“Are beech-trees ever struck by lightning?” (1889)

Short answer: yes!

It’s easy to forget how relatively little we knew about the natural world even only a hundred years ago.  I came across a rather amusing and macabre example in the July 19, 1889 issue of Science magazine some time ago, a letter with the odd title, “Are beech-trees ever struck by lightning?”  This was written in response to a short bit in the “Notes and News” section of the July 5th issue of Science, which read as follows:

ACCORDING to an ancient superstition, says Garden and Forest, the beech is never struck by lightning; and so general has been this belief, that a gentleman recently thought it worth while to write to an English journal that he had been told of a lightning-shattered beech in Ireland. Beliefs of this sort are rarely without some degree of justification in fact, and it would be interesting to know whether in this country the beech has been observed to possess any greater immunity from electrical dangers than trees of other sorts.

Keep in mind that this note, which appeared in Science, suggests that beech trees might be lightning-proof in some way!

Even for that era, such a statement was a bit of a stretch.  Electricity had been rigorously studied for over a hundred years, with much progress relating to lightning made by Benjamin Franklin in 1752 in his infamous kite experiment.  The statement in Science brought a near immediate reply from one H.D. Post with the title, “Are beech-trees ever struck by lightning?”  He provides some immediate background:

THIS is the question implied in your note on p. 7 of Science for July 5, 1889.

Post spends little time mincing words, and jumps right into an anecdotal counterexample to the assertion:

In August, 1885, at Mason, Ingham County, Mich., a number of men were at work harvesting wheat in a large field west of the village.

A heavy thunder-storm came up, and all but one of them, Aura Hines, fled for shelter to a saw-mill about a quarter of a mile distant. He said that his shoes hurt his feet, and he did not like to run so far; he would go to the woods, which bounded the field south, not far distant. After the storm (accompanied with heavy thunder and lightning) had passed, the men returned from the mill to their work, but Hines did not appear. They went in search, and found him sitting under and against a large beech-tree, dead.

Without disturbing his position, they sent to the village for help, and I went and saw him.

The tree was a large and tall one, about two feet in diameter, and leaned a little eastward. A pile of brushwood had been burned on the east side, which had killed the tree on that side from the roots to the height of seven feet from the ground. The storm came from westward, and Hines sat on the east side crouched against the tree, which sheltered him from the rain. Two or three holes of half an inch diameter, near his right foot, showed where the current passed from the earth to his body, partly tearing the sole from his shoe, and passing through the crown of the coarse straw hat on his head, making a half-inch hole, as if a bullet had been fired through it; the broken straws pointing upward and outward.

There was a plain furrowed trace on the burned and dead bark of the tree above his head, to the green and living wood, but no farther.

The wood of the beech is very close grained, and in the living tree full of sap, and the green bark is also filled with sap, while the outer or ross bark is thin and quite smooth.

Has not such a tree the elements of a good conductor, over which the electric fluid passes, without shattering it or leaving a trace?

If this is true, beech-trees are probably struck by lightning as often as any others, but it leaves no trace of its passage over them.

In short, argues that beech trees are struck as often as any other type of tree, but they might be more conductive on their outer surface, allowing them to convey the electricity to ground without damage.

This turns out to have been an accurate assessment; as noted by the Forest Preserve District of Cook County, IL:

In a bad thunder storm, people used to run for a beech tree. There is a superstition that lightning will not strike a beech. As a matter of fact, they probably are struck as often as any other tree but without being damaged. Because of the fatty content of the wood, their smooth bark, and their many fine twigs and buds, beech trees are good conductors of electricity. Therefore a bolt of lightning is usually carried down into the ground harmlessly.

Therefore the beech tree is more resistant to lightning, but provides no protection from lightning.  The confusion about its properties is a great example of how appearances can be deceiving in the natural world, sometimes with fatal consequences.

UPDATE: Here’s a slightly different take on the resistance of the beech tree to lightning, from UMN:

Trees high in oils (birch and beech) are poor conductors of electricity, whereas trees high in starch content (oak, maple, ash, and poplar) are good conductors. Conifers (pine, spruce, hemlock, and fir) have high resin content. They conduct more electricity than trees with low resin content and are more susceptible to explosion and internal heating.

The two statements seem to be at odds, one saying beech is a good conductor, the other saying it is a poor conductor!  My attempt at reconciliation is that the beech wood is a poor conductor, while the beech bark is a good conductor.  Lightning striking a beech tree will therefore convey the high current on its exterior, leaving it relatively unscathed.

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6 Responses to “Are beech-trees ever struck by lightning?” (1889)

  1. J Thomas says:

    The anecdote described a beech tree which was dead on one side, and didn’t show whether normal beech trees would tend to protect people from lightning.

    There’s a possibility that they might.

    But there would be some bother and expense in testing it, and the result might not be publishable. It might not be reliable either. It might be that people would be safer to travel across an open field to a building without a lightning rod, than to sit under a healthy beech tree, even if the tree did turn out to provide some protection.

    • As I noted from the latter quote from Cook County, it seems that later studies indicated what Post suggested: the trees can get struck just as any other, but tend to take less damage in the process. To me, it seems that people interpreted the lack of apparent damage of beech trees as an indication that they don’t get struck, which is about the worst conclusion one can make.

  2. tgaw says:

    Fascinating! I never knew of that beech tree superstition. Thanks for kicking off my Sunday morning with such an interesting read!

  3. BruceK says:

    According to John Packham (I think) the smooth bark allows a film of water to conduct electricity down the outside of the tree, rather than frying its innards.

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