessment report is to describe the main promotional policies and support schemes for bioenergy and to assess to what extent national policy frameworks contribute to Sustainable Development and integrate related sustainability principles and criteria. At present and in the foreseeable future, the main source of raw materials for bioenergy in Norway is likely to be the forests. However, waste from agriculture, households and industry is another promising source. Investment support needs to be continued, at least at present levels. The main bottlenecks for increased use of bioenergy in Norway are economic, so economic support is necessary. Further development of the standard for sustainable forestry is required, in order to take into account aspects that are not yet covered (see above under Point 3.5). However, there is currently disagreement between the parties to the Living Forests standard, so revision is not likely to take place soon. Current research is being carried out, for example in CenBio and the project “Ecological consequences of increased biomass removal from forests in Norway” on the effects of whole-tree harvesting compared to stem-only harvesting on soil nutrients, carbon stocks, ground vegetation and regeneration). In addition, work is being carried out to study the applicability under Norwegian conditions of the guidelines of other countries such as Sweden, Finland, the UK and Ireland and to prepare preliminary guidelines for Norwegian forestry. There is disagreement on the likely short-term effects of biomass harvesting for bioenergy on carbon sequestration in forest ecosystems (see above under 5.2) and this needs to be further studied. In their present form, the binding EU sustainability criteria for biofuels/bioliquids should not be extended to solid/gaseous biomass used for electricity and heating/cooling. Some changes are necessary to take account of specific conditions e.g. in forestry. For example, it is stated in Point 4 of Article 17 of the Renewable Energy Directive that biofuels and bioliquids shall not be obtained from land that was continuously forested in January 2008 and is no longer continuously forested. It is unclear how this would affect clear-cuts. Also, in Point C7 of Annex V, the 20-year period for calculating carbon stock changes is completely unrealistic for forestry (although this refers to land-use change and it could be argued that felling is not land-use change if the land is used for forest afterwards; this should be clarified). These aspects of the Renewable Energy Directive are already problematic if forest biomass is to be used for biofuels or bioliquids.
Abstract
Our aim is to investigate the temporal dynamics of the Fraction of Absorbed Photosynthetically Active Radiation (fAPAR) on a global scale and its relation to the main meteorological variables across space. We focus on complex patterns in time, which are neither regular (trend and seasonality) nor random (noise), but somewhere in between. We quantify complexity and information content or entropy using methods from order statistics and complexity sciences.Time series with high entropy are difficult to predict, whereas time series with high complexity are difficult to describe. This leads to a spatially explicit characterization of complex patterns in a very sensitive way. We use FAPAR observations (SeaWiFS and MERIS, 1998 to 2012) along with gridded global surface air temperature, precipitation and shortwave radiation.All these time series are explored on a pixelbypixel basis and clustered according to a very recent classification system of the land surface. In addition, we quantify the time reversal asymmetry of these data. We compare environmental time series with data from a stochastic candidate process temporally symmetric and long range correlated artificial knoise.Results were plotted in the ComplexityversusEntropy plane (CH plane), showing the particular footprint of each variable in a very sensitive way. Visualized in world maps, results revealed unexpected complex pattern in some dry regions, in particular on pixels surrounding deserts and in eastern Sahara. In this respect, the results provide a new classification of the climate and the biosphere. http://dames.pik-potsdam.de/Abstracts.pdf
Authors
Felix Herzog Michaela Arndorfer Debra Bailey Katalin Balázs Peter Dennis Tetyana Dyman Wendy Fjellstad Jürgen Friedel Salah Garchi Ilse Geijzendorffer Philippe Jeanneret Rob Jongman Maximilian Kainz Luisa Last Gisela Lüscher Gerardo Moreno Charles Nkwiine Maurizio Paoletti Philippe Pointereau Jean-Pierre Sarthou Siyka Stoyanova Stefano Targetti Davide ViaggiAbstract
No abstract has been registered
Authors
Hanne Gro Wallin Gunnar EnganAbstract
An overall societal aim is to ensure a sustainable use and management of agricultural landscapes. This requires continuous delivery of reliable and up-to-date information to decision-makers. To be able to deliver this information, a monitoring program for agricultural landscapes was initiated in Norway 13 years ago. The program documents and reports on land use / land cover changes from data captured through interpretation of true colour aerial photos using stereo instruments. The monitoring programme is based on a sample of 1000 squares of 1 x 1 km and the entire sample of squares is photographed over a five-year period. Each square is then mapped repeatedly every fifth year to record changes. Aerial photo interpretation is based on a custom classification system which is built up hierarchically, with three levels. The first level comprises seven land type classes: Agricultural land, Bare ground, Semi-natural open vegetation, Unforested wetland vegetation, Forest, Urban areas and Water. These land classes are further divided into 24 land types at level two, and approximately 100 land types at level 3. In addition to land type units we map both line elements like stone fences and point elements like buildings and solitary threes. By use of indicators that describe status and change focusing on themes of particular policy interest, we can report on whether policy aims are being fulfilled or not. Four indicator themes have been in focus hitherto: landscape spatial structure, biological diversity, cultural heritage and accessibility. Our data is stored in databases and most of the data quality check/structure process and analyses are now being made in open source software like PostGIS and PostSQL. To assess the accuracy of the photo-interpretation, ground truthing is carried out on 10 % of the squares. The results of this operation document the benefits of having access to photos of the same area from two different years. The program is designed first and foremost to provide reliable statistics at a national level but the aim is also to report at regional levels – for example for counties or for agricultural landscape regions. The national coverage and application of standardized methods enable frequent updating. This method is cost effective and enables us to quantify changes in landscape qualities as well as adapting the programme to take account of e.g. new findings on relevant indicators.
Abstract
The use of wood in outdoor constructions has long traditions in Norway. In the last decade, the environmentally demands for wood protective systems has become stricter. At the same time, new design solutions are arising that will challenge the decay protection in outdoor constructions. In this article, the potential for antioxidants as a wood protective agent was tested. Both natural and synthetic antioxidants have been used. All samples achieved a sufficient uptake of impregnation agent, and all the tested products showed a reduction in wood decay rate compared to the control. The protections by the antioxidants are more effective against brown rot fungi, than white rot fungi. The synthetic antioxidants stop the fungal degradation of the brown rot fungi, and should be considered as an additive in future and existing wood protective systems.