White trunk rot of conifers
Damage, symptoms and biology
Trees damaged by white trunk rot are prone to wind damage, usually breaking within 6 m of the ground. Decay is usually localized to tissues near the point of infection, but spreads 1 to 2 m up and down from each fruiting body.
The taxonomy of this fungus has been complicated by its morphological variation on different hosts. As a result, many names have been applied to the organism. In the past, many P. hartigii specimens were named Fomes or Phellinus robustus, a name that is now restricted to a related fungus on hardwoods. Another fungus, Poria tsugina (Murrill) Sacc. & Trott., now recognized as Phellinus punctatus (Fr.) Pilát, has resupinate fruiting bodies that are sometimes confused with those of P. hartigii.