With the future of Crow Hollow Farm in West Tisbury hanging in the balance, the town planning board this week approved a complicated agreement that will allow the owners of the farm to create a three-acre lot around the existing farmhouse that has been held by the Look family for generations.

The decision caps months of discord between two town boards, offers and counteroffers from the farm owners and legal opinions from attorneys on both sides.

In exchange for creating the lot, the owners of the historic farm off New Lane — Samantha Look and her husband Kristian Strom — must make a donation to the town affordable housing committee as part of a 1991 decision by the Martha’s Vineyard Commission that allowed the Look family at the time to subdivide the farm into seven lots.

Since that decision there have been many changes to the farm.

Five of the seven subdivided lots were sold, and the two remaining lots were bought by Ms. Look and Mr. Strom in 2005. Soon after, an agricultural preservation restriction was placed on the property through the Martha’s Vineyard Land Bank to protect the open space.

Ms. Look and Mr. Strom now operate a horseback riding facility at the farm that offers clinics, a summer riding program, trail rides and boarding for horses. Last year they proposed creating the new three-acre lot around the historic family home on the property, largely as a means to keep the remaining property within the family.

It has been a trying process for Mr. Strom and Ms. Look, who plan to sell the family homestead and move out because they can no longer afford to keep it.

“This has been 100 per cent emotional. We will be leaving behind a big part of our family’s history. This house was built by my great-grandfather, or my great-great-grandfather; it’s the place where my son came home after he was born. There are ledges in the house for sleigh bells and blocks of ice, that date back to the 1800s . . . so yes, this has been hard on us,” Ms. Look said.

The situation has been complicated by a provision in the commission’s 1991 decision requiring a donation to the town affordable housing committee in the event that the farm is further subdivided. When the Look family first subdivided the property at that time, a town bylaw required an applicant who created six or more lots to file what was called a flexible development plan that allowed for one lot to go to affordable housing. At the time there were already houses on two of the lots, and representatives for the family successfully argued the plan called for only a five-lot subdivision. So the donation to affordable housing was waived.

But the commission decision also included a condition stating any future subdivision on the property would retroactively trigger the clause requiring the family to donate one lot to affordable housing. Since that time West Tisbury has done away with the so-called flexible development bylaw, and adopted a provision stating that developments of three or more lots must give at least 20 per cent of the lots to affordable housing.

Under that provision a three-lot subdivision plan would require one lot to go to affordable housing.

The proposal by Ms. Look and Mr. Strom to create a new lot on the property fell into a gray area. Creating the lot does not trigger the requirement for an affordable lot today, but it did under the condition written in 1991.

The town planning board sought a legal opinion from special counsel Mark J. Lanza. Mr. Lanza found that any further division would require Ms. Look and Mr. Strom to donate 1.6 lots to affordable housing; in his opinion that meant two lots.

Rob McCarron, an attorney hired by Ms. Look and Mr. Strom, strongly disagreed with Mr. Lanza’s legal opinion. In the end Ms. Look and Mr. Strom agreed to a compromise: they would donate a single lot to be placed under the control of the town affordable housing committee, and make a cash donation of $40,000 to the same committee to satisfy the requirements of the second lot. The planning board agreed and on Feb. 8 voted to approve the plan.

But the affordable housing committee disagreed, and pushed the full donation of two resident home lots. Citing Mr. Lanza’s legal opinion, the committee wrote a letter to the planning board challenging its decision.

The planning board then referred the application to the commission as a modification to the previously approved development of regional impact (DRI). The affordable housing committee wrote to the commission on Feb. 11 requesting a full public hearing and urging the commission to require a donation of two lots. “[We] concur with [Mr. Lanza’s] legal opinion . . . which clearly states that Crow Hollow Realty Trust, or its subsequent subdividers or owners, owes the town of West Tisbury at least two affordable housing building lots . . . a money donation is not an acceptable alternative,” the letter said.

At a meeting of the commission’s land use planning committee on Feb. 16, the chairman of the affordable housing committee, Michael Colaneri, appeared to press the issue.

But several members of the land use committee questioned why they were being asked to adjudicate between two town boards. Last week the full commission voted that the modification did not require a new public hearing, and referred it back to the planning board.

On Monday this week the planning board voted again to accept the offer from Ms. Look and Mr. Strom. The only matter remaining to be decided is whether the donated lot can be off the farm. That will be decided by the MVC.

After the vote on Monday, Ms. Look reflected on the whole affair. “We tried to do the right thing by the town from the start, and I will say this has been a daunting process for someone like me,” she said.

Ms. Look said she and her husband hope to be able to donate an off-site lot, not because they don’t want an affordable home on their property, but because they are committed to preserving as open space what remains of the farm. The Crow Hollow property is a combination of farm field and woods; it lies between coves of the Tisbury Great Pond in an area framed by historic homes and barns.

To complicate matters, Mr. Strom has started a small vineyard in a corner of the property, which only now is starting to produce grapes suitable for wine-making

“The property is filled with huge open meadows . . . with vineyards on one side and an old farmhouse on another side. Placing a resident homesite [on the farm property] will be very tricky; and I’m not saying that not as the property owner, but as someone who loves the Vineyard, and loves these wonderful open spaces that makes this place what it is,” Ms. Look said.