Tree Struck by Lightning: Will It Survive, and What to Do Next

July afternoons around Houston come with thunderstorms, and after a loud one somebody walks out and finds a strip of bark in the grass and a raw white scar running down the trunk of the biggest tree on the property. The question is always the same. Is it going to die?

The short answer: a hardwood with a strike scar down one side usually lives. A pine usually doesn’t. And for either one, the smart move in the first few weeks is to do less than you think.

What a strike actually does

Lightning takes the path of least resistance to the ground, and a tall tree full of water is a good conductor. As the current runs down the trunk it turns the moisture in the wood to steam in an instant. Texas A&M AgriLife Extension’s tree care guidance describes it plainly: if that steam forms under the bark, the expansion blasts bark and branches off the tree. That is the strip of missing bark, and the wood along the path is dead.

Sometimes the current runs down a narrow line. Sometimes it wraps the whole trunk. Either way, the Georgia extension guide that AgriLife distributes for Harris County notes that some of the worst damage is where you can’t see it: the roots. A tree that looks scarred but fine above ground can have lost much of its root system, and that shows up as the canopy fails over the following weeks.

The other thing a strike does is invite insects. A damaged, water-stressed tree is exactly what borers and bark beetles are looking for, and that’s where the pine story gets short.

Reading the damage

The Georgia guide, which Texas A&M AgriLife Extension distributes for Harris County homeowners, sorts lightning damage by how much of the trunk’s circumference lost bark. That’s the number to look at.

A hardwood with less than about 30 percent of the bark circumference affected. Good odds. Extension guidance says that if only one side of the tree shows evidence of the strike, the chances of it surviving and eventually closing the wound are good. The treatment is to minimize stress, water it, and wait a full growing season before fertilizing or pruning to shape.

A hardwood with more than about 30 percent of the circumference gone. The Georgia guide puts this in the removal column. The tree has lost too much of the tissue it uses to move water, and what remains is open to decay and insects on a scale it cannot seal.

A pine, any strike. The same guide lists a lightning-struck pine as a removal regardless of how the scar looks. The reason is beetles. Texas A&M Forest Service lists lightning among the stresses that make a pine susceptible to engraver beetle attack, and the Georgia guide is blunt that southern pine beetle quickly destroys a lightning-struck pine. Around here the usual visitor is the Ips engraver, and once it’s under the bark the tree isn’t coming back.

Deep cracks, a split trunk, or a top blown out. Structural failure, not just tissue damage. Same column as the big-circumference strike.

What to do in the first month

Nothing with a saw, unless something is hanging. Loose bark that is peeling can be trimmed back to where it is still attached. Broken limbs that are a hazard come down. Beyond that, leave it. The tree is deciding whether it can live, and cutting healthy wood off it now removes the leaves it needs to recover.

Water it, slowly and deep. Extension guidance on struck trees pairs watering with reducing stress, and it’s the one thing you can do that helps. A slow soak at the drip line once a week through the summer, not a sprinkler at the trunk.

Hold the fertilizer. The Georgia guide says wait one growing season. A tree that’s fighting to survive doesn’t need to be pushed into new growth on roots that may be half gone.

Watch the canopy, and watch the trunk. On a hardwood, the sign you are looking for is whether it holds its leaves through the summer and leafs out normally next spring. AgriLife’s guidance is that a tree that makes it to the following spring and leafs out has a much better chance of full recovery. On a pine, watch for pitch tubes on the bark and reddish sawdust in the crevices. That’s beetles, and it means the decision has been made for you.

Don’t let anyone talk you into a wound dressing or a spray. Neither changes the outcome. On oaks, painting a fresh wound is a disease precaution, and that is a separate subject. On a lightning scar there is nothing to seal.

When it needs to come down now

A struck tree that is going to fail rarely fails the same week. That can lull people. What decides the timing isn’t the tree, it’s what’s under it.

Texas A&M Forest Service puts it at six to ten months after a pine dies before it has decayed enough for large limbs or the top to break. That is the window, and the Forest Service says a dead pine positioned to fall on a structure, a road, a fence or a power line should be considered hazardous and removed sooner rather than later. A dead pine leaning over the back of the property can wait. One over the roof cannot.

For a hardwood in the removal column, the same logic. If it’s over the house, the driveway, or the neighbor’s fence, take it down while it’s still sound enough to be dismantled safely. A tree that has started to decay is a harder and riskier removal than the same tree taken a few months earlier. Our guide to what makes a tree an emergency in Cypress covers where that line sits.

If a limb came down on the house in the same storm, our storm damage and insurance guide walks through the first day and what a typical policy covers.

The trees most likely to be hit

Lightning favors height and isolation: the tallest tree in an open yard, a pine standing above the rest of the canopy, an oak on a rise. Lightning protection systems exist, but the Georgia guide reserves them for historic or specimen trees and calls them expensive. For most yards, knowing which tree is the likely target and keeping it healthy enough to survive a hit is the practical answer.

If you have a fresh scar and can’t tell which column your tree is in, that is a reasonable thing to have someone look at rather than guess. Ask for a free estimate and we will come read it with you. We cover Houston, Kingwood, Humble, Conroe, The Woodlands, Spring, Tomball, Cypress and Katy.

Sources: Texas A&M AgriLife Extension Tree Care Kit guidance on lightning and associated tree damage; University of Georgia Cooperative Extension, “Storm Damaged Trees: Prevention and Treatment” (Circular 806), as distributed by Texas A&M AgriLife Extension, Harris County; Texas A&M Forest Service guidance on pine engraver beetles; Nebraska Extension, “Lightning Strikes: Will My Tree Survive?”