Section 7A. As used in this chapter the following words shall, unless the context otherwise requires, have the following meanings:—
''Agriculture'' and ''farming'', as defined in section 1A of chapter 128.
''Arbor'', an area of land devoted to the propagation and cultivation of fruitbearing trees and shrubs, and nut trees.
''Bureau'', the bureau of land use in the division of agricultural development.
''Chief'', the chief of the bureau of land use.
''Elderly persons of low income'', persons who are age 65 or over and whose annual income is less than the amount necessary to enable them to maintain a decent standard of living, except that where there exists a surplus of land appropriate for garden use, the age requirement may be reduced by the director to age 62; but the oldest of the applicants between 62 and 65 shall be given preference.
''Families of low income'', families and persons whose net annual income is less than the amount necessary to enable them to maintain a decent standard of living.
''Farm'', a body of land devoted to agriculture.
''Garden'', a piece of land appropriate for the cultivation of herbs, fruits, flowers, or vegetables.
''Use'', when applied to gardening; to make use of, without conveyance of title or any other ownership.
''Vacant public land'', any land owned by the commonwealth, or any county or municipality therein, that is not in use for public purpose.