OAKFIELD, Maine — A family trust that owns land near the proposed site of a windmill project in Oakfield will appeal the DEP’s decision to permit the project, the attorney for the trust said Friday afternoon.

The Maine Department of Environmental Protection earlier this week approved a permit for the project proposed by First Wind of Massachusetts that would involve up to 34 turbines generating enough energy to power 20,000 or more homes.

Evergreen Wind LLC, a subsidiary of First Wind of Massachusetts, the state’s largest producer of wind-to-energy facilities, filed the application with the DEP in April 2009.

While the permit was being considered, Rufus E. Brown, attorney for the Martha A. Powers Land Trust, contacted the DEP on behalf of the family trust and objected to the project based on concerns that included visual impact, noise and reduction in land values. The trust’s property adjoins the project’s boundaries.

The $120 million, 51-megawatt wind-to-energy facility will be constructed along Oakfield Hills. The DEP said Thursday that it finds the project meets the criteria of the Natural Resources Protection Act and stormwater law.

“I expected that the permit would be approved,” Town Manager Dale Morris said Friday afternoon. “We thought we might hear a decision in December, but other than that, this was not a surprise.”

“In town, there has not been much resistance to this project,” Morris said. “There has been resistance from people in [the nearby town of] Island Falls. Now that the DEP has approved the permit, there will be a 30-day period during which appeals can be filed. I expect an appeal.”

The DEP noted in its permit letter that visual impact was a significant concern to those who contacted it about the project. The department noted that it received 50 comments from property owners on Pleasant Lake expressing concerns related to the visual impact on the lake and other issues.

The Island Falls Lakes Association, which represents more than 120 individuals and households with property on and around Pleasant and Mattawamkeag Lakes, also voiced opposition to the project. Members of the association fear the project will have a significant impact on the scenic value of Pleasant Lake if users are able to see and hear the wind farm from the lake.

Brown said Friday afternoon that the Martha A. Powers Land Trust owns property in both Oakfield and Island Falls and bordering Pleasant Lake.

Officials with the DEP noted in a report accompanying the decision on the permit that they took a boat tour of Pleasant Lake last September and eventually found that “the proposed project will not have an unreasonable adverse scenic impact on Pleasant Lake” or nearby Mattawamkeag Lake.

Brown said he received word of the DEP’s decision on Thursday.

“There will be an appeal,” he said.

Morris said the project will benefit the town. The project would offer about $11.8 million in benefits to Oakfield over the life of a proposed tax increment financing agreement with the town. Power generated by the project for First Wind, a wholesale electricity provider, would not go directly to town residents.

According to the permit application, Evergreen Wind has agreed to establish a Community Benefits Fund with the town. This fund would be used at the town’s discretion to provide direct economic benefits to its residents by creating new programs or funding existing programs such as low-income home heating assistance or energy conservation and efficiency.