Lightning protection systems can safeguard your trees

Over the centuries, people have developed numerous ways to protect themselves, their homes, and their property from lightning strikes.

As arborists in North Florida, one of our major concerns is lightning that strikes trees.

When you consider that it may cost as much as $2,000 or more to remove a damaged tree and another $2,000 dollars or more to purchase and install a new sizable tree in your landscape, the consequences of a lightning strike can be significant. If the lightning jumps from a tree to a house, damage can be even more severe.

Over a million trees are struck by lightning in the United States each year. The National Lightning Detection Network shows that in North Florida lightning strikes four to eight times per square kilometer per year, or about one strike in every 50 acres per year. This is a significant level of risk for trees, houses, and people.

When lightning strikes a tree, it may cause significant biological and/or structural injury. If the damage is just biological, the tree may recover, or it may decline over a period of years and eventually die. If the damage is structural, the tree may be blown apart, throwing large splinters of wood hundreds of feet and shattering branches and stems.

Not only can lightning start forest fires, but it can also start fires that may transfer from a tree to a home. We know of several homes in Tallahassee that caught fire from lightning strikes that transferred from a tree to a house.

Tree damage occurs in a fraction of a second before the electricity leaves the tree. However, the damage that lightning causes may continue. It may jump or “side flash” to a more conductive structure such as metal on a house, or it may disperse into the soil often through the tree root system. When the lightning goes into the soil, it creates a condition known as “step voltage.” This is a difference in voltage that can injure people, animals, and household electronics.

One way to protect a tree from lightning strikes is to have a lightning protection system installed. These systems consist of ground rods and copper wires that transfer lightning’s electrical charge to the ground to help protect the tree from lightning damage.

According to Dr. Tom Smiley, research scientist at the Bartlett Tree Expert Companies’ research laboratory in Charlotte, North Carolina, “research at the University of Florida and other institutions have lead to improvements in the way we can protect trees that have lowered the price and increased the effectiveness of tree lightning protection systems.”

While tree lightning protection systems are intended to preserve trees, they may have the side benefit of reducing side flash to nearby structures and can lessen the effects of step voltage. Therefore, arborists often recommend lightning protection systems in large trees near houses, high value and historic trees, and trees near water. Trees with correctly installed and maintained lightning protection systems are almost never damaged by lightning strikes.

To learn more about protecting your trees, contact an arborist certified by the ISA (International Society of Arboriculture). To learn more about direct protection of structures, contact an Underwriters Laboratory certified lightning protection system installer.

To protect your household electronics, contact your local electrician and ask about a whole house surge protector.

Sam Hand, Jr. is Extension Faculty at Florida A&M University and an ISA Certified Arborist. Christopher Renn is an ISA Certified Arborist and is also qualified in Tree Risk Assessment by ISA. They are both volunteer writers for UF/IFAS Extension Leon County, an Equal Opportunity Institution. For gardening questions, email the extension office at AskAMasterGardener@ifas.ufl.edu.

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