.‘One Tam’ Plan: Mt. Tamalpais habitat restoration

Mount Tamalpais is perhaps the most recognizable landmark of Marin County, the peak of which towers majestically over the North Bay from an elevation of over 2,500 feet.

This mountain is more than a local icon and a symbol for the region—it is a testament to the efforts of the local community and their willingness to band together to protect and preserve one of the most important corners of Californian nature.

The mountain and its matrix of protected surrounding land are vast and cover approximately 195,000 acres of interconnected open spaces, according to onetam.org. Due to the sheer size and diversity of Mt. Tamalpais, five separate organizations work both independently and together to serve the best interests of the land, as well as the plants, animals and resources it provides.

music in the park san jose
music in the park san jose

One Tam is the name of the five-organization umbrella partnership, comprising the National Park Service, Marin Water, Mt. Tamalpais State Park, Marin County Parks and the Golden Gate National Parks Conservancy. Under One Tam’s shared management are more than 200 miles of hiking trails, many of which are available to the general public and can be easily accessed across much of Marin.

“Depending on where you draw the line, the mountain itself is 50,000 acres, and Marin Water is responsible for about 20,000 of those,” explained ecologist and volunteer coordinator for Marin Water, Suzanne Whelan. Whelan works from the ranger station by Lake Lagunitas and is a resident of San Rafael—she has held her role for the past 13 years and has a master’s degree in environmental education.

Despite the combined efforts to protect Mt. Tamalpais, invasive species, forest diseases and climate change continue to threaten the natural beauty, biodiversity and resources of the mountain. By working together as a community and through the One Tam partnership, Whelan and others hope to address these issues head-on and continue to serve and protect the greater Mt. Tamalpais region.

“The weeds don’t care if they’re on a state park or our side of the mountain, and the coyotes don’t care, so it’s really nice to be able to share the scientific and monetary resources, and collaborate,” said Whelan.

One of Whelan’s responsibilities is to help coordinate efforts for the Marin Water Volunteer Program, where locals may volunteer their time and energy toward conservation efforts. In an ongoing cleanup initiative at the Mt. Tamalpais Watershed, near Phoenix Lake, those who are interested in volunteering may sign up to come and help pull patches of the invasive plant species, broom.

French broom and Scotch broom (Genista monspessulana and Cytisus scoparius) grow prevalently on the mountain and are considered harmful to the natural habitat. Broom is considered an aggressive, incredibly tenacious invasive plant. It if gets into certain woodlands, it can become a significant fire hazard, making its removal a high priority to One Tam, as well as the individual organizations which comprise the organization.

“Our Mt. Tam habitat restoration volunteering typically happens the third Saturday of every month, and the sessions are typically from 9 in the morning until noon,” explained Whelan. “People come, we do a safety talk, everyone gets donuts, then we discuss what we’re doing and why before they get gloves and tools and start pulling broom.”

This cleanup initiative is an ongoing volunteer program and offers an opportunity to get outside, get moving and do something beneficial for the Marin County ecosystem. The Marin Water Volunteer Program aims to engage and educate the community so that they may be more informed about the challenges facing the local environment.

In an effort to ensure the safety and comfort of volunteers of all ages and demographics, the Marin Water Volunteer Program selects cleanup locations with nearby restroom facilities, parking and little to no poison oak.

“Habitat restoration is the gateway activity for anyone to volunteer,” said Whelan. “It’s very easy; you get out there, you get dirty and you end up finding all these cool native plants and animals in the environment you’re working to protect. You smell it, you touch it, you feel sore afterward and it’s great for families, and anyone over the age of six can do it!”

These volunteer outreach programs serve as an opportunity to learn about local plants and animals living in the oak woodlands, including newts, deer, turtles, salamanders and wood rats (to name only a small few).

According to the One Tam website, studies from the year 2016, which spanned 36,000 acres, accredited Mt. Tamalpais with being the home of 184 different species of birds, 250 different species of native animals and 1,000 different plant species. One Tam is currently in the process of gathering updates to these findings and will release a more current report when it is finished.

The biodiversity of Mt. Tamalpais is due, in part, to its coastal location and varied topography, both of which help to create an array of microclimates. And, while the plants and animals of the mountain live in protected open spaces, they continue to face the threat of invasive non-native plants and animals, wildfires, climate change and plant diseases such as Sudden Oak Death.

“Sudden Oak Death caused a pretty rapid recent landscape change—20 years ago we had a lot of Tan Oak, and now there are hardly any left and a lot of scientists are looking into it,” explained Whelan. “The death of those big canopy trees has opened up room for broom. By removing the broom from grasslands, we’re trying to roll back time to protect the mosaic of different habitats.”

“If we give nature half a chance, it’s going to come back,” concluded Whelan. “We try to make as many different ways to connect to the mountain; it really increases your quality of being and, frankly, if you’re up here, you have a responsibility to give back to the land that gives so much.”

To learn more about the Marin Water Volunteer Program, visit marinwater.org/volunteer. All volunteers are asked to follow a few simple guidelines, such as wearing attire appropriate for both the current weather and fieldwork. For safety purposes, this includes wearing close-toed shoes, long sleeves and pants. Though snacks and water are provided, volunteers are encouraged to bring a reusable water bottle to help cut down on single-use plastic.

To learn more about other Mt. Tamalpais volunteer opportunities, visit onetam.org/volunteer or send an email to [email protected]. Each of the five organizations associated with One Tam offers unique ways to get out, get involved and get working on protecting and restoring the majestic Mt. Tamalpais for present and future generations to come.


  1. Great article! Well done Suzanne for running such a GREAT program. Keep up the good work…one broom plant at a time!

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