For some years now, bark bleeding disease develops amongst many tree species. From the brown coloured areas and fissures at the trunk of the bark a viscous brown/black juice is flowing. Sometimes the bleeding is caused by Phytophthora ramorum or Pseudomonas syringae aesculi. Bleeding of the Horse Chestnut is at this time the most known tree bleeding disease in Europe.
There are no explanations for the expansion of bark bleeding. Although we expect that the bacterial affection is caused by Ps. s. ae, nobody can explain why this bacterial is so destroying at this time.
Probable some changed circumstances in our environment have a relation with this. More investigation is necessary.