Milwaukee opts to treat trees
Sunday, July 21, 2013
David Sivyer, forestry services manager for Milwaukee, said the annual cost to treat each tree with TREE-äge is about $70. That application will protect a tree for two years and possibly three, he said.
The cost to remove a tree is about $750 to $1,000.
“You can inject a tree for many, many cycles before you even approach that removal and replacement costs,” Sivyer said. “While doing so, we're protecting the canopy and the benefit those trees provide to the city, including pollution and stormwater control."
In-house crews inject about 14,000 trees each year.
In addition, the injections “put us in the driver's seat” as to when to remove ash trees and replace them with other trees, he said.
“It's a very cost-effective tool,” Sivyer said.
The same amount of money is included in the budget every year rather than the spikes that would occur as the infestation reached its height.
Milwaukee started injecting trees several years before the borer was found in 2012, protecting every tree 8 inches or larger in diameter. A tree that size presents a public safety risk as it dies, he said. Anything smaller can also be replaced in another eight to 10 years at a minimal loss.
Milwaukee also did a “tree economy services analysis” to determine the benefits the tree provides and the impact the loss of the tree would have. It determined the percentage of the city's canopy at risk.
The study showed the city had about 587,000 ash trees, the majority on private or state property. The city owned 33,000.
The city opted to let about 5,000 trees go, and they will be removed and replaced as they are infested.
The bug was found in trees that had not been treated, and those trees had 4 to 5-year-old infestations.
“That's typical of this pest,” Sivyer said. “We knew we couldn't wait.”
Sivyer said Milwaukee did not want the experience of other cities, with block after block of trees gone and neighborhood character destroyed.
Sivyer recalled when Dutch Elm disease struck the city, and workers took down more than 130,000 elms in 20 years.
“All the city did was take out elm trees,” he said.
“We were looking for a more moderate approach, and the injections provided that for us,” Sivyer said.
“We didn't want to run the risk of having more trees die than we could remove in a timely fashion,” he said.
“What a lot of cities will do, they'll wait until it's found in the city, then find it's pretty well entrenched. Then they are in crisis mode, and it is very expensive to deal with and causes huge spikes in the budget.”