The Jefferson city council heard bad news and good news about the city’s trees last week when Jason Walker, a Jefferson-Scranton 2000 graduate and now a district forester for the Iowa Department of Natural Resources, presented the 2016 urban forest management plant.
The bad news is that according to Walker, there is no question that emerald ash borer will come to Greene County. The only question is when that will be.
The good news is that only 15 percent of the city’s “street trees,” those located in the right-of-way between the street and the sidewalk, are ash trees, compared to 17 percent statewide.
Walker spent four days in Jefferson last June, walking every street and inventorying every one of the 1,731 street trees, noting its specie, size and condition. The inventory was funded by a grant from the USDA Forestry Service. “Take this information and use it to start to develop a plan for the future. Knowing what you’ve got currently is going to be a critical piece of information to appropriately plan for the future,” Walker said.
Walker found there are 42 species of city-owned trees, with 44 percent of them maple, 15 percent ash and 9 percent crabapple. He identified 118 trees as needing removal and noted that 28 of those trees are more than 24 inches in diameter at 4-1/2 feet above the ground and should be removed immediately. Those trees, he explained, are a liability to the city.
The inventory was done in response to the emerald ash borer infestation that is progressing across Iowa. Walker said the 253 ash trees in the right of way are generally very healthy, and that he saw no signs or symptoms of the damaging insect. “But with that, it’s when not an if this bug shows up. It’s a reality this is going to show up at some point,” he said. Once a tree is infected it must be removed, he added, and reminded the council EAB has been found in Boone.
The city currently spends $6,000 on trees. The city crew does much of the tree removal when its needed. Walker said that commercial companies get between $500 and $700 to remove a tree. At that cost, it would cost $177,000 to have all the ash trees cut down commercially. Walker pointed out that at an annual budget of $6,000, it would take 30 years to remove the trees.
EAB is typically in a location for five to seven years before it is discovered, and then within another five to seven years serious, significant defoliage has occurred.
Walker’s recommendations to the city are:
- Thirty-two trees are of “immediate concern” and should be looked at for removal. Of those, five are ash trees. They have rotted or decayed and are likely to topple over. He said the city should limit its liability and “eat the cost” of removal
- Replace the trees being removed. He noted that the same day he met with the council, students and the Jefferson tree committee had planted 30 trees with another 32 planted later by the tree committee. The trees were funded by Alliant Energy’s Branching Out program administered by Trees Forever.
- Continue at least the current $6,000 annual budget to remove trees. He said maple trees have a high incidence of rot and decay.
- Determine a course of action concerning EAB. Increasing the budget to $30,000 would remove all the ash trees within six years. A budget of $15,000 would take 12 years. “Cities who try to do that removal in-house are quickly overwhelmed,” he said.
- Set money aside now for when EAB shows up, or begin now taking out ash trees in a small number every year.
“Whatever it is, whatever you decide, the importance is that you decide something. Don’t just sit on your hands and hope it passes by. It always comes back to ‘it’s a matter of when, not if’,” he said.
Walker said there are EAB treatments that are “reasonably effective,” but the cost of treating each tree can be about $200, and the treatment lasts only two years. The chemical has no residual effect. Over the cost of 10 years, $1,000 would have been spent treating each tree. “I have a hard time justifying that, especially as a government agency that has so many trees to deal with,” he said. “If you have one tree in your yard and it’s a memorial tree or a really special tree, I can justify the cost for that, but you have to know it’s a forever thing.”
His inventory was of only street trees. He estimated there are 75 ash trees in Jefferson’s parks and there are many ash trees at the city-owned golf course.
Walker calculated annual financial benefits of Jefferson’s trees at $232,609. On average, each tree in Jefferson provides approximately $134 annual. Those benefits include a reduction in energy costs, intercepting rainfall or snow melt, improving air quality and “aesthetic” benefits.
To read Walker’s complete report, click here.
