Question: Is it possible for lightning to damage trees?

Answer: Afternoon thunderstorms are common during the summer months. With these thunderstorms often comes lightning which can strike various things, including trees.

Lightning occurs when negative charges in low clouds and positive charges on the ground meet in the air. These charges move so quickly in the air that, to the human eye, lightning strikes appear as an electrical bolt that travels from the clouds to the ground. Lightning seeks the path of least resistance through the best available conductor in the area, such as wood or metal. Trees, because of their height, are natural lightning rods.

Symptoms of lightning damage to a tree can vary greatly. A tree struck by lightning can appear to be perfectly normal immediately following a strike. On the other hand, some trees struck by lightning can explode or bust into flames. In some cases it is easy to diagnose lightning damage on a tree. Lightning strikes can strip off the bark often in a spiral fashion. Other times, lightning can strike a tree and the tree will appear normal immediately following the strike but will die soon after for no apparent reason. Often times when the tree appears normal immediately following a lightning strike, it can suggest damage on the tree’s inside or that the lightning caused root damage as the lightning exited the tree.

When lightning strikes a tree, you usually have to take a wait-and-see approach. Some trees die immediately from the damage while other trees will live for a number of years. For the trees that live for a few years, you can run into the problem of the lightning scars and loss of bark making the tree more exposed to insects and diseases.

It is common for a tree to be struck by lightning and you not even realize that it had been struck because the tree looks perfectly normal for a while and then will suddenly begin to die. This situation occurs because the lightning has stressed the tree severely on the inside. The electrical charge that was sent through the tree can disrupt vital functions within the tree. The intense heat that can be given off of the lightning strike takes a great deal of energy from the plant.

So what should be done to a tree that was struck by lightning? Most of the time the best thing to do is to wait and see if the tree survives or not. Many symptoms from the lightning strike will not appear until later on. Trees that appear to have damage severe enough to kill the tree should be removed to prevent them from possibly falling later. If the majority of the tree appears to be surviving after waiting a while, water and fertilize deeply in later winter to early spring just before new leaves appear. Keep an eye on the tree through the spring and remove parts of the tree that are dead. While going through the spring, if the tree appears to have more damage than previously thought, especially if the damage is in the main trunk or crown of the tree, you may have to decide that the tree will not be worth trying to save and that it will be better to remove the tree.

There is no way to avoid Mother Nature when it comes to lightning striking trees, but by being aware of the damage that lightening can do to a tree you will know what to do when a tree is struck.

Reminder: Please call the Sampson County Cooperative Extension Center at (910) 592-7161 with your horticultural questions and to register for any upcoming events. Be sure to check out the Ask An Expert Widget at sampson.ces.ncsu.edu for any questions you may have.