In this chapter:
I. "Discretionary preservation easement" means a preservation easement of an historic agricultural structure, including the land necessary for the function of the building, granted to a city or town for a term of 10 or more years.
II. "Public benefit" shall have the meaning described in RSA 79-D:3, II.
III. "Historic agricultural structure" means a barn or other structure, including the land necessary for the function of the building, currently or formerly used for agricultural purposes and as further defined by the advisory committee established under RSA 227-C:29.