Biology, Ecology, and Management of Biscogniauxia (Hypoxylon) Canker in the Southeastern U.S.

Oak decline – a gradual reduction of tree leaf area and health and sprouting of epicormic branches, resulting in eventual tree death – is the result of a combination of abiotic and biotic factors.  Trees in the red oak group are generally more susceptible, though those in the white oak group are by no means resistant.  Abiotic factors, such as drought, poor soils, or overcrowding, can weaken trees.  Once weakened, trees are susceptible to a number of insects and pathogens (e.g. cankers) that can more easily defoliate or colonize a stressed tree.  Management methods include those that promote tree health and vigor:  thin stands when appropriate, maintain diverse forests, use salvage cutting when mortality rates are high, or consider regenerating the stand if oak decline is prevalent in high rates over a large area.  In general, prevention is the best management for decline complexes with many different contributing factors.