About 25% of street trees in the city of Washington are ash, which could be bad news if the Emerald Ash Borer makes it's way to this area. Andy Dahl is the arborist at University of Iowa, and a member of Washington's Tree Beautification Committee. He says the destructive insect would have a devastating impact on Washington. Dahl says other states have had limited success controlling the Emerald Ash Borer. He says the best approach is to limit its spreading. He says that's why it's important to use local firewood, and not transport it.