Aspen trunk rot

Fruiting bodies of <em>Phellinus tremulae</em> — Fruiting bodies of *Phellinus tremulae* Eric Allen

French disease name: Carie blanche du tronc du tremble
Pathogen name: Phellinus tremulae (Bondarzev) Bondarzev & Borisov in Bondarzev
Kingdom: Fungi
Phylum: Basidiomycota
Class: Agaricomycetes
Order: Hymenochaetales
Family: Hymenochaetaceae
Partial list of synonyms:
- Fomes igniarius (L.:Fr.) J. Kickx fil. f. tremulae Bondartsev

Distribution

Canada

Damage, symptoms and biology

The fruiting bodies are hard, persistent and hoof-shaped. The upper surface is blackish, rough and cracked. The underside is composed of spore-bearing tubes and is brown, with a grey cast in winter. The infection enters the tree through branch stubs and the fruiting bodies develop for 4 to 6 years after the start of the infection. At that time, rot has already developed 2 to 3 m above and below the point of entry.

Aspen trunk rot is one of the most serious problems limiting the utilization of mature aspen in western Canada. The presence of a single fruiting body generally indicates a considerable volume of decay, as much as 82% of gross tree volume. Unfortunately, there are often no external indicators of decay, and it is difficult to predict decay volumes. Volume losses increase significantly with tree age.

Other information

Phellinus tremulae was once considered as a part of the Phellinus igniarius complex, but is now recognized as a distinct species. It occurs exclusively on aspen, and is the most damaging decay fungus associated with the tree species. Decayed wood in fresh cut trees has a distinct wintergreen odour.