Ala. Code § 31-2-80

All property, both real and personal, belonging to a unit of the armed forces of the state, officially recognized as such by the federal government, shall be exempt from ad valorem taxes, state, county, and municipal. This exemption shall apply to real property when leased to any unit of the Alabama National Guard, provided the agreement or contract of lease is approved in writing by the Adjutant General, while the same is under the custody and control of the National Guard unit, and said exemption shall not be vitiated should the National Guard organization sublease a part of the premises when the rental derived from such lease is used entirely and solely for the benefit of the National Guard organization, and when such sublease or permissive use shall be subject to immediate termination by the National Guard unit at the discretion of the Governor.