In a roadside nature preserve in the San Geronimo Valley of West Marin stands a grove of towering, 300-year-old trees that most motorists blow by without noticing. One of only four remaining old-growth redwood forests in Marin County, it has been open to hikers since it became public land 45 years ago, but it has never had a designed network of trails for them to follow.
Instead, visitors are left to pick their own way through the sensitive ecosystem along a mishmash of random paths that have been beaten down by foot traffic — and they are lucky if they avoid either getting lost or getting poison oak.
But help for the hikers and the trees in Roy’s Redwoods Open Space Preserve is in the works. Last month, a small excavator broke ground on a new footpath to announce the largest capital project ever mounted in open space by Marin County Parks.
When it is completed in fall 2024, the result will be 1.5 miles of clearly designated trail that respect the delicate ecosystem. The effort, which took seven years of planning, will cost $3 million, with $2 million already accounted for in grant funding.

Jon Campo, principal natural resources planner for Marin County Parks, walks a section that will be developed into an intersection of trails connecting to a boardwalk at Roy’s Redwood Open Space Preserve in Woodacre.
Lea Suzuki/The Chronicle“People use the creek channels as trails, and we want to avoid that,” said Marin County Parks planner Jon Campo. “We need to be able to direct people where to go and how to navigate the space so that we can build a healthy forest system.”
On a recent hot August morning, Campo observed as a common scenario played out among four explorers who parked along Nicasio Valley Road and dropped into the cool dimness of Roy’s Redwoods.
Looking for a definitive trail, they picked a path among dry creek beds and atop downed logs until one of them finally asked the obvious:
“Now what?”
That question goes back to 1978, when the county bought the 293-acre hillside property from its namesake owners, brothers James and Thomas Roy, who ran a dairy operation there.

David Frazier, left, machine equipment operator, and Joe Luchessa, seasonal trail tech, work on the beginning stages of building a network of trails at Roy’s Redwood Open Space Preserve in Woodacre.
Lea Suzuki/The ChronicleSince then, the preserve has been both open to the public and hard to find.
There is no signage marking the turnoff on either of its two approaches, Sir Francis Drake Boulevard and Lucas Valley Road. If you know in advance to take Nicasio Valley Road, you also have to know that the only parking is on the shoulder, opposite West Nicasio Road.
“It has always been a treasure for locals,’’ said Paul Berensmeier, who is about as local as they come. He grew up in neighboring Lagunitas and first came to Roy’s Redwoods on the back of his mother, Jean. She went on to become President of the Marin County Open Space District, and her first order of business was to push for acquisition of Roy’s, at a cost of $420,000.
Mother and son hiked together in the grove for 55 years and last visited during the planning phase of the restoration project. Jean died in March but Paul will be there to hike the new trails when they open, along with everybody else.
“It must be on the Internet because my wife and I hike up there regularly and meet people from all over the world,’’ said Berensmeir, now 61. “There are trees there larger than in Muir Woods. When you are back up in the redwoods you can’t hear any noise.”
That is remarkable because the old-growth forest is near the roadway. Down the embankment is an entrance sign with an enlarged map that marks three trails: Roy’s Redwoods Loop, David Hansen Trail and the Meadow Trail. The first two remain open during construction, but the Meadow Trail is closed as it is reimagined into the new trail network that will bring hikers among trees that are 300 years old and 200 feet tall.
Without planned, clearly designated trails, hikers currently go “wherever,” said Campo. “That in itself has caused a lot of environmental damage as they unknowingly impact the redwood forest.”
Some damage was caused when a hippie commune settled into one of the tree trunks in the 1960s. But it would have been worse if the plan to run a freeway into West Marin had been realized in the 1950s. That plan was beaten back and the land leased for grazing until the county acquired it for $420,000. Years later, George Lucas brought his crew from Skywalker Ranch into the redwood grove to film scenes for “The Ewok Adventure.”
The project area involves 20 of the preserve’s 293 acres. A total of 1.5 miles of trails will service it, with downed logs marking the edges of the trails.

Faye Coddington of Forest Knolls in Marin County makes her way down Roy’s Redwoods Loop Trail with her dog Jazz in 2017.
Erik Castro/Special To The ChronicleLarsen Creek runs through the grove and is active in winter. To protect the creek bed, a 6-foot-wide boardwalk will elevate a 100-foot-long section of the trail. A specified quarter-mile loop will be designated as inclusive access.
“This is the first time we are designing trails in open space suitable for people with mobility issues,” said Campo. The combined trails will bring people into several areas known as fairy rings, where the trees seem to form the walls of a house.
Roy’s Redwoods is the first project to be implemented by a countywide collaboration of agencies under the umbrella One Tam, named for Mount Tamalpais, the highest point in the watershed.
Marin County Parks is the lead agency on the Roy’s Redwoods project. It is conducting a vast evaluation of the trail system countywide, as part of a Road and Trail Management Plan inaugurated in 2016, the year Campo was hired after 18 years with the San Francisco Recreation and Park Department.
Twelve miles of new trails have been completed on old jeep roads, logging roads and social trails. Under construction at the same time as Roy’s Redwoods is Eagle Rock Trail, which runs 1.7 miles from the Eichler neighborhoods of Terra Linda to the ridgeline above San Rafael. It is also due for completion in 2024.
The single entrance to Roy’s Redwoods, now a gravel ramp from the roadway, will be replaced by two new ramps plus a stone staircase to get people out of the line of traffic, which moves fast on Nicasio Valley Road.
In keeping with tradition, there probably won’t be a grand opening, but there will be one indicator that the job is finished: a single freshly paved parking slot on the shoulder of Nicasio Valley Road, striped in blue to indicate ADA parking.
“It will be fantastic for visitors to come to Roy’s, know where to go, and know they are visiting in a responsible and sustainable way,’’ said Campo.
Reach Sam Whiting: swhiting@sfchronicle.com