43 CFR §21.5

1. (a)Those permittees who occupy Government-owned cabins, including those whose permits currently have expired, but previously have been renewed on a year-to-year basis, may have their permits renewed up to July 1, 1969. After that date, the permits shall not be renewed and shall be terminated finally except upon a determination by the Authorized Officer that a renewal or extension is fully consistent with the public use of the area.
2. (b)The provisions for amortization of substantial improvements do not apply to this type of occupancy.