Friday, July 21, 2006

 

Trees in danger!

From today's Daily Southtown:

The threat of the emerald ash borer

Thousands of trees in the Chicago area could succumb to the little green bug

Friday, July 21, 2006

By Paul Eisenberg
Correspondent


World War II had just ended and a full-scale housing boom was in progress. Everywhere in the south suburbs, new neighborhoods were sprouting, and municipal planners were scrambling to spruce up those new streets with rows of shade trees.

Oaks, while stately and beautiful, were ruled out because they took too long to grow. So, most areas instead turned to maple, chestnut, elm and ash trees.

The American chestnut trees were the first to go, stricken with a fungus so pervasive that it nearly eradicated the entire species and removed it from the suburban landscape. Next came Dutch elm disease, which continues to ravage American elm trees, eliminating them from area parkways.

In many cases, those diseased and dying chestnuts and elms were replaced by ash trees, a suitable substitute because of its quick growth, statuesque height and aesthetic appeal.

Today, as many as 30 percent of trees in the area may be ashes. And they could be the next to succumb to a foreign invader, leaving giant gaps in the suburban landscape, as well as the American psyche. After all, ash wood is used for, among other things, baseball bats and flooring.

The culprit is a little green beetle, no larger than a penny, which is so voracious it can kill a century-old ash tree in just a few years. And it has been spotted in the Chicago area.

An outbreak was discovered this spring in the northwest suburbs, and just last week, 16 trees in Wilmette were found to be harboring the pests.

On Wednesday, Kane County imposed a quarantine on 51 square miles after a beetle was discovered there.

Randy Knutson, a wildlife biologist for the National Park Service stationed at the Indiana Dunes, said one of the things that make the emerald ash borer so dangerous is it's difficult to detect.

"One of the best ways to find them is to cut down the tree and look for S-shaped galleries under the bark," he said.

The problem is that by the time an infected tree shows outward signs of distress, the damage has been done.

"By the time we discover the infestation, the beetles have usually moved on," he said.

Another sign is the beetle's D-shaped exit holes in the bark, Knutson said. Those small holes aren't easily noticeable, though, because the insects often start near the top of a tree.

The emerald ash borer, an Asian native, was first discovered in America near Detroit in 2002. Since then, it has killed more than 20 million ash trees in Michigan, Ohio and Indiana.

Knutson said an early strategy for dealing with it was to cut down all ash trees within a half-mile of an infested tree. At Warren Dunes State Park in Michigan, more than 4,000 ash trees were removed from the campground area, resulting in "a dramatic change to the area landscape and the appearance of modern campsites," according to the facility's Web site.

But that strategy didn't halt the beetles' westward journey.

"Now, we're concentrating on firewood," Knutson said. "People are moving it around in their firewood."

That's probably how an ash tree in the northwest suburbs of Chicago became infested, said Emily Kenny, of the Irons Oaks nature center in Olympia Fields. This past spring, an emerald ash borer was found in a spider web on a dying ash tree in St. Charles.

"Michigan is the place with the biggest problem," she said, "and for it to jump all the way over to the west suburbs, we'd be seeing a lot more trees (here) with problems.

"But we're waiting for it."

Likewise, while Indiana has reported infestations in South Bend, the Indiana Dunes National Lakeshore area has not had an infestation yet, Knutson said. There, they are advertising the problem, asking campers to not bring firewood in from out of state and advising them to burn all of the wood they bring in.

Officials in Wisconsin are getting worried as well, passing a law this year banning firewood from other states. But regulating the transportation of wood is merely a delaying tactic, Knutson said.

"The strategy is to slow it down and limit the spread," he said. "We want to give researchers some time to develop detection methods and control these pests."

As far as the individual homeowner is concerned, there is little to be done except keeping an eye out for D-shaped exit holes in the bark of ash trees, and planning for the future by planting a variety of trees, rather than relying upon one species, such as the ash.

Anyone who spots a suspicious bug or exit hole should contact the University of Illinois Extension service, he said. Beyond that, "There's not a lot you can do, except figure out how to take the tree down and plan on replanting something there," Knutson said.

"That's what's tough about it."

Still, Kenny and others at Irons Oaks are enlisting a small army of "beetle busters" to catch any south suburban infestation in its early stages. Children who participate in programs at the facility are learning about all the signs of emerald ash borer infestations and what to do if they spot one.

"They're the ones climbing and playing in the trees," she said.

While the alarm has been sounded, Kenny said she values the ash tree so much that she would still plant one, if the spot was right.

"If it's a good location for that tree, then go for it," she said. "It grows faster than an oak, and the seeds are small and easier to deal with (than a maple's). It's got a great yellow color in the fall, and it's a really good tree for this area."

For more information on the emerald ash borer, go to www.emeraldashborer.info. To contact the University of Illinois Extension office in Matteson, call (708) 481-0111.


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