LEBANON — A Massachusetts developer recently given the go-ahead to build 250 market-rate apartments on Mount Support Road geared to hospital workers says he hopes to begin construction next summer, if not sooner, now that the project has won support from the city’s Planning Board.

Donald Smith, a partner at the firm Saxon Partners, said Tuesday that he looks forward to starting work on two connected four-story buildings, parking and other amenities planned for a 75-acre parcel. What’s unclear, though is whether the owner of the neighboring Timberwood Commons apartment complex, which opposed the proposal during the city’s regulatory review, will challenge the project in court. Smith said that could delay work until next summer.

Pennsylvania-based Merion Residential, which operates the 252-unit Timberwood complex across the street from the Saxon Partners site — has for months opposed the new development, with its experts and engineers arguing that new buildings could negatively impact surrounding wetlands and wildlife.

The land houses an extensive trail system that connects to the Dartmouth College-owned Landmark property and the city’s Boston Lot Conservation Area. However, developers say they won’t disturb that trail system and set aside at least 19 acres, or about 25% of the Saxon property, for animal crossings.

Merion’s representatives and tenants also have complained that Saxon Partners’ proposal is too close to the roadway and could dampen sunlight that now shines into its apartments.

But Saxon Partners contends that Merion is really trying to secure its hold on a housing market geared toward medical workers. Both developments are about a mile south of Dartmouth-Hitchcock Medical Center.

As evidence, Saxon Partners said Merion didn’t participate in the recent Planning Board review of a 309-unit apartment complex put forward by Dartmouth College and New Jersey developer Michaels Student Living. That proposal is geared toward graduate students and isn’t expected to compete for DHMC employees.

Merion has opposed Saxon Partners’ approvals and permits, starting with the Lebanon Planning Board’s 6-1 vote that last week granted the project site plan approval.

“It’s unfortunate since there’s a well-known housing shortage,” Smith said of the possible challenges.

Messages left for Merion’s attorneys at Concord law firm BCM Environmental and Land Law were not returned Tuesday afternoon.

The Lebanon Zoning Board declined to take up an appeal that, if successful, could have seen the Saxon project seek a special exception.

Merion’s attorneys argued in filings that the Planning Board should have halted its monthslong review in September because of the New Hampshire Department of Environmental Services deeming the effort a “major impact project.”

The designation is reserved for construction expected to “disturb 200 linear feet or more of an intermittent or perennial nontidal stream or river channel or its banks” and usually triggers a preliminary review by the Zoning Board.

Saxon Partners said its project instead qualifies for a “minimum impact permit” and is being treated otherwise for “administrative convenience.” City planners also said the project was exempt from a Zoning Board review.

Ultimately, city officials determined Monday that they don’t have jurisdiction to settle the matter.

The Planning Board lacks authority to overrule city zoning determinations, and so its counterparts on the Zoning Board cannot “stand in their shoes” during an appeal, Lebanon Zoning Board member Jeremy Katz said during Monday’s meeting.

“This is not appropriately before us and I believe that this should be dismissed and not considered by us at this time,” he told colleagues during a meeting that was streamed online. “Whichever way we cut it … we shouldn’t be considering this.”

Instead, Katz said, Superior Court is better equipped to handle the matter.

City planners said during last week’s meeting that they expect a legal challenge.

“It is always a good idea for the board to be clear about the decisions that it’s making and the facts that you’re choosing to rely upon,” Lebanon Planning Director David Brooks told the Planning Board while acknowledging their approval of the Saxon Partners project was written to shield Lebanon from a court challenge.

 Tim Camerato can be reached at tca [email protected] or 603-727-3223.