Sooty Bark Disease (Sycamore)
Sooty bark is a fungal disease which can lay dormant within the wood of a perfectly healthy tree for many years and is likely only to become active when the tree is under stress, for example, after long periods of hot weather. Once under attack, the crown of the Sycamore either partially or fully wilts and eventually causes the tree to die.
How do I recognise it?
A dark brown or black layer of spores is present underneath a peeling paper thin outer layer of dead bark.
Usually the dead bark comes away in a rectangular shape to begin with then with long and broad black strips.
Part or all of the tree’s crown wilts and dies and leaves will fall before normal the autumnal drop. In the following year, part or all of the crown may fail to come into leaf.
The tree may produce smaller, brown leaves.
If seen early, the affected tree looks continually moist and has brown areas, these areas turn black and ‘sooty’ in appearance as the infection matures.
The fungus is also widespread on dead wood.
There is a small chance, if the disease is caught in the very early stages, the spread of it can be minimised which may save the tree. This involves pruning the affected branches with clean, sharp tools and disposing of the infected material in the household waste (the disease can still spread of the branches are chipped or burnt). This can be attempted at the very first signs of the disease and to prevent spread to other Sycamores or Maple trees nearby.
However, most diseased trees cannot be saved and must be removed.
Image courtesy of www.forestry.gov.uk