The landscape of Thompson Park's wetlands area was significantly altered last week after an invasive beetle forced the city to remove more than 100 ash trees.

The landscape of Thompson Park's wetlands area was significantly altered last week after an invasive beetle forced the city to remove more than 100 ash trees.

Upper Arlington officials said the trees were killed by the emerald ash borer.

City Forestry Superintendent Steve Cothrel said the dead trees were felled due to concerns they could fall on park visitors, a wetlands observation deck or other nearby trees.

"It's a depressing number of trees," Cothrel said. "We plan to replace them over time.

"People are definitely going to notice," he said. "The wetlands are going to change from a completely shaded ecosystem to a fairly sunny ecosystem."

The emerald ash borer is an Asian beetle that embeds itself in ash wood and kills trees by robbing them of vital nutrients. It has virtually wiped out the ash tree population in Ohio and various parts of North America over the past decade.

According to Upper Arlington officials, the city adopted an emerald ash borer management plan in 2006, three years before the beetle was detected in the community.

Despite those efforts, hundreds of local ash trees have been destroyed.

Cothrel said the city only treats commemorative and memorial ash trees located in city parks to combat the emerald ash borer.

He added that all ash trees in Thompson Park that haven't been treated have been infested by the beetle, and noted those in the wetlands area couldn't have been treated using traditional methods.

"It's a depressing thing to see, but we knew it was coming," he said.

Westerville-based JTS Tree & Landscape cleared the trees at a cost of $9,750, Cothrel said. He added that it typically costs the city approximately $200 per tree to plant replacements.

While the city will seek to replace as many of the felled trees as possible, Cothrel said the number likely will fall short of the 130 that were removed.

"That area of the wetlands was pretty dense and they were very tall and skinny trees," he said. "We may not plant 130 trees because the ash trees were really close together."

Cothrel's department is still determining the species of trees that might be planted as replacements. He said bald cypress trees are among those being considered.