You are asking about 'sustainability," the ability to preserve resources with an increasing need for them. There are myriad answers to this, depending on what resource you are looking at. For energy, use of renewable resources like solar energy and biomass, for many materials (plastics, glass, paper, metal) recycling works.
If you are referring to a "state/national park", install trash cans near the entrance so people don't have to litter. One it's disgusting and two, it's killing our natural resources and the people that visit don't want to come. Try that.