Wind, ice, and snow can damage trees of all species and ages. Wind may whip trees back and forth or twist them, causing branches or trunks to fail. Ice loading—and, to a lesser extent, snow loading—results in weight accumulation on tree limbs, resulting in branch failure. After damaging storms, injured trees should be examined carefully and treated appropriately.
Reasons for Storm Damage | Evaluating Damaged Trees | Repairing Damaged Trees | Uprooted Trees | Preventing Damage | Planting New Trees | More Information
What Make a Tree Susceptible to Storm Damage?
Different tree species vary in their resistance to storm injury. The following characteristics may increase a tree’s susceptibility to storm damage:
- Included bark (bark that turns inward at the point where branch and trunk or codominant stems meet) in branch junctures.
- Old or over-mature trees with increased crown size, internal decay, and decreased flexibility of limbs and trunk.
- Pre-storm conditions, such as unbalanced crown and dead wood.
- Numerous small twigs and branches that increase the total surface area.
- Broad crowns (decurrent branching habit) that increase ice and snow accumulation.
- Trees with horizontal branching.
Characteristics that may decrease a tree’s susceptibility to storm damage include the following:
- Trees with conical (excurrent) branching patterns
- Strong branch attachment
- Trees with coarse branching
- Trees that are small at maturity
The maintenance history of trees also affects performance during storms. Trees that have been neglected or improperly pruned may sustain more injury than trees that were carefully maintained. Failure to maintain a central leader or to remove weakly attached branches when the tree was young can increase the probability of damage by storms in later years.
Trees that have been “topped” often are damaged in storms. Vigorous regrowth arising just below the topping cut is weakly attached to the remaining stub. This weak attachment makes such trees vulnerable to ice, snow, and wind.
Evaluating Damaged Trees
After a damaging storm, carefully examine the injured tree to assess the type and extent of damage. Pay particular attention to trees that present obvious hazards to people or property. Large, broken branches or split portions of the main trunk that are still partially attached and hanging over houses, sidewalks, driveways, garages, or other buildings should be considered first.
For safety reasons, always allow the utility company to handle broken limbs or tree damage around power lines. Clean up debris on the ground before initiating tree repair.
The effect of storm damage on the survival, longevity, appearance, and function of the tree must be evaluated. This impact assessment is not easy; in many cases, it will simply be a judgment call. However, the safety and protection of people and property should be the most important consideration.
Severe splitting of the main trunk or any type of injury that results in the removal of more than one-third of the bark around the circumference of the main trunk is usually enough damage to make removal necessary. Larger trees that have had their tops broken are also likely compromised to a point where removal is needed.
Any type of significant injury may reduce the useful life of a tree. Such wounding can provide an entrance point for decay fungi or insects. Damage to trees also may reduce or destroy their intended function or severely disfigure the tree and ruin the appearance. The decision to retain or remove those trees depends on the individual situation, and no specific guidelines can be offered.
Broken side branches or minor trunk or top injuries do not typically put the tree at risk.
Carefully inspect the tree for hidden damage. Identify cracks in the trunk or large limbs. To reduce safety hazards, it is important to find hidden damage before repair work begins.
Repairing Damaged Trees
If it is determined that the tree does not have to be removed, the first decision is who will do the repair work. In situations where governmental units have jurisdiction (in the street right-of-way, for example), cities and counties typically repair or remove the damaged tree. For individual homeowners or rural landowners, the choice is either to do it themselves or hire a professional tree care specialist (arborist).
The choice will depend on the type and extent of damage. Severe damage high in large trees will necessitate the use of professionals, but minor limb breakage on the lower parts of smaller trees may be easily handled by the owner. Interest, skill, and access to equipment also influence the decision.
When to Hire an Arborist
Trimming large trees should be left to trained arborists. Consult a professional arborist if:
- Climbing or chainsaws are required
- Cabling or large branch removal is needed
- The injured tree or branch is leaning on another tree or structure
Learn more about hiring qualified professionals in this publication: Choosing an Arborist.
Tree Repair Tips for the Homeowner
If the resident or landowner is doing the work, they should understand the pruning methods needed to best treat tree injury. In addition, the resident must own or have access to the proper tools and equipment.
For pruning smaller branches (up to 4 inches in diameter), a good sharp bow saw or pruning saw is the most appropriate tool.
Safe, proper use of chain saws to remove or cut up larger material requires thorough knowledge of the equipment and experience in saw operation and maintenance. Never cut above shoulder height with a chain saw, and always wear proper safety equipment (e.g., hearing and eye protection, leather gloves, hard hat, steel-toed boots, and chain-saw chaps).
Pruning Tips
Much of the repair work needed for treating storm-damaged trees can be defined as pruning. Although the preferred time for pruning may not coincide with the occurrence of a storm, immediate repair once conditions are safe is recommended.
- Do not make the wound any larger than necessary. Storm breakage of limbs often leaves large, uneven stubs. The goal is to make the wound as small as possible to encourage prompt wound closure.
- Use the proper technique and avoid flush cutting. Locate the branch-bark ridge and use the three-cut method on larger limbs to prevent tearing bark. See the three-cut method in this video: Principles of Pruning: Making a Good Cut.
- In large limbs with broken tips or ends, pruning back to the first undamaged side branch may be most appropriate.
- Do not “top” trees at any time.
- The use of wound dressings or pruning paints is not recommended. Trees have natural defense systems that will begin to close the wounds with new woody tissue. Paints or dressings can actually slow this sealing-off process.
More information on pruning trees can be found in this publication: Pruning Trees: Shade, Flowering, and Conifer.
Uprooted Trees
Tree roots are not as deep as most people imagine. Most tree roots are in the top 12 to 18 inches of soil. While tree roots are quite shallow, they often extend into an area 2 to 3 times larger than the crown area. One of the chief functions of a tree’s roots is to “anchor” the tree and keep it upright.
While a tree’s roots are normally able to keep it upright, strong winds in storms can partially or completely blow over trees (especially when soils are wet).
In most cases, trees that have been uprooted, even partially, cannot be saved. When the root system is pulled from the ground, it is severed from a large percentage of its roots. Even if a large tree could be pulled upright, it will likely die within a short time because of the extensive root damage or be blown over again in a future storm.
It may be possible to save small, partially uprooted trees (those with 50 percent or more of their root systems intact and 10 feet or less in height) by carefully pulling them back upright and staking them.
If you decide to attempt to reset a partially uprooted tree, it could be several years before you know if the tree will survive. It will likely take several years for a tree to replace lost or damaged roots. If a tree can’t produce enough food (energy) to rebuild its root system, it will become stressed and susceptible to disease and insect pests that might cause death.
How to Prevent Storm Damage
While nothing can guarantee that trees won't be damaged by severe weather, well-structured, healthy trees are less likely to see damage. Avoiding storm damage starts when trees are young. The main reason for pruning young trees is to develop good branch structure and tree strength. Removing weak branches and correcting poor form when branches are small minimizes the size of the pruning wounds. Early pruning also promotes strength and balance that help make a tree less susceptible to damage from wind, ice, and snow storms. Developing good structure is critical during the first 15 to 20 years of a tree's life.
Learn more in this article: Pruning Young Trees.
Planting New Trees
When storm damage is severe enough to necessitate tree removal, it will become necessary to plant a new tree. It is not recommended to plant the new tree in the exact location of the removed tree, but it can sited 6 to 8 feet (or more) away, outside the area occupied by the removed tree's large roots.
Proper tree planting and after-planting care are essential. Use these resources to help:
- Tree Planting Basics
- Planting Trees in the Landscape
- How to Plant Bare Root Plants
- Care of Newly-Planted Trees
Selecting New Trees
When selecting a new tree to replace a storm-damaged tree, careful considerations should be made to choose the best species for your landscape. Consider the following factors:
- Soil conditions. Some species will perform better in wet soil conditions, whereas those that prefer well-drained soils would suffer in that wet location.
- Size. The mature width and height of the tree should fit in the space provided. Take special care to avoid trees that could interfere with utilities, both above and below ground.
- Diversity. Look to plant tree species other than those already in your landscape, block, or neighborhood. Your tree will contribute to the "urban forest" of your neighborhood. Forests with many different species are less impacted by major insect or disease problems.
- Ornamental Features. Select a tree that has appealing characteristics. Consider things like fall color, flowering period, form, and bark, among other things.
Learn more in this article: Guidelines for Selecting Trees.
Susceptibility of Tree Species to Storm Damage
When replacing storm-damaged trees, consider a species’ susceptibility to ice, snow, and wind damage. Planting the best species for your location decreases the likelihood of storm damage in the future.
Susceptible
- Silver maple (Acer saccharinum)
- Hackberry (Celtis occidentalis)
- Honeylocust (Gleditsia triacanthos)
- Black cherry (Prunus serotina)
- Black locust (Robinia pseudoacacia)
- Japanese pagoda tree (Styphnolobium japonicum)
- American linden (Tilia americana)
- American elm (Ulmus americana)
- Siberian elm (Ulmus pumila)
Intermediate
- Red maple (Acer rubrum)
- Sugar maple (Acer saccharum)
- White ash (Fraxinus americana)
- Tuliptree (Liriodendron tulipifera)
- White pine (Pinus strobus)
- Sycamore (Platanus occidentalis)
- Bur oak (Quercus macrocarpa)
- Red oak (Quercus rubra)
Resistant
- Norway maple (Acer platanoides)
- Serviceberry (Amelanchier spp.)
- American hornbeam (Carpinus caroliniana)
- Redbud (Cercis canadensis)
- Ginkgo (Ginkgo biloba)
- Kentucky coffeetree (Gymnocladus dioicus)
- Black walnut (Juglans nigra)
- American sweetgum (Liquidambar styraciflua)
- American hophornbeam (Ironwood) (Ostrya virginiana)
- White oak (Quercus alba)
- Swamp white oak (Quercus bicolor)
- Baldcypress (Taxodium distichum)
- Littleleaf linden (Tilia cordata)
- Silver linden (Tilia tomentosa)
- Eastern hemlock (Tsuga canadensis)
Note: All species of trees can become more susceptible to damage if improperly maintained and pruned.
More Information
- Managing Storm Damaged Trees (publication)
- I need to have some tree work done. How do I select a qualified arborist?
- Winter Damage on Trees
- How to Prevent Ice and Snow Damage on Trees and Shrubs
- Managing Hail Damage on Apples
- Cold and Freeze Damage to Garden Plants
- Your Complete Guide to Pruning Trees and Shrubs
Photo credits: 1: Aaron Steil; 2: Jeff Iles; 3: ALAN/AdobeStock; 4: ALAN/AdobeStock; 5: Aaron Steil; 6: bibi/AdobeStock; 7: Jeff Iles 8: Mickis Fotowelt/AdobeStock; 9: roger/AdobeStock; 10: Jeff Iles; 11: nd700/AdobeStock