Ann Arbor is launching a significant new replanting program this fall to add roughly 1,000 new trees every year.
The initiative begins half a dozen years after the die-off of once-plentiful ash trees.
City officials say they'll use aerial photos to identify the more pronounced holes in Ann Arbor's tree canopy and concentrate on those spots.
Street trees will be planted across the city, said Kerry Gray, urban forest and natural resources coordinator. City employees will likely do the work, but details are still being worked out.
Ann Arbor had an estimated 5,500 ash trees growing in rights-of-way when the emerald ash borer found its way to southeast Michigan around 2002.
An accidental import from Asia, the pest lays its eggs under the bark of ash trees. The larvae then feed on the material that carries water and nutrients, killing trees in just a few years. About 14 percent of the city's trees were ash.
Following a failed tax proposal to pay for removing the dead trees, city officials set the issue aside. But forestry activity is now being revived with a new funding stream.
The water utilities' stormwater fund will be tapped for $300,000 a year for at least three years to buy and install new street trees, officials said.
The rationale is research by the U.S. Forest Service and nonprofit group American Forests that documents the role trees play in stormwater management, Gray said.
"A large, 13-inch shade tree intercepts 1,000 gallons a year,'' she said.
Assuming 20- to 30-year life spans, trees are a bargain compared to the cost of constructed stormwater detention, said Gray, who coordinated the state Department of Natural Resources Emerald Ash Borer restoration program before joining the city.
The number of trees in the city that are or will eventually be large shade trees, approximately 30,000, provides the equivalent of $45 million in constructed detention, Gray said.
Earlier this year, city officials drew on the stormwater fund to help pay for mapping and a new inventory for the trees that remain. City water customers pay for stormwater management through a separate fee charged on quarterly water bills.
Gray said the replanting program will pay special attention to a diversity of species across the city. Maples are already plentiful, for example.
Trees also will be selected based on their ability to prosper in the sometimes confined space between sidewalks and streets, she said.
Judy McGovern can be reached at 734-994-6863 or jmcgovern@annarbornews.com.The Ann Arbor News
