Gather participants outside a home or in a park. Ask them why we construct sidewalks. Focus the resulting discussion on the need to provide durable surfaces for travel by many people. Explain that concentrating activity on one durable surface can help protect the surrounding land. Define the concept of durability for the group (see the Background on the Principles of Leave No Trace).
Break the group into pairs and give each pair the following assignment: Imagine you are looking for durable surfaces to travel over or set up camp. Find five different surfaces in the immediate area and rate them from one to five for durability, one being the most durable surface and five being the least durable surface. Give the group approximately 5 to 10 minutes to explore the area.
Ask the group to name all the durable surfaces they can identify. Be sure they include rock, gravel, sand, bare soil, firm snow, most grasses, and existing trails and campsites. Then ask them to identify non-durable surfaces. Make sure they include tundra, riparian areas, aquatic environments, fragile plants, muddy areas, spring melt, and cryptobiotic crust (the blackish crust with living microorganisms that is frequently found in desert areas).
Teaching Leave No Trace