A Walk in the Woods at Lake Lagunitas, Mt. Tamalpais

The trail around Lake Lagunitas, Mt. Tamalpais off­ers a glimpse into e­fforts to restore forests. Forest and woodland comprise over a third of Marin County and provide us with clean air, drinking water, recreational opportunities, habitat for diverse species, and much more. They also have significant cultural value.

Today, forests face threats such as diseases, introduced weeds, fire exclusion, human-caused climate change, and more. One Tam partners are working to address these threats on our public lands, improve forest health, and evolve our understanding of caring for forests.

This self-guided walk aims to show both the e­ffects of forest threats—in particular, fire exclusion—and work being led by Marin Water, a One Tam partner, to restore forest health. You can take the virtual tour by scrolling down this page, or you can do it in person - you can pick up a copy on site, at the Tam Van, or download it from this page. The walk starts in the Lake Lagunitas parking lot and leads you counterclockwise around the lake. It is a 2.6-mile loop with 394 feet of elevation, with the option to shorten to 1.7 miles.

Directions: From US-101 N, take exit 450B. Follow Sir Francis Drake Blvd, Bolinas Rd and Sky Oaks Rd to Lake Lagunitas.

You can click on the map below to preview the tour stops, then scroll through the story to lean more and view images that will help illustrate each place.

Before colonization, the Coast Miwok cared for these lands in a way that produced a diverse, interconnected landscape, supporting habitat for animals as well as sustainable sources of food, tools, and medicines. Instead of massive areas of a single resource type like Douglas-fir, many smaller grasslands, shrublands, woodlands, and forests were woven together in a patchwork across the landscape that facilitated efficient and productive access to these resources for people in those local areas. These lands experienced frequent natural and cultural burning.

When Europeans colonized this fire-adapted land, they banned cultural burns and suppressed natural fires. Fire exclusion interacts with other threats to make the region more vulnerable to higher severity wildfires.

Forest health work involves attempts to mimic fire using manual tools to reduce understory and fuels, reduce the spread of trees into other habitats like grasslands, and help preserve a patchwork of diverse habitats. You will experience this today as you walk through redwood forest, Douglas-fir forest, oak woodland, and grassland. Fires that do occur in patchy, open landscapes are likely to be less intense than in dense, untreated areas.

This work includes other activities like managing the weeds that reduce biodiversity, degrade habitat, and sometimes contribute hazardous fuels. It also takes a lot of planning and preparation, including caring for sensitive wildlife. All of this prepares the landscape for beneficial fire, which we hope to eventually return to treated areas as appropriate.

The next stop is through the picnic area and up the stairs, on the deck overlooking the lake at the top of the spillway.

Look up slope for thickets of overgrown tanoak. Tanoak is highly susceptible to sudden oak death (SOD), a disease caused by an introduced water mold called Phytophthora ramorum. After tanoak trees die from SOD, they resprout, grow only to the height of a few meters and then once again die and resprout in a continuous cycle. This cycle creates dense thickets of dead tanoaks and multiplies the fuel load in forests. In addition, the reduced tree height creates ladder fuels that help fires jump up into the forest canopy.

Continue walking until the first footbridge, stop #4. On your way, look uphill for an expanse of large, felled trees. These were madrone trees that died from another non-native plant pathogen, Phytophthora cinnamomi, closely related to P. ramorum. While discouraging to witness these beautiful trees felled, the regrowth of this area – with native species such as huckleberry, Douglas iris, native ferns, and grasses – also exemplifies the resilience of the land.

Continue until the intersection of Lagunitas Rd and Lakeview Rd.

At the junction, notice the difference between the hillsides on either side of the trail.

Look for trees that have a ring of bark removed. These are Douglas-firs, and this treatment is called girdling. Douglas-fir forest is native, but without fire their fast-growing saplings can encroach on other vegetation communities. Girdling causes trees to slowly decay and stops them from dropping seed, while retaining benefits that the trees provide such as wildlife habitat and carbon storage. This work protects the native grassland lying beyond these trees and its diversity of plants and animals.

From here, you can either return to the parking lot by following the trail along the lake or continue on Lakeview Rd up to Pilot Knob. The last stop will be the lookout at the end of the Pilot Knob spur trail.

Each time you visit an area where forest health work occurs, it may look different as the forest responds. Once work starts, we commit to ongoing care – we may rotate treatments over multiple years, while regularly removing weeds and monitoring wildlife species.

Below you can see two more examples from this area, before and after treatments - slide the arrows on the pictures to see the difference. How might these places look in two years, or in five?

This work is just the beginning, and it takes time. We need to scale up these efforts where most appropriate, we need to consider the use of beneficial fire as a tool for care, and we will need to continue caring for forests for generations to come.

Our tour ends here, but there's more! See below for more resources.

Cell service can be spotty at Lake Lagunitas - if you like, you can download a PDF of this tour, or pick up a paper copy on site, or at the Tam Van. Available in English and Spanish.

 Self-guided forest health walk (English) 

 Paseo autoguiado para aprender sobre la salud de los bosques (Español) 

LEARN MORE – get started at  onetam.org/forest-health  and check  onetam.org/calendar  for tours and events where you can learn more.

VOLUNTEER – check  onetam.org/calendar  for opportunities to get involved in caring for our public lands.

BECOME A MEMBER – join at  onetam.org/donate  to support our work and access member events.

CLEAN YOUR SHOES – before taking a walk in the woods, be sure to brush any soil off your shoes and spray them with rubbing alcohol – this helps remove weed seeds and pathogens that may be hitching a ride.

Beneficial fire – A term used to collectively refer to prescribed fire, cultural burning, and managed fire.

Fire exclusion – The exclusion of natural and indigenous fire ignitions and policies to suppress all fires.

Forest health – A condition of ecosystem sustainability and attainment of management objectives for a given forest area. There are many characteristics used to describe health, and health looks different in different forest types.

Fuels/fuel load – Burnable plant material/quantity of burnable plant material.

Girdling – A method of slowly killing a tree without cutting it down by removing a ring of bark (right). Girdling has the benefit of leaving standing snags for wildlife and is less labor intensive.

Ladder fuels – Fuel that can carry a fire burning in low-growing vegetation to taller vegetation.

Resilience – The capacity of systems to absorb or recover from disturbance while undergoing change to retain desired ecosystem services and functions within a mosaic of forest types.

This self-guided tour was created by One Tam to help illustrate our forest health work, which is guided by the  Marin Regional Forest Health Strategy . One Tam brings together its five partners - California State Parks, Marin County Parks, Marin Water, National Park Service, and Golden Gate National Parks Conservancy - and inspired community members to support the long-term stewardship of Mt. Tamalpais. Get involved at  onetam.org .

Our forest health stewardship and community engagement are supported by GrizzlyCorps, an AmeriCorps program designed by Project Climate at UC Berkeley’s Center for Law, Energy, and the Environment in partnership with California Volunteers.

Let us know what you thought of this self-guided experience by emailing info@onetam.org.

THANKS FOR TAKING A WALK IN THE WOODS WITH US!