How the emerald ash borer is changing the suburban landscape

First of three parts

Bare suburban streets. Thousands of gallons of rainwater with nowhere to go. Billions of dollars in public money. Higher air-conditioning and heating bills. Lower property values. And millions of dead trees that could pose hazards to people and property.

In the next five to seven years, the tiny emerald ash borer will utterly change the landscape of the Chicago region. In some places, it will happen one tree at a time; in others, whole blocks of trees will be felled at once.

Illinois has the largest population of public ash trees in the nation, with at least 5.5 million on developed land statewide and nearly 3 million of those in the Chicago area, according to a study on emerald ash borer damage expected between 2009 and 2019.

Between those public trees and millions more on private property and in forest preserves, nearly 1 in every 5 trees in the region is an ash — all of which will be destroyed by the ash borer if not treated.

“This is like a natural disaster in slow motion,” said Scott Shirmer, emerald ash borer program manager for the Illinois Department of Agriculture.

“We didn't see it coming very far in advance, and once we did, we tried to prepare as best we could,” he said. “We'll just have to pick up the pieces afterward.”

Worse, that slow-moving disaster is actually speeding up. Ash borer treatments don't work nearly as well on trees that are not well watered, and trees have been weakened in general by the drought — making some people wonder if treatments are even worth it.

That same study, done by experts in entomology, forestry and economics, says that in the 25 states where emerald ash borer infestation is at its peak, dealing with it will cost upward of $10.7 billion.

Illinois' share of that is estimated at $2.1 billion, split up among municipalities, forest preserves, private landowners and other government units.

Michigan and Indiana have already gotten the worst of it. Fort Wayne, Ind., has lost thousands of ash trees and plans to remove another 4,500 in 2012.

Chad Tinkel, manager of forestry operations for Fort Wayne, said knowledge and planning are key to avoiding the “massive catastrophe” his city has seen.

“Act now,” he warned. “Do not wait and think you can handle it as it comes.”

Andi Dierich, forest pest outreach coordinator for the Morton Arboretum in Lisle, said the ash borer is devastating everywhere it strikes.

“But, there's so much ash that was planted here, so the devastation is just magnified,” she said.

Ash tree overload

The suburbs are heavily populated with ash trees, which make up nearly 35 percent of some towns' tree populations.

As suburbs expanded in the past half-century and developers looked for trees to decorate the new subdivisions, ash was an inexpensive, fast-growing, large-canopied option. As well, it had no known predator, an important factor in the post-Dutch Elm disease years.

The emerald ash borer, which evolved in Asia, first came to the U.S. around 1990, hidden in packing crates and pallets aboard ships and planes. The bug was first seen in 2002 in Detroit suburbs.

It would traditionally take years for borers to move even a few miles, but humans sped up the infestation by moving infected pallets and firewood around the country, Shirmer said.

Ironically, while the ash borer evolved in China and Korea, it has not destroyed the Asian ash trees. If it had, the insects would have destroyed their means of survival — as will eventually happen here.

Instead, ash species in Asia have something in their DNA that makes them resistant to the insects until near the end of their lives, said University of Illinois Extension entomologist Phil Nixon. In Asia, ash borers hasten the demise of trees already in decline, unlike the U.S. where they attack ash trees in all stages of their lives.

Scientists are studying to find what is in the Asian trees' genetic makeup that makes them resistant, but it's a natural defense compared to the chemical treatments being applied here, Nixon said.

Arborists are hoping municipalities will learn from this disaster that they need a greater variety of trees.

“This shouldn't have had to happen twice,” said Mark Spreyer, naturalist at Stillman Nature Center in South Barrington, referring to the lessons not learned from the Dutch elm debacle of the last century.

“There's no new lessons to be learned here that shouldn't have been learned last time.”

Already some suburbs are taking the lesson to heart. In Schaumburg, for instance, no single species will be allowed to make up more than 7 percent of the total forestation.

Environmental costs

As millions of trees begin to come down, experts are concerned about the environmental costs of so much canopy loss concentrated in the Chicago area.

Studies show large shade trees can reduce summer energy use by 20 to 25 percent, Dierich said.

Even scarier is the effect on local and regional stormwater systems.

A large ash tree, 18 inches in diameter, prevents about 2,200 gallons of water from hitting the ground each year as rainwater is soaked into the leaves, bark and roots.

“If you lose that one tree you have an extra 2,200 gallons hitting the ground every year,” Schirmer said. “That in itself is not significant, but if you lose 10,000 trees or a million trees, it's that much additional water to flow into the sewer systems.”

As more water reaches the ground, erosion problems and basement flooding will follow, he said.

The loss of trees also will make property less attractive to buyers. A study published in the Southern Journal of Applied Forestry estimates that each large front yard tree adds 1 percent to a house's sale price, while large “specimen” trees can add as much as 10 percent to a property's value.

“You have a lot of residents who purchase homes or select neighborhoods based on the trees,” Nixon said. “The idea of moving to an area without trees or where the trees are all about to be cut down may not be that appealing.”

The USDA Forest Service's Center for Urban Forest Research cites research that says 100 mature trees remove 53 tons of carbon dioxide out of the air per year, and 430 pounds of other air pollutants.

Other research says tree-filled neighborhoods are safer and more sociable, and trees even lessen cases of domestic violence.

“Trees are a resource — whether in a wood lot, on private property or parkways, they do serve a purpose,” Shirmer said.

The effect of the major tree loss on wildlife is unclear, Nixon said, and may not be known until most North American ashes are wiped out. Until then, he said, we may not know how integral ash trees have been to the life cycles of other species of insects or birds.

Another looming problem is dead ash trees also have a tendency to fall down relatively quickly — within a year of dying — softened by disease and having weaker wood than other species.

“As these trees die — and they are pretty brittle to begin with — they will become standing hazards that put the public and property at risk,” Shirmer said.

High costs

The emerald ash borer war is being waged in hundreds of communities, all of which are making individual decisions about whether to fight to save trees, or let them die and tear them all down.

Either way, the cost is high. Treating a tree can cost $100 or more every year, although less expensive treatments are available. Removing, and then replanting, a tree can cost more than $1,000.

Since many suburbs have thousands — or tens of thousands — of ash trees on public parkways, that puts the price tag for dealing with the emerald ash borer in the millions for many suburbs.

Arlington Heights estimates the cost to remove and replace 13,000 ash trees at more than $11 million. Schaumburg will spend $9 million over 10 years in a combination of treatment, removal and reforestation. Naperville has budgeted $467,000 to save as many of its 16,000 parkway ash trees as possible.

A tree with an infestation caught early enough can be treated with a variety of chemical compounds now on the market. If a municipality chooses not to treat or treats too late, it will still have to pay to remove the infested tree and possibly replace it.

“It's a snowball effect,” said Robin Usborne, communications manager for Michigan State University's College of Agriculture and Natural Resources. As one of the first infested states, Michigan and its universities have pioneered the research on the emerald ash borer.

“The trees start dying, and you have to spend money to treat them or take them down; you have to spend more money to replace them. Where is all the money going to come from?” Usborne said.

Although treating can be a less expensive option, not everyone is convinced.

“Should we be spending money to try to save a tree that's going to die sooner or later anyway, especially when we don't know for sure that this will even work?” asked Alderman John D'Astice of Rolling Meadows, where officials ultimately decided not to treat most of the 1,700 public trees.

And if the drought doesn't ease, Dierich said, treating trees this year might be a waste. The chemical won't make a difference.

“With the drought there's not enough water to move the chemical through the tree,” she said. “Unless you are watering your tree consistently, you're wasting you're money on treatment because the tree won't be able to do anything with the chemical.”

It's not a one-size-fits-all situation, Dierich said. Every community has different challenges and has to understand all the factors before deciding the best way to approach it.

“There's going to be an ongoing battle against this,” Shirmer said. “I hate to use the term 'natural disaster' because it won't take human lives, but when you see a tornado coming, you go into the basement. That doesn't stop the tornado from coming.”

Ÿ Daily Herald staff writers Deborah Donovan and Eric Peterson contributed to this report.

Emerald ash borer series

<b>Today</b>: The impact on the suburbs

<b>Monday</b>: Treat or tear down: Governments and residents make choice

<b>Tuesday</b>: Can a future disaster be prevented?