College of Agriculture & Natural Resources

Reprinted from LSJ.com

 by Scott Davis

For roughly a decade, a war has been quietly waged to save mid-Michigan’s ash tree population.

For the most part, that war has been lost.

Experts say ash trees will die off in large numbers in mid-Michigan due to the infestation of the emerald ash borer insect. In Lansing alone, city officials say crews have removed 5,000 infested ash trees along streets and in parks — about half the city’s ash tree population.

“We’re past the peak. You will see a lot of dead ash trees,” said Deborah McCullough, a Michigan State University professor of forest entomology. “There is a three- or four-year period, where trees are really getting clobbered, and we’re in year three.”

Experts say there is little mid-Michigan cities can do to save remaining trees as they step up tree removal efforts. But new chemicals on the market have given hope to homeowners who want to save that beloved ash tree in the backyard.

McCullough said one chemical, TREE-age, registered in 2010, has been shown to be 99 percent effective against infestation by the wood-boring beetle for three years. The chemical is typically injected underneath the bark by a landscaping company; applications usually cost $100 for a 10-inch tree.

“If you already haven’t treated your (ash) tree with a chemical in the greater Lansing area, your tree is dead,” said Stephen Woods, vice president of Smith Tree & Landscape Service in Delta Township.

The Asian-native emerald ash borer was introduced to Michigan in the late 1990s — likely through imported materials from China — and the ash tree infestation was first discovered in the southeast part of the state in 2002. A year later, experts say, it cropped up in mid-Michigan and has since progressed to several other states.

Quarantine efforts

In 2006, state officials quarantined the lower peninsula to contain the spread of the ash borer through firewood, and the Michigan Department of Agriculture and Rural Development has been engaged in a campaign that encourages travelers and campers to buy firewood locally.

Despite these efforts, the ash borer has killed tens of millions of trees, mostly in southeast and mid-Michigan, state officials say. In mid-Michigan, it mostly is a matter of time before ash trees die off without chemical treatment, said John Bedford, pest response program specialist with the state Department of Agriculture and Rural Development.

“It’s pretty bad, and it’s pretty entrenched in the area, but there are a lot of years to go before we see the demise of the ash,” Bedford said.

Lansing and East Lansing have been able to keep up with tree removal efforts in recent years, even though the cost of removing an infested tree can run as high as $2,000. Dead trees are typically removed out of safety concerns.

Dave Smith, an environmental specialist with the city of East Lansing, said the city has used its entire annual forestry budget of $50,000 in recent years to remove infested or dead ash trees, forcing it to scale back on trimming and planting.

Smith said the city has removed 700 of the 850 trees in city right-of-ways and parks in recent years, and expects to remove the rest of them within two years.

Smith added the devastation in East Lansing would have been worse if the city had not planted many other species of trees in parks and along city streets in recent decades. The same approach was adopted in Lansing, where ash trees make up about 8 percent of trees planted in parks and right-of-ways.

“We try to plant of lot of different trees so this kind of problem doesn’t come along and wipe everything out,” said Paul Dykema, forestry and grounds manager for the Lansing Parks and Recreation Department.

Bedford said the best hope for saving ash trees elsewhere in Michigan is the introduction of Asian wasp populations that feed on ash borer larvae in the trees.

The state Department of Agriculture and Rural Development has joined with the U.S. Department of Agriculture to introduce the wasps in mid-Michigan and others parts of the state, mostly in state recreation areas.

“It’s one of the most promising things we have going for widescale control," Bedford said. “It’s going to be very slow moving. It won’t save the trees already heavily infested…..(But) it’s the best tool that we have."