WATERLOO | Todd Derifield has a virtual dining guide for emerald ash borers at his fingertips.
A computerized tree inventory lets the city forester pinpoint the location of every ash in city parks and roadsides, find out the trunk size and health and determine the last time his crews trimmed its branches.
"This has really organized our day-to-day operations ... (replacing) piles and piles of paper," Derifield said. "It's going to be difficult to deal with the emerald ash borer the way it is, but it would be more difficult without this inventory."
The Leisure Services Commission and City Council voted in 2007 to begin the tree inventory when experts warned the destructive insect eventually would find its way to Waterloo and start destroying the entire ash forest.
When officials with the Iowa Department of Agriculture and Land Stewardship last week confirmed the beetle had been found in a northeast Waterloo neighborhood, experts said the city was ahead of most by having an inventory in place.
The Treekeeper software through Davey Tree Resource Group has improved efficiency in the forestry operations and allowed local forestry crews to begin proactively removing and replacing ash trees on public property.
The 4,364 ash trees represent 18 percent of the nearly 25,000 trees the city maintains along roads and in its 52 parks and three golf courses. That's easily the most common tree in the city, outpacing second-place silver maples, which make up 11 percent of the total.
"Ash trees started to be planted extensively as a replacement to the American elm after the Dutch Elm Disease outbreak in the early 1970s," Derifield said. "They proved to be a tough tree that could survive in almost any conditions so they continued to be planted and perhaps overplanted."
Roughly one-third of the ash trees in Waterloo are 13 to 18 inches in diameter. About 1,100 trees are 7 to 12-inches diameter with another 900 being 19 to 24 inches across the trunk.
The inventory does not include trees on private property, which are the responsibility of the property owners.
State Forester Paul Tauke said other communities need to follow Waterloo's lead and do their own inventories. While most communities have about 17 percent ash trees, he said, they need to know the other varieties' counts to make informed decisions on replacing the trees being removed.
The city of Mechanicsville, for example, has 31 percent ash and 40 percent maple trees.
"My recommendation is not to plant any more maple (in Mechanicsville)," Tauke said, noting an infestation of Asian longhorned beetles, which kill maple trees, would be devastating.
Derifield said the city has already been using its digital database to prioritize ash removal and improve diversity of the urban forest.
Forestry crews removed two of every three ash trees planted along Airport Boulevard and replaced them with other varieties. New varieties of trees have been planted amongst the rows of ash trees buffering homes from Lloyd Randall Park, hoping to mitigate the impact when the ash is gone.
Derifield said homeowners should consider similar diversity if they replace ash trees.