The International Ecotourism Society defines ecotourism as, "Responsible travel to natural areas that conserves the environment and improves the well-being of local people." The first principal of ecotourism is to minimize impact and, with a little preparation and forethought, that principle is easy to practice while hiking.
Research the area for your hike. Find out if trash receptacles will be available along the trails, if not then put a trash bag in your backpack to avoid littering the trails. Bring out everything taken in; such as water bottles, wrappers and even pet waste if bringing the dog. Stay on marked trails, hiking is appreciating about enjoying existing trails, not forging new ones and damaging the ecosystem there.
Practicing ecotourism will make the experience for hikers much more pleasurable. The hiking areas will be preserved for the hikers behind you and for generations to come. A hike through a pristine trail is ruined when garbage is wrapped around bushes and trees. Green living has become part of our consciousness and doesn't have to left behind when enjoying Mother Nature.