When used in this chapter:

(1)  “Farmland” means:

(i)  Any tract or tracts of land, including woodland and wasteland constituting a farm unit;

(ii)  Land which is actively devoted to agricultural or horticultural use including, but not limited to: forages and sod crops; grains and feed crops; fruits and vegetables; poultry, dairy, and other livestock and their products; nursery, floral, and greenhouse products; other food or fiber products useful to people;

(iii)  When meeting the requirements and qualifications for payments pursuant to a soil conservation program under an agreement with the federal government, the director of environmental management is authorized to promulgate and adopt rules and regulations defining particular categories and minimum acreages of land eligible for designation as farmland under this chapter.

(2)  “Forest land” means any tract or contiguous tracts of land, ten (10) acres or larger bearing a dense growth of trees, including any underbrush, and having either the quality of self perpetuation, or being dependent upon its development by the planting and replanting of trees in stands of closely growing timber, actively managed under a forest management plan approved by the director of environmental management.

(3)  “Open space land” means any tract or contiguous tracts of undeveloped land, where the undeveloped land serves to enhance agricultural values, or land in its natural state that conserves forests, enhances wildlife habitat or protects ecosystem health, and that is:

(i)  Ten (10) total acres or larger, exclusive of house site, where “house site” means the zoned lot size or one acre, whichever is smaller, and land surrounding dwellings or devoted to developed facilities, such as tennis courts, pool, etc., related to the use of the residence; or

(ii)  Tracts of land of any size that are designated as open space land in the comprehensive community plan; or

(iii)  Tracts of land of any size that have conservation restrictions or easements in full force and applied for as open space, which shall be taxed on an equitable basis.