Echinodontium

Echinodontium is a genus of fungi belonging to the family Echinodontiaceae, widely recognized for causing extensive heart rot in various coniferous tree species. The most well-known species, Echinodontium tinctorum, is often referred to as the Indian paint fungus, reflecting its historical use by indigenous peoples for pigment.

The disease is classified as a white heart rot or internal decay, depending on the host. The fungus acts as a latent parasite, entering the tree through wounds or broken branch stubs. Once inside, it slowly consumes the heartwood, which provides the primary structural support for the tree.

Host trees primarily include mature conifers such as fir, hemlock, and spruce. Because the fungus progresses very slowly, it is most frequently encountered in old-growth stands. The long-term presence of the fungus often goes unnoticed until significant internal damage has occurred.

Typical symptoms include the emergence of perennial, hoof-shaped fruiting bodies (conks) on the tree trunk. The undersides of these conks feature a distinct, tooth-like surface rather than pores. Internally, the wood becomes soft, fibrous, and discolored, often losing all commercial and structural value.

Management of this fungus focuses heavily on silvicultural practices. Key strategies include identifying and removing infected trees during harvest, avoiding damage to standing timber, and maintaining overall stand health. Since there is no chemical control for internal heart rot, prevention remains the only viable strategy for forest managers.