As mountain biking booms in Minnesota, pro builders help meet the demand for trails

A person uses an excavator to move rocks.
Adam Harju uses a 3-ton excavator to move huge rocks into place on a new mountain bike trail he’s building near Split Rock Lighthouse State Park in northeastern Minnesota on Aug. 9.
Dan Kraker | MPR News

On a steamy late summer day last month in a remote forest along the North Shore of Lake Superior, Mica Harju used what looked like an oversized hoe to place dirt and rocks along a new stretch of mountain bike trail carved through the woods.

"This is the real sexy part of trail building,” the 46-year-old said with a laugh. “Moving dirt. Moving rock."

Harju’s husband, Adam, maneuvered huge rocks inside a trench crossing the trail with a 3-ton excavator, while she did the detailed, finishing work on the 3-foot-wide, hard-packed track that's designed to follow the contours of the land, swooping and flowing around banked curves, over rocks and through the trees.

"We're trying to make it approachable for people that like to jump or want to learn how to jump,” said Mica Harju. “And so we're trying to work with the terrain and keep the speed up and give lots of opportunities for features where you can get your wheels off the ground."

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The Harjus own a small Grand Marais-based trail building company called Dirt Candy Designs, one of several companies that have popped up in Minnesota, and around the country, to meet the growing demand for professionally built mountain bike trails that are being built nationwide, including this new 21-mile system of trails near the small town of Beaver Bay called Split Rock Wilds.

A builder places a rock on a bike trail.
A builder with Rock Solid Trail Contracting, the country’s largest mountain bike trail building company based in Copper Harbor, Mich., places a rock on part of the Split Rock Wilds trails in northeastern Minnesota on Aug 9.
Dan Kraker | MPR News

Professional builders have constructed more than 100 miles of trails in northeastern Minnesota in just the past five years, fueled by a surge in interest in the sport, local volunteer groups that maintain the trails and hefty public investments to fund the construction of the trails.

“That kind of trail-building renaissance has really changed the sport,” said Scott Linnenburger, a Colorado-based consultant who’s overseen trail development around the country, including at several mountain bike parks on the Iron Range.

“The quality of the trails that have been created have really made it more accessible to all levels of riders.”

A new kind of trail

In the early days of mountain biking, cyclists rode on whatever trails they could find — old logging roads, cross country ski trails, even game trails. Some riders hacked new trails through the woods, often illegally. Building a modern mountain bike trail is completely different.

Trail builders, of course, try to make the trail as fun as possible for bikers.

But Dave Cizmas, the recreation forester for Lake County who's managing the construction of Split Rock Wilds, said preventing erosion is an even more important consideration.

A person rides down a rocky mountain bike trail.
Lake County recreation forester Dave Cizmas rides down a section of trail dubbed “Joe’s Diner,” part of the Split Rock Wilds mountain bike trail system, in August.
Dan Kraker | MPR News

"The biggest thing about mountain biking trails is making them sustainable, and making sure that you get the water to do, maybe not exactly what you want it to do, but at least it's predictable what the water is going to do."

That means using different techniques to keep water off the trail to prevent it from eroding, including raising the tread, using rocks to filter water away, and building trenches to funnel it off the trail.

That takes expertise, and requires meticulous, time-consuming work. It took the Harjus almost a month and a half to finish a 1-mile-long trail. And it's expensive.

"I would say the sweet spot for high quality, professional-built trail is in that $50,000 to $70,000 a mile [range]," said Mike Repyak, planning and design director for Trail Solutions, which designs and builds trails around the country for the International Mountain Biking Association. More technical trails can exceed $100,000 per mile.

Repyak, who's based in Madison, Wis., said as the demand for trails has grown, new builders are popping up all over the country.

Two people build a mountain bike trail.
Jurrien Davison of Grand Rapids, Mich., and Michael Uppenkamp from San Diego, Calif., who both work for Rock Solid Trail Contracting, build a mountain bike trail by hand near Beaver Bay, Minn., in August.
Dan Kraker | MPR News

"And we need that, we need a lot more planners and designers especially, and builders, too. The biggest thing is finding experienced operators of machines,” he said.

“So a big push for the industry right now is training, education and maybe some sort of certification. We're still a really young industry."

College programs have even popped up to teach sustainable mountain bike trail building.

Builders range from small two-person teams like Dirt Candy Designs, all the way to big companies like Rock Solid Trail Contracting out of Copper Harbor, Mich., which employs more than 60 people, and also had crews building the new trails in Lake County.

“There’s more work than we know what to do with,” said Blu Tenbrink, while he took a break from running an excavator.

Tenbrink said good trail builders have an artistic flair, laying rock and carving winding trails amid the trees. He said he likes to create a space for bikers to “dance through the woods.”

A person sits on his excavator.
Blu Tenbrink of Rock Solid Trail Contracting takes a break on his excavator while building a new trail in the Split Rock Wilds trail system.
Dan Kraker | MPR News

Tenbrink is from Marquette, Mich., but has spent his last couple summers in Minnesota, building trails in Lake County and on the Iron Range, where new trails have recently been created on top of the old pits and tailings piles of abandoned iron ore mines. He said he enjoys breathing new life into rural areas.

“I kind of dig … turning the old mine areas into usable zones, and bringing people into those zones,” he said. “Being part of the growth of it is pretty cool actually, seeing these dead towns coming back to life, and the locals getting into biking too, I feel like everybody's growing because of it."

Living in the woods

Trail builders spend weeks at a time, even months, building one trail. And they don’t just work all day in the woods, they live there, too.

Adam and Mica Harju spent a month and a half this summer living in their camper along the North Shore, parked off an unmarked dirt road in the woods near Beaver Bay.

During the summer they work long hours, seven days a week, building trail. Then they retreat to their camper for a shower and a meal, before hitting the trail again the following day.

Two people outside their camper.
Adam and Mica Harju sleep in this camper for weeks at a time when they travel around the country to build mountain bike trails. They’re pictured here in Lake County on Aug. 9, where they were building a new trail in the Split Rock Wilds trail system.
Dan Kraker | MPR News

Adam Harju started about a decade ago when he quit his job at Lutsen Resort. A couple years later, Mica Harju quit her job at North House Folk School to join him, “to reinvent myself as a trail builder,” she said.

Since then they've built trails in seven states, from Colorado to Arkansas to the upper Midwest. Mica Harju said some days are dreamy, with picture-perfect weather.

“But the reality is like, you're sweaty, you're dirty. Mosquitoes are everywhere. We're working in the Midwest, the ticks are bad. So it's definitely not roses all the time.”

But at the end of the day, she said, it's totally worth it. She loves the lifestyle and taking winters off to travel. As long as her body holds up, and they continue to land trail-building projects around the country, she said she's in it for the long haul. Adam Harju is, too.

"It's definitely not lost on us how fortunate we are to be able to do what we're doing, you know, it's getting to make your craft and share it with people, it's really special,” he said.

Two people stand next to each for a photo.
Adam and Mica Harju own Dirt Candy Designs, a small mountain bike trail company based in Grand Marais, one of dozens that have popped up around the country in recent years to help meet the growing demand for professionally built trails.
Dan Kraker | MPR News

Blu Tenbrink said when he first started trail building about five years ago, people asked him if he thought the job was sustainable. Now he’s working year-round, traveling to Arkansas to build trails in the winter.

Living in the woods, away from friends, can get old, he said. “It’s not for everybody.” But when he’s back home for a while, he misses camping out, roughing it. He said when it comes down to it, he doesn’t want to do anything else.

“We're a bunch of dirtbags hiding in the woods,” he said. “But we love it.”