Honey fungus, bootlace fungus (Armillaria mellea)
Fruiting bodies: July – November
Area of infection: roots and trunk base
Wood decomposition: white rot
Mycelium: between sapwood and bark, glows in the dark
Comment: Counts as the largest living thing because the mycelium can stretch over hundreds of hectare.
Effect: Vessels are interrupted – thinning of the crest and flaking of the bark – dying of the tree.
Recommendation: Tree should be evaluated. More photos.
  
  
Photos honey fungus, bootlace fungus