Beefsteak fungus

Beefsteak fungus (lat. Fistulina hepatica) is a wood-decay fungus that primarily causes brown heart rot in various broadleaf tree species. While often noted for its biological interest, in forestry and orchard management, it acts as a parasitic agent that degrades the health and structural integrity of the host plant.

The fungus is commonly found on oak and chestnut trees, although it can occasionally infect other deciduous varieties. It invades the tree through open wounds, bark damage, or pruning sites, where it establishes its mycelium within the heartwood and initiates the slow decomposition of wood cellulose.

The symptoms of the disease include the emergence of fleshy, liver-colored fruiting bodies on the trunk or base of the tree. Internally, the wood becomes discolored, typically turning a dark brown, and loses its tensile strength, which often leads to tree collapse or branch failure during adverse weather conditions.

The development and spread of the fungus are favored by humid environments and stagnant air circulation, which facilitate the dispersal of spores from the fruit bodies. These spores land on vulnerable spots of susceptible trees, beginning new cycles of infection and slowly spreading throughout the wooded area.

To protect trees, it is essential to focus on wound prevention and proper pruning techniques. Any exposed wood should be sealed with wound dressings or antifungal sealants to create a physical barrier against spore infiltration. Regular monitoring and the removal of severely infected specimens are critical strategies to maintain the health of the remaining tree population.