By: Teo Spengler
A tree is often the tallest spire around, which makes it a natural lightning rod during storms. Some 100 lightning strikes happen every second around the world, and that means there are more trees hit by lightning than you might have guessed. Not all trees are equally vulnerable to lightning strikes, however, and some trees struck by lightning can be saved. Read on to learn about repairing lightning damaged trees.
Lightening damage in trees is instantaneous. When lightning strikes, it turns the liquids inside the tree to gas instantly, and the tree bark explodes. Some 50% of trees hit by lightning die immediately. Some of the others become weakened and susceptible to disease.
Not all trees have an equal chance of getting hit. These species are commonly hit by lightning:
Birch and beech rarely get hit and, because of that, suffer little lightning struck tree damage.
Lightning damage in trees varies widely. Sometimes, a tree splinters or shatters when hit. In other trees, lightning blows off a strip of bark. Still others appear undamaged, yet suffer unseen root injury that will kill them in short order.
Whatever amount of damage you see on a tree after lightning strikes, remember that the tree has been severely stressed, so knowing how to save a tree struck by lightning in this instance is imperative. There is no guarantee of success when you begin repairing lightning damaged trees. However, in some cases, it is possible.
When trees suffer the stress of being hit by lightning, they require additional nutrients to heal. The first step in overcoming lightning damage in trees is to give the trees generous amounts of water. They can take up supplemental nutrients with supplemental irrigation.
When you are repairing lightning damaged trees, give them fertilizer to stimulate new growth. Trees hit by lightning that survive until spring and leaf out are very likely to recover.
Another way to start repairing lightning damaged trees is to prune out broken branches and torn wood. Don’t do extensive pruning until a year has passed so that you can assess the actual damage done.
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Melvin R. Koelling Department of Forestry Michigan State University,
Russell P. Kidd Department of Forestry Michigan State University
When storms strike, along with damage to property such as houses, power lines, and commercial buildings, they may cause damage to trees in the urban forest. There are six main types of storm damage to trees: 1) blow-over, 2) stem failure, 3) crown twist, 4) root failure, 5) branch failure, and 6) lightning. Each type is the result of a complex and interactive mix of tree problems and climate.
Damage is often relatively minor with only the smallest braches of the tree being injured. Usually damages of this type result in little or no permanent damage to the tree. All that is required is clean up of the broken twigs and branches and perhaps some light pruning to restore a pleasing shape.
Severe damage consisting of large broken branches, split crotches and removal of bark, and splitting or splintering of the trunk can also occur. Strong winds, lightning and heavy ice storms are the most probable causes. When a tree is severely damaged, the first question that must be answered is: “Is the condition of the tree such to make keeping it worthwhile?” Take the time and effort to save a tree only if a substantial portion of the tree remains intact and if, when repairs are made, the tree will still be attractive and of value to the property owner.
Assuming the decision has been made to repair the tree, the next question is: “Am I capable of repairing the damage myself or should I seek professional help?” Unless experienced in the use of such equipment and comfortable working off the ground, it may be best to have the work performed by a competent professional. Once it has been determined that a tree can be salvaged there are certain procedures that one should follow.
Branches smaller than 3-inches in diameter can be removed using pruning shears or a pole-pruner. Sharp, properly aligned shears or pruners will make a clean cut, not crush or tear bark tissue and reduce cleanup time. Use a sharp saw to remove larger branches. If a power saw is used, a safety rope and harness are essential. The most efficient and least damaging way to remove large branches without causing further damage to the tree is the 3-cut procedure. The first cut is the undercut. From the underside, saw approximately 12 to 18 inches from the main stem or branch to which the damage limb is attached. Cut into the branch about 1 to 1½ inches deep and withdraw the saw blade before it begins to bind. For the second cut, or over cut, saw approximately 2 to 3 inches beyond the undercut and continue until the branch is removed. The final or flush cut is made to remove the remaining stub. Saw in the natural depression flush with the trunk or branches. Careless pruning can result in death of the entire branch or in excessive sprouting and the eventual development of more problems later on, since these sprouts are generally short lived and weakly attached.
In some instances the tearing of bark on large limbs or the main trunk occurs. This is especially common when trees have been struck by lightning. Carefully trim away all loose bark back to the area where it is solidly attached. Do not cut too deeply into the wood of the tree. This cutting of the bark is referred to as a bark tracing. If possible, all bark wounds should be cut into an elliptical shape, being careful to keep the trace as narrow as possible. This may be difficult on large areas. However, trimming the bark in this manner will encourage rapid healing with minimal wood decay.
Some forks and main branches that are split apart or partially broken may be repaired without removing one or both branches. This type of work is usually beyond the capability of most homeowners unless they have experienced assistance. If the break is nearly even, it is possible to draw the split portions back together and secure them with a large diameter steel bolt and threaded screw rod placed through the split section. The proper procedure for repair begins with drawing the split together using a small block and tackle or winch. Place this 6 to 8 feet or more above the split to obtain maximum leverage. Drill holes through both halves of the split in which the bolt or rod is inserted. With long split areas, 2 or more bolts may be necessary. In addition to the bolts, it often helps to install a steel cable between the two main braches of the split fork several feet above the split. Use lag screws to attach the cable to each branch. Do not wrap the cable around the branch or it may eventually girdle it. This cable system helps hold the crotch together, thus reducing the chance of further breakage.
After pruning is complete, all wounds larger than 1½ to 2 inches in diameter can be coated with wound dressing or pruning paint. Recent research has shown that dressings and paints probably do not increase the rate of healing. However, they may prevent drying out and provide some cosmetic effect. Several commercial materials are available or a couple of coats of orange shellac suffice. Areas of torn bark where tracings have been made can also be treated in this manner.
Trees may be uprooted as a result of severe storms. If the tree is large, it cannot be saved and therefore must be removed. For some smaller trees it may be possible to straighten the tree and brace it using guy wires or cables. Some type of power lift or equipment is usually necessary to pull the tree upright. Do not attempt this procedure unless 1/3 to 1/2 of the roots are still in the soil and the remaining exposed roots are relatively compact and undisturbed.
Before the tree is pulled upright, remove some soil from beneath the root mass so the roots will be placed below the existing soil grade level. Once the tree is back in the upright position, fill in soil as needed. Water the tree to help firm the soil and remove air pockets. Attach 2 or 3 guy lines to the trunk as is often done for newly transplanted trees, at a point approximately two-thirds of the height of the tree and to anchors placed some 12 to 15 feet from the base of the tree to hold the tree in place.
Materials from fallen or salvaged trees can be used in several ways. The larger branches can be cut and used for firewood. Add smaller branches and twigs to the compost pile or cut up for kindling. Branches can also be converted into chips for use as compost, mulch or other landscaping purposes if chipping equipment is available to local residents.
Melvin.R Koelling and Russell P. Kidd, MSU Forestry Department, Extension Bulletin E-1364
Mary L. Duryea, Ph.D., forest resource extension specialist, School of Forest Resources and Conservation, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, 32611
Manfred E. Mielke, Plant Pathologist Northeastern Area, Forest Health Protection, USDA Forest Service, St. Paul, Minnesota 55108
It is hard to predict just how much damage lightning will do to an oak tree. The outward damage is obvious, like a burnt off limb or the bark blown off.
If your oak tree is still standing even after a limb has been blown off by lightning, that's a good sign. The tree will likely survive if the limb absorbed the brunt of the lightning's force. In this case, you will only have to do some light pruning to reduce and balance the weight distribution.
It may be difficult, but often times the best thing you can do is wait and see what happens when a tree has no obvious injury after being struck by lightning. The tree might recover on its own or parts of it might die off and need to be removed. Sometimes a tree that appears to have sustained a lot of damage will end up being just fine. Oak trees have good energy reserves and can often recover from serious injury in just over a year or so.
It is always best to wait before taking action with a tree that has been struck by lightning. If you are worried about your tree, talk to a tree surgeon and see what they think. They will likely tell you the same thing, just wait and see.
If an arborist evaluates the tree and determines it can be saved, they may recommend providing the tree with plenty of water as well as fertilizer to help regrow damaged areas. ItвЂ™s essential to attend to any damage promptly, as it can spread and weaken the rest of the tree. This could make it susceptible to pests and diseases. The arborist can also prune any broken branches.
If the arborist determines that the tree cannot be saved, itвЂ™ll have to be removed. Leaving it there may spread infection to other healthy trees in your yard. A tree removal service can come and pick up whatвЂ™s left of the tree.
If you need an arborist to evaluate or remove your tree, contact Nelson Tree Company in North Huntingdon, PA. These experienced and affordable tree experts have been serving Westmoreland County since 1987. Whether you need aВ tree trim to beautify your lawn or storm damage cleanup, their teamВ has you covered. For more information on their services, visit them online or call (724) 863-7682.
Central Florida residents usually associate summer with afternoon thunderstorms and lightning. Although rain is beneficial to trees and plants, the accompanying lightning often is harmful, particularly to trees.
The trees that are the most susceptible to lightning damage are tall pines, but oaks and other trees also are prime candidates for lightning strikes.
Lightning damage usually is conspicuous, but sometimes damage can't be detected by outward signs. The usual sign of damage on pine trees is a seam of split bark running down the tree in a spiral.
On oaks and other hardwoods the signs often are varied. Sometimes branches are shattered and bark and wood can be seen several yards around the tree. Often patches of bark will be knocked from the tree occasionally lightning will damage the root system without even splitting the tree's bark.
Lightning doesn't always kill a tree when it strikes. The effect of the strike is determined by the intensity of the bolt and the moisture content of the tree. If the bolt is of sufficient strength the tree may die within a week.
In many cases the tree may survive the strike, only to succumb to an insect or disease attack that results from the weakened condition caused by the lightning strike.
Proper treatment can help save the tree if the bolt is of low intensity. Damaged branches should be removed and splintered wood trimmed or shaped so that proper healing can occur. A fast-release fertilizer should be applied to stimulate growth.
Oaks and other hardwoods should be watched closely for borers. Pines should be inspected daily for bark beetles and borers and at the first sign of these insects the tree should be sprayed with lindane. Spray the trunk of the tree as high as you can reach and spray it down the trunk to ground level.
When valuable or historic trees are involved, special lightning rods can be used. This treatment is fairly complicated and might be best entrusted to a competent arborist.
The simplest repair method is reattaching bark to the trunk. If the bark has been scaled from the tree, you can possibly reattach it.
Wayne K. Clatterbuck, Associate Professor Forestry, Wildlife & Fisheries University of Tennessee, David S. Vandergriff, UT Extension Urban Horticulture & Forestry, Kim D. Coder Professor, Silvics/Ecology Warnell School of Forest Resources The University of Georgia
Lightning is one of nature’s most powerful forces. Lightning can have devastating effects on people, property and trees. Each strike of lightning can reach more than five miles in length, and produce temperatures greater than 50,000 degrees Fahrenheit and an electrical charge of 100 million volts. At any given moment, there are 1,800 thunderstorms in progress somewhere across the earth. Lightning detection systems in the United States sense an average of 25 million lightning strikes per year.
Trees occupy a particularly susceptible position in the landscape, since they are often the tallest objects. Tall trees are the most vulnerable, especially those growing alone in open areas such as on hills, in pastures or near water. Many of these trees line our community streets and surround our homes, schools and businesses.
A tree’s biological functions and/or structural integrity are affected by lightning strikes. Along the path of the strike, sap boils, steam is generated and cells explode in the wood, leading to strips of wood and bark peeling or being blown off the tree. If only one side of the tree shows evidence of a lightning strike, the chances of the tree surviving and eventually closing the wound are good. However, when the strike completely passes through the tree trunk, with splintered bark and exploded wood on each side, trees are usually killed.
Many trees are severely injured internally or below- ground by lightning despite the absence of visible, external symptoms. Lightning or electrical current passes from the trunk of the tree through the roots and dissipates in the ground. Major root damage from electricity may cause the tree to decline and die without significant aboveground damage. If the tree is in leaf, the leaves wilt and the tree will probably die within a few days. If the tree survives long enough to leaf out the following spring, then the chances of recovery are much greater. Watering and fertilization are suggested to reduce tree stress.
Generally, when lightning damage has created hazardous broken branches, corrective pruning should be done. However, waiting two to six months is recommended before doing major and expensive corrective pruning to assess whether the tree will recover. If during this waiting period, the tree shows no obvious signs of decline, then the pruning is probably worth the expense. Consult with a certified arborist for recommendations concerning the health of your damaged tree. Commonly prescribed practices are water management, bark repair, pruning, fertilization, pest management and tree monitoring. Expensive treatments should not be taken until the tree appears to be making a recovery. Otherwise, when it becomes obvious that the tree will not recover from the lightning strike, the tree should be removed.
Historic, rare, and specimen trees, especially when they are the center of landscapes or they shade or frame recreational areas, are valuable and can be protected by a properly installed lightning protection system. Trees with special significance, or that people or animals might move under in a storm, should be protected. Trees closer than 25 feet from a building or structure should also be protected to minimize “side-flash.” Parks, golf courses, and public buildings should have large or important trees protected to minimize liability risks.
Tree lightning protection is expensive in labor and materials. Lightning protection systems must be installed properly with correct materials to insure long-term protection. For example, aluminum should not be used for any link in a system, nor should solid wire of any type be used. It is essential to consult with a trained arborist or urban forester, and a lightning protection system installer before designing a protection system for a tree.
Lightning protection systems in trees do not attract lightning. The purpose of a protection system is to dilute and slowly release electrical charge potential between the ground and cloud. Trees are not good conductors of electricity but can act as a better conduit than air. Protection systems dissipate the electrical charge before it can build to high levels.
Lightning damage in trees is much more effectively prevented than repaired and is often less costly. Qualified arborists can recommend the installation of lightning protection systems where appropriate or the proper course of action if a tree has been struck by lightning.
Coder, K.D. 2004. Lightning damage in trees: the spark of death. Arborist News 13(3):35–43.
Curran, E.B., R.L. Holle and R.E. Lopez. 1997. Lightning fatalities, injuries and damage reports in the United States from 1959-1994. National Oceanic & Atmospheric Administration (NOAA) Technical Memorandum NWS SR-193. U.S. Department of Commerce, National Weather Service, Scientific Services Division, Southern Region, Fort Worth, TX. (www.nssl.noaa.gov/papers/techmemos/NWS-SR-193/techmemosr193.html)
Howland, R. 2003. A striking danger in trees. Tree Care Indus- try 14(5):40–42. National Arborist Association, Inc. 2001. American National Standard for Tree Care Operations, ANSI Z133.1. Manchester, NH. 31 p. National Arborist Association, Inc. 2002.
Lightning Protection Systems, ANSI A300, Part 4. American National Standard for Tree Care Operations – Tree, Shrub, and other Woody Plant Maintenance – Standard Practices Manchester, NH. 9 p.