Mountain bikers and self-described “foot people” have clashed in recent months over how much access bikers should have to trails on Marin County’s Open Space Preserves. 

The most recent dispute followed a county workshop in Lagunitas in October, where open space staff solicited input on how to designate usage of around 50 miles of trail on seven preserves in the San Geronimo Valley. Maps released last month show that bicyclists will be able to use nearly six miles of new trails.

But members of a group of hikers and equestrians who call themselves the FootPeople have criticized the county for catering too much to mountain bikers, whose numbers and support have grown steadily since the 1980s. The FootPeople claim the bikers have urged the district to legalize and make available more trails to bikers at the expense of hikers, equestrians and the valley’s wildlife.

In a report issued last month, the FootPeople called on the Open Space District to reform the public-review process as it implements the Road and Trail Management Plan, a plan that determines which county trails should be kept for recreational access, which should be decommissioned and what activities—such as hiking, biking and horse riding—should be allowed on each trail. 

“While the [district] wants to conduct an orderly democratic process, it has not yet found the secret,” the report concluded. “The [plan’s] implementation process continues to give sensitive natural resources and ‘foot people’ short shrift and to respond to the loudest and most persistent voices.” 

One FootPeople member, longtime valley resident Jean Berensmeier, viewed the presence of so many bikers at the workshop as an “aggressive” act meant to overwhelm the voices of other trail users. 

“They want access to everything,” said Ms. Berensmeier, a former 20-year Open Space commissioner. “They’re not satisfied with fire trails. They’re not satisfied with multi-use trails. They want single-track trails.”

The report noted that though an estimated 75 percent or more of Open Space users are hikers and equestrians, mountain bikers dominated the Lagunitas workshop, where participants studied large trail maps and expressed their opinions on what uses each trail should be designated for. The result, according to FootPeople member and Fairfax resident Linda Novy, is that the district may be straying from land preservation in favor of more recreational pursuits.

“We’re afraid it’s going to become a more active recreation hub when activities on public Open Space lands should be more passive,” said Ms. Novy, who added that FootPeople was created four years ago to give voice to the “silent majority” of trail users. “And I think it’s going to attract more and more mountain bikers from the surrounding areas.”

The FootPeople’s report expressed fears that a larger wave of bike riders could disrupt the valley’s coho salmon and spotted owls. Ms. Berensmeier suggested that bikers keep to wider, already-impacted fire trails in the valley and for organizations to make a greater effort to have bikers licensed on public lands.

But the president of the nonprofit advocacy group Access4Bikes, Vernon Huffman, countered in an email that narrower trails help slow down bikers and “are just much more fun than wide, steep, loose, and dangerous fire roads.” He also challenged FootPeople’s environmental critiques, citing a study published by the National Center for Biotechnology Information that found impacts from hiking and biking do not differ greatly.

“They don’t use any facts or peer-reviewed studies,” Mr. Huffman said. “They just use insinuation and hearsay. We use facts.”

Mr. Huffman praised the workshop as one of the first opportunities for bikers to participate in an open process that gives them a say in how the county divvies out access to preserves. For that reason, he said, it was no coincidence that bikers showed up in droves. “That’s an indication of the changing demographics,” Mr. Huffman said. “If 90 percent of the room is mountain bikers, then the policy ought to change to reflect that.”

Forest Knolls resident and the Marin County Bicycle Coalition’s off-road and events director, Tom Boss, said the trail plan could benefit the environment by forcing the county to provide better routine maintenance. He also said the coalition met a couple of months ago with FootPeople to hash out solutions for how the two groups could work together.

Carl Somers, the district’s chief of planning and acquisition, said that the county intends to keep out of the debate over which of the two groups has a bigger impact. He said that the real source of environmental degradation is not particular activities, but the trail system itself—meaning, the large numbers of people who use decades-old trails built with no thought to future impacts.

He added, however, that disputes between trail user groups are nothing new. 

“People have been fighting about trail designations for at least 30 years,” Mr. Somers said. “What’s new in Marin County is that we finally have a program and a process that, I hope, will become a container for these conflicts.”