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.
2015
Authors
O. Janne Kjønaas Nicholas Clarke Toril Drabløs Eldhuset Ari Hietala Hugh Cross Kjersti Holt Hanssen Tonje Økland Holger Lange Jørn-Frode Nordbakken Ingvald RøsbergAbstract
Tree harvest and different harvesting methods may affect the soil carbon (C) pool in forest ecosystems. In con- ventional stem-only timber harvesting (SOH), branches and tops that are left in the forests may contribute to the build-up of the soil carbon pool. In whole-tree harvesting (WTH), inputs of organic matter from branches and tops are strongly reduced. We established field experiments at Gaupen, SE and Vindberg, SW Norway, to study the short-term effects of SOH and WTH on processes affecting the accumulation and loss of soil C. Logging residues on the WTH plots were collected in piles that were removed after 6 months, rendering two sub treatments (WTH- pile and WTH-removal areas). We weighed selected trees and logging residues, surveyed understorey biomass production, quantified pre-harvest soil C and nutrient pools down to 30 cm. Soil respiration was measured and soil water sampled monthly during the growing season, while temperature and moisture were measured continuously. Organic and mineral horizons were incubated at different temperatures to estimate potential C and N mineraliza- tion, and deep sequencing of the ITS2 barcode region of fungal DNA was performed on the samples. Litterbags were deployed in the SOH plots. The logging residues amounted to 2.2-2.4 kg C m-2 At Gaupen, the mean in situ soil respiration rates increased following harvest with all treatments, but were significantly higher in WTH-pile and SOH relative to the WTH- removal areas in the first year as well as the fourth year of treatment. The former rates included aboveground decomposing needles and twigs but excluded coarser branches. The observed increase in the WTH-removal areas may be related to decomposing roots, as well as to increased C mineralization partly due to the higher soil tem- peratures following harvest. Soil temperature was the single most important factor explaining the variability in soil respiration rates over all treatments. At Vindberg, a decrease in soil respiration was observed with all treatments in the second and third years following harvest. At both sites, decomposition of logging residues from needles was more rapid relative to twigs and fine roots. The decomposing residues released a substantial amount of nitrogen which was gradually reflected in the soil water at 30 cm soil depth. A considerable increase in the NO3-N concen- tration also in the WTH-removal areas in the second year following harvest suggests an increase in N availability from decomposing fine roots and/or soil organic matter. The increased N availability in the WTH-removal areas was supported by results from short term lab incubations of undisturbed soil from the forest floor. The changes in the WTH-removal areas were also reflected in the soil fungal diversity: saprophytic ascomycetes on decaying plant material showed a striking increase in all treatments. For the WTH-removal areas, this may, again, be related to the increased input of root litter; however, the decrease in mycorrhizal basidiomycete species and the vigorous increase of ascomycetes following harvest may also affect the C mineralization of soil organic matter.
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2014
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No abstract has been registered
Authors
Frank MillerAbstract
No abstract has been registered
Authors
Frank MillerAbstract
No abstract has been registered
Authors
O. Janne Kjønaas Nicholas Clarke Toril Drabløs Eldhuset Kjersti Holt Hanssen Ari Hietala Holger Lange Jørn-Frode Nordbakken Tonje Økland Ingvald RøsbergAbstract
No abstract has been registered
Authors
Tonje Økland Jørn-Frode Nordbakken Holger Lange Ingvald Røsberg O. Janne Kjønaas Nicholas Clarke Kjersti Holt HanssenAbstract
No abstract has been registered
Authors
Oijen Van Oijen J. Balkovi C. Beer D.R. Cameron P. Ciais W. Cramer T. Kato M. Kuhnert R. Martin R. Myneni A. Rammig S. Rolinski J.-F. Soussana K. Thonicke L. XuAbstract
No abstract has been registered
Authors
Årolilja Svedal JørgensrudAbstract
Norwegian agriculture is undergoing rapid structural changes leading to larger farm units and fewer farms, altering the context of farming and the capacity to respond to change. At the same time, climate change is manifesting as seasonal changes, warmer temperatures, and increased precipitation. This study applied a combination of contextual vulnerability and double exposure frameworks to assess current adaptive capacity and vulnerability to the combined effects of climate change and structural change in a rural community in Western Norway. This study employed a triangulation of research methods, covering case study interviews, informal observations and secondary data analysis, to get insight into the process of adaptation and deepen the understanding of how adaptive responses feed back on vulnerability and future adaptive capacity. The objective of this study was to identify to what extent there is a disparity between structural changes in Norwegian farming and building climate adaptive capacity in agriculture. It is assumed that developed countries such as Norway have a high capacity to adapt to climate variability and change. However, this study found that farmers are vulnerable to changing climatic conditions because socioeconomic and political processes of change undermine climate adaptive capacity. Results further suggest that all farmer types, independent of scale, production type, values, and size, are to some degree vulnerable to a diminishing farming community due to the contagious nature of farm closures and lack of understanding among non-farmers. Moreover, this study found that the way in which farmers currently respond to other processes of change affect long-term adaptability of individual farm households and farming communities to future climate change. Policymakers should encourage a diversity of farm sizes rather than focusing on increasing production on a few large farms, particularly in the context of Western Norway where there are certain physical and social limits to the expansion of production that are determined by local contextual conditions such as topography, climate, and the culture of farming.