Trees are valuable parts of a property owner’s landscape. Damage from lightning is a common occurrence in Virginia. Lightning damage can come from a direct hit or a side flash. Damage to trees and other shrubs can vary from slight limb or twig damage to total annihilation. Lightning’s electrical charge can boil the liquid sap, causing the bark to split open or the tree to literally explode. In some instances, the only evidence of a lightning strike may be the internal browning of the xylem, causing a gradual decay of the tree. According to agricultural specialist, Derek Morris, “lightning is most likely to strike a lone tree, the tallest tree in a group, a tall tree at the end of a group of trees, trees growing in moist soil or close to a body of water or trees closest to a building.” Morris cites the ten species of trees that are most often struck by lightning as : maple, ash, poplar, pine, oak, hemlock, elm and sycamore. Those struck less often are: birch, beech and chestnut. Trees with a high starch content such as ash, maple and oak are better conductors than those high in oil such as beech and birch. Since few trees survive a direct lightning hit, vulnerable trees, specimen trees, historic trees or a tree over public shelter should be protected with lightning rods. In some situations, lightning-struck trees will continue to decline over years and require removal. Most often, property owners will notice signs of decay within two weeks of a lightning strike.
(Courtesy of Kim Loehr)