Die Bodenkultur - Journal for Land Management, Food and Environment
R. Jandl, H. Anglberger, M. Reh and E. Halmschlager:
Effect of fertilization of a secondary spruce stand in the Kobernaußerwald with shoot blight symptoms
Many secondary spruce forests in central Upper Austria are affected with Sirococcus conigenus, a fungus causing shoot blight. Affected trees show progressive crown deterioration and often stands need to be harvested long before they reach the prescribed rotation age. In an experiment in the Kobernaußerwald we investigated whether an improvement of the nutritional status helps to preserve these stands. Several plots in a 60 year old spruce forest were treated with combinations of organic fertilizers, magnesium rich carbonate fertilizers and classical NPK fertilizers. We assessed the defoliation of the canopies, the intensity of Sirococcus shoot blight, the chemical soil condition and the nutrient content of needles. Seven years after the fertilization the soil pH was only slightly raised. The magnesium pool was enhanced where magnesium fertilizers have been applied. The response of nutrient content in needles was quite variable.
The greatest improvements were achieved with magnesium carbonate fertilizers. The intensity of Sirococcusshoor blight was reduced. The improvement of the nutritional status seems to have modified several resistance mechanisms of trees and have promoted recovery. Therefore stand fertilization is a valuable tool to stabilize stands that are affected with S. conigenus in order to facilitare the consecutive stand conversion by means of silvicultural methods.
Key words: amelioration fertilization, secondary spruce forest, Sirococcus conigenus, shoot blight, Kobernaußerwald.