Prior to the assessment of any parcel of real estate under any ordinance adopted pursuant to this article, the local assessing officer shall:
2. Determine further that real estate devoted solely to (i) agricultural or horticultural use consists of a minimum of five acres, except that for real estate used for agricultural purposes, for purposes of engaging in aquaculture as defined in § 3.2-2600, or for purposes of raising specialty crops as defined by local ordinance, the governing body may by ordinance prescribe that these uses consist of a minimum acreage of less than five acres; (ii) forest use consists of a minimum of 20 acres; and (iii) open-space use consists of a minimum of five acres or such greater minimum acreage as may be prescribed by local ordinance, except that for real estate adjacent to a scenic river, a scenic highway, a Virginia Byway or public property in the Virginia Outdoors Plan or for any real estate in any city, county or town having a density of population greater than 5,000 per square mile, for any real estate in any county operating under the urban county executive form of government, or the unincorporated Town of Yorktown chartered in 1691, the governing body may by ordinance prescribe that land devoted to open-space uses consist of a minimum of one quarter of an acre. The minimum acreage requirements for special classifications of real estate shall be determined by adding together the total area of contiguous real estate excluding recorded subdivision lots recorded after July 1, 1983, titled in the same ownership. However, for purposes of adding together such total area of contiguous real estate, any noncontiguous parcel of real property included in an agricultural, forestal, or an agricultural and forestal district of local significance pursuant to subsection B of § 15.2-4405 shall be deemed to be contiguous to any other real property that is located in such district. For purposes of this section, properties separated only by a public right-of-way are considered contiguous; and