Extension Educator, Horticulture
At first glance trees encased in ice have a magical appearance. The magic quickly turns to vapor once the damage becomes evident.
About the only thing to do once trees are covered in ice is to hope for warmer weather. Some branches may be propped up with boards until the ice melts. If branches are not broken, most trees will slowly regain their original shape.
Many of our upright evergreens such as arborvitae have multiple trunks that are susceptible to breakage from ice. Damage can be prevented or reduced by tying the trunks together with soft material such as pantyhose. If necessary, support can be secured while arborvitaes are covered in ice. Be sure to remove the ties every spring.
Trees with broken branches should be evaluated. A certified arborist may be needed. Any trees with broken branches that may be a danger to people and property should be pruned as soon as possible. Damaged branches should be removed by cutting back to a side branch or the trunk. Do not top trees or leave branch stubs.
Unfortunately ice damage often rips branches from trees leaving ragged wounds. First decide if the tree is worth saving. If a tree is grossly disfigured or has lost several major branches it may be best to remove the tree.
If the tree is determined salvageable, the best course of action is to remove the branch completely than remove the jagged edges from the wound with a sharp knife. Try not to remove much of healthy, tight bark. Tree paints for wounds are not needed or recommended.
Check out this website for more information on repairing ice damaged trees.
When planting trees avoid or at least limit the number of trees prone to storm damage. For various reasons Siberian elm, American elm, hackberry, green ash, honeylocust, river birch, littleleaf linden and redbud may suffer from storm damage.
Trees that show good resistance to ice damage include American sweetgum, baldcypress, eastern hemlock, ironwood, Norway maple, Kentucky coffeetree, gingko, white oak and swamp white oak. Ice storm susceptibility should not be the sole criterion for selecting trees.
Bill Vander Weit, city arborist with the City of Champaign outlines a few characteristics of trees prone to ice damage. Trees particularly vulnerable to ice damage have narrow angles of attachment between the branch and trunk. Branches with a tight angled, V-shaped crotch have a weak connection and are prone to failure with ice or wind. For best strength, the ideal branching angle for most trees approximates 10 o'clock and 2 o'clock. Branches with narrow angles should be removed or reduced when trees are young.
Another characteristic that makes a tree prone to storm damage is a broad spreading crown that arises from several large competing trunks. In addition trees with this form typically have narrow branch attachments. Bradford Pear is the poster child for poor branch attachment. Trees with fine branches such as river birch can also suffer ice damage.
To reduce storm damage, also remember proper tree placement and regular pruning. When planting large trees next to electrical lines, trees should be located a minimum of 30 feet from above ground lines. If planting closer, choose trees that will be no greater than 20 feet at maturity.
Pruning trees on a regular cycle will reduce a tree's susceptibility to damage by removing deadwood and structurally weak branches. Cyclic pruning will also allow regular visits to assess hazardous trees before they fail. A good tree framework starts with proper pruning and training early in a tree's life.
Remember, in Champaign or Urbana a permit is required to plant a tree on public right-of-way. Both cities regulate planting to insure that appropriate trees are planted. For more information, visit:http://www.city.urbana.il.us/