LIGHTNING & TREES

by Grandpa Cliff

Oct 21, 2005

  Each year in the United States, more than a million trees are struck by

  lightning.  Lightning also strikes almost a thousand people yearly, about a

  hundred of whom die.  Most of the those deaths occur as a result of people

  taking cover under a tree that was struck by lightning.  

  A lightning bolt can have a temperature as high as 55,000 ^oF, which is 

  about five times as hot as the surface of the sun.  After lightning strikes a

  tree, it's electricity goes through the tree into the ground.  The voltage of

  the electrical charge in lightning is about 10 million to 100 million volts.

  Lightning often travels down the tree through the outer sapwood and

  cambium.  Such high lightning temperatures cause the water to 

  immediately turn into steam.  But, steam takes up much more room than

  liquid water does.  As the water instantly expands to become steam, an

  explosion results.  That knocks off the bark of the tree, and sometimes 

  some of the outer sapwood as well.  If the lightning travels more deeply in

  the tree, the whole tree can be blown apart.

The trees which get struck most frequently are Ash, Black Locust, Catalpa, Elm, Maple, Oak, Pine, Poplar, Spruce, and Sycamore.  Beech, Birch, and Horse Chestnut get struck very seldom.

   June 11, 1999 near Denver, Colorado    

The outer part of the sapwood is shredded.  Some of the shreds are still attached to the trunk.

June 8, 2002  Oakville, Washington

Notice what looks like a line of burned wood in the middle of 

the lightning damage.  Near Boulder, Colorado.  May 24, 2004.

Notice the light edge to the dark bark on the tree on the right.  

That is where the tree tried to heal itself.

                                                Colorado Springs, Colorado

In the left photo, the missing bark can be seen from the top to the ground.

Two views of the same tree.  The right photo gives us an idea of how far the bark was thrown.

June 30, 2005 in Litchfield, New Hampshire

Click HERE to go to another website with many interesting photos of two trees that had been struck by lightning.  One photo shows a tree that had completely healed its exploded bark.  

And here is another website with many photos.

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