Pruning caused oak tree deaths in Highland sub

When a tree cutting company came around Highland Township’s Axford Acres subdivision in April offering to prune trees at a discount, residents didn’t realize that they were possibly condemning their trees to die.

“The guys from the company just knocked on the doors and offered to prune our trees. It seemed like a good deal. They said they were already in the neighborhood and needed some work,” said Axford Acres resident Karen Simonich.

However, within three weeks, the oak trees in her yard began to die.

“It’s been kind of devastating to people. In three weeks, people’s trees were completely dead,” said Jeanne Jeffries, the subdivision association president.

Through the expertise of Michigan State University arborist Dr. Dave Roberts, oak wilt was determined to be the cause of the trees’ sudden death.

“The rapid death of red oaks after injury while other oak trees not pruned in the vicinity remained healthy is sufficient proof and is typical of how the disease operates,” he said. “There is nothing else that will do this. The symptoms of oak wilt include rapid death, leaf fall, brown leaves sometimes hanging on the tree, etc. A classical symptom, not often seen, is the outer extreme portion of the leaf turning tan.”

Roberts reportedly observed tan leaves on one of the resident’s oak trees.

Oak wilt is a fungal disease which kills trees by initially blocking the water conducting vessels.

“It’s a lethal fungus disease that is transmitted to new wounds on oak trees,” Roberts said.

These wounds can be caused in a variety of ways, including storm damage and pruning, which causes a problem when performed during the “warm” months of April through October.

The trees in Axford Acres were pruned in April. At least three residences were affected.

“Most professional arborists know not to prune oak trees during the warm season but a number of unprofessional people continue to prune oak trees, take the money and run,” said Roberts, who has been trying to spread awareness about this disease for the past two decades.

The problem occurs because sap beetles spread the disease to fresh wounds created by pruning or storm damage. The beetles are attracted to the odors given off by the tree after wounding, and then haphazardly spread the fungus on their bodies.

Sap beetles have the ability to spread the disease for “quite some distance,” according to Roberts.

Another mode of transmission is through root grafts. However, that can only occur with trees that are sufficiently close to be root grafted together.

Roberts has several suggestions for preventing the spread of oak wilt, including:

• If trees are injured by storms during the warm season, the affected limbs should be cut immediately at the appropriate location and sealed with a barrier to prevent beetle transmission of the fungus;

• Trees not immediately affected can be treated with a fungicide trunk injection;

• To prevent further spread through root grafts, trenching between healthy and diseased trees may be an option;

• Don’t prune or remove oak trees during the warm weather season.

“Don’t let anyone prune oak trees during the warm season. What turned into a rather cheap pruning job will now result in many thousands of dollars in tree removals and property loss,” Roberts said.

Unfortunately, the residents of Axford Acres had to learn this lesson the hard way.

“We’re stinking mad. We paid for these trees to be cut, and now we are now paying even more money for these trees,” Simonich said.