A landscaping crew, armed with noisy leaf blowers, clears debris from the sidewalks of this well-groomed suburban allotment.

Jennifer Milbrandt oversees the city of Strongsville’s urban forest. She’s here to inspect a row of 155 medium-sized ash trees that line the street.

Some of the ashes are crowned with dead, bare branches, a sure sign of emerald ash borer infestation. But some still seem healthy, with full, green canopies.

Milbrandt says the allotment is part of an experiment Strongsville began in 2007 with Kent-based Davey Tree Expert Company to test strategies to save the ashes.

The experiment began just before the invasive pest struck Strongsville, so Millbrandt says the city was willing to take a chance on prevention "because we were hoping that they would find something that would stop the bug.”

Davey’s Anand Persad is comparing the survival rates of treated trees to those left untreated in this real-world insect onslaught.

He says the goal is not to save every ash tree, "but to find products and delivery systems that can potentially preserve ash trees for other municipalities, other districts, other regions of the country.”

Persad tested more than a dozen different pesticides and application techniques.  He’s not quite ready to share all the details of the Strongsville experiment, but he does say some prevention techiques work better than others, and with proper attention trees can be saved.

Diversity is best defense against pests
Not every city is willing to spend any money on treatments. I met Jonathan Malish, an arborist with the city of Akron in a neighborhood lined with dozens of massive, majestic trees, part of the cities oldest stand of ashes.

Malish says the city also has about 900 smaller ash trees planted in the 1990s in other neighborhoods.

But Malish is resigned to the fact that even these healthy huge trees are doomed, and he’s not trying to save them.

“I can’t justify the cost, and when we brought that to the administration it was the same conclusion.”

These ashes were planted in the 1950s after Dutch elm disease devastated the previously popular street tree.

Malish says it’s time to throw out the idea that all trees on a street need to look alike. 

He says Akron is following a new state protocol for urban forests that emphasizes diversity.

In restoring trees in this neighborhood, Malish says the city has planted red maples, beech, American yellowwood and red oak "so we have diversified from a monoculture of ash.”

The most devastating forest insect pest ever 
The costs of replanting, treating or cutting down ash trees, combined with losses to the timber and nursery industries is estimated at around $26 billion for Ohio and three other hard-hit states.

“It’s already the most economically damaging exotic forest pest ever introduced to North America.”

Ohio State entomologist Dan Herms says emerald ash borer has now spread to 23 states and has killed 99.7 percent of the trees since the Asian insect was first found in Michigan in 2002.

But he’s studying the 0.3 percent of trees that survived.

“We don’t know if they’re lucky or naturally resistant," says Herms, "but those trees have been propagated and are being screened to determine if they’re truly naturally resistant and if they are that be the ideal natural germplasm that could be used in a breeding program of native trees.”

Herms says it could be decades before an ash restoration program could begin in earnest.

Meanwhile, he says he’s turned the stricken ash trees on his property into flooring and furniture.

He says his cabin in Michigan has an ash floor, ash table, ash chairs -- "souvenirs of what will be a vanishing resource.”