San Luis Obispo is famous for its more than 6,500 acres of open space containing a network of nearly 40 miles of trails.
But before anyone could set foot on any of those trails, someone had to do the complicated and often physically demanding job of scouting the trail, marking it and clearing away the brush down to bare dirt.
“It’s more complicated than most people would imagine to create a sustainable trail with proper drainage that flows and is fun to ride,” said Bob Nanninga, a trail crew volunteer with the Central Coast Concerned Mountain Bikers, or 3CMB.
Those trails also have to be maintained or they will become overgrown or damaged by erosion. Most of this work is done by volunteers from such groups as The SLO Stewards and the mountain bikers group.
Every Wednesday, a dozen of the mountain bikers spend the morning building or maintaining trails and doing other resource protection work within the city’s network of 12 open spaces.
On a recent Wednesday morning, a team of city park rangers and volunteers, including Nanninga and mountain bike group president Greg Bettencourt, scouted the first segment of a new mile-long trail that will connect the Irish Hills Natural Preserve with the Johnson Ranch Open Space. On the same day, another group of volunteers spent the morning maintaining a trail up Froom Creek.
The connector path is one of about 10 miles of new trail the city plans to build in the near future, said Freddy Otte, city biologist. “We’ve got our work cut out for us,” he said.
The city’s supervising ranger, Doug Carscaden, considers the mountain bikers to be a key resource. The group has built about 25 miles of trail in the county and maintains about 75 miles of trail.
“If you want consistent, high-quality and dedicated workers, it’s the 3CMB,” Carscaden said.
The new connector trail will run from a dirt road in the Froom Creek area, over a chaparral-covered ridge and along another dirt road before it drops down to Johnson Ranch from an oak-covered hill.
During the recent Wednesday gathering, the trail survey crew got ready for the most challenging part of mapping the new trail, a stretch through dense, head-high brush. All the participants wore protective clothing and gloves and had clinometers, an optical device with a dial that indicates the steepness of the terrain, hanging by a lanyard around each person’s neck.
“There are three ways to do this,” park ranger Dan Dixon said with a grin. “You can go over it, under it or through it.”
With that, the crew spent the next three hours bushwhacking through the growth in order to flag the corridor for the new trail. This involved tying brightly colored tape to branches at regular intervals. The crew stopped frequently and checked the slope of the terrain using their clinometers.
Ideally, the trail will have a steepness of no more than 5 to 7 percent, Bettencourt explained. This makes the trail useable for the maximum number of people.
One reason Johnson Ranch is so popular with hikers and bikers is that the trails have very few steep spots, allowing people of all ages and fitness levels to enjoy the park. The goal is to extend that user-friendly quality to the new trail segment, Bettencourt said.
“The planning phase of a new trail is about this long,” he said, holding his thumb and forefinger a fraction of an inch apart. “But the life of that trail is about this long,” he said holding his arms as far apart as he could. “So you might as well do it right and have something you can be proud of when you’re finished.”Because the terrain influences where the trail will go, the rough-flagging crew had to go where the terrain led them, no matter how thick the chaparral. In the Irish Hills, the chaparral is a dense mixture of ceanothus, toyon, coffeeberry, yucca and leather oak over many serpentine rock outcroppings.
Mostly, the crew forced its way through the dense growth, stomping on and breaking dead branches as it went. Other times, the volunteers had to crawl on their bellies or hop from limb to limb to get through dense stands of leather oak. As a last resort, they used pruning shears and foldable hand saws to get through an area.
At regular intervals, the flagging crew stopped, and a lively debate between the rangers and the volunteers ensued about where the trail should cross a seasonal creek or some other technical aspect. The trail builders must be cognizant of the fact that the serpentine chaparral is home to many rare and sensitive plant and animal species and the route must minimize impacts on them.
“They’re the gatekeepers,” Bettencourt said of the rangers. “I look upon my role as giving them options.”
After the trail is rough-flagged, the crews will go through the area again and fine-flag the route using numbered and color-coded small pin flags. A pin flag goes into the ground about every 10 to 12 feet and identifies high and low points for drainage purposes, Nanninga said.
Ideally, a trail will meander across the landscape, creating many low spots where water runs off without causing erosion. Many trails in the Irish Hills follow old dirt roads cut to reach manganese mines.
In November, the rangers will hold two general work days on Saturdays in which dozens of volunteers will clear the trail corridor. Later, the trail will be cleared down to bare dirt. The California Conservation Corps is likely to help out on these labor-intensive days.
“We need the fall rains for the serious dirt work, so we are anticipating a November or December work day,” Nanninga said.
If all goes well, the new trail could be complete by next spring, Carscaden said. It will include a new trailhead at Mountainbrook Community Church to relieve overcrowded parking at existing trailheads.