As Hilliard residents forego air conditioning and open windows in favor of their furnaces, wood-burners and fireplaces, a tiny insect has once again become a concern.

As Hilliard residents forego air conditioning and open windows in favor of their furnaces, wood-burners and fireplaces, a tiny insect has once again become a concern.

The emerald ash borer (EAB) has become a problem in central Ohio in recent years, and will continue to be this fall as residents need more firewood to heat their homes, according to Chris Ahlum, of Ahlum & Arbor Tree Preservation.

Ahlum works at the Hilliard-based business as an International Society of Arboriculture certified arborist, and is registered with the American Society of Consulting Arborists as a consulting arborist.

"I would say that the (EAB) problem has exploded more this year than in recent years," Ahlum said. "In the last couple years you've seen some outbreaks closer to Columbus, but this year we started looking in areas such as Dublin and Bexley and have found a lot more infestations."

Ahlum said it's easy for the tiny beetle to gain a foothold when it goes unnoticed.

"The problem is, once we find or notice an infestation, we typically don't see it until the tree is already declining. Once it's noticeable, the tree is pretty well infected," he said.

"In Hilliard alone it's hard to say how many ash trees there are; Hilliard doesn't have as many street ash trees as other communities, but there are still a fair amount," he continued. "Probably a third or a quarter of the native trees in Ohio are ash trees."

The small insect was first noticed as a problem in Michigan, Ahlum said, and although it moves slowly on its own (flying about half a mile a year), humans have propagated the problem by transporting firewood.

"All of our wood here is locally sourced, and the Department of Agriculture has a quarantine in some counties regarding the transportation of firewood," he said. "If a homeowner is caught transporting firewood (where it is quarantined), there's a pretty hefty fine. The key is to find a good, reliable local source of firewood."

Ahlum said that treating an infected ash tree can be pretty costly for a homeowner, but that Ahlum & Arbor often helps customers determine their best course of action.

"The first step is really identifying the trees on your property, and if you have ash trees," he said. "We help owners to determine if their trees are infected and if it makes sense to perform a treatment - if the tree is back in the woods it might not be worth it to the owner, as opposed to treating that 100-year-old ash tree in the front yard."

Ahlum said ash trees can be protected from future infestation with a preventative "soil drench," which is a chemical treatment of the soil surrounding the tree. This process typically can cost $4-$8 per each inch of the tree's diameter, he said. The other option is injecting chemicals directly into the trunk of an infected tree, which can cost $8-$12 per each inch of the tree's diameter.

"I think the local residents have become a lot more aware of the problem this year," Ahlum said. "We've been doing these treatments for about five or six years now, and people are starting to educate themselves about the problem."

A Web site devoted to information on the EAB problem in the state is maintained by the Ohio Department of Agriculture at www.agri.ohio.gov/EAB.

lrice@thisweeknews.com