The board of county commissioners of any county which acquires any lands through foreclosure of tax liens or otherwise, which by reason of their location, topography, or geological formation are chiefly valuable for the purpose of developing and growing timber, and which are situated within the boundaries of any national forest, may, upon application by the proper forest service official of the United States government, convey such lands to the United States government for national forest purposes under the national forestland exchange regulations, for such compensation as may be deemed equitable.