Rockford treats some ash trees with life-saving insecticide

ROCKFORD — As Brian Jacobi and Steve Farra drove down Weaver Road in northeast Rockford mid-June, their activity mirrored that of doctors delivering life-saving vaccines. The only difference?

Their patients are trees.

The city wants to save some of its ash trees from being eaten alive by emerald ash borers. Jacobi and Farra, city arborists, are innoculating trees this summer.

Millions of ash trees in more than a dozen states have died in the past decade because of the deadly emerald ash borer. Many of those trees were on public property and therefore the responsibility of municipalities and other government bodies — forcing cities like Rockford to face the harsh realities about the costs of tree maintenance and the value of a particular type of tree.

Without treatment, Rockford Streets Superintendent and city forester Mark Stockman says the city’s stock of about 8,000 ash trees will be dead in the next five to seven years. Those on private property will face the same fate, he said, unless residents start treatments in the next couple of years.

“Ash trees are pretty neat trees,” Stockman said. “They are very stable and strong trees. Outside of this particular insect, they’re almost indestructible. ... So we need to ask ourselves — Is this worth losing an entire species over?”

Weighing the costs
Rockford’s plan, which will take several years, has two parts: removal and treatment. Removals started last year. Treatments, which need to be started before infestation, began last week.

Removals run the city about $400 a tree. Treatment costs about $50 a tree. But once a tree is cut down and hauled away, it no longer costs the taxpayers money. Treatment is a different story.

To save an ash tree from what is seen as almost certain infestation and death, the tree needs a shot, explained Stockman. And it’s going to need that shot again every two years until the threat of the borer subsides.

No one is quite sure, however, when — or even if — that will happen.

If the city saves 800 ash trees with biennial insecticide injections, it will incur an annual $20,000 expense for as long as injections need to be given.

The $20,000 is coming from the Streets Department operating budget. 

Trees have more than just aesthetic value, Stockman said. They help keep the city’s air clean and decrease storm water runoff.

“I look at this as a very small investment for a large return,” he said. “To put it in perspective, we spend about $20,000 in salt for a citywide salting operation when we get about an inch of snow.” 

Debate continues
Debates over what to do about dying ash trees and whether treatments are worth it are escalating across northern Illinois.

Some communities are just removing them. Others, like Rockford, are opting for removal and treatment. Some, like Chicago earlier this month, still are debating just how much they want to spend on removal versus treatment.

In Aurora, no ash trees are getting injections or any other type of treatment.

Kevin Stahr, spokesman for the city of Aurora, said city leaders are not convinced that treatments work in the long-run.

“We’ve studied some of the chemical offerings and what the research is telling us is that the treatments don’t really ensure survival,” Stahr said. “It just spreads out the time. ... In about 10 years the cost for treatment or removal will be about the same.”

Stahr said Aurora is focusing its efforts on removal and replacement with other species.

Last year, the city removed 885 ash trees. So far this year, it’s removed 778 with plans of taking down at least 1,000 more by 2013. It planted 1,234 new trees.

Lessons learned
The 50 ash-replacement trees planted earlier this year in Rockford were paid for with a $20,000 grant.

The city selected a variety of species of all shapes and sizes, including disease-resistant elm trees to help bolster the city’s elm population, which was decimated by Dutch elm disease in the late 1950s and early 1960s.

Stockman said he and other members of the Community Tree Advocate group continue to seek grant dollars for ash tree replacement. More new trees could be coming in the fall.

The treatment appears to be working, Jacobi said. The difference between trees he treated last year and those nearby that didn’t get the treatment “are like night and day.”

The trees he treated, he said, are thriving while the others are losing their fullness and showing signs of weakness, especially in their extremities, a classic sign of EAB infestation.

The process involves drilling holes into the base of the tree and injecting the tree with a chemical formula developed to kill emerald ash borers before they bore their deadly tunnels through the tree’s vascular tissue.

“We do what we do because we like to do this. We love trees,” Farra said. “If Dutch elm disease taught us anything, it taught us that we need to diversify our species.”

Corina Curry: 815-987-1371; .(JavaScript must be enabled to view this email address)

Ash trees by the numbers
8,000: on city property
30,000 to 50,000: on private property in Rockford
168: removed in 2011
269: removed so far this year
50: replacement trees planted so far this year
800: city-owned trees will receive insecticide injections
7,200: city-owned trees will be chopped down in coming years