Lightning Protection Systems (LPS)
Most homebuyers want to buy property that has an established landscape. Older trees add dollar value and give the look of an established neighborhood. Preserving trees that provide aesthetic beauty or have sentimental value may also need protection. Trees with lightning protection tend to reduce the hazard of injury or death to family, friends and neighbors when near or under a tree during a lightning thunderstorm. Trees that are in close proximity to buildings present an increased danger to the building from lightning strikes. The National Arborist Association recommends protecting trees of historic interest or high value, trees in recreational areas, parks golf courses or other areas where people may be injured. Additionally trees are at a higher risk due to their location on isolated hills, on pastures, or near water. Let an arborist at the Rayal Tree Care Company explain how a lightning protection system can protect your most valuable trees and preserve their beauty for many years to come.
Limitations of Tree Lightning Protection Systems
These systems are intended to reduce the risk of damage to trees and adjacent structures from lightning strikes. They are not intended to directly protect people from lightning strikes. Protected trees are not considered safe havens from lightning strikes during storms.
Basic principles of lightning
Lightning is a transient, high current, electric discharge with a path length measured in miles. Lightning connects positive and negative electrical charges that build up between clouds and ground. The “stepped leader” that descends from a storm cloud typically initiates the lightning strike. As the step leader nears earth, “streamers” are drawn to it from tall, conductive structures such as trees. The streamers and leader meet 10 to 100 yards above the structure or tree. At this connection the first stroke of lightning occurs. The electrical current tries to neutralize the opposite charges. A typical strike has 3 to 4 of these strokes. Each stroke and each strike last a fraction of a second. The total current in a strike is usually between 20,000 and 50,000 amps at about 10,000 volts.
Lightning protection systems (LPS) in trees are intended to be receptive to lightning strikes and safely conduct them to ground. The system protects your trees by providing a preferred, non-damaging path to ground. Properly installed and maintained, the concept is to be 98 % effective at preventing serious damage to trees.
Lightning strike frequency
Susceptibility often is thought to be related more to the trees location and size than to the species. The frequency of lightning strikes increase as:
- Trees are nearest to water.
- Trees located on hilltops or on slopes facing approaching storms.
- The tallest tree located among others.
- Trees located in an open area.
- Trees that border woods or line a street.
Installing a Lightning Protection System requires components specified by the Tree Care Industry Association (TCIA) and the International Society of Arboriculture (ISA). These components must consist of copper, copper alloys or bronze allow. Parts commonly used are ground rods & clamps, air terminals, conductor cables, splicers and drive fasteners. Air terminals and cables are routed carefully through the upper part of the tree. The cable is fastened to the tree using drive fasteners that are spaced accordingly. After all the cabling is downward towards the base of the tree, the ground connection is made. The ground is implanted 8 - 10 feet below the surface and approximately 10 feet from the trunk of the tree.
The working life of conductors and major components of a lightning protection system can be 50 to 100 years. If component parts deteriorate, they can be replaced or upgraded. Systems should have periodic inspections and be maintained to ensure reliability.
Lightning Damaged Trees
Evaluation of lightning damage to a trees structure is paramount to making treatment decisions for any lightning-struck tree. Often the damage is not visible during an inspection. Life expectancy depends on the biological disruption caused by the lightning damage. Bark damage disrupts phloem function. This damage may take years to become apparent. Sapwood damage has an immediate effect on the water status of portions of the tree crown supplied by the damaged areas. Root damage, which is difficult to access, mimics drought symptoms.
Sometimes bark is shattered off a lightning struck tree. This type of injury can lead to inviting insects and future decay. Bores and bark beetles often are attracted to the odor when trees are injured such as with lightning damage. Decay can advance rapidly because of damage to pre-existing barrier zones and reaction zones within the wood tissue.
A Rayal Tree Care Company arborist can assess the amount of damage and determine an appropriate treatment plan. Each case is specific and therefore needs to be evaluated by an expert. Even with appropriate treatments, some struck trees decline and die after a few years. Remember lightning damage is much easier to prevent than to repair.
At Rayal Tree Care Company, our qualified arborists are ready to explain how our Lightning Protection System can preserve your most precious trees, which will continue to add beauty and value to your property. Contact our customer service department to schedule a walk through of your property at you earliest convenience.