Open Space Vegetation Management

Reducing fire risk, controlling invasive species, and restoring native habitat on open space lands.

Marin County is a regional and national leader in ecologically sound open space vegetation management. Throughout Marin County are 34 open space preserves that harbor unique species and ecosystems and provide visitors a chance to experience some of the most treasured landscapes in northern California. Vegetation management goals:
  • protect sensitive habitats
  • reduce fire fuel hazards
  • manage invasive plants
  • provide safe and sustainable recreation opportunities

Vegetation Management Projects Map 

With the support of Measure A funds, the Marin County Open Space District (MCOSD) has expanded collaborative initiatives to reduce fire risk in high priority areas, while maintaining natural resource preservation. This map outlines key vegetation management projects in open space, including those planned for the coming year. Use the filters to see different views of the data.


Because of Measure A, vegetation and biodiversity management capabilities have significantly expanded. Marin County Ordinance 3760 puts boots on the ground, by funding the Tam crew and Foundry crew in collaboration with Marin County Fire. It also supports Conservation Corps North Bay crews, and other contracted services, including substantial numbers of seasonal grazing animals. This provides an array of tools to draw upon in the effort to reduce fire fuel, maintain emergency access, reduce invasive plant species, create healthier habitats, and support safe recreation in Marin County preserves.
Foundry Crew clearing brush
Tam Crew clearing brush
Tam Crew pile burn
This Marin County Fire crew takes on biomass removal through pile-burning, and management of large eucalyptus as their schedule permits. During fire season and as needed, their first priority is fighting fires.
FIRE Foundry is a workforce development program. This crew focuses on high priority areas by reducing understory fuels, clearing dead and woody debris, and addressing invasive species for defensible space and emergency access.
Crew member clearing a fallen tree
Crew member mowing emergency access road
Crew member clearing fallen tree
Marin County Open Space District dedicates staff to performing routine maintenance, such as mowing of high priority areas. This team is also on call to assist in evaluating hazards to keep open space trails passable and safe.
As needed, contracted services help support tree hazard mitigation and removal of down trees in parks and open space preserves.
Crew clearing defensible space.
This non-profit organization focuses on providing skills and training to young people so they can pursue environmental careers. Teams from Conservation Corps North Bay (CCNB) assist the Marin County Open Space District on a variety of vegetation management projects – clearing brush, weed whacking, and removing debris.
Goats grazing
Herder bringing the flock to graze
Cows grazing
The vegetation and biodiodiversity management team employs a variety of grazing strategies in different areas of county preserves, including sheep, goat, and cattle herds. Grazers are focused on grasslands, maintaining defensible space near homes, and fuel reduction along fire roads and ridgelines. Year over year, Parks scientists assess results,to determine the most effective use of grazing.
Contract crew clearing debris
Contract crew chipping wood
Contract crew clearing brush
Marin County Open Space District also employs contracted service crews as needed to meet vegetation management objectives in high priority areas. The work of the contract crews are coordinated by MCOSD staff.
Marking goat grass infestation area
Field staff holding up example of an invasive plant
Field staff surveying for invasive plants
The EDRR team conducts comprehensive surveys for invasive plants throughout all Marin County preserves. Surveys focus on the areas most likely to have new weed introductions - roads, trails, and preserve edges - as well as sensitive areas that are most critical to protect. During surveys, the crew will treat high-priority, small populations with hand tools. For more established stands, location and data are recorded so that future treatments can be planned and prioritized.
By detecting a new invasive plant before it has a chance to spread or build a large seed bank, managers can respond early enough in the invasion process to fully eradicate the species from a given area...well-informed surveillance can avoid costly long-term control efforts. - California Invasive Plant Council


Volunteers of all ages and abilities support vegetation management through community volunteer opportunities, special events, and programs. These efforts help restore natural habitats and engage the community in a shared commitment to protecting open space lands. Learn more about Parks volunteer opportunities.
Volunteers leaning on weed wrenches
Man and woman pulling broom together
Kid holding up big broom root

Funding Vegetation Management

Measure A has allowed Parks to significantly increase spending on vegetation management. As wildfires in California and the Bay Area have become more frequent and of greater intensity due to a warming climate, this work has become more important than ever.

Treatment Methods

MCOSD uses a wide array of techniques and tools, but most of the work is done by hand wearing a sturdy pair of gloves. Staff puts a priority on non-chemical solutions. After careful consideration, limited and targeted herbicide may be introduced, only in critical use situations, as a means for bringing infestations under control to effectively manage the site organically over the long term. The goal regarding herbicide use is “getting to zero” at each project site. 
Hand pull. This frequently used method is simple and often most effective. It may be used alone or with other methods. Even when mature plants are impossible to pull by hand (as with invasive trees), hand pulling can be used on new seedlings. Weed wrenches help to remove difficult, woody plants. 
Mow. Strategically timed mowing reduces the seeds of many weeds, such as invasive annual grasses, but the window for effective control is short. Mowing can also be used to temporarily reduce fuels or to make some weeds easier to see and remove. Mowing early tends to favor plants that develop later. 
Animal grazing. Cattle, sheep, goats, and horses can help reduce fuels and weeds. They are able to cover large areas that are difficult for people to maneuver. Like all methods, negative impacts are weighed against the positive to obtain a net benefit. Like mowing, the time of grazing will impact or favor certain species. Grazing is one of very few methods that can be applied at a landscape scale to address widespread challenges. 
Flaming and prescribed burns. Environmental conditions must be perfect, and this tool is best combined with active follow-up. Safety of staff, visitors, and nearby residential areas must be the top priority. Often fire is used to burn small piles for fuel reduction projects. Prescribed burning is one of very few methods that can be applied at a landscape scale to address widespread challenges. 
Insect predators and pathogens. New helpful organisms are being developed and released by qualified scientists. While they usually target agricultural weeds, some support the fight against wildland weeds. 
Mulch or Tarp. Covering an area with tarps, straw, chips, and/or cardboard to prevent plant growth or seedling establishment is a good tool in some locations. However, it does not allow for preserving desirable plants in the area. Tarps are often difficult to install and maintain, and they must be removed so they don’t become trash on the landscape. 
Organic herbicides. Organic chemicals typically cause the top of a plant to wither. Existing products don’t impact large rooted plants, so they aren’t effective at managing most priority wildland species, although they may provide assistance in special cases. These products should be considered over conventional herbicides when tackling annual weeds within smaller areas in residential landscaping or urban areas. 
Conventional herbicides. This method, used sparingly, can help manage some of the toughest invasive species threats. Some conventional herbicides have the ability to target the roots of a plant, which is important when it is not feasible to remove roots by hand (as with invasive trees). 
Herbicides that may be used  include:
  • Garlon 4 Ultra (Tryclopyr)
  • Habitat (Imazapyr )
  • Fusilade II (Fluazifop)
  • Milestone (Aminopyralid)
  • Aquamaster (Glyphosate)
  • Weed Slayer (Eugenol) - OMRI Organic
  • Suppress (Caprylic/Capric acid) - OMRI Organic

Guidance and Governance

Developed with substantial feedback from the community, the Vegetation and Biodiversity Management Plan guides vegetation management work on Marin County Open Space District (MCOSD) lands. It provides a comprehensive, long-term framework for a science-based, ecologically sound approach to vegetation management.
Vegetation management work on MCOSD lands is governed by the Marin Open Space District Board, as well as the Parks and Open Space Commission.

Vegetation and Biodiversity Management Team

Mischon Martin, Chief of Natural Resources and Science 
Mischon has worked professionally in Natural Resources and Science for over 20 years. In addition to her current role, she has served in a number of positions with Marin County Parks, including Resource Ecologist and Natural Resources Program Manager. Mischon oversees the planning and implementation of a variety of landscape-level restoration and vegetation management projects throughout Marin County parks and open space preserves. Her work focuses on improving habitat for endangered species, as well as reducing fire fuels and managing the spread of invasive species. Mischon holds a Bachelor of Science in Biology. 
Jim Chayka, Parks and Open Space Superintendent Jim serves a key role overseeing vegetation management initiatives in collaboration with Marin CSAs and other community organizations. He is on the Executive Committee of FireSafe Marin. Jim served as Director of Natural Resources at Conservation Corps North Bay and has been working in the field of natural resources and watershed management for 17 years. He started his career in environmental stewardship as an AmeriCorps member at the CivicCorps (formerly the East Bay Conservation Corps), and subsequently managed education and restoration programs with Student Conservation Association, Watershed Sciences, Urban Creeks Council, and Sonoma Ecology Center. Jim holds an MS degree in Applied Geosciences from San Francisco State University. 
Sarah Minnick, Vegetation and Fire Ecologist 
Sarah has over ten years of experience in land conservation and vegetation management, including six years working for the National Park Service. In her current position at Marin County Parks, she focuses on vegetation and biodiversity management, including habitat restoration and monitoring, fire protection, invasive weed control, rare species mapping, monitoring and preservation, and community engagement. She holds an undergraduate degree in Mathematics/Biology and a graduate degree in Conservation Ecology. 
Nathaniel Clark, Biodiversity and Fuels Management Coordinator 
Nate holds a B.A. in Environmental Science from UCLA, and a Master's degree in Environmental Management from the University of San Francisco. He first worked for Parks as a Biological Monitor, conducting wildlife surveys and maintaining cameras for the Marin Wildlife Picture Index. After working as a Regulatory Permitting Specialist, he returned to Parks in his current role, where he collaborates with Marin County Fire and local Marin communities, coordinating the fire fuel reduction work of the Tam Crew.
Julian Geoghegan, Resource Specialist 
Julian has worked for a variety of conservation agencies over the last decade, and began working for Marin County Parks in 2017. His work focuses on invasive plant management, habitat restoration, and vegetation mapping, with a particular interest in rare native plants. Julian holds a Bachelor of Science in Biology. 
Greg Reza. Volunteer Program Coordinator 
Greg has organized volunteer projects at Marin County parks and open spaces for over 20 years. He builds community with local schools, groups, businesses, and non-profit organizations, coordinating the many thousands of volunteers each year needed to support ecologically sound vegetation management and habitat restoration. Greg holds a Bachelor’s degree in Environmental Studies and Planning with a concentration in Conservation and Restoration.
Seasonal Technicians and Assistants
Seasonal workers are responsible for a wide array of duties, including organizing and conducting bird habitat and compliance surveys; supporting the Marin Wildlife Picture Index Project; supporting new native plant nursery operations; mapping native plant populations; assisting in regulatory compliance and planning, organizing trail maintenance crews; collecting program data, and engaging with volunteers and members of the community.
For more information about Marin County Parks, visit
Link to Marin County Parks website.