When trees are close to buildings or structures, lightning strikes pose a serious danger to the landscape and property as well as people using that property. Beyond this immediate threat, strikes can kill trees or weaken them so severely that they are then attacked and killed by insects and disease. Trees that are featured prominently in the landscape or those of particular value or historic significance can be devastated in an instant. After a strike, the tree may be completely shattered. It is also possible for a tree to show little to no external damage, but be impacted nonetheless.
Many property owners and managers do not realize that when lightning strikes a tree, it can then “jump” or side-flash to a more conductive material nearby. Metal objects on a building such as downspouts can conduct the strike, potentially resulting in severe damage and even fire. Structures that have a tree within three metres, a tree taller than the roof, or a tree with limbs hanging over that structure are most at risk of a side-flash.
Special consideration should also be given to strike-prone species including Sequoiadendron, sequoia, poplar, cedar, and Douglas fir. Trees close to water, on hilltops, or those growing in the open or in small groups also pose a higher risk.
To help protect trees, Bartlett Tree Experts can install lightning protection systems. Comprised of copper conductors installed on the tree and connected to a ground rod, these systems effectively minimise the risk of damage from a strike. Instead of damaging the tree, the charge is conducted to the earth where the energy is dispersed.
As with all weather-related events, there are no guarantees when it comes to lightning strikes. However, lightning protection systems do effectively provide a preferred, non-damaging path for lightning to follow to the ground. Lightning rarely injures trees that have a properly installed and maintained system.
Maintenance is an important part of the equation. As trees grow, the system should be adjusted to accommodate that growth. A yearly inspection will help ensure the system is working to optimal effectiveness.