Marin County Parks and Open Space is set to undertake projects that would restore habitat and redesign five trails, including Roy’s Redwoods Loop Trail in the San Geronimo Valley. The projects figure into the county’s Road and Trail Management Plan, which aims to designate a large swath of open space trails for hiker, biker and equestrian use and has sparked the ire of some local residents who feel the county is unfairly catering to cyclists. At Roy’s Redwoods, the county plans to shore up muddy spots along the trail and reduce sediment in the bordering Lagunitas Creek. The work would follow the replacement of a bridge over Larsen Creek completed last year and would add several small bridges and puncheons over difficult crossings. “It’ll be a much, much more comfortable and usable trail,” said Carl Somers, Parks and Open Space’s chief of planning and acquisition. “And in improving the trail, we’re going to improve the environmental function of the creek.” Mr. Somers said the county plans to undertake four other projects to re-water and drain several trails—including ones in the valley’s Gary Giacomini Preserve, in Fairfax’s Loma Alta Preserve and in Corte Madera’s Camino Alto Preserve—in anticipation of designating some of those trails for additional uses and decommissioning others. The trails pegged for those four projects were identified during a public workshop on the Road and Trail Plan last October, which many pedestrian and equestrian advocates said was unfairly dominated by bikers. Trails in the four projects will add four miles of bicycle paths, while Roy’s Redwoods will remain bike-free. Mr. Somers said other projects in West Marin’s open space are being designed for implementation next year, though he does not yet know how many trails will be involved with those projects. He doubted the work would encourage an increase in visitors.