Leave tree wounds to self-heal

Q. What do I use to seal a large wound on my tree?

Craig from Canfield

A. Nothing. Unless it is an oak and there is a chance the tree may get oak wilt.

This is a common question at our clinic during fall cleanup time in the lawn and garden. The broken branches and damage from storms this year weren’t out of the ordinary, but many times tree wounds are not noticed until late in the season.

The best thing to do for tree wounds is inspect them to see if there is any pruning that is needed to help the tree heal from the damage. This would include cutting back stubs to near the trunk so the wound can better heal itself. A branch stub is just as bad as cutting the branch back too far. According to our plant pathologists at Ohio State, “numerous studies demonstrate that favoring callus formation can significantly reduce infection and colonization by decay organisms and other pathogens.”

The most important thing to remember about this process is to never cut past the branch collar on the lower side of the connection to the trunk and the bark ridge on the upper side. These areas are somewhat swollen or raised tissue. Studies show that leaving these areas intact help the wound heal faster. Think of the branch collar and bark ridge as “wrinkled” areas on the tree. This means they are wise – so don’t cut them away.

When pruning large branches, the three-cut method must be used. Even if branches are not large, this method prevents the branch from tearing through the branch collar, opening up the tree to pathogens. All sizes of branches may be heavier than you think. So, do it the safe way and make three cuts.

The first cut should be about 10-12 inches away from the trunk, cutting up 1/3 of the way from the bottom of the branch. This creates a fail-safe to prevent tearing into the trunk. The second cut should be made from the top of the branch, cutting downward about 6-8 inches away from the first cut. This cut will make the branch fall from the tree back to the first cut. Then, cut the stub back to the branch collar and bark ridge to finish the job. Leave the wound to heal itself. Nature knows what to do. If you do your job to cut correctly, it will be just fine.

Storms and other accidental damage occurs on trees all the time. Just do your best to clean it up and let nature take its course.

Read all about the science behind tree wounds, how to prevent tree wounds and how to best prune large branches on our factsheet at http://go.osu.edu/treewounds.

Eric Barrett is OSU Extension educator for agriculture and natural resources in Mahoning County. Winter hours for the Plant and Pest Diagnostic Clinic vary. Submit questions to the clinic at 330-533-5538 or drop samples off at the Extension office in Canfield.