After seven years of planning and fundraising, another large tract of Western Massachusetts land owned by W.D. Cowls Inc. is about to be protected from commercial development via permanent conservation restriction. The estimated payment to the company for the restriction would be $3 million. Negotiations are expected to be concluded by January, according to Cowls President Cinda H. Jones. She said in a written statement that the plan involves just over 2,000 acres the company owns in Shutesbury, Leverett and Pelham “in a relatively straight and consistent area between” — but not including — the Cushman Village of Amherst and the Quabbin Reservoir State Reservation.