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Cost of saving trees a factor in battle with ash borer

Marked with red white ribbthindicates it is being treated with pesticide Kane County Forest Preserve District Ben Haberthur restoratiecologist shows

Marked with a red and white ribbon that indicates it is being treated with a pesticide, Kane County Forest Preserve District Ben Haberthur, a restoration ecologist, shows one of the 30 mature Blue Ash trees they are trying to protect from the Emerald Ash Borer beetle at Johnson's Mound Forest Preserve on Thursday, October 11, 2012 in Elburn. | Steven Buyansky~Sun-Times Media

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Emerald Ash Borer facts

Ground Zero for the Emerald Ash Borer in North America was Detroit, in June 2002, where it was first detected.

The Emerald Ash Borer is native to
Asia and is suspected to have arrived in this county in cargo utilizing wood packing material.

In its native range, the beetle attacks and kills trees that are weakened by stresses such as drought, disease, and mechanical injury. In North America, it also attacks and kills healthy trees.

Already, tens of millions of North American ash trees have succumbed to this borer. If the beetle is not contained, the devastation to ash trees may be similar to that of American elms, which were decimated by Dutch Elm Disease.

The potential impact from the beetle in Illinois is significant. Ash trees account for 6 percent of forests statewide, and 20 percent of urban forests in communities in the northeastern part of the state, or approximately 130 million ash trees.

$10.7 billion was spent in 25 states for treatment, removal and replacement of than 17 million ash trees in developed land by 2010.

Source: Morton Arboretum and the Ohio Agricultural Research and Development Center

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Updated: November 13, 2012 6:08AM



The good news in the battle against the emerald ash borer is: there is hope for the future. The bad news: the Fox Valley and the rest of the Chicago area still is in the middle of an historic infestation.

“Think of it like a tidal wave,” said Cliff Sadof, a professor at Purdue University in Indiana. “You want to protect your trees in a bunker. After the wave goes over, you can poke your head out. Right now, you should be in a bunker mentality.”

Sadof recently addressed a group of Chicago area municipal leaders, staff members and forestry staff at a symposium on treatment possibilities that might save ash trees, rather than have them cut down and destroyed.

The symposium was held in Hazel Crest, a south suburb that is the site of a treatment research trial started in 2007. The trial is being run by the Morton Arboretum, the village of Hazel Crest, the U.S. Department of Agriculture, Davey Tree Expert Co. and Rainbow Treecare. Sadof has been collecting data and doing research on possible treatment alternatives since the emerald ash borer was first discovered in the early 2000s in Michigan and Indiana. The bug was first spotted in Illinois in a subdivision west of St. Charles in June of 2006.

Sadof said new information about how pesticides can be used have made treatment a viable alternative to cutting down trees.

“I would hope that you understand that it is indeed possible to save trees,” Sadof said.

Tree ‘death curve’

One of the pieces of newer information is the so-called “exponential death curve”. The curve shows where a specific city, county or region is in its infestation. This timeline can help local officials determine how to treat trees.

The curve shows how infestation starts slowly, but at a certain point, kicks in and suddenly becomes very destructive. For instance, the curve for the Upper Huron River Watershed in southeast Michigan — that area is ground zero for the U.S. emerald ash borer infestation — shows the infestation beginning in 1994, and progressing slowly through 2002.

At that point, eight years into the infestation, less than 10 percent of trees had died.

That number began to rise quickly, though, and by 2004, the death percentage was at about 20 percent of trees. But by 2006, the death percentage rose exponentially to almost 80 percent of trees and onto 100 percent by 2010.

The infestation begins

Infestation in Illinois was not discovered until 2006 in the Windings subdivision in Campton Township, west of St. Charles. When that infestation was confirmed by the state, the Kane County Forest Preserve District did a quick survey of the Campton Forest Preserve just across the street, and found infestation there.

“We got hit so fast that there might have been insecticides, but nothing was approved for use,” said Drew Ullberg, Kane Forest Preserve director of natural resources. “We had literally thousands of ash trees in parklands and on public lands that succumbed so quickly.”

What that means is the infestation was probably well along the curve by the time it was discovered, and it didn’t take long for it to spread. While infestation was discovered only in Campton at first. Soon, it was in a grove at the Dick Young Forest Preserve west of Batavia, and was in four preserves by 2007.

“Now it’s basically everywhere,” Ullberg said.

At that point, the district began a program of managing the hazard trees — ones in more public areas of the preserves — by cutting them down to make sure they didn’t fall on someone.

How many trees?

In 2010, Ullberg began a conservation program at Johnson’s Mound Forest Preserve in Elburn and in another preserve, on about 200 blue ash trees. He chose the blue ash because they demonstrated more strength against the infestation than other ash trees. There about 200 blue ash trees being treated, which Ullberg admits “doesn’t sound like very many.” But he said that at the very least, he hopes to use those trees to save the genetic strain and keep the ash “as a legitimate species for the future,” after the infestation has passed.

Officials in the fight against the emerald ash borer said the key to any program is to do a rigorous survey of the ash trees in a given community first. The survey needs to determine how many ash trees a community has, how many are infected and what condition the trees are in.

“The pattern of tree loss is the ultimate decider for the decision you get to make,” said Jim Zwack, director of technical services for The Davey Institute. “The key is where you are on the curve.”

Ullberg said the Forest Preserve District did a survey and found about 10,000 ash trees in the more public areas of the preserves. But that did not count the more natural areas, where it was almost impossible to do a complete survey.

“Maybe if I could hire 10 more people, then call me in five years, and I could give you an accurate count,” he said.

That more accurate count for all forest preserve lands is likely in the tens of thousands, Ullberg said. The district has already taken down thousands of trees.

Naperville, Elgin act

The situation is different in Naperville and Elgin, where programs that combine cutting down trees with treatment will save thousands of ash trees. In Elgin, Jim Bell, director of the city’s Forestry Department, said an assessment shows the city is “just entering the curve.” That has allowed the city to treat between 1,500 and 1,700 of its 6,900 ash trees to date. The combination of catching the infestation in an earlier stage, and the greater amount of information available now, has worked in both cities’ favor.

“When the infestation was discovered in the Windings, they were thinking, cut down ash trees,” Bell said. “The recommendation wasn’t for treating at that time.”

Naperville has what might be considered the poster child program for treatment. In 2008, when the city first discovered its infestation, it did an inspection and inventory, had the state install traps to determine the extent of the beetle’s presence, removed and disposed the trees it had to, and started treating all parkway ash trees within a half-mile radius of the discovered infestations.

In 2012, the program was expanded to include treatment of all healthy parkway ash trees. Naperville uses a hybrid of three chemicals to treat trees, depending on their size. Naperville has 16,300 ash trees, most of which the city will treat. Officials there anticipate taking down about 700 trees.

Cost a factor

Of course, a key factor in deciding on treatment is economics. In their program, Naperville has analyzed that it would take much more money over time to remove all the ash trees. Its treatment program for 2012 cost about $480,000. That will be only about $175,000 in the second year, because one of the treatments is done every other year.

The estimated cost to remove all the trees and replace them was almost $14 million.

The strategy has been different in Aurora, although just as pro-active. City spokesman Kevin Stahr said Aurora conducted chemical studies early on, when its infestation was discovered on the East Side in 2008. He said it showed that chemical treatment was not feasible.

“The cost of treatment over a 10-year period was more than removal of trees less than 18 inches in diameter,” Stahr said.

The city’s strategy has been to remove ash trees and replace them with other species of trees. In 2011, Aurora removed 885 ash trees and replaced them with 1,234 of other varieties, paid for in part by a $40,000 federal grant.

By the end of 2012, officials anticipate they will remove about another 2,000 trees, and replace them with 1,100 new ones, Stahr said.

“Many of those will be planted within the next 30 days,” he said.

Any Auroran who knows of a tree suspected of infestation is supposed to report it to the city’s public information line, 630-256-INFO. Property owners are responsible for tree on their private property.

No one knows what that next infestation could be, and it may not be for many years. No one recalls a situation like this, affecting one species, since Dutch Elm disease swept across America more than 60 years ago.

“Emerald ash borer is a pest of historical significance,” said Zwack, of the Davey Institute. “And hopefully it’s a once-in-a-lifetime pest.”



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