Wind, lightning pose risk to trees
April showers bring May flowers, the saying goes, but they can also bring destructive wind and lightning.
Although nature’s meteorological shows of power occur throughout the year, spring is prime time for thunderstorms — and large trees are often the victims.
“Lightning damage can be very severe,” Eric Brownlee, a certified arborist and the manager of the Columbus office of Bartlett Tree Experts, said by phone. “It’s possible that any tree could get struck.”
As for wind, “it’s just as damaging to trees as lightning can be,” he said.
Fortunately, homeowners can take pre-emptive steps to minimize or even prevent damage from both wind and lightning.
“You can identify structural issues in a tree that may fail in high wind,” Brownlee said.
For vulnerable branches, an arborist can install cabling or bracing for support.
In addition, judicious pruning can remove weak branches and strengthen structure without threatening a tree’s health.
Tree species aren’t equally at risk in windstorms, he added.
“Typically, your sprawling types (such as maples and oaks) are more prone to wind damage.”
Trees with a pyramidal shape, such as pine and spruce, are usually less susceptible.
Similarly, some types of trees are more vulnerable to lightning strikes than others.
“The tree that stands out to me is London plane tree and sycamore,” Brownlee said.
Others considered to carry a higher risk are black locust and tulip poplar, which have a relatively high moisture content, according to the International Society of Arboriculture.
Low-risk species include beech and horse chestnut.
No tree is immune, however, and “lightning strikes the United States about 25 million times a year,” according to the website of the National Weather Service.
As a result, many experts suggest having an arborist install what’s called a “tree lightning-protection system.”
“These systems use copper conductors connected to a ground rod to reduce tree damage and conduct the electrical charge to the earth, where the energy is dispersed,” according to Bartlett’s website.
“Lightning will travel down the wire as opposed to the tree,” Brownlee added. “It’s a very simple system.”
In addition to protecting the tree, such a system can shield nearby buildings from a phenomenon called “sideflashing,” which occurs when lightning “jumps” from a tree to another structure.
He and other arborists recommend lightning-protection systems in particular for very tall trees, trees close to buildings and specimens with historical significance.
Without protection, a lightning-struck tree might suffer fatal damage and require removal, or be weakened enough to give insects or diseases the upper hand.
“You might not see any signs,” he said. “In other cases, we’ve seen bark blown off. We’ve seen trees that exploded.”
But you don’t have to own a tree-studded estate to heed Brownlee’s most compelling advice:
“During a thunderstorm, you do not want to be under a tree.”