The borer makes trees brittle and dangerous. So even though most of the 8,500 trees slated to get the ax aren't infested yet, over the next few years, they'll have to come down.
What to do with these trees, whether it's mulch, lumber or an artisan-made showpiece table, is something the city is still figuring out. Mulch is cheap and easy, but to some it seems like a waste of a strong, valuable ash tree.
Urban ashes could be milled into lumber or used whole as building beams. But first the city has to learn how to harvest the trees properly, and either find or establish a market for Wisconsin's urban lumber.
There are an estimated 21,700 public ash trees in Madison. Preventative treatment of trees that meet the city's criteria — larger than 10 inches in diameter, not located under power lines or otherwise weakened — began last week. The city hasn't planted new ash trees since 2006.
Treating and removing infested (or pre-infested) city ash trees could cost $19.1 million, according to a State Journal story in late May, "roughly the combined cost of a new library branch, police station and 14 Metro Transit buses through 2020."
So far, residents who want to save the ash trees don't have many options beyond an "Adopt a Park Tree" program, for trees in city parks only. Saving a tree means paying for an injection of a chemical pesticide that costs $10-15 per diameter inch, which works out to at least $100-150. Those pesticides last about two years before they must be reapplied, repeated for the life of the tree.
Into the wood chipper
For the majority of cut ash trees, the city plans to mulch them. What doesn't become animal bedding for cattle could be used as "safety surfacing" for some of the city's 172 playgrounds.
"We are embarking on a 10-year process of revitalizing and renewing all playgrounds, which will be about 10 to 20 playgrounds each year," said Laura Whitmore, a spokeswoman for Madison Parks.
Mulching is the easiest, fastest way to process the wood compared to firewood, compost, lumber and biofuel, all options Dane County considered for its own pre-infected ash trees.
The city makes about $127,000 a year on mulch, selling it for $250 per semi load to farmers for animal bedding. Private homeowners can pick up wood mulch for free in quantities less than 30 gallons.
But mulch, to some, seems like a waste of good trees. In a recent column, Wisconsin outdoors writer Patrick Durkin bemoaned the loss of "our native wood," which he estimated at about 15 percent of state forests and 25 percent of street trees.
"We're wasting money and beautiful wood by chipping felled ash into mulch," Durkin wrote. "Granted, ash lumber isn't as valuable as walnut or black-cherry lumber, but most people would admire floors, trim or wainscoting made from ash that's locally grown, harvested and milled.
"You're wrong if you think it's good only for firewood, ax handles and Louisville Sluggers."
Ashes to decks, floorboards and joists
Another option for the ash is rough-cut or milled lumber. The city has received a two-year, $25,000 grant from the Department of Natural Resources to hire a portable sawmill and "test the market for lumber from urban trees."
With money from the grant, Baraboo Woodworks will train city forestry staff on how to identify trees that have the potential for use as lumber, as well as how to harvest them.
"It's not limited to just ash trees," said city recycling coordinator George Dreckmann. "That's the motivating force, but the overall purpose is to show that urban trees are a perfectly good resource as lumber."
After stripping, some ash beams will go to a kiln for drying. The city could use rough-cut lumber as sideboards on its trucks or as floorboards.
Some could also be sold. According to a Milwaukee Journal Sentinel story about how that city was using its ash trees, a 10-foot-long ash board could be worth $15 to $20, is "as strong as oak" and could be used for flooring, furniture and decks.
Another option, though on a very small scale at this point, is to use trees whole in buildings as round timber.
WholeTrees, an innovative business with an office on Williamson Street, has been talking with the city and three Madison area developers about harvesting urban timber.
"Cities are interested in finding streams of revenue to offset the cost of removing all these trees," said WholeTrees founder and co-owner Amelia Baxter. "That's the attitude we find when we meet with parks districts."
Madison doesn't want to be in the sawmill business long term, Dreckmann said. What the city does with ash and other useful trees in the future depends on how much the wood costs to process and transport, as well as the demand for it.
It's wishful thinking at this point, but Dreckmann imagines a "locavore lumber" movement, literally taking trees from terrace to table.
"You're seeing, with discussions about the ash borer, the attachments that people have to the trees growing out in front of their house," Dreckmann said. "If people can keep that tree in the form of a table or a bench or chairs or bookshelves, it's not as wrenching as just losing the tree."
Making a market for city trees
Unfortunately, spotting a marked-for-cutting tree on one's street and deciding to turn it into a table is not (yet) a simple proposition.
City trees, because of their location, are under more stress than their country counterparts. They may have been trimmed for power lines, or have nails or staples in them — hazardous to milling blades.
They're also sometimes more difficult to harvest. Clearly, it's easier to fell a whole tree without houses or cars around.
And if someone hasn't already laid claim to the tree, there's also the question of who will want the wood once it's down.
"A lot of the mill guys, they don't even want the urban forest wood," said Darrell Krenz, co-owner of Capital City Tree Experts. "Half the time they have squirrel feeders, bird feeders, fence lines ... every time they hit a nail they bust a blade, and those aren't cheap."
But Dreckmann remains hopeful. Later this summer, he hopes to have Baraboo Woodworks bring its sawmill out to Warner Park, where the ash borer made its first confirmed appearance, and do a demonstration where they turn a few ash logs into lumber.
"We want to show folks that this is the thing we're trying to do," he said. "Anytime people get to see a board made out of a tree from the city, it creates potential demand for urban wood.
"If we prove you're not going to ruin sawmill blades while cutting stuff up, we have a product for the marketplace," Dreckmann added. "We really think there is market demand for this."
As the city grapples with thousands of trees, private home owners of ash trees have started calling tree experts as well. Krenz said his call volume has nearly tripled in the past few weeks.
"The problem with this whole thing is what to do with all this wood that's coming down," said Krenz. "I think a lot of people are going to have good firewood, honestly."