Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2009
Forfattere
Nicholas Clarke O. Janne Kjønaas Wenche Aas Kjell Andreassen Isabella Børja Harald Bratli Susanne Eich-Greatorex Toril Drabløs Eldhuset Kjersti Holt Hanssen Holger Lange Tonje Økland Ingvald Røsberg Trine Aulstad Sogn Volkmar TimmermannSammendrag
In Norway, it is planned to double the stationary use of bioenergy from all sources by up to 14 TWh before 2020, with much of this increase coming from forest resources, including residues like branches and tops (which are not much used today) being removed after tree harvest. This removal will reduce the supply of nutrients and organic matter to the forest soil, and may in the longer term increase the risk for future nutrient imbalance, reduced forest production, and changes in biodiversity and ground vegetation species composition. However, field experiments have found contrasting results (e.g. Johnson and Curtis 2001; Olsson et al. 1996). Soil effects of increased biomass removal will be closely related to soil organic matter (SOM) dynamics, litter quality, and turnover rates. The SOM pool is derived from a balance between above- and below-ground input of plant material and decomposition of both plants and SOM. Harvest intensity may affect the decomposition of existing SOM as well as the build-up of new SOM from litter and forest residues, by changing factors like soil temperature and moisture as well as amount and type of litter input. Changes in input of litter with different nutrient concentrations and decomposition patterns along with changes in SOM decomposition will affect the total storage of carbon, nitrogen and other vital nutrients in the soil. To quantify how different harvesting regimes lead to different C addition to soil, and to determine which factors have the greatest effect on decomposition of SOM under different environmental conditions, two Norway spruce forest systems will be investigated in the context of a research project starting in 2008/2009, one in eastern and one in western Norway, representing different climatic and landscape types. At each location, two treatment regimes will be tested: Conventional harvesting, with residues left on-site (CH) Aboveground whole-tree harvest, with branches, needles, and tops removed (WTH). Input of different forest residues will be quantified post harvest. Soil water at 30 cm soil depth will be analysed for nutrients and element fluxes will be estimated to provide information about nutrient leaching. Soil respiration will be measured, along with lab decomposition studies under different temperature and moisture regimes. Long term in situ decomposition studies will be carried out in the WTH plots using three different tree compartments (needles, coarse twigs, fine roots) decomposing in litter bags, in order to determine their limit value. The structure of the fungal community will be determined by soil core sampling and use of molecular techniques allowing qualitative and quantitative estimation. Understorey vegetation will be sampled to determine the biomass, and the frequency of all vascular plants, bryophytes and lichens will be estimated. After harvesting, replanting will be carried out. Seedling survival, causes of mortality and potential damage, growth, and needle nutrients will be monitored. Results from these studies will be used to identify key processes explaining trends observed in two series of ongoing long-term whole-tree thinning trials. We shall combine knowledge obtained using field experiments with results of modelling and data from the Norwegian Monitoring Programme for Forest Damage and National Forest Inventory. This will help us to predict and map the ecologically most suitable areas for increased harvesting of branches and tops on a regional scale based on current knowledge, and to identify uncertainties and additional knowledge needed to improve current predictions.
Sammendrag
General questions that arise while investigating hydrological extremes are whether these have distinct spatial and temporal variations and how these variations are linked to mean flow conditions. We analyze a large set of European stream flow series. Based on daily observations we derive annual series of stream flow deciles ranging from the minimum to the maximum, resulting in a set of eleven series for each station representing the year to year variability of the flow regimes....
Sammendrag
Wood modification with furfuryl alcohol is an extensively investigated process and already produced commercially. Furfurylated wood is in the focus of a European project on its use for the production of high performance windows. Different wood species were treated with furfuryl alcohol and tested on water uptake, dimensional changes, leaching in water, resistance to fungal degradation, and ecotoxicity. The results show a reduced water uptake and a reduced swelling of the furfurylated wood samples. A high resistance against fungal attack of the treated wood samples can be shown. A low amount of furfuryl alcohol was leached out and the water samples of two different leaching tests showed in general low toxicity. Southern yellow pine showed good results in all of the tests and has potential for the production of window frames according to the tests performed.
Sammendrag
In recent years the market share for wooden window products has continuously decreased in Europe. Plastics and aluminum have partly replaced wooden window constructions. Service life and maintenance costs lead the customer to a preferable use of other materials than wood. Additionally the use of tropical hardwoods is decreasing because the market demands sustainable alternatives. A transnational research project is initiated to evaluate the use of an alternative wood material for the production of wooden windows. This project involves both, industry and research institutes from Germany, Sweden and Norway. The objective is to establish Kebony furfurylated wood within the window market of the involved countries. Furfurylation of wood using European timbers has been a research topic for many years and is already commercially produced for different applications. The treatment improves dimensional stability, durability and some mechanical properties. This paper presents the first part of the project, where wood properties such as dimensional stability, water sorption, ecotoxicity, capillary water uptake and water vapor diffusion are evaluated.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Evaluation of climate change consequences and national carbon reporting such as under the Kyoto protocol require long-term monitoring of carbon fluxes. We report on an ongoing project aimed at a national-level assessment of the terrestrial carbon sequestration potential under present conditions and under various climate and land use change scenarios, in particular in terms of their temperature effect. We develop empirical models for national soil carbon stock assessment and evaluate process-based soil carbon models for prediction of future carbon dynamics.....
Sammendrag
The CO2 uptake of the terrestrial biosphere (Gross Primary Productivity, GPP) plays a key role in the global carbon balance. This carbon flux cannot be determined directly on a global scale. Yet, the remotely sensed Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) is a valuable proxy for GPP. This study aims at characterizing global FAPAR dynamics on different temporal scales and extracting corresponding spatial structures. The time series were analyzed to uncover the presence and extent of trends, and to identify quasi-oscillatory patterns from intra- to interannual time scales....
Sammendrag
In high-latitude areas, landscapes with flat or moderate relief areas usually contain lakes and mires. The identification of flowpaths in such areas is a difficult issue. The increasing availability of high resolution topography from airborne Lidar measurements offers new opportunities for automatic or semi-automatic channel extraction from DEMs in small watersheds, substantially outperforming the hydrographic network in conventional digital maps....
Sammendrag
Stream flow observations from a geographical region are known to often exhibit strong common behavior. In order to assess the temporal evolution of the complexity of stream flow time series from all over Europe, we employ the recently developed Linear Variance Decay dimension density (δLV D). It is estimated as the parameter of an exponential decay function fitted to the remaining variances of the eigenvalues of a covariance matrix. Scaling between zero and one, δLV D can be interpreted as a measure of the proportion of linear independent components in a multivariate record.....
Forfattere
Tor Myking Per Arild Aarrestad John Derome Vegar Bakkestuen Jarle Werner Bjerke Michael L. Gytarsky Ludmila Isaeva Rodion Karaban Vladimir Korotkov Martti Lindgren Antti-Jussi Lindroos Ingvald Røsberg Maija Salemaa Hans Tømmervik Natalya VassilievaSammendrag
The effect of air pollution from the Petchenganickel industrial complex, northwestern part of the Kola Peninsula, on forest vegetation was studied by combining three dormant monitoring networks in Finland, Russia and Norway, comprising a total of 21 plots that were revisited in 2004. Chemical composition of precipitation was monitored during 2004–2005, and indicated continuing high deposition of heavy metals and SO2 in the border area. The cover of epiphytic lichens on the trunks of downy birch (Betula pubescens) and Scots pine (Pinus sylvestris) was severely affected by pollution, and there was also a consistent negative effect on the abundance and richness of lichens and bryophytes on the forest floor in a more limited area. The effects of pollution on crown condition and stand growth were weak or absent. This study is an important reference for evaluating the effects of the planned renovation of the smelter in Nikel.