Repairing ice damaged trees
December 7, 2006
Ice cubes, ice skates, iced tea - ice is not always bad. Iced trees are another matter. Recently we experienced life in a giant Chihouly sculpture. Arborvitaes that were once lovely evergreen pyramids are now contorted horror movie topiaries - a demented squirrel and a hunchback dragon. It makes for ominous evening walks.
Ice and wind damage can be devastating to trees and to our scene psyche. First, evaluate the damage. If over half of the tree has to be removed then it's time to ask yourself, "is the tree worth saving?" If the tree is no longer aesthetically pleasing or considered hazardous after the damaged limbs are removed, perhaps it is time for a new tree. Also consider if the tree is a species vulnerable to future ice and wind damage. Siberian elm, American elm, silver maple, river birch, honeylocust, hackberry, 'Bradford' pear and green ash often suffer storm damage.
Decide if you can do the pruning or if it requires a professional. Branches smaller than 3 inches in diameter can be removed with pruners, loppers or pole pruners. Larger limbs will require a bow or pruning saw. Chain saw usage and tree climbing should be left to the experienced. Certified arborists are listed in the phone book. Or go to the International Society of Arboriculture to find one near you.
A few tips when dealing with storm damage
- Use correct pruning techniques. Avoid flush cuts. The branch bark ridge (the roughened bark area between the branch and the trunk) and the branch collar (the swollen area on the bottom of the branch) should be maintained after pruning. The branch collar appears similar to the first knuckle (closest to your palm) of your thumb.
- Remove branches to the nearest lateral branch, bud or main stem as soon as possible after the storm. Do not leave branch stubs that can lead to insect and disease problems. Refrain from removing many other live branches in a quest to develop a symmetrical shape. It's like trying to correct a bad haircut. You always end up with too much good stuff on the floor that you can't glue back on. Allow the tree time to recover before doing any major shaping.
- Do not top trees. It causes a proliferation of small branches which are susceptible to future damage. Plus it's just ugly.
- Large branches should be removed by the three-cut method. The first cut is an undercut partially through the branch beyond the final pruning to prevent bark stripping. The second cut is beyond the undercut and removes the majority of the branch. The third cut is the final cut. Do not apply any wound dressings.
- Sometimes broken branches strip the bark. If more than one third of the bark around the circumference of the trunk has been stripped, the odds of the tree's survival are reduced. Remove only hanging bark. Do not make the wound any larger than necessary. It is no longer recommended to shape the wound into an ellipse.
- If the tree suffered a split fork, it may be possible to save the branches with cabling. Split forks require a professional to evaluate and install cabling if deemed appropriate.
- Ideally trees should be pruned throughout their life to reduce narrow branch angles and situations which make storm damage more likely.
- Don't give up on unbroken limbs that are still bent over once the ice melts. Arborvitaes can be lightly bound with six inch wide strips of fabric or burlap to bring them back to their pyramidal shape. Remove binding after a few weeks and see how well the branches have returned to their former glory.
- Contact your local city arborist or public works office to report large (six inch diameter or more) hanging limbs in city trees.
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