Lightning Strikes a Tulip Poplar

February 24, 2009

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Photographer: John Adam, John’s Home Page
Summary Author: John Adam

Early one Saturday morning this past November, I was listening to the sounds of heavy rain outside and jumped out of my chair at the crack of a loud thunderclap very close by. Later that morning, a neighbor knocked on my door and said “Come and see this, and bring your camera.” The above photo shows what I saw -- just across the street from my house. The tree shown is a tulip poplar (Liriodendron tulipifera) of the family Magnoliaceae. It seems that poplars, along with oaks, elms, pines, spruce, maples, and ash have a slightly higher predisposition to be struck by lightning than do other tree species. Beech, birch and horse chestnut receive the fewest strikes, though, the location of the tree, on a hill as opposed to in a valley, is of course an important factor.

The obvious indicator here of the strike is the vertical stripping of the bark from a considerable height down to the base of the tree. It appears that the mechanical and structural damage to the tree is relatively slight; however, time will tell. The electrical discharge of a lightning bolt may be as high as 100 million volts, at thousands of amperes, and can vaporize water inside the tree. This creates superheated steam, which explodes if it exceeds the structural strength of the wood. As can be seen from the close-up, this bolt appears to have run just underneath the bark’s surface, resulting in the stripping, perhaps because it was soaked by the earlier rain and therefore readily conducted the lightning. Thanks to Christine Bradish for identifying the details of this tree.