Md. Code, Tax-Prop. § 9-220

(a) (1) In this section the following words have the meanings indicated. (2) “Conservation land” means real property that is: (i) subject to a perpetual conservation easement donated to a land trust, the Department of Natural Resources, or the Maryland Environmental Trust on or after July 1, 1991; (ii) 1. acquired by a land trust on or after July 1, 1991; and 2. owned in fee by that land trust; (iii) owned by the Potomac Conservancy; or (iv) owned by the Western Shore Conservancy. (3) “Land trust” means a qualified conservation organization as defined in § 3-2A-01 of the Natural Resources Article. (b) The Mayor and City Council of Baltimore City or the governing body of a county or municipal corporation may grant, by law, a property tax credit against the county or municipal corporation property tax imposed on conservation land or property owned by a land trust that qualifies under subsection (d) of this section, that is used: (1) to assist in the preservation of a natural area; (2) for the environmental education of the public; (3) generally to promote conservation; (4) for the maintenance of: (i) a natural area for public use; or (ii) a sanctuary for wildlife; or (5) to conserve agricultural land and to promote continued agricultural use of the land. (c) The Mayor and City Council of Baltimore City or the governing body of a county or municipal corporation may provide, by law, for: (1) the amount and duration of the property tax credit under this section; and (2) any other provision necessary to carry out the property tax credit under this section. (d) To qualify for a property tax credit under this section, a land trust shall: (1) be certified by the Maryland Environmental Trust to be a land trust in good standing and to have a cooperative agreement in effect; and (2) obtain a written certification every 5 years beginning July 1, 1998, or as scheduled by the Maryland Environmental Trust.