RCW 79.70.040: Powers as to transactions involving public lands deemed natural areas—Alienation of lands designated natural area preserves.

The department is further authorized to purchase, lease, set aside, or exchange any public lands which are deemed to be natural areas: PROVIDED, That the appropriate state land trust receives the fair market value for any interests that are disposed of: PROVIDED, FURTHER, That such transactions are approved by the board of natural resources.

An area consisting of public land designated as a natural area preserve shall be held in trust and shall not be alienated except to another public use upon a finding by the department of natural resources of imperative and unavoidable public necessity.