Leave No Trace, sometimes written as LNT, is a set of ethics promoting conservation of the outdoors. Originating in the mid-20th century, the concept started as a movement in the United States in response to ecological damage caused by wilderness recreation. In 1994, the non-profit Leave No Trace Center for Outdoor Ethics was formed to create educational resources around LNT, and organized the framework of LNT into seven principles.
Plan ahead and prepare
Travel and camp on durable surfaces
Dispose of waste properly
Leave what you find
Minimize campfire impacts
Respect wildlife
Be considerate of other visitors
The idea behind the LNT principles is to leave the wilderness unchanged by human presence.
By the 1960s and 1970s, outdoor recreation was becoming more popular, following the creation of equipment such as synthetic tents and sleeping pads. A commercial interest in the outdoors increased the number of visitors to national parks, with the National Park Service seeing a five-fold increase between 1950 and 1970, from 33 million to 172 million. Articles were written about the wild being “loved to death,” problems with overcrowding and ecological damage, and the need for management. To solve this, regulations were imposed, including limits on group sizes and where camping was allowed. This was met negatively, with people writing that it took the joy and spontaneity out of wilderness recreation.
The focus was shifted towards education, with the National Park Service (NPS), United States Forest Service (USFS), and the Bureau of Land Management (BLM) training Wilderness Informational Specialists to teach visitors about minimal impact camping. In 1987, the three departments cooperatively developed a pamphlet titled "Leave No Trace Land Ethics".
At the same time, there was a cultural shift in outdoor ethics from woodcraft, where travelers prided themselves on their ability to use available natural resources, to having a minimal impact on the environment by traveling through wilderness as visitors.