Investigations on the relationsships between Sirococcus- shoot blight, tree nutrition and growth of Norway spruce

Within this study a field plot will be established in order to investigate the impact of tree nutrition upon severity of Sirococcus shoot blight. Furthermore, measurements of increment will be carried out to examine the impact of fertilisation on Sirococcus damaged and unaffected mature Norway spruce trees. In contrast to previous investigations, where the impact of different types of fertilisers was evaluated on ¿old¿ (already established) diagnostic fertilisation plots with an insufficient number of replications, a randomised design will be applied in the current project. In order to characterise the current nutritional and health status of trees and to derive treatments, soil analyses and needle analyses as well as an evaluation of disease severity will be carried out. Element concentrations will be determined for the current year and 3-year-old needles collected from 72 mature trees (36 Sirococcus diseased and 36 unaffected trees) randomly distributed in the investigated stand prior to fertilisation and 3 years after fertilisation. Disease severity of individual trees (n = 144) will be evaluated by hemiview photographs and by using a pair of binoculars and will be classified into 4 damage classes. Growth reaction due to treatment and tree health status will be evaluated by dendrometer measurements, carried out in monthly intervals. Investigation are intended to be continued within a research project that will be applied for at the Austrian Science Foundation.