When Allerton Park Foreman Larry Corum was growing up in Urbana in the 1950s, he remembers a long archway of elm trees that were planted through the University of Illinois campus.
When Dutch elm disease invaded East Central Illinois during that decade, Corum said, the disease killed most of the trees and destroyed the archway.
"It was devastating to see all those trees die," Corum said.
Corum and area arborists fear the same kind of devastation could strike ash trees if the emerald ash borer arrives here.
The borer is a pest that has killed between 12 million and 15 million ash trees in Michigan, Indiana and Ohio since it was discovered in eastern Michigan in 2002.
This week, state agriculture officials discovered some emerald ash borers in central Kane County.
Urbana Arborist Michael Brunk estimates that as many as 6 percent of the 13,000 trees owned by the city are ash trees.
"And we probably have twice that many ash trees on private property," Brunk said Wednesday.
After learning about the devastation the borer was causing in Indiana, Michigan and Ohio, Brunk said, Urbana stopped planting ash trees about two years ago.
"As far as we know, there is nothing we can do to stop the borer," Brunk said.
City of Champaign Forestry Supervisor Bill VanderWeit said 2,100 of the city's 20,000 street trees are ash trees.
VanderWeit said ash trees have been popular in the new subdivisions on the edge of Champaign because they grow well in areas where the soil is disturbed by construction work.
"They are all susceptible," he said. "We've been getting prepared for the arrival of emerald ash borers for years."
VanderWeit said there isn't much his staff can do at this point except check all the trees for evidence of the borers.
VanderWeit urged residents not to confuse the emerald ash borers with the more common native ash borers. While the emerald ash variety create "D" shaped holes no larger than an eighth of an inch, the less deadly native ash borers create round holes that are at least a quarter of an inch in size, he said.
While Corum doesn't know how many ash trees there are at Allerton Park, he said it is a fairly common species there.
"The beetle is a half-inch long, and it emerges through a hole shaped like the letter D," Corum said. "The beetle tunnels underneath the bark of the tree, and it bores into the stem and the trunk."
Corum said his staff is considering applying insecticides on Allerton's collection of ash trees, but he isn't confident they will do much good if the borer makes an appearance there.
"I'm not sure what chemicals we can use to kill the borers off," Corum said.
Brunk said one way that area residents can protect the local ash tree population is to be careful when purchasing firewood.
Brunk said the pests might be hidden inside firewood from Indiana, Michigan or Ohio.
"We want to warn people not to purchase firewood that has been cut and brought to this community from other states, especially from Indiana," Brunk said. "When you purchase firewood, make sure you know the source."
Champaign County Forest Preserve District Director Jerry Pagac said at he, too, remembers when Dutch elm disease struck.
"The irony is that ash trees were a common replacement tree many years ago when the elms were lost to Dutch elm disease," Pagac said.
Pagac said all four of the forest preserve district's parks contain ash trees. He said the district doesn't have enough money to pay for pesticides to fight the pest.
"We haven't done an inventory of them, but we have a lot of ash trees," Pagac said. "The emerald ash borer is a real concern."
Pagac said the pests killed ash trees in Indiana, where he worked before coming to Champaign County.
"It probably is only a matter of time before it marches to the rest of the country," Pagac said.
The Associated Press contributed to this report.