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.
2008
Authors
Line RosefAbstract
No abstract has been registered
Authors
Haiying Liu Tonje Økland Rune Halvorsen Jixi Gao Quanru Liu Odd Eilertsen Harald BratliAbstract
Monitoring of ground vegetation and environmental variables in subtropical forests in China was initiated in 1999 as part of the “Integrated Monitoring Programme of Acidification of Chinese Terrestrial Systems”. The study areas were selected to span regional gradients, in deposition of airborne pollutants and climatic conditions. All five study areas are located in the southern and south-western parts of China and consist of subtropical forests. In each study area 50 1-m2 plots were randomly chosen within each of ten 10×10 m macro plots, each in turn positioned in the centre of 30×30 m extended macro plot. All 250 1-m2 plots were subjected to vegetation analysis, using frequency in subplots as measure of species abundance. A total of 33 environmental variables were recorded for 1-m2 plots as well as 10×10 m macro plots. A major objective of this study is to identify the environ¬mental variables that are most strongly related to the species composition of ground vegetation in S and SW Chinese subtropical forests, as a basis for future monitoring. Comparison among DCA, LNMDS and GNMDS ordination methods, an additional objective of the study, was achieved by using a set of different techniques: calculation of pair-wise correlation coefficients between corresponding ordination axes, Procrustes comparison, assessment of outlier influence, and split-plot GLM analysis between environmental variables and ordination axes. LNMDS and GNMDS consistently produce very similar ordinations. GNMDS ordinations are generally more similar to DCA than LNMDS to DCA. In most cases DCA, LNMDS and GNMDS extract the same main ground vegetation compositional gradients and the choice of LNMDS or GNMDS is therefore hardly decisive for the results. GNMDS was chosen for interpretation and presentation of vegetation-environment relationships. The dimensionality of GNMDS (number of reliable axes) was decided by demanding high correspondence of all axes with DCA and LNMDS axes. Three dimensions were needed to describe the variation in vegetation in two of the areas (TSP and LXH), two dimensions in the other three areas (LCG, LGS and CJT). Environmental interpretation of ordinations (identification of ecoclines; gradients in species composition and the environment) was made by split-plot GLM analysis and non-parametric cor¬relation analysis. Plexus diagrams and PCA ordination were used to visualize correlations between environmental variables. Several graphical means were used to aid interpretation. Complex gradients in litter-layer depth, topography, soil pH/soil nutrient, and tree density/crown cover were found to be most strongly related to vegetation gradients. However, the five study areas differed somewhat with respect to which of the environmental variables that were most strongly related to the vegetation gradients (ordination axes). Litter-layer depth was related to vegetation gradients in four areas (TSP, LCG, CJT and LXH); topography in four study areas (TSP, LGS, CJT and LXH); soil pH in three areas (LCG, LGS and CJT); soil nutrients in one area (LGS); and tree density/crown cover in one area (LCG). The ecological processes involved in relationships between vegetation and main complex-gradi¬ents in litter-layer depth, topography, soil pH/soil nutrient, and tree density/crown cover, in subtropical forests, are discussed. We find that gradient relationships of subtropical forests are complex, and that heavy pollution may increase this complexity. Furthermore, our results suggest that better knowledge of vegetation-environment relationships has potential for enhancing our understanding of subtropical forests that occupy vast areas of the S and SW China.
Authors
Ingunn M. VågenAbstract
No abstract has been registered
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Harmonization was achieved by carrying out joint sampling and assessment exercises at selected sites, inter-laboratory ring tests for the chemical analyses of deposition, plant and soil material, and by drawing up data compilation, data analysis and reporting guidelines and templates for the researchers working in the three countries.
Authors
Line Tau Strand Per H. Nygaard Odd E. StabbetorpAbstract
No abstract has been registered
Authors
Olafur Eggertsson Per Holm Nygaard Jens Peter SkovsgaardAbstract
The last late glacial from 22,000 up until just before 13,000 years ago was very cold and dry throughout Europe. Large ice sheets were present over much of northern Europe, and ice caps covered the Alps and the Pyrenees. Forest and woodland were almost non-existent, except for isolated areas of woodland vegetation and close to the mountain ranges of southern Europe. Instead, a sparse grassland or semi-desert covered most of southern Europe, at the same time as a mixture of the dry, open steppe tundra and polar desert covered the parts of northern Europe not occupied by ice sheets (Figure 1). Ice-wedge geomorphological features suggest that permafrost extended across most of Europe, down to about the latitude of central France. At this time drifting sand and wind erosion were common in north and central Europe.
Authors
Gert-Jan Nabuurs Esther Thürig Nanny Heidema Kestutis Armolaitis Peter Biber Emil Cienciala Edgar Kaufmann Raisa Mäkipää Petter Nilsen Richard Petritsch T. Pristova Joachim Rock Mart-Jan Schelhaas Risto Sievänen Zoltan Somogyi Patrick ValletAbstract
This paper is the outcome of a group discussion held at the Savonlinna meeting ‘Management of forest ecosystems and its impact on the GHG budget’. The aim of this break-out group discussion was to ‘Characterize forest management impacts on the GHG budget of forest ecosystems in different European regions’. In this paper we briefly characterize different options that a forest owner has in order to maintain or maximize forest carbon pools and carbon sequestration. These hectare scale descriptions of measures are then regarded in connection to the current state of European forests and how they can be combined with ongoing management trends and local issues. We point out the various possibilities that exist in European forests, where they are located, and where they could possibly be combined with adaptation. We identify these hotspots for largest growing stocks, largest peat areas, and, e.g. largest risks for loss of carbon due to fire or urban sprawl. We conclude that one common strategy cannot be designed. Within each region, local solutions have to be found that optimize goals and aim at integrated and sustainable land use.