In a national park you do not need a permit to photograph. You may photograph at will and sell prints so long as you don't fall into any of the following: (Fom the NPS.gov Website) NPS.GOV
Commercial Filming and Still Photography Permits
Lands of the United States were set aside by Congress, Executive or otherwise acquired in order to conserve and protect areas of untold beauty and grandeur, historical importance, and uniqueness for future generations. This tradition started with explorers who traveled with paint and canvas or primitive photo apparatus before the areas were designated as a national park. The National Park Service permits commercial filming and still photography when it is consistent with the park’s mission and will not harm the resource or interfere with the visitor experience.
When is a permit needed?
All commercial filming activities taking place within a unit of the National Park system require a permit. Commercial filming includes capturing a moving image on film and video as well as sound recordings.
Still photographers require a permit when
1. the activity takes place at location(s) where or when members of the public are generally not allowed; or ///// i.e. CLOSED AREAS///////
2. the activity uses model(s), sets(s), or prop(s) that are not a part of the location’s natural or cultural resources or administrative facilities; or ///////A tripod does not count/////////
3. Park would incur additional administrative costs to monitor the activity. /////No admin cost involved by you photographing a landscape//////
National wildlife rufuges, state parks, and internationally may and most likely will be different