I'm Dave Thurlow from the Mount Washington Observatory and this is the weather notebook. Today we talk about oak trees, which are common across the US and Europe, and the source of many a weather proverb. One of the Oak's weather associations has to do with thunder and lightning.
Early Slavic and Norse cultures considered the oak to be the god of thunder. It was, for instance, thought that a charred oak log, kept on the hearth all summer long, would protect one's house from lightning. What these observant folks were noticing about the oak was that it was more likely than other trees to be struck by lightning, and more likely to survive a strike, than say an ash or a pine. And this is true. The Oak typically has a very deep central root that plunges straight down beneath the tree. Also, hollow water filled cells run up and down in the wood of the oak's trunk. These two qualities make oak trees better grounded and more conductive than trees with shallow roots and closed cells.
So the Oak attracts lightning, which passes through to the grounded root, the lightning causes thunder and the connection between the Oak and the God of Thunder must have seemed obvious. This is a point however that these days should not be used in lightning safety. The last thing you want to do when caught in a thunderstorm is pause for a little tree identification. Be it oak, birch or hemlock, you don't want to be standing next to an isolated tree in a thunderstorm. It's best to head for the woods or head inside. The Weather Notebook is engineered by Sean Doucette and underwritten by Subaru, maker of the all-weather legacy, Subaru the beauty of all wheel drive.