Emerald Ash Borer (EAB) is killing trees in Duneland.

Lots of them.

A two-year study just completed at the Coffee Creek Watershed Preserve shows just how much impact the small Asian insect has made, since first appearing in Chesterton in 2008.

“The number of elm trees killed by Dutch elm disease will be dwarfed by the number of ash killed by the EAB,” professional forester Gina Darnell said in a statement released by the Watershed Preserve. “I have never seen any insect spread so quickly and kill a tree without prejudice to condition.”

Ash is a native hardwood tree with both ecosystem and timber economic value. Ash is a predominant species along area streams and a popular landscape tree.

Ash trees at the 151-acre park that were six inches in diameter and larger were marked with blue paint and measured. The bad news is that all 1,593 trees are infested with EAB and are likely to perish within five years.

“And there are environmental consequences,” the statement said. “Mortality of ash will contribute over 2 million gallons of additional storm water flowing annually into Coffee Creek at an estimated dollar value of $60,356. This represents approximately 11 miles of stream corridor. The ash trees have stored 6.2 million pounds of carbon from CO2 sequestration. Over 67,000 board feet of a native hardwood have depreciated in timber value from an estimated $17,000 to zero once EAB has killed the trees. As part of the study, a 10-acre site north of CR1050 will have dying ash salvage-harvested this winter and funds used for tree purchasing and trail repair.”

The Coffee Creek Conservancy Board received a grant in 2010 from IDNR Community and Urban Forestry and Entomology departments for the study. The grant is also funding the planting of native trees to mitigate for the loss of ash. Seven-hundred trees were planted in May 2012 and another 1,000 trees are on order for April 2013, the statement said.

The insect cannot be stopped by insecticide treatments in a woodland setting. Homeowners with ash in their yards are encouraged to treat trees in the spring, before April 15, and to continue treating trees for up to ten years. But, according to Darnell, once a tree shows 25 percent or more canopy dieback, it is too late to treat an ash. “A tree removal bill may be in your future,” she said.

For information on treatment options, visit

www.extension.entm.purdue.edu/EAB

Posted 11/20/2012