The Purdue Plant and Pest Diagnostic Laboratory

What's Hot at the P&PDL
June 2, 2011

Lightning Casualty

Tom Creswell, P&PDL Director, Purdue University

Tall trees are natural targets for lighting strikes and the results can be a dramatic explosion of the bark as shown in these photos. When most of the moisture in the tree is concentrated in the water-conducting vessels (phloem) just below the bark the electrical charge may cause such rapid expansion of the water that the bark is literally blown off the tree. The damage may be minimal if the tree bark is water soaked from rain so that the lightning follows the water on the outside of the tree in it's path to the ground.
For more detailed information see these articles:

When Lightning Strikes, Is The Tree Out? - Rosie Lerner, Extension Consumer Horticulturist

Trees and Lightning, FNR-FAQ-9-W (pdf file) - Forestry and Natural Resources

Click image to enlarge

Lightning damage

Bark peeling off after lightning damage

Images courtesy of Doug Hyland

Purdue Plant & Pest Diagnostic Lab Purdue Cooperative Extension Service