Pow! Bam! Kaboom! No, those aren't the captions of cartoon fistfights between superheroes. Those are the sounds we often associate with the rumblings we hear overhead from the clouds that accompany thunderstorms.
Of course, when you hear thunder, you automatically anticipate and look for what? You guessed it! Lightning! Depending upon how close a storm is, a rumble of thunder will usually be followed rather quickly by a flash of lightning.
But what exactly is lightning? Quite simply, it's a bright flash of electricity. Lightning can occur within a single cloud, between clouds, and between a cloud and the ground. The latter, often called cloud-to-ground lightning, is what we commonly think of as a lightning bolt that we see during a thunderstorm.
Small particles of ice collide within thunderclouds, causing an electric charge to build up. Objects on the ground, especially taller things like mountains, buildings, trees, and even people, can also build up an electric charge. When electrical charges coming down from clouds meet opposite electrical charges coming up from the ground, they connect and electric current flows rapidly from the cloud to the ground in what we call a flash or a lightning strike.
You may have experienced a similar phenomenon known as static electricity. If you've ever walked across a carpet and then felt a shock when you touched something metal, you've felt the power of an electrical discharge. That shock you felt was static electricity moving between you and a metal object.
Not only is there a great deal of electricity in a flash of lightning, it's also very hot. A lightning bolt can generate temperatures of about 54,000º F — or about six times hotter than the surface of the Sun!
Although it might seem like a foregone conclusion that a tree might be burned up in an instant, lightning can actually have a variety of effects on a tree. What exactly happens depends upon several factors, including what kind of tree it is, how much moisture it contains, the overall health of the tree at the time of the strike, and the intensity of the lightning strike.
Much of the damage that lightning does to trees is a result of what happens when the moisture inside a tree is subjected to the super-hot temperatures caused by lightning. A tree's moist tissues often sit just below the outer layer of bark. This is why some lightning strikes result in the bark of a tree appearing to explode in large chunks.
If the outer layer of bark is soaked from excessive rainfall, however, the lightning may travel along the outside of the tree to the ground, resulting in little damage. At other times, though, intense lightning bolts may split trees in two and cause them to burst into flame from the inside out.
A tree that has been hit by lightning may survive intact for many years. Other trees, though, might need to be cut down if they pose a danger of falling on people or property. Some large trees have been known to have been hit by lightning on many separate occasions.
If a tree struck by lightning doesn't catch on fire and burn to the ground, it may live for quite a while even with extensive injuries. Lightning-damaged trees, however, will often be more susceptible to other types of damage, such as that from insects, disease, and decay.