A number of people in Walton County have had problems with oak trees on their property recently. Some trees have declined in health, others have died. Several factors contribute to this issue, and not every tree may be suffering from the same combination of things. One major culprit, however, is hypoxylon canker.

Hypoxylon canker is caused by a fungus that is normally present only in the outer bark of oak trees, and usually doesn’t hurt them. When other sources of stress weaken the tree, however, the fungus can quickly take over and eventually kill it. Hypoxylon canker usually appears as pale patches on the trunk of the tree where the bark is missing. Unfortunately, once it becomes enough of a problem to be noticeable, there are no easy options to fix it. In fact, the fungus itself is almost always a secondary problem – it moves in when the tree is weakened from other factors.

Instead of trying to treat the canker, it is better to prevent sources of stress that could lead to disease such as hypoxylon canker taking over. When planting trees to begin with, make sure to choose a suitable location that is not too close to other trees, gets plenty of sunlight, and is not either waterlogged or too dry. Owners of pastures in which animals such as cattle or horses graze should try to ensure that the soil around the tree does not become too compacted, by excluding animals from the area where most roots are present or by aerating the soil. Controlling moisture levels, if possible, can also help – too much or too little water for an extended period of time can cause stress. If a tree does succumb to the disease, it should be removed and the debris disposed of by burning to avoid spreading spores to other nearby plants.

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