Illegal trail building came out of a passionate community of early mountain bikers and helped contribute to the birth and growth of the sport. But these days, what’s the impact of mountain bikers building rogue trails in the woods?

A new Flylow-sponsored film by Mountain Grown Media called “The Wild Side” explores the complicated nature of trail usage and trail building within the mountain biking community. In the film, we meet a handful of distinct characters and avid mountain bikers who each approach the trail with a different lens.

There’s Ashli Lewis, a wildlife biologist and downhill rider, who loves the feeling of a powerful turn or soaring through the air on her bike but also recognizes the environmental impact trails can have on a landscape. There’s Jeremy Benson, a cross-country rider who logs miles upon miles in the saddle and also serves as a volunteer trail builder, and there’s Dillon Osleger, a mountain biker, trail builder, and scientist.

“What is mountain biking without trails? I don’t want to disparage unsanctioned trail building. It’s the root of this weird sport,” says Osleger in “The Wild Side” film. “But I think you evolve more toward some sense of coexistence with the environment, the path forward, the trail to somewhere. Everyone thinks they can build a trail, but maybe not.”

Also featured in the film are brothers Cody and Henry Wilkins, avid mountain bikers and also professional trail builders who work with communities and municipalities around North America to build sanctioned trail networks. But they too understand why and how illegal trails get built.

“Illegal trails have played a big role in progressing the sport,” Cody Wilkins says in the film. “If you look at every cool feature that you see on legal trails now—whether it’s a jump, or a berm, or a wooden feature—I guarantee you it was inspired by something that was done illegally in the woods.” Cody says later: “A rider can build what they feel is missing in their community. If there’s an illegal trail there, why is that trail there?”

It’s a good question: Why do illegal trails get built? The answer is varied. For years, mountain bikers have hand-crafted pirate trails through the forest on public (and sometimes private) land. They do this to get the kind of flowy, switchbacking singletrack they want to ride but also because getting legal trails built can require a lot of red tape. Sometimes, these rouge trails are simple, short connectors; other times, they’re fully rideable routes with miles of singletrack and features like jumps and berms.

Land managers from California’s Marin County to Colorado to Vermont have battled off-the-map trail building for decades. “When mountain biking first came about in the ’80s, finding spots to recreate was hard,” says Patrick Parsel, trails director for TAMBA, the Tahoe Area Mountain Biking Association. “They were fighting the battles of hey, we’re not allowed here. Instead of hanging up their bikes and walking away, it was, ‘Let’s find our own way of doing things,’ and that was building trails.”

Eventually mountain biking became mainstream, and knobby-tired bikes were allowed on multi-use trails, but as the sport has progressed, land managers have had a hard time keeping up with the style of trails that mountain bikers like. “You still see in places, even where they’re doing a decent job of building new trails, it’s hard to keep up with the demand for what people want to get out of the rider experience, whether that’s a mellow beginner trail or a steep, expert trail,” Parsel says. “If these users feel like they’re not able to have the experience on a trail that they want, they’re building their own trails.”

Mountain biker Dieter King has been building rouge trails around his hometown of Nevada City, California, for years now. He’s also a volunteer trail builder for BONC, Bicyclists of Nevada County, where he works on sanctioned mountain bike trails. Most of the trails he’s built by himself have been practical ones: short links that connect trail systems or keep mountain bikers off paved roadways.

If you’ve ridden the short link trail called Dieteronomy from downtown Nevada City toward the trail systems off Highway 20, for example, you have King to thank. He never got permission to build that trail, but it’s used and appreciated daily by mountain bikers. “It takes a lot of bureaucratic paperwork to get a trail built,” King says. “Whereas if it’s just me out there, I can get it done right away.” King understands the consequences of illegal trails, but without them, he says, some important aspects of mountain biking would be lost.

There’s certainly an environmental impact if a trail isn’t built properly, ranging from erosion to harmful impacts on native species, plant life, or watersheds. There can also be cultural impacts, if a trail is built illegally on sacred lands or private property or if people get lost or hurt on unmarked, non-sanctioned trails. There’s also a chance that an illegally built trail just gets closed down right away.

“It’s very easy for a land manager if they find out about an illegal trail to just get rid of it—put up signs, put up game cameras, drop trees, get out there with an excavator. Is that how you want land managers to spend their time?” says Parsel. “If we have that dialogue of here’s the kind of trails we want to see, it might take five years to get the trail built, but in the long run, that trail won’t go anywhere. We need to be considerate of some of the factors that go into building trails legally. It doesn’t happen overnight, but when it happens, the trail is there for good.”

From Parsel’s perspective, if trail organizations and land managers work together, everyone wins. Building sustainable trails with the cooperation of local and state agencies is what the sport of mountain biking needs to sustain itself in the future. “We’re speaking on behalf of mountain bikers and working closely with land managers to figure out what are the upcoming needs that users have?” Parsel says. “And how can we work together to service those needs before they go out and do it illegally?”

[Want to get involved with local trail building in your area? Great. Here’s how.]