How does national park authorities provide services to tourists without spoiling natural landscape?

Answer 1

This is, of course, the paradox of the National Park Service "to protect the scenery, wildlife," etc. and to "provide for the enjoyment of the same." In general, we do this by limiting impacts in every possible case - visual, noise, or physical. When plans are being made to build anything new or change the way the park manages a resource, there is a lengthy process of producing an "Environmental Impact Statement," which assesses the situation and the options for proceeding to deal with it, then this statement is usually open for public review, then the park produces another document detailing the preferred alternative(s) and the public gets another chance to comment before the park moves forward. If you are near a library that retains federal documents, you might be able to find some of these reports for a national park. Many examples of current documentation of this type is online at http://parkplanning.nps.gov