Infestation of Predisposed Pinus nigra by Sphaeropsis sapinea : Disease/Environment Interactions in Forest Decline. Proceedings of a Workshop of the Working Party Disease/Environment Interactions in Forest Decline IUFRO 7.02.06, Vienna, Austria, March 16-21, 1998
In August 1996, a servere decline in a mixed stand of Austrian pine and American red oak (Pinus nigra 95 yrs, Quercus rubra 33 yrs) was determined in the south-east of Saxony-Anhalt. The damage was restricted to this stand only. The neighbouring stands of Scots pine (Pinus sylvestris) did not reveal any damage. Until summer 1997, 40% of all trees had did or had to be removed on account of severe damage. The original assumption that the direct influence of gaseous ammonia from a nearby fertilizer factory was responsible for the damage could not be maintained. Instead, Sphaeropsis sapinea was diagnosed to be the cause of the damage. The intensity of the damage was brought about by the strong predisposition of the tree caused by drought stress and unfavourable site conditions. The limitation of the damage to the Austrian pine stand can be explained by the higher susceptibility of P. nigra due to the simultaneous competition with the American red oak understorey.
