Ganoderma applanatum

Artist's Conk

BeneficialPathogen
HabitatIn broad, flat, gray-brown perennial shelves at wounds, stumps, and the trunk base of living and dead hardwoods, especially maple, beech, elm, and poplar; causes a white rot of the heartwood.
Background

Artist's conk forms large, flat, semicircular brackets — gray to grayish-brown on top with faint concentric growth zones, woody and hard with age, sometimes reaching a foot or more across. Unlike most bracket fungi, it is perennial: the same conk survives for years, adding a new white layer of pores to its underside each growing season, so a cut cross-section shows layered growth rings much like a tree. The flat white pore surface is the source of its common name — any mark or scratch on fresh growth bruises brown within minutes and stays that way permanently, which is why the fresh underside has long been used as a natural canvas for scratched or etched drawings.

Pathogen
Symptoms

White rot of the heartwood and lower trunk; broad, flat, gray-brown woody shelves form at wounds, old branch stubs, or the trunk base and persist for years, adding a new white pore layer each growing season.

Conditions

Enters through wounds, old pruning cuts, or root damage on mature hardwoods, especially maple, beech, elm, birch, and poplar; favored by injury and age.

Treatment

There is no cure for the internal rot. Manage the tree rather than the fungus: avoid wounding the trunk and roots, prune cleanly, and have trees fruiting conks near paths, structures, or other targets professionally assessed for structural safety.

Beneficial — decomposer

Also colonizes dead stumps and fallen hardwood logs, slowly breaking down lignin over many years as a long-lived wood decomposer.

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