P&PDL Picture of the Week for
January 17, 2005

Winter Ice Damage to Trees

Rosie Lerner, Extension Consumer Horticulturist, Department of Horticulture, Purdue University

Homeowners assessing tree damage from the ice storm will want to make a few important decisions soon.

"First assess if there are breaks in branches that have not yet fallen," said B. Rosie Lerner, extension specialist in Consumer Horticulture at Purdue University. "For small, lower branches it is relative easy for the homeowner to remove them from the tree."

Lerner emphasized using proper pruning tools to ensure a clean smooth cut that will allow the tree to seal off the wound. Proper tools include hand sheers, lopers, and pruning saws. Hand sheers are used on branches up to 1/4 inch in diameter. Lopping sheers are used on branches up to one and a 1/2 inch diameter. Pruning saws are used on branches over one inch thick.

For larger limbs, or those that are too far up for the owner to reach, Lerner suggested hiring an arborist.

The next step is to make a cleaner cut on jagged broken branches to allow proper healing. Lerner noted that this does not need immediate attention, but should be done before spring growth.

"People often ask if they need to apply pruning sealants or tar," said Lerner. "There is some controversy regarding these products, but generally they have not been shown to be helpful."

Lerner adds, "Some scientists believe that the sealant may interfere with the tree's ability to form a protective callous over the wound."

Just because a trunk is split does not necessarily mean the tree will die soon. Large, split branches or trunks that have not broken off the tree can be braced and possibly saved by an arborist.

"If limbs have fallen completely off the tree there is nothing that can be done to save the branch," said Lerner.

In either case, the wounded area in the tree will always be a weak spot that is susceptible to disease, rotting, and insects.

In typical ice storms, the trees hardest hit are weak wooded species such as silver maples, Siberian elms, river birch, and willows."Evergreens are also particularly vulnerable because they still have foliage and so tend to collect more ice" she said.

Many of the evergreens, such as pines and spruce are not capable of filling in new growth where the damage has occurred, so the natural shape of the tree can be permanently affected," said Lerner.

In many cases, topping causing trees to re-grow numerous weak branches that are susceptible to breakage," said Lerner. "These are among the first of the branches that fall during an ice storm."

For more information on pruning contact a Purdue University cooperative extension service office and ask for bulletin "HO-4, Pruning Ornamental Trees and Shrubs" or go online to http://www.hort.purdue.edu/ext/HO-4.pdf

For an arborist, look for companies listed in the local phone directory under tree service. It may pay to get estimates and references of others who have used the tree service before signing a contract agreeing to service.

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Purdue Plant & Pest Diagnostic Lab Purdue Cooperative Extension Service