Time is getting short to prune tree damage

By Beth Berlin
Minnesota Extension

In early March the entire state of Minnesota experienced several days of strong winds. This may have led to tree damage in your yard. It isn’t too late to prune trees that may have lost limbs, but the best window to do so is narrowing.

Gary Johnson, University of Minnesota professor and forestry Extension educator and Ben Johnson, ISA certified arborist said there are several treatment options to consider.

The first is corrective pruning where small branches that have been damaged should be removed back to the next branch or trunk but using caution to not cut into the branch collar. The branch collar is the enlarge area at the base of the branch next to the trunk; cutting into this will cause slower healing and potentially disrupt the tree’s water and nutrients from traveling up and down the trunk. Remember to use the three-cut method if the branch is of reasonable size and weight to prevent bark near the trunk from tearing. The three-cut method consists of the first cut taking place on the bottom side of the branch cutting about 4-6” or more away from the trunk; cut about one-third the way through the branch. The second cut should occur a few inches down the branch from the first cut and cut all the way through the branch. The purpose of these two cuts is to get the bulk of the weight off and prevent bark from tearing into the critical branch collar. This allows you to do a precision third cut close to the branch collar, which is your final cut starting at the top and cutting all the way through.

A second treatment option is to straighten or stake the tree. If the tree is less than 25-feet tall and experienced minor uprooting one option after a storm is to immediately re-correct it back to a straight position and then stake the tree to make sure the roots are covered and moist. Stakes need to be placed evenly around the tree and attached firmly to the tree without pulling on it. Thin rope or wire should not be used as it may cause damage to the trunk of the tree.

The third option is to repair wounds. Where split, cracked or torn branches occurred, they should be removed back to a point where there is no damage. Leaving these wounds is not only unsightly but also are entry sites for disease or insects.

Keep in mind do not remove more bark exposing areas greater than already present from damage.

Finally a misconception is to always treat wounds with a paint type product. This is not true with one exception; oak trees damaged in April, May or June should have their wounds sealed to help prevent oak wilt. Simply use a latex paint or shellac to deter insects that are the carrier of the disease from being attracted to the wound.

Another option is to cable or brace a tree damaged in a storm. This is a more complex process and a trained professional should be contracted to do the work. To find a certified arborist, visit www.isa-arbor.com where you can search for an International Society of Arboriculture certified arborist in your area.

Safety first, always know your limitations when doing tree work and contact an arborist for assistance. For more information about storm damaged trees, visit www.extension.edu and search for “storm damage.”