Beech woodwart

Beech woodwart (scientific name Hypoxylon fragiforme) is a common ascomycete fungus that acts primarily as a saprotroph, but often transitions to a facultative parasite. It is frequently associated with the decline of beech trees, contributing to the decay of bark and underlying woody tissues.

The fungus is host-specific, predominantly targeting the European beech (Fagus sylvatica). While it is often found on dead wood, it can colonize living trees that have been compromised by environmental stressors, such as drought, frost damage, or infestations by wood-boring insects.

The symptoms are highly distinctive. The fungus produces hard, globose, strawberry-like stromata on the bark surface. When young, these fruiting bodies are bright reddish-orange; as they mature, they become dark brown or coal-black. These formations effectively push the bark outward, causing it to flake off and exposing the decaying wood beneath.

Disease progression is favored by high atmospheric humidity and the presence of wounds on the trunk. The fungus utilizes these wounds to colonize the host, after which the mycelium penetrates the vascular system. This disruption leads to the formation of white rot, which significantly weakens the structural integrity of the tree over time.

Effective management focuses on preventative silvicultural practices rather than chemical control. Key strategies include:

• maintaining forest vigor to resist infections;
• prompt removal of infected wood to reduce spore loads;
• minimizing mechanical damage to standing trees during maintenance;
• monitoring tree health to detect early stages of fungal colonization.