Restoring Natural Areas in San Francisco
Historical Essay
by David D. Schmidt, 2026
An excerpt from the book, San Francisco Bay Area: An Environmental History, by David D. Schmidt (Backcountry Press, 2025).
Bernal Heights in 2022, after decades of work to re-establish native plants and to reduce the presence of invasive species.
Photo: Chris Carlsson
Of all the Bay Area counties, San Francisco has the least remaining habitat for native plants and wildlife, though it still has an amazingly diverse 509 species of indigenous plants—down from 766 in the late 1800s.(1) In 1974, recognizing the city's last chance to save dwindling fragments of undeveloped land, the Board of Supervisors placed Proposition J on the ballot, to create an Open Space Fund for buying these properties and preserving them as city parks. These grassy hillsides and hilltops were already being used as parks by local residents, who were often shocked and upset when developers showed up with bulldozers to begin construction. City voters approved Proposition J and its successor, Proposition E in 1988, to renew the fund.
After acquiring these lands, however, the city's Recreation and Park Department did nothing with them—not even picking up trash. Neighbors such as California Native Plant Society (CNPS) members Roland and Barbara Pitschel began to pick up litter regularly on Bernal Hill in 1986. They noticed that invasive weeds like wild radish and fennel were threatening the small remnant native plant areas on the hill, so they began pulling these weeds, too. Jake Sigg, leader of the Yerba Buena (San Francisco) CNPS chapter, saw that invasive French broom was spreading over the grasslands of Twin Peaks and Mount Davidson, two of the city's biggest native plant habitats, so in 1988 he asked the parks department for permission to start removing it from these and other natural areas in the city’s parks. Sigg recruited another CNPS volunteer, Greg Gaar, and started weekly broom-pulling sessions.
Throughout San Francisco’s 31 natural areas, the remnant patches of native plants were shrinking before advancing thickets of French broom, radish, and other invasive weeds. Removing them was far too big a job for two volunteers, so Sigg and local CNPS members pleaded with the city's park managers to assign staff to care for the natural areas. Park planner Deborah Learner drafted a management plan in 1995, and the parks department in 1997 began hiring a crew of eight to carry it out.
These eight, the park department’s Natural Resources Division (NRD), have been working with Sigg, CNPS and other volunteers for more than 25 years at 31 natural areas throughout the city, including the native live oak forest in Golden Gate Park’s northeast corner. The NRD also grows native plant seedlings, and plants them by the thousands each year in areas cleared of invasive weeds. Among NRD’s biggest successes was the restoration of riparian habitat in Glen Park along the city’s last remaining stretch of natural creek (outside the Presidio), in the late 1990s and 2000s. There, they removed English ivy and reintroduced Scarlet monkeyflower in the creekbed, which had been extirpated from San Francisco in the late 1800s.
Islais Creek running through Glen Canyon, 2013.
Photo: Chris Carlsson
In the early 2000s an overzealous volunteer girdled several Eucalyptus trees on Bayview Hill and Mount Davidson, provoking intense opposition from neighbors. The parks department promised not to remove large trees without community input, and commissioned detailed restoration plans for each natural area, balancing existing park uses with native plant restoration. The plans were released, and public hearings held in 2005.
Through several years of turmoil, the NRD and CNPS volunteers persevered, pushing back the tide of invasive plants and convincing even some of their detractors that native plant restoration, by removing dense thickets of invasive weeds, increases usable parkland for everyone.
Pier 98/Heron's Head Park
On San Francisco's gritty industrial shoreline near Hunters Point, a 25-acre artificial peninsula remained from an abandoned 1960s container ship dock project. A proposal to use the peninsula as the eastern end of a new Bay Bridge fell through when voters rejected the bridge plan in 1972. Environmentalists lobbied the city’s Port Commission for decades to restore the area to its original state—open water—by removing the fill, but the commission rejected the idea as too expensive.
Heron's Head Park looking southwest.
Photo: Chris Carlsson
Meanwhile, the bay’s waves reshaped the fill. Tidal pools formed, providing habitat for migratory birds. Pickleweed, a salt marsh plant, began to appear—the first sign of a salt marsh in San Francisco in more than half a century.
Recognizing the natural restoration underway, the Port Commission agreed to make the peninsula a park, and transition the tidal pools to tidal marsh. The peninsula's shape suggested a heron's head and beak, so they named it Heron's Head Park.
In 1998, workers removed 5,000 tons of debris and dug a meandering trench to restore tidal flows. The following year, a crew put down 550 cubic yards of topsoil, and put in 3,000 native plant seedlings on the dry, non-tidal area. Over the next five years, students from nearby schools and San Francisco City College, brought in by the nonprofit Literacy for Environmental Justice, planted native salt marsh plants in the tidal area, added more natives in the dry area, and uprooted invasive weeds. Additional native plants came in spontaneously, brought by the tides or birds. By 2004, 68 plant species had gained a foothold at Heron’s Head Park.
San Bruno Mountain
San Bruno Mountain, home to an incredible array of 314 species of native plants, has been the focus of ecological restoration projects since the early 1990s. This massive ridge, just a mile north of SFO, is the largest intact remnant of the Franciscan ecosystem that once covered San Francisco and the mountain.
In 1993, the San Mateo County Parks Department called in loggers to take out about 40 acres of Blue Gum Eucalyptus trees spreading in the middle of the park. Though moist and green, the grove was a biological wasteland, its understory consisting mostly of South African Cape Ivy. As soon as the loggers began piling up tree trunks, however, the county parks department started getting complaints from people outraged by the destruction of trees. So the department halted the operation, leaving more than 10 acres of Eucalyptus intact. The 30-acre cleared area was restored with native plants.
In the 1990s and early 2000s there were two ongoing restoration efforts: The first involved San Mateo County Parks consultant Thomas Reid and Associates, who were tasked with eradicating the thorny, invasive European shrub gorse, which had spread into a gigantic impenetrable thicket over the mountain's northern plateau. Herbicides were powerless against it: The resilient shrubs came back thicker than ever from millions of seeds on the ground. In 2004, Reid brought in an excavator that uprooted and shredded more than 95% of the gorse. These didn’t come back, but a few dozen escaped the shredder, and continued spreading into the 2020s.
The second, ongoing since about 1990, was started by San Bruno Mountain Watch founder David Schooley. The group has led volunteer work parties in Buckeye and Owl Canyons, near the small city of Brisbane, to uproot French broom, Italian thistle, poison hemlock, fennel, Ehrharta grass, and other invasive plants.
On January 1, 2023, severe landslides swept down both canyons, scouring the creekbeds and leaving barren areas of rocks and mud at the bottom. In the next six months, thousands of invasive weeds sprang up, including dense patches of poisonous South American forked nightshade. Over the next year, the Yerba Buena (San Francisco) Chapter of CNPS teamed with San Bruno Mountain Watch on five volunteer days with up to 20 people pulling and digging out a total of about 20,000 weeds, from nightshade seedlings to 7-foot-tall poison hemlock. By mid-2024, dozens of native plant species had re-populated the barren areas.(2)
Questions? Email the author: davidnaturesf@gmail.com
Notes
1. Wood, Michael, Annotated Checklist of the Vascular Plants of San Francisco, Third Edition (San Francisco: California Native Plant Society, Yerba Buena Chapter, April 2022), 7.
2. Personal observations by the author, April 2023-June 2024.
Excerpted from David D. Schmidt's San Francisco Bay Area: An Environmental History. Available from Backcountry Press.