TERRE HAUTE —
Terre Haute officials are prepared with a proposed budget and battle plan once the emerald ash borer, which has already killed millions of ash trees in the U.S. since its discovery in 2002, hits the city.
However, Vigo County officials including county commissioners, as well as representatives of Indiana State University, Rose-Hulman Institute of Technology and St. Mary-of-the-Woods College, were made aware Monday of potential costs associated with the insect, now present in nearby Clay County.
“I expect it to reach here within one to three years,” said Clifford S. Sadof, a professor of ornamental horticulture and forestry at Purdue University, speaking to about 20 city, county and university officials at the Vigo County Annex.
A tree is killed within one to three years of being infested. The bug lives under the bark of the tree most of the time, eating the inside of the tree, until May when it turns into a flying bug and feeds on the leaves of the tree.
The emerald ash borer, Sadof said, reproduces once a year, but one square meter of bark area can produce 90 ash borers.
The emerald ash borer arrived in the U.S. from Asia in the early 1990s.
Sadof told officials it would be costly to do nothing and let the emerald ash borer kill all ash trees in the county. Sadof used Terre Haute as an example. The city has about 1,070 ash trees in its inventory of about 17,000 trees in city tree rows. If officials wait until the third year after the insect has been detected to remove trees, as they die, it would cost $413,000 for removal, he estimated.
The number of infested trees doubles every year, so by the eighth year of infestation, 100 percent of the trees would be infested and be beyond saving, Sadof said.
Instead, Sadof recommends saving trees with new insecticides. He recommends saving at least 50 percent of ash trees to reduce tree replacement costs.
Over an eight-year period, it would cost $164,000 to replace the ash trees with different variety of trees, but would cost just $64,000 to save half of the ash trees with a chemical insecticide.
Savings are even greater when officials act quickly.
If officials act after the insect is first detected, removing trees as they die would take $280,000, with replacement costs at $139,000. Comparatively, the cost to save half the trees with a chemical insecticide would be $48,000. Trees can be treated every two years.
“We recommend an aggressive treatment program in the first 12 years. After that you can have a much less aggressive approach and just treat trees that show symptoms,” as the population of the emerald ash borer will drop significantly.
Sadof recommends utility companies remove ash trees rather than trim them to protect power lines. He also recommended county highway officials quickly remove the trees along busy roads or treat trees with insecticide.
Sadof said ash trees have a value to a community.
He said a 20-inch white ash tree has a value of $270 a year, with $102 of that in property value, another $80 in stormwater collection value. It also has value in air quality and removal of carbon dioxide, plus reduces cooling and heating costs.
City Engineer Chuck Ennis attended the presentation, along with other city officials, including Mayor Duke Bennett. Since Terre Haute has been a Trees USA city for the past 10 years, it already has a GPS-based forest inventory, listing the trees, their location and status, if in good, fair or poor condition.
Ennis said the city has about 744 ash trees with diameter under 18 inches. The majority of those ash trees — 553 — are under 12 inches in diameter.
That means the city can treat those with insecticide at the roots, a much cheaper application, than injecting a tree.
Most of the city’s Ash trees are along Ohio Boulevard between 13 1/2 Street to Fruitridge Avenue and on Wabash from 15th to 25th Streets. It also has a large concentration around Fifth and Ohio streets, and along Maple Avenue, from Lafayette Avenue to 31st Street.
“In an area near St. Joseph’s church, there are a lot of ash trees. When the borer gets here, it would completely destroy this neighborhood, so we are looking at places we have concentrations of ash trees, which would be easy to treat, as they are all in the same neighborhood,” Ennis said.
“We are also looking along prime corridors such as Ohio Boulevard and Wabash Avenue,” Ennis said.
Terre Haute also has a state’s champion ash tree, with a diameter over 5 feet, in the 2200 block of College Avenue.
Howard Greninger can be reached at (812) 231-4204 or email@example.com.