It has been almost thirteen years since an invasive beetle revealed its metallic-green-shelled self to scientists outside Detroit. Since then, emerald ash borer (or EAB) has killed tens of millions of ash trees in Michigan alone and has moved on to 23 other states and two Canadian provinces.
Wisconsin isn't new to the list. EAB was first reported here back in August 1, 2008.
Over the years, WUWM has been checking in with scientists and foresters in our neck of the woods to learn how they deal with the threat of EAB.
Between 2009 and 2014, Riveredge Nature Center was a hub of emerald ash borer control experimentation. Wisconsin’s first documented EAB hit was discovered less than a mile away from its forested canopy in Ozaukee County.
Scientists swarmed there from both UW-Madison and Milwaukee as well as the state’s Department of Natural Resources and APHIS, the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service. All of them focused on finding solutions.
Some teamed tested multiple insecticides for their ability to stave off EAB infestation. Others set up traps of different sizes and colors to try to trap the beetle.
WUWM first spoke with Todd Johnson four years ago. The UW-Madison graduate student – in collaboration with APHIS - shared his experience as he released wasps native to the EAB’s original habitat.
Johnson’s project ended last year. And, many of Riveredge’s ash trees are now dead or dying.
But APHIS’ work experimenting with predatory wasp continues. One of its newer partners is the Milwaukee County Parks Department.
"We give them a couple of sites where we’ve found heavy infestation in continuous tracks of land. In the Root River, they’ve done some test release and they’re working to develop a population that can help keep EAB in check,” Ramsey Radakovich says.
Radakovich is land resources regional manager with Milwaukee County Parks. “I don’t think it’s ever going eliminate EAB," he says.
County parkland covers 15,000 acres. Twenty four percent of its canopy is ash.
The trees are abundant in Whitnall Park.
“You can already see signs of infestation up in the upper canopies where the bark looks really flecking, it looks like a checkerboard pattern. That’s a sign that EAB has entered the tree; and usually by you’re seeing it here, it’s a three or four year infestation; so unfortunately by the time the naked eye catches it, it’s pretty far gone,” Gregg Collins says. He oversees the county’s forestry program.
Both Collins and Radakovich say the prognosis is bleak.
So, Radakovich says Milwaukee County has elected to treat a miniscule fraction of its ash by injecting a special insecticide. Safety, he says, comes before aesthetic or habitat.
“We’ve defined what trees we’re going to treat by what kind of quality they are, where are they, what kind of condition are they, are they historical trees or trees that highlight a golf course hole, but ultimately we realize that we can’t save every tree in the woodlot so we have to have a selection process,” Radakovich says.
Gregg Collins points back to the maze of trees before us.
“We want to try to eliminate anything in the first 30 to 40 feet in. As you get further in, the hazard drops so we let nature take its course and it will become a woodpecker habitat,” Collins says.
Ramsey Radakovich says silver lining might not be the best choice of words, but the appearance of emerald ash borer gave county parks the opportunity to learn more than which areas to target for treatment.
“Through an urban forestry grant in 2007, we conducted an overall inventory throughout the 15,000 acres of the parkland,” Radakovich says.
It was the first ever cataloging of the county’s canopy.
“We determined, at that time, that we have 1.5 million trees in the park system and of those 24 percent or close 356,000 are ash trees,” Radakovich.
But Radakovich says the inventory also revealed how much oak, locust and hackberry occupy county lands. Over time, Radakovich wants to use that information to further diversify its trees to try to avoid the devastation that followed in the wake of Dutch elm disease in the 1950s.
“We want to have a balanced tree resource population that can weather, if we have lose a certain species we have another to fill its place,” Radakovich says.
Unlike Milwaukee County, which is treating very few of its ash, the city started injecting most of its ash – the healthiest and established in 2009.
Ian Brown, Urban Forestry Technical Services Manager for the City of Milwaukee, says crews are treating 28,000 ash trees.
“The research continues to indicate that is it effective and we haven’t lost one of our treated trees yet,” Brown says.
He’s just about to hire and train 20 summer interns who will inoculate trees around town.
“I’m working very closely with them to give them individual training, so they’re not only informed about what they’re doing but why they’re doing it. They don’t exactly hide on the street; they’re wearing bright yellow vests that say City of Milwaukee on the back; and it’s not uncommon for citizens to come up and learn what are you doing, why are you doing it. It’s an opportunity for college interns to get some first-hand experience sharing and communication directly with constituents,” Brown says.
Brown embodies the mission of caring for the urban canopy and justifying its cost with equal passion.
He says while it costs $35 a year to treat an individual ash tree, the cost to remove and replace a tree is $750 and, then layer in the environmental benefits of the canopy.
"Storm water mitigation, air pollution mitigation and when you stack it up over the years that we’ve had it, it’s a huge impact. Going forward we can use ash and EAB as a surrogate to what we saw with elm and Dutch elm. There’s definitely more benefit than cost associated with maintaining and keeping an urban canopy,” Brown says.
He hopes to facilitate a gradual transition of the city’s ash-dense pockets and avoid the devastation Dutch elm left in its wake.
”You’d have an entire block that either get it or be removed. It could be as drastic as going to work and they have canopy and they come home and there is none.” Brown adds, “ instead over a period of five, ten, hopefully 20 years, we’ll replace the ash with other trees. So that by the time we take back our last ash tree, we’ll have other trees established in the landscape.”
Inside the East Library off North Avenue, Brown says it showcases another element of the city’s urban forestry program.
“We have 200,000 street trees, we take down 3,000 to 4,000 trees a year. We have storms that come through, we can see construction damage. We direct that wood to the best and highest use, rather than (doing) whatever is easier and most convenient," he says.
Instead of the old days of sending removed trees to landfill, Milwaukee passes its felled trees to a couple of nearby lumber companies. Fashioning furniture, flooring, and even library art work from urban wood are beginning to catch on.
Brown points to the floor to ceiling piece inside East Library.
“The mural is composed entirely of urban wood; and I believe from the immediate neighborhood. So rather than have that wood chipped or turned to firewood, we actually reclaimed the wood, and now here it is part of this 20-foot mural that is topography of the east side,” he says.
Marc White does not have time to contemplate the splendor of re-purposed urban wood. He’s busy getting to know the parcel for which he’s responsible and preparing for emerald ash borers that reportedly are a mile from his doorstep at Schlitz Audubon Nature Center.
Forty percent of its 185-acre canopy off Lake Michigan in Bayside is ash.
White has over two decades of restoration ecology experience, but he’s been with Schlitz Audubon just less than a year.
Before he came on about 150 ash trees scattered throughout the property were inoculated with insecticide.
White rethought the strategy. “So what I’ve decided is to take our highest quality land on our ravines and our lake bluff and do our insecticide treatments on the larger ash in those area where the ash are really important in stabilizing those slopes and maintaining the habitat quality in those areas,” he says.
Among Schlitz Audubon’s richest habitats are its wet zones.
“It’s about 60 acres and it’s very rich with ephemeral wetlands that support the breeding of frogs and salamanders. We have Blanding’s turtle. So it’s an extremely important piece of habitat, especially in Milwaukee County, for the conservation of these very scarce reptiles and amphibians,” White says.
These are areas which harbor lots of ash that shade the delicate ecosystems. White unilaterally will not treat any of those trees.
“If we the insecticide into the tree, that insecticide is systemically taken up into the tree, goes into the leaves, every part of the tissue of the tree has the insecticide in it. And it’s actually a fairly broad-spectrum insecticide. And it doesn’t just go away when it gets into the leaves. It falls down from the branches and twigs. It gets into the soil and it’s still an active insecticide. And so it could potentially destroy the foundation of the food web that supports amphibians in those ephemeral ponds,” he says.
White says he began to consider the potential lingering impacts, when he remembered another set of living creatures that freely move about Schlitz Audubon.
Three, four and five year olds frolic its nature preschool. Some of their favorite locations to explore are punctuated with massive ash.
White says he’s taking no chances.
As for the ravines and bluff he might treat a tree or two, he remains in wait and see mode until he sees evidence of EAB.
“I’m out there every day, worrying about it and inquiring what’s going on, where is emerald ash borer because once it’s in a county, basically the state stops monitoring it. They don’t track where it is in that county. They just color that whole county red, the emerald ash borer there and they move on. So, what’s important to me is to know where EAB is as that wave approaches us, so that strategically I can decide how fast I have to move,” White says.
He echoes the theme shared by the City and County of Milwaukee. Emerald ash borer presents them with an opportunity.
“In a way, the loss of ash is going to be a tremendous opportunity for us to improve the diversity and the long term quality of forest that we’re able to have,” White says.
In Ozaukee County, the wave has arrived; Riveredge Nature Center reports much of its ash are either dead or dying.
