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Lightning damages trees

View tree damage from lightning strikes.

Lightning strikes trees on a regular basis in the eastern US and elsewhere causing various injuries to trees. Lightning can kill trees or injury them, and sometimes the damage is hidden. The following are some of the common symptoms:

  • Trees die within a few days or a few months.
  • Trees die the following year.
  • Trees loose most of their leaves and then re-foliate.
  • Cracks form down the side of the trunk, sometimes to the ground.
  • The top or other portion of the tree declines over a period of years.
  • Cankers and sunken dead spots can form on various locations along the trunk and major branches.
  • Symptoms of Armillaria root rot can occur.
  • Sprouts form along major branches or along the trunk.
  • Brown barrier zones form along the cambium that was present when the lightning struck. Of course this can not be seen from the outside of the tree.

Lightning protection can be installed in high value trees in order to reduce the likelihood of damage (see photo). American National Standards Institute (ANSI A-300) publishes standards on installing lightning protection in trees. Professionals installing lightning protection devices are encouraged to follow these standards.

Treatment: Care for lightning struck trees is irrigation in dry weather. Lightning can kill the cambium and interrupt the water flow to the top of the tree. It can take several years before the tree fully recovers. Stored starch in the wood can be trapped when barrier zones form induced by the lightning strike. This can starve the tree. Do not heavily fertilize the tree since this can further reduce energy reserves in the tree. Watch the tree for signs of declining branches including yellow or dying foliage. Remove dead branches.