The biology of Heterobasidion – implication on silviculture
One of the most important pathogen for the Scandinavian forest sector is the root and butt rot disease of Norway spruce and Scots pine, caused by the fungi Heterobasidion annosum s.l. It is now divided into several species of which two exists in Sweden, Heterobasidion annosum s.s. and Heterobasidion parviporum. For an individual forest owner, the disease causes major economic losses and at the same time it constitutes a threat to the forest industry, which is dependent on a steady flow of high graded timber and pulp wood. Improved knowledge about the different species of Heterobasidion and how they infect individual trees and stands is needed to reduce the problem.

 Biological differences between H. annosum and H. parviporum might necessitate partly different management practices that are tree species specific and adapted to climate variations. The aim of the project is to identify some of these differences. A particular emphasis is given to defining critical features of and conditions for spore infection and establishment of H. annosum and H. parviporum in Norway spruce. Differences in the ability to compete and establish on stump surfaces between spores of H. annosum and H. parviporum will be investigated and a possible different infection route for spores of H. annosum s.s. will be looked into.