Oak bracket

Oak bracket (Inonotus dryadeus) is a parasitic fungus that causes white root rot and butt rot in various broad-leaved trees. It is a significant pathogen that colonizes the roots and the base of the trunk, gradually degrading the wood and compromising the tree's overall structural stability and health.

The primary hosts of this fungus are oak species, but it is also known to attack other broad-leaved trees such as elms, maples, and horse chestnuts. The infection typically begins when fungal spores or mycelium enter the tree through wounds on the roots or the lower trunk, allowing the pathogen to invade the heartwood and sapwood tissues.

The most visible sign of an infection is the emergence of large, bracket-shaped, or cushion-like fungal fruiting bodies at the base of the tree. These fruiting bodies are initially pale and fleshy, often exuding clear to amber liquid droplets, which eventually harden into dark, woody structures. Infected trees may show signs of thinning crowns, chlorosis, and reduced annual growth as the rot progresses.

Environmental factors such as high soil moisture and poor site drainage are conducive to the growth and spread of Inonotus dryadeus. The fungus can persist in the soil and on old tree stumps for many years, acting as a reservoir for further infections. It is particularly dangerous in urban landscapes and parks where root systems are frequently damaged by construction or soil compaction.

Managing the disease requires strict monitoring and risk assessment, as heavily infected trees often become hazardous.

• Removal of infected trees and their stump systems.
• Avoiding injury to roots and trunks during site maintenance.
• Improving drainage in areas prone to infection.
• Regular inspection of older oaks for signs of fruiting bodies.