Nearly 3,000 trees have been removed in Milwaukee County Parks since 2009 because they were infested with the invasive emerald ash borer. Others were cut down as a prophylactic to prevent further infestation, said Gregg Collins, forestry supervisor for the Milwaukee County Parks system. The emerald ash borer (EAB) is an invasive, wood-boring, metallic green beetle (Agrilus planipennis) originating in eastern Asia. It was first discovered in Wisconsin in August 2008.
“We are actively removing Green Ash trees (Fraxinus pennsylvanica), which are certainly infested and already debarked, and completely dead,” Collins said. “At the same time and often in the same park, we will remove Green Ash, which do not exhibit outwardly visible symptoms. We do this with the understanding that when EAB has infested an area, 100 percent of the remaining ash trees will become infested during the population explosion if not chemically treated with a pesticide.”