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This article presents a method for examining Norway spruce for susceptibility and resistance to the spread of Fomes annosus. An easily applied method is discussed for determining the results of infections and the reactions of young Norway spruce to Fomes annosus. By the use of genetically homogeneous material that is clonal plants, the importance of environmental factors such as nutrient supply and also the varying virulence of different fungal strains may be studied.

This article discusses the root-rot caused by the fungus, Fomes annosus in the forests of western Europe. Reports have been received from all the European countries about the appearance of this most dangerous germ of root-rot of coniferous forests. The attack shows considerable differences in various countries. In Great Britain, Picea silvestris and Picea nigra, calabrica are attacked, whereas in Southern France and Portugal, the indigenous Picea pinaster is damaged. However, the most important host plants for Fomes annosus in Western Europe are the two spruce-species: Picea abies, Picea sitchensis and the Scots Pine Pinus silvestris.

This article presents a study report of the salt tolerance of various poplar and willow species and clones conducted in the laboratory and field. The resistance of 10 black and 10 grey poplar clones and of 36 willow-clones was examined by dipping shoots in a highly concentrated NaCl solution. All the black and most of the grey poplars showed high resistance. Only eleven willow-clones showed sufficient resistance. The studies are to be continued with enlarged material under various ecological conditions.

The article examines the resistance of several white poplar-clones against Pollaccia radiosa. Clone-typical forms of resistance against spring defoliation that is shoot-dieback, caused by Pollaccia radiosa were investigated in several Leuce-poplar-clones. The most obvious differences in attack occur under natural conditions. The observed differences concerning the type of resistance that is infection versus spreading in the host seem to depend on the anatomical structure of the host.