This is the second of two blog posts highlighting natural habitats along the SF Crosstown Trail. This post covers Sections 3, 4 and 5; Sections 1 and 2 are highlighted in Enjoy Nature on the Trail.
This project was supported by two SF high school students, Zaina Habib and Yibin Zhu, who were summer interns with Climate Career Corps, a program led by Enterprise for Youth and Nature in the City. Thanks to Zaina, Yibin, and others who joined us as we walked the 17-mile Trail for their contributions to Nature on the Trail!
Get detailed directions for all Sections under Plan Your Trip.
Section 3: Forest Hill Muni Metro Station to Intersection of Judah and 16th Avenue
After exiting the Laguna Honda Trail System, stop to admire the Laguna Honda Hospital Mural, a 600-foot long story of San Francisco’s human and natural history, created by Precita Eyes’ artists and community members. This impressive mural winds around the corner in front of the hospital, and hopefully soon will be extended further up Woodside.
You begin Section 3 across the street, walking uphill to the right of the Forest Hill Muni Station. This triangular public space has a lawn and Mediterranean climate plants, though primarily not California natives. The Forest Hill neighborhood was designed as a “residence park” with public transit access to downtown SF when Muni was extended underground west of Castro station in the early 1900s. The neighborhood’s winding streets and steep stairways are shaded by mature trees, primarily Monterey cypress (Cupressus macrocarpa) and Eucalyptus planted by Adolf Sutro, who owned extensive lands west of Twin Peaks, an area formerly known as Rancho San Miguel (read more about this area’s history and development in Found SF). While Monterey cypress are native to the Monterey Peninsula, many consider them to be invasive in non-native habitats like San Francisco. Certainly many in the City are near the end of their natural life.
Section 3 has two main natural areas, both in Golden Gate Heights: the Green Hairstreak Butterfly Corridor and Grandview Park, as well as two beautiful mosaic stairways.
Green Hairstreak Butterfly Corridor
The Green Hairstreak Butterfly Corridor comprises multiple small public areas (see map) that support this nickel-sized, iridescent green butterfly (Callophrys viridis), previously thought to be extinct within the City. Restored and stewarded by Nature in the City, neighbors, and SF Rec & Park, this chain of habitats – including Hawk Hill, Golden Gate Heights Park, Grandview Park and smaller sites between them – demonstrates the importance of native plants to support native wildlife like this tiny butterfly. Typically emerging from their chrysalises in early spring, these butterflies don’t travel far in their brief life. They feed off the nectar of flowering plants like the purple seaside daisy (Erigeron glaucus) or sea thrift (Armeria maritima v. californica). After mating, the butterfly lays its eggs on plants that will provide food for the growing caterpillars, primarily Coast buckwheat (Eriogonum sps). The caterpillars create chrysalises that are protected over the winter in the leaf litter underneath the host plants, until the butterflies emerge the following spring. Like Grandview Park, the Corridor’s eleven sites support other native coastal scrub plants. Even if you don’t get to see a Green Hairstreak Butterfly, you can learn more in this Nature in the City brochure.
On the north end of the Green Hairstreak Butterfly Corridor, Grandview Park offers sweeping views from Lake Merced and the Pacific Ocean to Golden Gate Park, downtown SF, and Mt. Sutro. Before development, the City’s westside was largely sand dunes. As we saw in Glen Canyon, Golden Gate Heights has several areas of rocky outcroppings of Franciscan chert. Chert is made up of the shells of ancient marine creatures called radiolaria, indicating that this uplifted land was once underwater, long before humans evolved. Now, Grandview is topped by a handful of windswept Monterey cypress and a native coastal scrub and dune habitat, including these common and usually easy-to-recognize species: California poppy (Eschscholzia californica), Coast buckwheat (Eriogonum spp), Silver bush lupine (Lupinus albifrons), Beach strawberry (Fragaria chiloensis), and Dune tansy (Tanacetum camphoratum).
In late summer, the blooming Coyote bush (Baccharis pilularis) displays either male or female flowers. Species that separate male and female flowers on different individual plants are called dioecious, meaning “two houses” (learn more from this Jepson Herbarium video).
Community members, local artists, and grassroots fundraising are responsible for the two stunning mosaic stairways in Section 3. Just below Grandview, the humbly-named 16th Avenue Tiled Steps, from 15th down to Moraga, have a “sea to stars theme”. Stop frequently as you walk down to look back up at the mosaic, or wait until you get to the bottom to appreciate the full scope of this ambitious public art installation. Further along 16th Avenue you come across the Hidden Garden Steps, designed by the same artists who created the 16th Avenue steps. Like those, the nature-themed Hidden Garden steps are best viewed from below (read more in SF Gate). Section 3 ends just a block away at 16th Avenue and Judah.
Section 4: Judah and 16th Avenue to Geary and Presidio Parkway
Section 4 crosses Golden Gate Park and follows the greenway that borders Park Presidio to Geary. Golden Gate Park, a three-mile long human-constructed landscape, consists of many different habitats – far too many to describe here! We highlight a few natural areas that differ from those we’ve seen in Sections 1, 2 and 3.
At Stow Lake, the Trail crosses the stone Rustic Bridge and circles around Strawberry Hill, the island in the Stow Lake. This human-made lake, created in 1893 as part of Golden Gate Park’s original design, provides a year-round freshwater habitat for a diversity of birds, fish, insects, and mammals (157 distinct species were identified on iNaturalist in a 2017 Bio-Blitz sponsored by the California Academy of Sciences). Though the shoreline is tangled with invasive Himalayan blackberry (Rubus armeniacus) and ivy and the water is often a creepy greenish color, many species of water and shorebirds thrive in this habitat. Strawberry Hill, in the center of the lake, also provides good woodland habitat for birds and other critters. Depending on the season and weather, you may see nesting Great blue herons (Ardea herodias) or hear Great horned owls (Bubo virginianus) in the Monterey cypress trees.
The Trail takes you through the Rose Garden to exit Golden Gate Park. While California has nine native rose species, including California wildrose (Rosa californica) which grows throughout most of the state, most roses are cultivated, created and selected for their elegant, showy flowers. There are over 300 naturally occurring rose species (Roseacea family), the majority native to Asia, and tens of thousands of cultivars (identified with quotes around ‘their names’). The Rose Garden includes some gorgeous and amusingly-named cultivars. Many roses are named after people, some for friends or relatives of the person who cultivated them and many more for royalty and other famous people, real or fictional. Check Wikipedia’s list of rose names to see if one has been named for you!
Park Presidio Pollinator Garden
After exiting Golden Gate Park at Fulton, continue along the greenway trail on the east side of Park Presidio. Before crossing Cabrillo, you can cross Park Presidio to see the Park Presidio Pollinator Garden, made up of mostly native California plants with abundant, colorful blooms. This sweet little garden hosts volunteer work days on the first Saturday of the month (sign up on the SF Rec & Parks volunteer calendar). The garden’s sign links to the Xerces Society for Invertebrate Conservation, where you can learn more about supporting pollinators.
Back on the greenway trail on the east side of Park Presidio, you’ll find several native California trees, including Monterey cypress that we’ve seen elsewhere and Pacific madrone (Arbutus menziesii) with their smooth, colorful trunk, peeling bark, bell-shaped flowers, and strawberry-like fruits (strawberry tree is a common name).
We also saw more recently-planted Island ironwood (Lyonothamnus floribundus), native to central and southern California and the Channel Islands, which can be identified by its peeling, reddish bark and fern-like leaf shape.
Section 4 ends at Geary.
Section 5: Geary and Park Presidio to Lands End Lookout Visitor Center
The final section of the Trail takes you through the Presidio to Lands End, the northwest corner of the City. From time immemorial, the native Yelamu people, a local tribe of the Ramaytush Ohlone, stewarded the land and waters and the natural resources of this area. From the late 1700s until the late 1900s, Spain, then Mexico, and then the US established military posts here to protect the Golden Gate, which to some extent prevented extensive development of these beautiful landscapes as San Francisco’s population grew (read more history on the Presidio Trust website).
We highlight the newly-restored Lobos Creek and the stunning Lands End Coastal Trail.
Lobos Creek Valley Trail
Right after you enter the Presidio, stop at the Lobos Valley Overlook for a view of the restored coastal dune habitat below. Lobos Creek is one of several freshwater habitats in the Presidio that have been restored to a more natural state. Follow the Lobos Creek Valley Trail boardwalk through this coastal dune habitat and enjoy the blooms, butterflies, and birds. Lobos Creek is one of a handful of freshwater streams in SF that still flow out to the Bay. Once a primary freshwater source for native people, the creek now provides water for the Presidio. After you cross Lincoln, you’ll follow Lobos Creek out to Baker Beach. Notice the dense willows and other shrubs along this riparian habitat, reminiscent of Islais Creek in Glen Canyon in Section 2.
Lands End Coastal Trail
Part of the Golden Gate National Recreation Area (GGNRA), the Lands End Coastal Trail offers beautiful views of the Golden Gate and the Marin Headlands (see brochure and map). Birdwatching was fun here, as this was our first chance to see seabirds like the Brown Pelican (Pelecanus occidentalis) soaring gracefully overhead and Brandt’s Cormorant (Urile penicillatus) resting on the rocks below. The native and non-native woodland habitat along the trail also supports a diversity of bird species (learn more about birds in the GGNRA here).
As you reach the end of the trail, you’ll notice that the native coastal scrub habitat has been restored in some areas, including the steep hillside above Sutro Baths. By now you may recognize some species we’ve seen elsewhere on the SF Crosstown Trail! The Golden Gate National Parks Conservancy and the Presidio Trust offer fun and informative volunteer opportunities in these beautiful landscapes.
Our 17-mile journey ends at the Lands End Lookout. We hope you enjoy exploring Nature on the Trail as much as we did!
Written by Helen Doyle (LinkedIn) with research and photos from Yibin Zhu and Zaina Habib.
Find more information about San Francisco ecosystems at SF Dept of Environment.