You’ve probably been told to stay away from trees during heavy thunderstorms and downpours, but why does lightning strike trees?
Lightning tends to strike the tallest object in an area. Therefore, a tree near a lake, pond, or river and surrounded by taller trees on the shore is a likely target.
Lightning often travels down the path of least resistance, and trees have a lot of moisture in them. It is easier for lightning to strike a tree than to travel through the air, so lightning tends to strike trees more often.
Most Vulnerable for Lightning Strikes
The best advice for avoiding lightning strikes is to get inside as soon as you hear thunder and before seeing lightning.
Unfortunately, trees can’t simply pick up their roots to take cover in case of a thunderstorm. They’re stuck in one spot.
Here are some locations where trees are likely to experience lightning strikes:
- Trees with electrical lights on their branches
- Trees in open areas
- Trees close to buildings
- Trees near other strands of trees or forests
- Trees on hilltops or mountainsides
- Trees near water bodies
What Happens After A Tree Is Struck By Lightning?
When a tree is struck by lightning, the damage to the tree can range from a few dents to the total destruction of the trunk.
Once the electricity from the lightning bolt hits the tree, water in the tree’s cells heats up, causing steam to form, which expands and enlarges the cells.
This sudden change in size and shape can wreak havoc on a tree’s structure, and some trees will explode as a result.
Moisture, Water in Trees, and Lightning
The water inside a tree is converted to steam, which can cause the tree’s bark to explode or even explode the tree.
Lightning often ignites the gases in wood rather than causing them to expand when it strikes a tree.
The gas expands and creates pressures that blow apart the innermost layer of bark.
When this happens in sapwood, it usually results in catastrophic effects.
Note: If lightning strikes near the bark, its heat causes moisture from the outside of the bark to evaporate and travel deeper into the tree. This effect lessens with depth.
Prevent the Damage
So, it’s worth asking can a tree survive a lightning strike?
The simple answer is YES.
Some trees or plants, particularly valuable or vulnerable ones, risk damage during a lightning strike.
In areas with a lot of lightning, property owners install lightning protection systems to protect trees from the damage usually associated with high electric charges.
These systems release the electric charge slowly, so it doesn’t build up and become dangerous.
Prevention is Better than “Cure”
If a tree or tree branch is prone to lightning strikes, you’re better off installing a lightning protection system to protect trees rather than repairing the damage later.
Tree protection can be accomplished with a variety of systems installed close to a tree.
A tree-mounted lightning protection system includes an air terminal mounted near the top of the tree, a conductor cable connecting this air terminal to a ground rod placed well away from the tree, and a ground rod.
Fact: This system diverts the lightning current from the tree through the cable to the ground, keeping the tree from being damaged.
Saving Vulnerable Trees
The U.S. Department of Agriculture recommends lightning protection systems for trees in high-risk areas.
Lightning strikes pose a serious threat to the health of trees and may kill them if the strike occurs on a vulnerable portion of the tree’s trunk.
Professional installation is required for maximum effectiveness, so talk with your local extension agent about what kind of system is right for your property.
This is the surest way on how to save a tree hit by lightning.
After the Lightning Strike
If a tree in your yard is hit by lightning, the best thing to do is keep the tree standing upright, protect the exposed trunk, and then watch for signs of life.
The chances of a tree dying after being struck by lightning are influenced by many factors, including:
- How old is the tree
- How healthy it is
- Where it’s located
The position of the tree is the most important factor for risk assessment.
The location of a large tree with a damaged trunk hanging over your home or children’s play area will increase the risk.
Note: If the tree is located in a large backyard with no structures nearby, you have much more flexibility in taking the wait-and-see approach.
Repairing Damaged Trees
Lightning can damage tree branches, the sap flow, and the bark. Trees damaged by lightning should be pruned to remove deadwood and to reduce the risk of fire.
Fertilization increases a tree’s ability to withstand drought and insect attacks.
Spraying trees with insecticides reduces the number of pests on a tree, reducing infestations and keeping the tree healthy.
Trees Most Susceptible to Lightning
It’s probably unlikely that you will see lightning strike a tree in a city or suburban area.
Four species of trees are susceptible to lightning since they match all the criteria on why does lightning strike trees; they’re taller, with more moisture content and grow on higher grounds.
1. Oak Tree
Oaks are more susceptible to lightning than other tree species because of the high moisture content in the leaves and bark.
Oaks also grow taller than many other trees, giving lightning a greater starting point from which to strike.
2. Poplar Tree
Poplar trees get struck by lightning predominantly while they are still young.
This is because they grow very tall and thin, making them the tallest trees in their area.
The poplars retain very little water, so there will be no flashover or fire hazard even if they are hit by lightning.
3. Willow Tree
Willows are known for their invasive root systems. Willows are excellent conductors of electricity and are prone to lightning strikes because of their high water retention.
The trees also have a tendency to entangle sewer lines, sidewalks, and other structures.
4. Ash Tree
Lightning strikes can be very damaging to ash trees.
For one thing, ash trees near water often have high moisture content in their root systems, so they will sustain more severe damage than other trees.
Debunking Common Myths About Trees and Lightning
Now that you understand why does lightning hit trees let’s delve into some of the misconceptions and myths about trees and lightning.
Myth #1: It Is Safest To Stand Underneath The Tallest Nearby Tree During A Thunderstorm
The fact is, that trees are tall and have high moisture content. This makes them particularly susceptible to being struck by lightning.
The electricity will travel through the tree into the ground, just as it would with any other tall object.
Myth #2: A Lightning Strike Usually Strikes The Same Place Only Once During A Storm
The claim that lightning never strikes twice is not true.
A tree may be hit multiple times, although a tree that has been struck once may not always be as good at conducting electricity as a healthy tree not hit by lightning.
However, the likelihood of being struck again is quite low.
Myth #3 When Lightning Strikes A Tree, It Does Not Affect The Surrounding Area
When lightning strikes a tree, it moves through the trunk and into the root system.
This can affect any nearby metal pipes and wires, which the electricity may damage.
The electricity in the tree may also “jump” from one object to another. This is called “side-flash.”
When there is a thunderstorm, lightning can strike. Lightning can be five times hotter than the sun; therefore, trees must be protected from each strike.
The tree, however, is not more important than the human body’s safety. So, it’s not just enough to know why does lightning strike trees.
Thousands of people are killed by lightning each year; protect yourself and your family members from being a part of that statistic.
Contact your local public works department to learn about the pros and cons of installing lightning protection on your trees.
And even if you decide to do it yourself, you will need to follow municipal or county regulations for this type of installation.