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.
2004
Authors
Per Holm Nygaard Heleen A. de WitAbstract
Aluminium (Al), mobilized by acidic deposition, has been claimed to be a major threat to forest vitality. Fine root mortality, decreased root growth and reduced nutrient uptake have been observed in controlled laboratory experiments where roots of tree seedlings were exposed to elevated concentrations of Al. Yet, evidence for Al-induced root damage from forest stands is scarcely reported. Nevertheless, Al dissolved in soil water has received a key role in the critical load concept for forests. Here, we present effects of artificially elevated concentrations of Al in the soil solution on fine roots in a middle-aged stand of Norway spruce (Picea abies (L.) Karst.). Although the inorganic Al concentrations about 200 M and Ca:Al ratio about 0.7 that were established in the soil solution within this experiment have been associated with reduction of root growth and root mortality for spruce seedlings in hydroponic studies, no acute damage on fine roots was observed. Three years of treatment did not cause visual root damage, nor were effects on fine root necromass observed. Fine root necromass made up about 10 % of fine root biomass for all treatments. However, significantly lower molar Ca:Al and Mg:Al ratios in living and dead fine roots were found in the plots where Al concentrations were highest and ratios of Ca to Al in the soil solution were lowest. The lack of response on fine root biomass suggests that forest stands tolerate higher Al levels than results from laboratory experiments indicate. We conclude that effect studies in the laboratory have limited value for field conditions. The key role of Al toxicity, expressed as the Ca/Al ratio, in critical load calculations for forests may have to be reconsidered.
Authors
Nina Elisabeth Nagy Carl Gunnar Fossdal Lars Sandved Dalen Anders Lønneborg Inger Heldal Øystein JohnsenAbstract
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Authors
Sissel Torre Päivi Rinne Carl Gunnar Fossdal Heather Danforth Stein Erik Lid Ragnhild Nestestog Chris Van der SchootAbstract
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Since 1993, Norwegian governmental subsidies have been applied to preserve valuable semi-natural grasslands in Norway. After 8 years of management and payments, the effects of the subsidies were investigated in the county of Nord-Trøndelag. The intention of the subsidies, to secure both open landscapes and biodiversity, was not obtained due to a general lack of knowledge of ecology and biodiversity at all levels. This clearly demonstrates the importance of knowledge and information exchange between scientists, authorities, politicians and farmers to secure maintenance of the most valuable semi-natural grasslands. In addition, transdisciplinary research and exchange of knowledge between archaeologists, historians and ecologists are necessary to preserve the most valuable cultural landscapes with regard to both biodiversity and cultural monuments. This study was presented at the EGF meeting 21-24 June 2004, Luzern, Switzerland.
Authors
Tove M. Østensvik Kaj Bo VeierstedAbstract
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Authors
Guro BrodalAbstract
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Authors
Halvor B. Gjærum Kåre Arnstein Lye Halvor SolheimAbstract
No abstract has been registered