The dreaded emerald ash borer has arrived in Madison, which means some local ash trees have to go.
While the city looks at some 8,500 trees that may have to be cut and makes plans for playground mulch and ash wood tables, the county has a much smaller crop of ash trees to manage.
Dane County is responsible for 974 ash trees in county parks, according to a 2009 report, with the current total closer to 800 ashes.
The county has not decided which trees will be preserved and treated, but it has been removing “the trees we felt would have the least resistance are in poor shape to start with,” said Darren Marsh, director of Dane County Parks.
Some of these trees have already been converted to milled lumber and used to build "green" park shelters in Stewart Lake County Park in Mount Horeb and Brigham Park in Blue Mounds.
Three more shelters are in the works — two at Festge Park in the town of Berry, west of Cross Plains, and one at Indian Lake, also in Berry.
"We harvest a log out of the tree," Marsh said. "Anything that isn't used as part of the log, the smaller components, are chipped up into mulch that would go into trails or other areas in our park."
The county could use trees both from its own parks and local municipalities, like Stoughton or Mount Horeb, Marsh said.
"We have a county executive that is very supportive of creating these green-built structures using recycled materials," he said, "using materials that are local, coming off our own land."
Financially, local governments ultimately may not be able to recoup much from the loss of their ash trees. Still, for years, the ash was an excellent addition to the urban canopy, Marsh said.
"The ash has been the perfect tree," said Marsh. "It can take damage from lawn mowers, weed trimmers and storms and keep on living.
"It grows fairly quickly, yet has a harder, denser wood. It's also salt tolerant — when you're plowing the streets and have salt pile up on the curb, the ash can handle that. It's very viable and has taken a lot of abuse.
"Unfortunately, here we have a beetle that is taking them out."
Many have noted that the emerald ash borer is just the latest attack on the urban canopy, the last being Dutch Elm disease in the 1950s. Marsh and his colleagues are already hoping to preempt whatever might come next.
Ash trees have already been thinned out or “underplanted,” Marsh said, in a number of places: Lake Farm Park in the Capital Springs Recreation Area on the west side of Lake Waubesa, Mendota County Park near Middleton, Alliant Energy Center and Lakeview Hill County Park off of Northport Drive.
Underplanting means the county goes into areas where there are currently ash trees and plants a mixture of trees; for example, the city is planting Princeton Sentry Ginkgo, Skyline Honeylocust and New Horizon Elm trees. The next time a pest comes through, it won’t wipe out the urban forest.
“The goal is to have diversity,” Marsh said. “When we move forward, we want to make sure we have the least amount of impact ... the county parks system is not dissimilar to the streetscapes in Madison.”