Above: A flyer from the Iowa Department of Agriculture
DES MOINES, Iowa – All 99 of Iowa’s counties are now under the shadow of the emerald ash borer. On February 4, authorities enacted a statewide restriction on the movement of hardwood firewood, ash logs, wood chips and ash tree nursery stock out of the state.
The quarantine was prompted by the discovery of emerald ash borer in Black Hawk County; city officials in Waterloo trimming street trees found the insect in three separate locations. Waterloo City Forester Todd Derifield says there are no doubts that the infestation is widespread.
“I’ve seen at least three dozen that I”m sure have [an infestation] just by the symptoms that they show,” says Derifield, “but we physically didn’t feel the bark and find the insect.”
Waterloo is estimated to have 4,364 public ash trees, which Derifield estimates at 17% of public trees in the city. The latest infestation marks the sixth confirmed case of emerald ash borer in the state, after its discovery in 2010. In Waterloo, ash trees will be removed from the ten square block area surrounding the infested trees, and Derifield says the overall reduction of ash trees in the town is ongoing.
“We are removing ash trees in the rights of way that are adjacent to property owners who have requested those ash trees to be removed now,” Derifield says. “So those are just public trees between the sidewalk and street in front of an address. We’re doing these advantageous removals where we remove a number of ash trees that are in a grove, in a park, or in a golf course, and sprinkle some other plantings in there so that those established while we still have some ash trees present there.”
Infestations of the emerald ash borer in Iowa have been discovered in Allamakee County in May 2010, Des Moines County in July 2013, Jefferson County in August 2013, Cedar County in October 2013 and Union County in December 2013.
Once ash trees are out, there’s not exactly a replacement tree. Iowa State University Extension Horticulturalist Jeff Iles explains.
“Boy, the last thing we want to do is recommend one species to come back and replace the ash,” says Iles. “I think that’s what continually gets us into problems. What we’re preaching to communities is to get a handle on what you have, and then diversify.”
Instead, Iles suggests communities decide how to replace ash trees based on lists provided by ISU Extension, one of which concerns shade, while the other addresses stature.
