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Studies Weigh Mountain-Biking, Hiking Impacts

By Michael Lanza from AMC Outdoors Magazine

New research suggests that mountain suggests that mountain bikes and boots leave equal wear and tear on trails. How bikers ride and where hikers step may make more of a difference.

Describing himself as "sort of stubborn," Bob Moss is the type of person who questions assumptions. Do in the 1990s, when he saw the New York-New Jersey Trail Conference(NY-NJTC) and other hiking groups angrily blaming trail widening and ruts on mountain bikers, he decided to conduct his own study.

A few years ago, he began counting hikers and mountain bikes and monitoring the condition of trails in New Jersey's Ringwood State Park, near his home. After months of observation, though, he realized he didn't have enough time to correlate the types of users and trail impacts. But he did note that trails popular with mountain bikers sometimes widened in spots.

Moss enters this emotional issue as no defender of mountain bikers. "I really don't like bicycles in the woods," he says, "but I also don't like people talking and not knowing (what they're talking about). At all these meetings it always seemed to me the same thing: the bicyclists saying, 'We don't damage the trails,' and the hikers saying (to bikers), 'You're ruining them.' That's where the curiosity came from."

He is not aone in pondering the question of whether mountain bikes accelerate trail erosion more than the boots of hikers-something some hikers, especially on the Northeast's heavily used trails, have alleged for years. As NY-NJSTC President Gary Haugland says, "We are a trail-maintaining organization. We see the evidence of (bike) impacts," Since the mid-1980s, a host of scientific studies has attempted to measure the comparative effects of hiking boots and fat tires on trails. But interviews with hiking and bicycling groups and researchers in the field-including the co-author of a new study slated for publication this year-reveal that very little hard data exist to prove conclusively that bikes do more damage to trails than do boots. And those studies that have examined the evidence widely conclude that the charge against mountain bikes simply does not stick.

Many people interviewed for this story cite a 1995 study conducted by researcher Gordon Cessford for the New Zealand Department of Conservation, which concluded, "It has not been established in the research done to date that mountain bikes have greater overall impact on tracks than do walkers." Another researcher, Donald Weir an environmental consultant and engineer in Alberta, Canada, authored a report in 2000 that synthesized the findings of various studies. "I found there's very little statistical difference in physical impact on a trail between a hiker and a mountain bicyclist," Weir says.

As a result of her graduate research at the University of Guelph in Ontario, Canada, Eden Thurston co-authored a paper to be published this year in the Journal of Environmental Management on a study that measured trail damage from an equal number of one-way downhill passes by bikers and hikers on 10-15 degree slopes on an Ontario park. Thurston's study took place on about 667 acres at an elevation of approximately 350 feet, in maple forest with fine, sandy-loam soils. Hikers and bikers traveled over separate plots of ground, with researchers measuring the effects at intervals up to 500 passes. While emphasizing that her work "isn't the last word on this topic, (and) a lot more needs to be done," she found "there was no significant difference in the direct physical impacts of hikers and mountain bikers."

"There seems to be a suburban myth that observable trail degradation is the result of mountain biking," says Thurston. "People can see the tire treads, but is that really causing trail erosion?"

Yu-Fai Leung Ph.D, an assistant professor at North Carolina State University, who has examined trail erosion for the National Park service and others, says the type and amount of use has far less to do with erosion than factors like amount of rainfall and trail steepness and design. "Environmental factors"-including trail slope and precipitation-"have more to do with (causing) erosion."

"Mountain-bike impact (is most likely to result from) someone skidding brakes, which is bad technique and not a good thing to do," says Phil Keyes of the New England Mountain Bike Association (NEMBA). Keyes agrees with many researchers that "water going down a trail does infinitely more damage than bikes." But critics in the Northeast charge that research results so far have reflected other regions' soils, topography, and more dispersed use, and therefore don't necessarily apply here, The NY-NJTC is interested in finding answers to these questions based on conditions in the Northeast, according to Haugland, Late in 2000, the NY-NJTC formed an advisory committee of scientists from various disciplines to examine trail erosion. As of early February, the committee had just begun to meet and had no timetable for releasing findings.

"We have to move the issue beyond out respective passions," Haugland says. "our feeling is that the data (from elsewhere) don't conform to the needs here in the eastern forest. We see the evidence of (bike) impacts, but it has not been studied scientifically." If, in fact, boot and tire impacts do turn out be roughly equivalent, is biker-hiker animosity likely to evaporate? No, suggests other research that concludes conflicts between recreational user groups arise partly because one group considers another's behavior unacceptable, and their motivations for being outdoors are very different. Andrew Norkin, the AMC's White Mountains Trails manager, points out, "There were trails that historically were limited to hiking before biking came along, and folks weren't receptive to a new user group"

Scott Reid of Leave No Trace, which advocates low-impact recreational practices, calls the problem "a turf thing. Especially in the East, the trails have been built by hikers, they've put in the sweat equity, and suddenly along cones the new kid on the block riding fast, skidding around turns, and they're loud. There are social issues."

What's the solution? In the 1990s, the NY-NJTC actively opposed "the redesignation of hiking trails as mountain biking trails without our knowledge of consent," Haugland says, while also encouraging land managers to establish separate bike trails. "We believe that in order to serve hikers and mountain bikers, there need to be separate networks of trails." The AMC trail-use policy also recognizes that in some cases land managers "should consider designated single-use trails" in a given areas and "may wish to designate mountain-biking-only trails as well." George Cartamil, a volunteer trailmaintenance supervisor with the AMC's New York-North Jersey Chapter, points out that he has advocated for parks allowing mountain-bike groups to build their own trails. But he says he has yet to see the bike community step forward.

Even if bikers did build their own trails, Cartamil adds, they will invade hikers' trails. What are you going to have, a ranger on every trail? That's impossible. It's an ongoing battle, and it creates a constant friction between both groups."

Back in New Jersey, Bob Moss points to Ringwood State Park as a model for reducing conflicts between mountain bikers and hikers. The park set up a single-track bike race route. Plus, bikers have approached him seeking advice on how to avoid trail widening, and Moss later saw where bikers had done trail work. "There are ways to build trails that will stand up to bicycle use.or heavy hiking use," Moss says. "If there are enough trails to keep mountain bikers happy and they don't have to go on hiking trails, that should take care of the problem."