What to do with the surfeit of wood likely to result as Iowa’s ash trees succumb to the emerald ash borer is a “big concern,” said State Forester Paul Tauke.
“That’s going to be a huge issue” in the next several years as most of Iowa’s approximately 55 million ash trees die, Tauke said.
So far the state has recorded infestations of the tree-killing insects in eight counties, and Tauke and other officials expect the pest to kill almost all Iowa’s ash trees within a decade.
“Somebody will get them out of the woods if there is money to be made, but a glut of dead trees could crash the market,” he said.
Tauke said he is more concerned about the state’s 3.1 million urban ash trees, most of which will have to be removed at an estimated cost of $1,000 each.
Urban trees, he said, have less intrinsic value because they are often misshapen and hide nails and other metal objects that could damage sawmill blades.
“There is no magic, golden answer as to where all the wood can go,” said State Entomologist Robin Pruisner, a member of Iowa’s Emerald Ash Borer Team.
Both Pruisner and Tauke predict that firewood will be the top use for Iowa ash, followed by chips for landscaping and trail surfaces and by lumber and other high-end uses.
Ted Wieland, CEO of Wieland & Sons Lumber Co., said ash makes up about 5 percent of the trees processed each year by the Winthrop firm.
“Ash is good wood in high demand. We export most of it to China. We can’t get enough of it,” he said.
Parts of a good ash log can be milled for furniture-grade wood, construction-grade lumber and pallet lumber, Wieland said.
The company burns the bark and chips in a boiler to heat its kilns and buildings, he said.
The company, which subjects each log to a metal detector, does not routinely reject urban wood.
“About 15 to 20 logs a week get kicked out, and we can usually trim off the suspect areas and use them,” Wieland said.
The University of Iowa is gearing up to burn ash in the boilers that generate the steam that heats and cools campus buildings, said Ben Fish, UI’s assistant director of utilities and energy management.
The university will soon finish burning 3,000 tons of wood harvested from dead trees at Johnson County’s F.W. Kent Park, he said.
That project, which blended wood chips with coal in proportions ranging from 20 percent to 40 percent, “really has gone very well,” Fish said.
Fish said the university will likely ask potential wood chip suppliers to submit bids this summer.
Burning ash chips, supplementing the ongoing use of oat hulls, will help the university reach its goal of generating 40 percent of its energy through renewable sources by 2020, Fish said.
In Wisconsin, which has about 16 times more ash trees than Iowa and a more advanced ash borer infestation, officials anticipate “wall of wood,” a surplus that occurs when large numbers of trees die at once, according to Bill McNee, Department of Natural Resources forest health specialist for southeast Wisconsin, ground zero of the state’s ash borer infestations.
Trees in rural areas, which can be used for pulp and lumber, have more economic value than urban trees, McNee said.
Most ash in urban areas ultimately gets turned into wood chips, which can be used for landscaping, trail surfacing or blown into woods to decay naturally, he said.
“We are encouraging high end, high value uses – stairs, benches, desks, wall paneling and other building products – for the trees that are suitable,” McNee said.
“The mindset is changing on how we value these trees,” said Pete Jopke, a resources planner with Wisconsin’s Dane County, where an emerald ash borer infestation was confirmed in October.
“There is a big push to use urban ash wood in value-added applications (furniture and lumber, for example), rather than burning it or chipping it,” Jopke said.
Firewood and chipping are among the easiest and most economical ways to dispose of ash, and they provide some value to users, but officials would prefer to see such uses reserved as a last resort, he said.
Dane County Parks Director Darren Marsh said ash wood is being used to build park shelters, cabins and other “green-built” structures in a program reminiscent of the Depression-era Civilian Conservation Corps.
In the Milwaukee suburb of Oak Creek (30 square miles, 34,451 residents), where the EAB infestation was confirmed in 2009, almost half the city’s ash trees have already been removed, according to City Forester Rebecca Lane.
Though tree removal has not been especially noticeable, “we have a few former shady lanes that are now sun-drenched streets,” she said.
Lane said the city has encountered hurdles in putting the wood to good use. “We started out giving firewood to residents to heat their homes, but it is not the best use of the wood,” she said.
Although the city still chips upper branches for mulch and provides some firewood to residents, it now has an arrangement with a lumber company to pick up logs suitable for lumber, Lane said.
“Wisconsin cities are not going in the direction of landfilling. Firewood is the use of last resort,” she said.