Fighting to save an urban forest

DNR officials from Michigan, Wisconsin tour Farms to learn about ash tree treatment program

By K. Michelle Moran
C & G Staff Writer

Grosse Pointe Farms’ successful ash tree injection program is getting national attention.

The city’s innovative use of insecticide injections to control the deadly emerald ash borer, an invasive species native to China, has attracted the interest of at least two documentary film crews, and neighboring states — now facing the bug themselves — are looking to the Farms for ideas and answers. Believed to have entered the state via shipping pallets, the bug was identified in Michigan in 2002.

On Aug. 29, representatives from the Wisconsin Department of Natural Resources, accompanied by representatives from Michigan’s DNR, toured several cities — including the Farms — and spoke with officials about their experiences with the borer. The officials also visited Dearborn, Belleville, Monroe and Romulus.

The Wisconsin officials — who represent districts from across the state — saw something in the Farms they hadn’t seen in the other communities: Living, thriving ash trees.

Leading the tour and responding to questions were Farms Public Service Director Terry Brennan and Sue Shock, one of the managers of Shock Brothers Tree Care, the Warren-based firm that injects the Farms’ trees. Shock Brothers came up with the treatment program, but Sue Shock credits a proactive City Council and administration with taking a chance and injecting the city-owned ash trees with an insecticide that had proven effective against a similar native species, the bronze birch borer.

“We’re interested in the firsthand lessons learned by communities dealing with the emerald ash borer,” explained Laura Wyatt, an urban forestry communication specialist and council liaison with the Wisconsin DNR’s Bureau of Forest Management. “We’re hoping to take advantage of what Michigan learned.”

While neighboring communities throughout the state have resorted to cutting down their ash trees, the Farms has managed to save most of the more than 600 city-owned ash trees that have been identified so far.

“Admittedly, we have lost some trees, but ash trees are very resilient,” Brennan said. “We’ve lost about 30 trees over the last three years (including some that weren’t identified and treated immediately). I can honestly say this has been a very successful program.”

Not that there haven’t been some bumps in the road. Brennan said the green ash trees haven’t responded as well to treatment as the white ash.

“They’re surviving and they’re holding OK, but they don’t look as full and as lush as the white ash do,” he said.

Roughly a dozen visitors inspected and photographed trees, including some that hadn’t been treated and were suffering as a result.

“It’s amazing that you don’t see dead trees, and it’s not because you’ve cut them down — it’s because you don’t have them,” Michigan DNR representative Kevin Sayers told Farms officials.

The precedent for the Farms ash program was the city’s treatment program for its elms. Although Dutch elm disease is still a prevalent threat, the Farms now has the largest elm population per capita in the country, Brennan said.

“And unfortunately, we will probably have the largest ash population soon in the state of Michigan,” he said.

For the Farms, attempting to preserve its ash population made aesthetic and economic sense. Over roughly the last five to six years, Brennan said, the city has spent about $160,000 to treat its ash. Cutting down and replacing more than 600 trees, in contrast, would have cost almost $750,000, he said.

“It’s an economic impact you can’t take in one lump,” Brennan said.

And those numbers don’t take into account the value mature trees add to homes and business properties.

Although trees can still recover after infestation, the success rate is higher among trees treated in the early stages of infestation. Shock said it’s best to treat trees that have at least 50-60 percent of their canopy intact. Based on the Farms experience, Wisconsin officials should make their decision to treat early, Sayers noted.

At press time, the Wisconsin officials said the emerald ash borer had not yet been detected in their state. Clearly, though, they want to be ready when it inevitably arrives. As one Wisconsin DNR official noted, the state tree population is estimated at 20-38 percent ash. To lose them all would be a devastating blow to Wisconsin’s environment and aesthetics.