It may have been a mystery to Marion Selectmen, but neighbors say the Department of Public Works cleared a swath of trees in Washburn Park earlier this month.

“We watched [the DPW] do the work over there,” said Heidi Duarte of Wareham. Duarte said crews using vehicles marked as department property worked while she visited her sister Lisa Laing, who lives near the park.

Last week, Town Administrator Paul Dawson brought the issue to Selectmen after a complaint was filed with the state’s Department of Environmental Protection. The department notified the town’s Conservation Commission who visited the site on Saturday to investigate.

Dawson said that an “extensive area” was cleared of trees near a pond behind the park’s ball fields. He noted work had been done up to the pond’s shore in violation of wetland bylaws.

“Nobody knows who did it,” Dawson said at the time. “You can see by the amount that was cleared that this took, at a minimum, a full days worth of work if not more.”

Conservation Commission member Norm Hills said no one filed plans with his board to clear the trees.

“Nobody I know of was permitted to do that work,” he said. If work was approved, crews would have had to stay at least 100 feet from the pond. On the site, tire tracks were seen leading to the water’s edge.

Selectmen Chair Jon Henry said he would not comment on the matter, except to say that town officials are looking into the issue.

Hills said this isn’t the first time park trees were cut without permission.

In March 2012, Hills had questions for Recreation Director Jody Dickerson about tree cutting that took place in the same spot. Dickerson was elected to the Board of Selectmen in May of that year.

The state requires a Request for Determination of Applicability form to be submitted to the Department of Environmental Protection before any work is done near wetlands.

More than seven months after the trees were cut, Dickerson filed the form for and received a Request for Determination of Applicability at the Conservation Commission’s request.

But it is still unclear who requested that the trees be removed and who cut them down.

“Over the years the area in question has been neglected,” Dickerson wrote in the form. “It is the intention of the Recreation Department to have the area return to its original grandeur.”

In the 1950s and 1960s the area featured picnic tables, benches and grills. The pond had a well-kept beach where people swam in the summer. In winter, skaters took to the ice. In the form, Dickerson wrote that the area near the pond would be maintained to discourage ticks and mosquitoes.

A Marion native, Dickerson said he remembers visiting the area before it was overgrown. He described the situation as, “the high cost of low maintenance.”

Dickerson has worked to revamp the park over the last few years.

“I’ve said before Washburn Park is a gem that needs to be buffed,” he said.

The last time the Recreation Department did maintenance near the area was in March. Crews worked closer to the ball fields and stayed out of the buffer zone required by the Wetlands Protection Act, he said.

The buffer zone on the pond’s south side was a point of contention in 2012. According to minutes from a Nov. 28, 2012 Conservation Commission public hearing, former member Sherman Briggs disagreed with the delineation. At the hearing, Dickerson said he could not locate a map indicating where the buffer zone would be.

He told members his department would not work on the south side for the time being.

“Dickerson said he’d really like to start working in the area, and asked the commission whether they would close the hearing if he didn’t work on the south side of the pond,” according to the minutes.

Dickerson said he’s unsure who was responsible for the recent cutting.

“Hopefully, we’ll be able to get this straightened out in short order,” Dickerson said.