Lightning striking trees can be a concern not only to the safety of homeowners, but the continued health of an otherwise healthy tree. Understanding their impact can help in mitigating and lessening the damage.
While Florida and Texas are generally the most lightning prone states, with the summer months being the majority of the timeframe, lightning strikes can happen anywhere and at any time of year. One of our client’s trees was stuck by lightning in February during an off season thunderstorm. It is an old Oak in the original part of town common to locals. It’s not the tallest thing around; there are many other tall trees, taller homes, and taller buildings are in the immediate area. Oaks and cottonwoods are commonly struck but any tree can be hit.
The first thing to do on site for our ISA Certified Arborist was to inspect for physical damage – broken or damaged limbs that could fall or should be removed. The intense heat of the electrical charge causes the sap to instantly vaporize into steam. And, since lightning seeks ground, a path is created from the initial entry point down the trunk and into the soil.
Sometimes, the lightning will fork and enter the tree in multiple spots in the canopy before traveling down the trunk. The energy created by the expansion of the sap into steam tears the tissues of the cambium and bark. Every tree is different and every lightning strike is different. There is still a lot we don’t know about lightning and it is difficult to predict when and where it will strike.
With this particular tree, the path to ground was clear – two points of entry and a relatively straight and narrow path down the trunk. Unfortunately, some strikes result in wide or twisted wounds down the trunk in addition to split limbs or blown out tops.
Since we can’t know how much internal tissue damage happened in the roots, trunk, or canopy we must make a judgement about the tree’s health prior to the strike. We had pruned this tree two winters ago and can tell, even in February, that the canopy was in good condition prior to the strike. This is another great reason to have a professional, and ISA Certified Arborist view and monitor your tree health – it can offer many perks to your property value as well a mitigate safety concerns ahead of time. Being proactive, instead of reactive, can be the difference between a tree’s life and death.
Our plan was to perform bark tracing, systemic insecticide, and add an organic fertilizer blend that is a little higher in nitrogen than our usual application for this particular Oak. The bark tracing process involves cutting along both sides of the wound from the entry points down to ground. Two climbers went into the tree and cut along the edge of the bark to smooth out the edges giving the tree a better surface to grow wound tissue.
Systemic insecticide is meant to reduce the amount of feeding by opportunistic insects, such as borers. While a healthy tree can withstand a certain amount of insect activity, borers are considered secondary pests and will take advantage of stressed or damaged trees. This can lead to declining health as a tree’s resources are diverted. Using a good, organic fertilizer with higher nitrogen content can also give help encourage wound tissue growth.
While trees don’t “heal,” we can help them to manage stress and injury. Our team will be checking in with this old tree as spring progresses. If there is some dieback in the canopy, we can consider pruning again this winter.
Keep posted as we will share the continuous story of this tree in the future!