Fistulina

Fistulina (Fistulinales) represents a group of fungal infections, most notably associated with the beefsteak fungus (Fistulina hepatica). This fungus acts as a parasite that primarily affects the heartwood of broad-leaved trees, causing a specific type of brown cubical rot that weakens the structural integrity of the host.

The pathogen typically enters the tree through wounds, such as broken branches, frost cracks, or pruning cuts. Once established, the mycelium spreads throughout the interior, digesting the cellulose and lignin components of the wood, which leads to a gradual loss of the tree's internal strength over several years.

The disease is most commonly found in older oak and chestnut trees, although it can infect various other hardwood species in managed landscapes. Environments with high humidity and poor tree health are more susceptible to infection, as these conditions favor the colonization and spread of fungal spores.

Symptoms become visible through the emergence of tongue-shaped, liver-colored fruit bodies on the trunk. As the infection progresses, the inner wood becomes soft, discolored, and prone to breaking. Early detection is often difficult, as the primary damage occurs internally, away from visible inspection.

Prevention and management focus on minimizing physical damage to the bark and trunk. Essential practices include keeping tools sterile during pruning, applying wound dressing to significant cuts, and ensuring the tree remains vigorous through proper fertilization and watering. In cases of severe structural decay, professional assessment is necessary to prevent tree failure.