Lightning
Key Features

  • Vertical line of ripped bark
  • Exit wound (not always visible
Lightning strike on cottonwood.Photo by Lindsey Purcell
Lightning strike on cottonwood.Photo by Lindsey Purcell
Lightning strike split and shreaded bark on cottonwood
Lightning strike split and shreaded bark on cottonwood
Lightning strike following tree roots. Photo by Richard Griffin.
Lightning strike following tree roots. Photo by Richard Griffin.
Symptoms

Lightning strikes create a diversity of symptoms, from a simple entrance wound and exit wound (which may occur via the roots and not be visible), to more dramatic vertical rips, spiral rips, or shredding. Weeping may be associated with damaged tissue. Wounds left when lightning exits the tree are visible when they occur at or above the crown. It is difficult to predict the outcome of a lightning strike--some trees live and others die. It depends upon the severity of wound, and the directness of the strike.

Lightning strike on oak that resulted in tree death.
Lightning strike on oak that resulted in tree death.
Lightning, sap weeping from lightning entry wound
Lightning, sap weeping from lightning entry wound
Biology

Tall trees, (especially, tuliptree, oak and cottonwood) can be struck by lightning. Electricity from the lightning strike and burn and rip plant tissue and it races its way to the ground. Sometimes the damage is compartmentalized and leaves a scar. Other times the tree can be killed. Both the structural integrity and the biological function of the tree are impacted by lightning strikes. As the strike travels the length of the tree, conducted by the trees vascular system, water and sap boils creating steam that superheats the surround area, directly damaging the tissue, or building up steam that can explode through the wood.

Management Recommendations

Have your tree inspected by a professional arborist after a lightning strike to assure that it will be structurally sound and won't fall and become a hazzard to people and property.

Effective Pesticides

Pesticides are neither available nor recommended for managing this condition.

Resources

landscape report
Purdue Landscape Report
PPDL
Plant & Pest Diagnostic Laboratory