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Ice, snow, and wind can damage all species and ages of trees. The dynamic force of 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.
In fact, accumulations of ice can increase the branch weight of trees by 30 times or more. After damaging storms, injured trees should be examined carefully and treated appropriately.
Back to topTree Species & Stress
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 bole (trunk)
- Prestorm conditions, such as unbalanced crown and dead wood
- Numerous small twigs and branches that increase 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:
- Trees with excurrent (conical) branching
- Strong branch attachment
- Trees with coarse branching
- Small, mature trees
Evaluate Damaged Trees
After a damaging storm, carefully examine each injured tree for 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 still are 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.
Any type of major 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.
Back to topRepairing Damaged Trees
After deciding treatment is necessary, the first decision to make is who will do the work. In situations where governmental units have jurisdiction, the choice may be obvious; cities and counties typically employ individuals assigned that responsibility.
For individual home owners or rural land owners, the choice is either to do it themselves or hire a professional tree care specialist (arborist). The choice may depend on the type and extent of damage.
Severe damage high in large trees may 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 may influence the decision. Trimming large trees should be left to trained arborists.
Consult a professional arborist if:
- climbing or chain saws are required
- cabling or large branch removal is needed, or
- the injured tree or branch is leaning on another tree or structure.
Pruning to Help Against Future Storms
The main reason to prune young trees is to develop good branch structure and tree strength. Removing weak branches and correcting poor form when branches are small minimizes 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. Limit pruning of newly planted trees to the removal of dead and broken branches or the correction of multiple leaders. Begin developmental pruning of deciduous trees two to three years after planting.
Other key things to remember when pruning young trees include the following:
- Always leave 70 percent of the tree height with live branches, and avoid removing lower branches too quickly.
- Leave the temporary lower branches on the tree until they reach 1 inch in diameter to increase trunk growth and root development.
- Concentrate efforts on removing crossing, rubbing, broken, diseased, and weak-angled branches in the upper portion of the tree. Also, eliminate double leaders and basal sprouts.