Hardwood trunk rot, Phellinus igniarius
 

Fig. 362   Fruiting body of Phellinus igniarius on birch stem.	Fig. 363 Phelllinus igniarius fruiting body.

Distribution:  Common throughout the range of its hosts in B.C. 

TREE SPECIES ATTACKED:  Paper birch, black cottonwood, red alder (rare), and bigleaf maple are the major hosts.

WHAT TO LOOK FOR: Large, hoof-shaped, perennial fruiting bodies (conks) on stem. 

SIGNS & SYMPTOMS: FRUITING BODIES: Conks are perennial, woody, and generally hoof-shaped.  The upper surface is zoned, grey to black, and will roughen and crack vertically with age.   The lower surface is brown and velvety, with small pores.  The conk interior is rusty-brown with distinct tube layers flecked with white mycelium.  Fruiting bodies form on living and dead standing trees and slash, and are associated with branch stubs or wounds.  Fungal spread is via windborne spores that invade exposed dead tissues.

DECAY: This fungus causes a white heart rot.  Distinguishing characteristics are thin black lines bordering decay columns, with surrounding wood stained reddish-brown.  In advanced stages of decay, the wood inside zone lines becomes soft, yellow-white with fine black zone lines running throughout.  Decay symptoms are very similar to those of aspen trunk rot.

DAMAGE: The fungus has an economic impact on host trees grown for timber and pulp.  It also raises safety concerns in recreation sites.  The presence of a single fruiting body generally indicates a considerable volume of decay.  Trees with conks should be considered hazardous.

SIMILAR DAMAGE: Decay symptoms and fruiting bodies can be confused with those of P. tremulae, but P. igniarius is found on other hardwoods, while P. tremulae is restricted to aspen.  Fruiting bodies are also very similar to those of Fomes fomentarius, but the upper conk surface of P. igniarius is dark, rough in texture, and cracked, while that of F. fomentarius is light grey and smooth.

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Contact Tim Ebata if you have comments on the presentation of this information.

BC Ministry of Forests
Forest Practices Branch
P.O. Box 9513 Stn. Prov. Gov.
Victoria, BC
V8W 9C2

Section phone: (250) 387-8739
Section fax: (250) 387-2136

Last updated January 05, 2005