Oakland has built over most of its iconic woodlands, but we can still visit undeveloped oak woodland and other local plants along Sausal Creek in four of that creek’s watershed parks: Dimond Park, Dimond Canyon open space, Joaquin Miller Park, and Beaconsfield Canyon Park. Construction of walkways and buildings before World War II did not remove the parks’ existing vegetation, much to our present benefit. Despite intrusion of exotic horticultural plants, stands remain of coast live oaks (Quercus agrifolia), California buckeyes (Aesculus californica), alders (Alnus sp.), bays (Umbellularia californica), redwoods (Sequoia sempervirens) and several willow (Salix) species. I’ve always enjoyed the continued survival of green pockets of riparian vegetation through the oak woodlands in these local parks.
Friends of Sausal Creek, a local stewardship nonprofit, has posted a variety of maps and plant lists, freely available on their website. The map of the entire Sausal Creek watershed traces a fan of tributary creeks uphill and east past Highway 13. Downhill and west of Highway 13, these tributaries merge into Sausal Creek. As it proceeds to San Francisco Bay, Sausal Creek emerges to daylight in several locations, only to return to another culvert further downstream, and finally it emerges again to empty into the Oakland Estuary near the Fruitvale Avenue bridge.
When I went east on Dimond Avenue from MacArthur Blvd., I came to the west entrance of Dimond Park at the end of Dimond Avenue. A recent daylighting project for Dimond Park’s section of Sausal Creek removed the stream culvert up to the park boundary and then proceeded to rebuild more naturally sloping creek banks with riparian plantings. Between the picnic area and the creek, I walked through cow parsnip (Heracleum maximum) and native bunchgrasses to view songbirds in the arroyo willows (Salix lasiolepis). As I walked upstream past the swimming pool area, giant horsetails (Equisetum telmateia ssp. braunii) sprouted beneath the willows and alders up to the parking lot entrance on El Centro Avenue. Older, taller willows and white alders (Alnus rhombifolia) mark the creek’s path where it passes under El Centro Avenue.
Opposite the willows along the guard rails, a crosswalk points upstream to more of the Sausal Creek Trail where it enters Dimond Canyon open space. At present, upstream travel stops below the aging Leimert Blvd. bridge. However, Friends of Sausal Creek volunteers have outpaced Oakland street repair, as evidenced by diligent, prolonged weeding and replanting of nearby creek banks. Willows and red twig dogwoods (Cornus sericea) grow here thanks to tip cuttings propagated and replanted by Friends of Sausal Creek, started from older, surviving trees along the creek.
Persistent stream trackers can follow Sausal Creek upstream beyond the Leimert Blvd. bridge by taking the Bridgeview Trail north from Bridgeview Drive. Starting instead at the trailhead near the Montclair Golf Course entrance on Monterey Blvd. provides a downstream alternative to trying to find the Bridgeview trailhead amid a rabbit warren of residential streets around Bridgeview Drive. I started from the ceramic sign for Bridgeview Trail, set into the path just below Monterey Blvd., and hiked downhill, first through second-growth redwoods, and then through oak woodlands with a mixed native/exotic understory.
The restoration work of Friends of Sausal Creek appears on this trail also. Not only did volunteers fence off and stabilize the trail switchbacks, they also beat back invasive Algerian ivy (Hedera canariensis), Cape ivy (Delairea odorata) and Himalayan blackberry (Rubus armeniacus). Algerian ivy grows fast and crowds over native plants, shading them and sinking adventitious roots into whatever plants grow in its path. Unlike my walks here in years past, this time I saw sky through coast redwood trunks growing with less weedy interference, and I discovered the “unusual” redwood sorrel (Oxalis oregana, rare in the East Bay) growing alongside trail steps. Himalayan blackberry and Algerian ivy still grow in patchy retreat but no longer smother creek banks.
About a hundred meters southeast of the Bridgeview trailhead, a pedestrian underpass leads from Monterey Blvd. to the Palos Colorados trailhead on the opposite, uphill side of Highway 13. On past field trips, we have gone the distance from the trailhead, starting in a thicket of Himalayan blackberries and hiking uphill along a branch of Sausal Creek until we finished under more second-growth redwoods near Skyline Blvd in Joaquin Miller Park.
Joaquin Miller, a Victorian-era writer, purchased the land of this eponymous park shortly after loggers had clear-cut all of the old-growth redwoods. Summer musicals, numerous exotic trees, and surviving second-growth forests now exist in this park courtesy of Joaquin Miller’s legacy to the city of Oakland. As a condition of his will, the writer turned over this land to Oakland with the requirement that the city keep it as an open space park with regular theatrical performances on the site. Amelia Sue Marshall provides detail on the redwood clear-cuts and a thumbnail biography of the writer in her 2017 book, East Bay Hills: A Brief History.
However, I cannot blame Joaquin Miller for starting all of the exotic plants in the park, and certainly not all of the exotic trees in Oakland’s open spaces. Many of the acacias, eucalypts, and natives from elsewhere in California, like Monterey pines (Pinus radiata) and Monterey cypresses (Hesperocyparis macrocarpa), started from an early, misguided attempt at tree farming, which subsequent housing developers often continued. Introduction of these trees to the East Bay hills continues to affect both wildlife and human dwellings. For a more complete guide to 20th century exotic trees in the East Bay hills, read Jerry Kent’s account of “Diablo winds, wildfires, and flammable vegetation.”
Sausal Creek tributaries cover the west side of the hills from Shepherd Canyon in the north to the main course of Sausal Creek in Joaquin Miller Park. A middle tributary runs through Beaconsfield Canyon Park, with several black cottonwoods (Populus trichocarpa) above another plunge into a culvert. In concert with Friends of Sausal Creek, the Friends of Beaconsfield Canyon save this patch of riparian woodside from yet more Himalayan blackberry and upright veldt grass (Ehrharta erecta) through regular restoration work parties.
The plant lists on the Friends of Sausal Creek website identify the plants found in Beaconsfield Canyon as well as those in other parks within the watershed. Visit the Friends of Sausal Creek website for more of the watershed’s history and natural history, for maps and guides to exploring it on your own, and for information about Friends of Sausal Creek’s many restoration projects and how you can volunteer to help.
— Janet Gawthrop, Field Trips Chair, CNPS East Bay Chapter
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