This fungus is relatively rare in the UK but can be found usually at the base (or on logs or stumps) of hardwood trees such as oak and beech. The word Ganoderma comes from the Greek ‘Ganos’ and ‘derma’ which translates to shining skin.
How do I recognise it?
Ganoderma is characterised by large leathery double-walled brackets which grow in a fan like shape on either living or dead trees causing a white butt and root rot. When broken or damaged, the Ganoderma fungus oozes a thick yellow resin that quickly hardens forming a hard and shiny surface from which the name is derived. The cap ranges from yellow to black as it ages.
Like many fungi the first sign of damage to the tree is the appearance of the brackets on the truck or main body of the tree. These can be up to 60cm and may appear after crown thinning or die-back or by falling branches, although this is not always the case but by the time the brackets appear there will most likely already be extensive internal decay.
The infected tree has natural chemical barriers that can limit the internal infection and it is no longer advised to paint pruning cuts with wood paints as over time these crack and trap water and may increase the risk of infection.
Removing brackets also has little effect on the overall risk as it is likely that the tree will already have extensive internal damage by the time these brackets appear and so, as with all bracket fungi, there is little you can do to prevent this type of infection.
Did you know…?
Ganoderma is one of the most popular medicinal mushrooms in Asia and the United States?