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To: Bluedot Living
From: Adam Kaye, San Dieguito River Valley Conservancy
Subject: Restoration at the Arroyo Preserve
With a glance, resource ecologist Jonathan Appelbaum takes in the work at Arroyo Preserve in Rancho Santa Fe, where crews are removing invasive trees as part of a 12.5-acre restoration project.
Looking right, Jonathan points out a restored stretch of the San Dieguito River, where sycamores and cottonwoods stand tall and the shimmering, yellow leaves of willows signal fall in San Diego County. As the river wanders through this tableau of native, riparian trees, an endangered bird — as if on cue — lets out its mewling call. “That’s a California gnatcatcher,” Joanthan says.
Looking left, the picture darkens. A dense grove of red gum eucalyptus has crowded out the natives. So have unwelcome fan palms, tamarisk trees, reeds, and pampas grass. There isn’t any birdsong, but on this day there is a chorus of chainsaws. “That’s the sound of hard work,” Jonathan notes.
As a consultant for the San Dieguito River Valley Conservancy, Jonathan is managing the $1.5 million restoration of riparian habitat funded by the state’s Wildlife Conservation Board.
On this December morning, crews from the California Conservation Corps and San Diego Canyonlands clear undergrowth and deadfall to prepare for felling large eucalyptus and palms. Crews from West Coast Arborists bring down the largest trees, which a helicopter will remove from the fragile waterway.
A healthy riparian community, populated with fire-resistant native trees and plants, serves as a kind of natural fire break. Invasive species, by contrast, provide abundant fuel for wildfires.
The work window for tree cutting will close from Jan. 15 through Sept. 15, the nesting season for raptors. Removing smaller vegetation, including thickets of acacia and salt cedar, can continue until March 15. After that, state and federal permits require silence from power equipment to avoid bothering nesting birds.
The project will provide important habitat for the endangered least Bell’s vireo and light-footed Ridgway’s rail, and connections to other conserved lands for mammals such as mountain lion, coyote, bobcat, mule deer, and gray fox. Beyond their importance for birds and other wildlife, thriving riparian corridors are critical for climate change resiliency and for the safety of both property and people. A healthy riparian community, populated with fire-resistant native trees and plants, also serves as a kind of natural fire break. Invasive species, by contrast, provide abundant fuel for wildfires.
Wildfire safety has been a driving force behind habitat restoration, and its funding, in the Santa Fe Valley. From their ground-level deadfall to the tips of their canopies, eucalyptus trees contain volatile oils that burn furiously in a wildfire and can send embers flying into the wind for up to a mile. Invasive palms, in the words of the fire service, become “Roman candles.”
“In 2007, the Witch Creek Fire burned through the valley — homes lost,” Jonathan says. “In 2014, the Bernardo Fire burned through [nearby] Lusardi Creek — homes lost.”
At the bustling restoration site, the work also will reduce flood risks and improve streamflow. Jonathan expects surface and groundwater levels to rise after the water-sucking eucalyptus forest is gone. That could encourage the return of southern steelhead trout, an endangered fish that once spawned in the San Dieguito River.
Arroyo Preserve’s 68-acres are owned by the Rancho Santa Fe Association, and the restoration project is scheduled to continue through summer 2027. Plans for revegetation include seed, live cuttings, and purchased plants at 125 plants per acre, for a total of more than 1,500 plants. The state grant also covers monitoring of the restoration area after the project is finished.
The project is part of a larger, 181-acre restoration program in Santa Fe Valley, which began in 2015. Through the years, grants and gifts have funded the treatment of more than two-thirds of that area.
Collaborators include the Rancho Santa Fe Association, Rancho Santa Fe Fire Protection District, the San Dieguito River Park Joint Powers Authority, Fairbanks Ranch Association, U.S. Fish and Wildlife Service, California Native Plant Society, California Conservation Corps, San Diego Canyonlands, the Resource Conservation District of Greater San Diego County, and many others.
In addition to securing government funding and entitlements for large-scale projects, the San Dieguito River Valley Conservancy runs hands-on projects for people of all abilities to participate in habitat restoration. In related work, the conservancy raises funds from public and private sources to acquire land within the San Dieguito River watershed. Learn more at www.sdrvc.org.
