Madison city parks officials are collecting ash branches from street trees in search of signs of the emerald ash borer.
The collection began this week and involves peeling away the bark of the branches and searching for larvae. The branch sample method is believed to be more effective at finding emerald ash borer in low-level infestations, according to city forestry officials.
The invasive, non-native beetle has been found in numerous areas of the state. Its larvae kill ash trees by tunneling into the wood and feeding on the tree's nutrients. The beetle has killed tens of millions of ash trees in 18 states, including Wisconsin, Iowa, Illinois and Minnesota.
Testing was conducted in Madison last year and the beetle was not detected, but has been found in Janesville.
Some counties have been quarantined, meaning hardwood firewood cannot leave the area, no matter what the tree species is. Some businesses that use ash products are also affected by the quarantine.
About 25 percent of Madison’s street trees are ash trees, according to city officials. City staff will sample five city ash trees in designated plots spaced at 6/10th-mile intervals throughout the city and contact affected property owners.
The city keeps updated information on its emerald ash borer monitoring efforts here.