the tenure or occupation of land, a single unit, both technically and economically, which has a single management and - which has a wine-growing area of at least 10 ares, or - which is subject to a declaration required under Community or national wine legislation if the unit concerned has a wine-growing area of less than 10 ares, or - which produces from its wine-growing area quantities exceeding certain physical or economic thresholds set by the Member State concerned if the unit concerned has a wine-growing area of less than 10 ares and is not subject to a declaration as referred to in the second indent