The Importance Of Low-Impact Hiking
As annual park visits increase, hikers’ care for trails is more important than ever
By Jefferey Spivey
The nation’s parks are attracting record numbers of visitors. Official National Park Service (NPS) numbers show that 73 parks had more than one-million recreation visits each in 2021, up from 60 parks the year prior. On one hand, this is great news for parks as more and more Americans rediscover the joys of the great outdoors.
James Townsend
But, on the other hand, with increased use it’s rare that visitors—especially hiking amateurs—enjoy their time on trails without altering the landscape. This creates a unique challenge for park staff, officials, and land managers. What’s the best way to welcome visitors while reducing their impact on the land?
How Hikers Leave Their Marks
To make sense of trail misuse, it first helps to understand the intended purpose.
“Trails concentrate use and impact in one place, and that place is a durable surface,” says Jack Haskel, Trail Information Manager for the Pacific Crest Trail Association (PCTA). “But it’s not infallible.”
Despite trails limiting activity to specified areas, the degree of use and the use type determine how well a trail holds up over time. For example, low-use trails will see less degradation than high-use trails, and trails that allow horseback riding will have more soil displacement than trails that don’t.
However, when degradation occurs, there are some common impacts. Chief among them are soil-related impacts, which can be narrowed down to three primary categories:
Soil loss (erosion)
Trail widening
Muddiness.
“Widening is the one that is most correlated with the amount of use,” says Jeff Marion, an industry-leading federal scientist at the U.S. Geological Survey, who specializes in recreation ecology. Widening happens for a variety of reasons. Hikers may step off trails to avoid tread problems, such as muddiness or points of a trail where soil loss is so severe there are exposed roots and rocks, or even trenches. During rainy seasons, hikers may move laterally to avoid water. On popular trails, if the tread isn’t wide enough, hikers move out to pass other hikers. And, perhaps most commonly, hikers go off trail to explore on their own, leaving behind visitor-created, or social, trails.
“People that create social trails usually have little to no experience designing a trail, so they're just trying to get from point A to point B as quickly as they can,” says JD Tanner, Director of Education and Training at the educational nonprofit Leave No Trace.
Leave No Trace has found that hikers often create these social trails while trying to access fishing holes or climbing sites. They may achieve their objectives in the moment, but they introduce problems that remain long after their visit ends.
One prominent example of social-trail creation was highlighted in a 2017 study published by Jeffrey L. Marion, Karen S. Hockett, and Yu-Fai Leung. Along the Billy Goat Trail in Potomac Gorge, a popular site outside of Washington, D.C., Marion and his research team discovered 1.8 miles of formal trail and 9.5 miles of informal social trails.
“It was literally a spaghetti map of these informal, visitor-created trails,” Marion says. The problem wasn’t just that the trails were unauthorized; they cut through an area co-owned by The Nature Conservancy, in which there’s a high density of rare plant and fauna species.
Marion and team studied why the social trails were being created, and then instituted a mix of education-based and site-management actions to discourage off-trail hiking. Among those initiatives, his team placed logs with signage at the 155 intersections of formal and informal trails, and even used organic litter to naturalize the social trails so they appeared less desirable for hiking.
Another major issue involves hikers cutting switchbacks. The term “switchbacks” refers to the zigzagging routes on a trail, which reduce the intensity of climbs up steep paths and also ensure that water moves off the trail. In practice, this may look like a trail that winds around a high hill or mountain, as opposed to one going straight up a slope. Hikers may go off-trail to avoid switchbacks, which means they’re traveling up or down much steeper grades, creating unnecessary safety risks. Most important, however, sidestepping switchbacks exacerbates soil-related impacts, including the creation of new creeks, which worsen during storms and result in more damage over time.
Beyond the most frequent impacts, visitors can leave their marks in other ways.
Pacific Crest Trail is built for horseback riding, but Haskel stresses the importance of following best practices to minimize trail degradation, including keeping stock away from water sources, knowing when and where to let stock graze, properly tying up stock during rest periods, and correctly raking and cleaning out horse manure.
There are social impacts, too. Campers affect natural habitat when they branch out from designated campsites; improperly bathe, use the bathroom, or wash dishes, affecting water quality; and use their own tools to cut branches for firewood.
But surprisingly, hiker impacts may not be land managers’ biggest concern.
The Role Of Sustainable Trail Design
As important as it is for hikers to respect and properly use trails, Marion believes visitors aren’t solely to blame for trail impacts.
“My personal view is that managers owe it to the visitors to give them a usable trail,” he says. Without that, problems abound.
U.S. Geological Survey
In his research, Marion has found that design, and not use, is actually the primary contributor to poor trail conditions. To explain this, he uses a simple example. When hikers are on familiar trails, they should pay close attention to the trail’s condition. They’ll likely find that most of the trail they’ve hiked is in good shape, but they’ll probably notice a few spots that aren’t, either mud holes, spots of erosion, or portions that are uncharacteristically wide. Marion says most of the trail is intact because, more or less, hikers use the trail homogenously. It’s the trail’s design that causes the isolated points of degradation.
For instance, let’s say a trail is too steep—it goes straight up the fall line. (If you dumped a bucket of water on a hill slope, it would run straight down the fall line.) When a trail is aligned with the fall line, water can’t get out of the tread once it becomes incised or eroded. Then those soil-related impacts take shape.
Marion’s research has revealed there are four key factors to consider when designing trails sustainably. First is trail grade, defined as the steepness. A grade ranging from three to 10 percent is optimal; anything steeper leads to greater soil loss.
Second is trail alignment. Alignment with the fall line causes quick erosion. Consequently, when aligned with the contour line, which is essentially level, water can pool on the trail, leading to mud holes and widening (from hikers seeking alternate routes).
Third is the amount of rock in the soil—more rock makes trails more durable.
Fourth is tread drainage. Marion says trails should have periodic grade reversals, or rolling grade dips, in which the trail goes in the opposite direction.
“Was the trail designed, for example, where the trail is coming down a slope but then it temporarily goes up a little bit around a tree maybe, and then continues maybe going down the slope?” Marion asks. Proper drainage ensures that all water drains off the trail.
When these criteria are satisfied, life is easier for land managers and for visitors.
“When a trail is easy to walk, people stay on it,” Haskel says.
But proper design isn’t the only option in the toolbox in encouraging low-impact hiking.
A Joint Effort Between Hikers And Park Staff
At a high level, the steps hikers can take to reduce their impact are quite clear. Staying on established trails or designated campsites significantly reduces any chance of damaging or destroying habitats. Marion, who was a founding board member of Leave No Trace and authored Leave No Trace in the Outdoors, takes these suggestions a step further. He advises that hikers try to avoid trails during wet seasons, wear appropriate footwear so there are fewer reasons to sidestep parts of a trail, and stay on a trail or on a trail’s edge as much as possible. Getting visitors to understand these guidelines, however, is a complex effort.
Tanner says Leave No Trace emphasizes education, but in so doing, the reason behind low-impact practices matters most.
“That why is really important,” he says. “Not only should you not hike on this trail because there's a closure, but also letting people know this is why you shouldn't hike on this trail, or this is why we've closed this trail off and we're rehabbing it.”
In terms of how, Haskel points to an omnichannel approach that funnels messaging through a combination of social media, websites, pamphlets, and direct conversations with hikers. Trailhead signage can be important, too, but hikers often gaze at this information in the moment but may not remember it. The greatest chance for getting their buy-in comes before they step onto a trail.
Clinton Hart
Tanner points to trends where land managers keep minimum-impact information regularly updated on trail websites. Leave No Trace has partnered with various tourism entities to post the same information on their sites as well. He also notes that many hikers are becoming exposed to minimum-impact education during the booking process, especially when reserving campsites or applying for hiking permits.
In lieu of education, permitting has become a popular approach. Tanner says land managers often follow the EEE method—educate, enforce, engineer. If visitors aren’t receptive to education, next comes enforcement, then engineering. Permits have become an enforcement tactic to limit the number of hikers on high-use trails, which can potentially slow or reduce degradation. But Marion finds this isn’t the best option.
He says, “If you’ve got a sustainably designed and drained tread, you can put thousands of people on it if they stay on the trail. The use-impact relationship is very weak.” Permitting can have more of a social impact, solving a crowding problem or conflicts between hikers.
However, education, enforcement, and engineering (design) aside, hikers have a duty to do their part, long before they visit.
Haskel says, “It takes a community. We need all visitors of nature lands to care about nature and to talk to others and teach others about the importance of traveling lightly on the land.”
Jefferey Spivey is a writer based in Urbandale, Iowa. Reach him at jeffereyspivey@gmail.com.