Redwoods Restoration

Deepening understanding of Roy's Redwoods, to set restoration priorities.


The purpose of the proposed project is to implement the MCOSD Road and Trail Management Plan (RTMP) to provide the public with a safe multi-use trail system to enhance the visitor experience, reduce the environmental impacts on sensitive resources by reducing sedimentation and erosion, and establish a sustainable system of roads and trails that meet design and management standards and would provide year-round access along the trail alignment. The project includes the following elements, which are summarized below and fully described in the Project Description section of the IS/MND.

Ecological and Hydrologic Restoration:
Reestablish a multi-threaded Stage Zero wetland-channel complex to reconnect Upper Larsen Creek to its surrounding floodplain, reduce erosion, restore hydrologic functions, and increase infiltration and raise the groundwater table, rehabilitate approximately 77,170 square feet of heavy visitor use areas throughout the valley floor to reduce soil compaction and increase conditions for natural regeneration of vegetation, halt development and persistence of incised channel reaches of Upper Larsen Creek through the valley floor using large and small wood structures, and re-orient existing fallen trees and downed branches and obtain and place additional logs, where needed, through the floodplain to improve natural hydrologic function by slowing and spreading water throughout the floodplain to allow flows to infiltrate into the soil.

Trail Improvements:
Upgrade and realign approximately 5,670 feet if existing trails to improve drainage, prevent future erosion and sedimentation, meet RTMP trail design standards and upgrade approximately 1,900 feet of existing trails to meet Marin County Parks Inclusive Access Plan standards for an Access and Discovery Trail.

Parking and Entryway Improvements:
Develop two new designated entryways and improve the existing entryway adjacent to Nicasio Valley Road, relocate the existing porta-toilet out of the floodplain and closer to the existing entryway, install one inclusive parking spot on the shoulder of Nicasio Valley Road, and reinstall fencing along the Nicasio Valley Road shoulder.

Social Trail Decommissioning:
Decommission approximately 6,465 feet of existing social trails located in sensitive areas using passive trail closure methods and active methods that involve heavy equipment and hand tools.

Visitor Education:
Install new fencing and visitor information signage to notify visitors of closed trails and discourage development of new social trails, construct a Nature Exploration Area and Scramble, provide visitor interpretive services and wayfinding signage.

Summary of Potential Impacts and Mitigation Measures:
The IS/MND identified potentially significant environmental impacts in the areas of Biological Resources and Transportation. Mitigation measures to reduce the significance of these impacts to a less-than-significant level is included in the IS/MND. The IS/MND concludes that, with implementation of the mitigation measures, the proposed project would not result significant environmental impacts.


Implementation of the proposed project would achieve the following project objectives:

  • Restore and enhance the health and resiliency of the redwood forest by restoring healthy soil conditions through decompaction of social trails and heavy visitor use areas, re-establishing a diverse forest understory plant community, and reducing impacts to wildlife habitat and the forest ecosystem by limiting the number and distribution of trails through the forest.
  • Restore and enhance hydrologic process and function by stopping the development and persistence of incised channels through the alluvial valley floor, re-establishing a multi-threaded and dynamic wetland-channel network that is closely connected to the floodplain, storing a majority of the total sediment delivered to the valley floor on-site, and reducing winter peak flows and increasing the volume and longevity of spring and summer low flows.
  • Improve the public access by providing an immersive visitor experience that is consistent with restoration goals, providing safe and sustainable year-round access to the bay and redwood forest portion of the Roy's Redwoods Open Space Preserve, improving access consistent with MCOSD’s Inclusive Access Plan, and providing visitor interpretive services.

Project Development

Planning and Site Assessment, Site Analysis Technical Memo
In 2014 a Memorandum of Understanding establishing the One Tam partnership, formerly known as the Tamalpais Land Collaborative, was signed by the four land management agencies charged with stewarding Mt. Tamalpais including the National Park Service, California Department of Parks and Recreation, Marin Municipal Water District, MCOSD, along with the Golden Gate National Parks Conservancy (Parks Conservancy). Through a prioritization process, One Tam established a list of priority projects that the partners would collaboratively undertake which included the proposed Roy’s Redwoods Restoration Project with the goals of protecting the diverse biological resources of the site, improving hydrologic function, preserving the rich history of the landscape, and providing access and amenities for visitors to enjoy Roy’s Redwoods into the future. Since the spring of 2017, the Parks Conservancy and the MCOSD have led a multi-agency team through scoping and project design.

Marin County Parks and Parks Conservancy staff assessed the area between 2017 and 2018 and presented recommendations in the Roy’s Redwoods Open Space Preserve Site Analysis Technical Memo November 2018. The technical memo includes descriptions of the bio-physical site characteristics and the historical, cultural, and recreational planning context. It also includes the results of a visitor use survey, a literature review, a series of technical workshops, site inventory and mapping, and community engagement. This early project planning phase helped to ground the project in the best available science, and gain understanding of community values and visitor use.

Through this site analysis process, the project team defined “Restoration of Roy’s Redwoods” to more specifically mean restoring the degraded hydrologic function of the alluvial valley and habitat of the old growth redwood forest. Key to this understanding was the hydrologic assessment conducted by Prunuske Chatham, Inc that detailed the degraded conditions and opportunities for improvements to hydrologic processes and function . In addition to the visitor experience benefit, the site analysis process helped confirm that providing a comprehensible trail circulation system through the redwood stand would be a critical element to successful restoration.

Subject Matter Experts Workshop
The MCOSD and One Tam hosted a subject matter expert workshop to develop an initial site inventory, identify opportunities and constraints, and provide guidance to the project team on areas to focus further study. The workshop was held on May 9, 2017 and included staff from private organizations, local, state, and federal agencies. A primary outcome of the meeting was identification of the need to understand the hydrology of upper Larsen Creek and its relationship to important habitat downstream and identification of hydrologic restoration opportunities.

Tribal Consultation
The MCOSD staff provided notification of the proposed project to the Federated Indians of Graton Rancheria (FIGR), the Guidiville Indian Rancheria (GIR), and the Coast Miwok Tribal Council of Marin (CMTCM) on July 19, 2021 and asked if a consultation process pursuant to California Assembly Bill 52 should be initiated. FIGR provided an email confirming receipt of this notification but no further comments and did not respond to the MCOSD’s request to meet. The GIR did not respond. The CMTCM provided a response including a formal AB52 request from our Tribal Council designating a contact person to consult on the proposed project but did not follow up with the MCOSD’s request to meet.


  • March 2017: Community Biolblitz
  • November 2017: Community Walk & Talk
  • May 2017-March 2018: Visitor Surveys
  • May 2018: Community Field Day Workshop
  • August 2018: Second Community Workshop
  • October 2018: Draft Site Analysis Technical Memo
  • 2019: Conceptual Designs
  • 2020: Design Refinement
  • 2021: Prepare Draft CEQA Document
  • February 06 – March 10, 2023: Public Review Period of the CEQA Document