According to a German folk wisdom, in a lightning storm one should avoid oaks and seek out beeches.
„Buchen sollst Du suchen, Eichen sollst Du weichen“
beeches you should seek, oaks you should avoid
The German "knowledge site" waswiewo claims without sources:
Das verblüffende Ergebnis: es wurden praktisch nur Eichen und andere Bäume von Blitzen getroffen, Buchen fast immer verschont. Die Forscher vermuten, dass der höhere Feuchtigkeitsgehalt der Eichen die Blitze anzog – eine interessante Erklärung für die Volksweisheit.
Meaning (emphasis mine):
The stunning result: there were practically only oaks and other trees hit by lightning, beeches were almost always spared. Researchers suspect, that the higher humidity of oaks was attracting lightning – an interesting explanation for the folk wisdom.
However, the column Stimmt's? (Is it true?) from this article in Die Zeit from 1998 states without sources:
es gibt keine Unterschiede bei der Blitzgefahr.
which means (again emphasis mine)
There are no differences in the the lightning danger.
which rings true to me, and the same is stated in other sources, but what seems obvious is not always true. (NB: Die Zeit is a quality newspaper and normally reliable.)
The Skulls in the stars weblog quotes a 1889-07-05 article in Science:
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.
And then quotes The Forest Preserve District of Cook County, Illinois, USA as stating:
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.
But also the University of Minnesota which states (still emphasis mine):
Although no species of tree is totally immune to lightning, some are definitely more resistant to lightning strikes than others. Birch, for example, is rarely struck, whereas elm, maple, oak and most conifers are commonly hit. The reason for the wide variation in susceptibility between species is not clear. In some cases it is because some trees simply tower over others in the landscape, in other cases it is because some trees have a greater ability to collect water on their leaf surfaces (conifers) or to shed water on their bark surfaces (oak). Some authorities attribute the variation among species to the composition of the trees. 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.
So, it may indeed not be as obvious at it appears...
A colleague speculated that beeches are struck less because they grow in forests whereas oaks grow in fields, which would mean that the folk wisdom is true but for a reason that can easily be misunderstood, but I could not find a source for this interpretation/explanation.
Are beeches less likely to be struck by lightning than oaks?
Am I safer near a beech than near an oak during a lightning storm?