Florida is one of the world’s highest lightning strike regions. Securely grounding homes and buildings is a common practice (and building code requirement) to mitigate the damage done by random hits from these high voltage events.
This same type of system can be used on trees to improve their chances of surviving a lightning strike. The technology to ground trees has been in existence for decades and is used on high value heritage and/or specimen trees.
The structure consists of three distinct parts. The first is an air terminal in the tree’s top to catch the strike. The energy charge of the strike travels through a copper cable “down conductor” which connects to the third part, a ground rod system in the earth to dissipate the charge.
Since metal is a far better conductor than the cellulose-based tissue of the tree, the lightning will follow the copper cable, keeping the energy out of the tree and avoiding the destruction normally seen when a tree is struck.
A lightning strike gives no warning of its approach, but a tree, especially a tall one, is a likely candidate for a high voltage hit. Much like lightning rod systems on buildings, an arboreal lightning protection system will minimize the potential for damage to a tree.
While the primary purpose of a lightning protection system is to protect the tree, it may also keep the strike from damaging adjacent elements such as nearby structures or landscape plants. Ideally it will discharge the entire energy load into the grounding rods.
When an unprotected tree receives a strike, the charge can ricochet to objects in near proximity. This could be other trees close by, but if the voltage encounters metal it will quickly travel to a more distant dissipation point.
Lightning is uniquely unpredictable and there are no absolute guarantees as to the path it will take. Under certain circumstances the lightning may still jump to other objects, even if a grounding system has been installed.
Any object close to a tree or trees, especially if the tree is the tallest structure in the landscape, should be thoroughly grounded. Having a better path-to-ground than just the tree certainly reduces the potential for secondary damage even though it may not completely eliminate it.
Another reason to have a lightning protection system in a tree is if any metal components are present on or near the tree. This includes, but is not limited to, a cable bracing system on the tree, steel or aluminum devices such as swing sets, or street signs on metal poles.
None of these metallic objects increase the likelihood of a lightning strike, but a hit could result in a concentrated charge being directed into the tree. The focused amperage may severely damage the tree’s tissue resulting in fatal injury.
Unfortunately, many times the damaged tree will have to be removed. With a properly installed and grounded system, the electrical charge can be harmlessly disbursed in the ground and away from the tree and nearby structures.
Lightning protection is not a do-it-yourself project, and qualified professionals must be engaged. Industry standards and local building codes must be followed and pass inspection.
As with any project, budgets must be considered, but an injured or deceased tree with the potential to inflict damage on residents and structures is almost always more expensive than an installed lightning protection system.
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