The City of Irvine is taking steps to reduce wildfire risk and restore native habitat in Bommer Canyon Preserve. The project is funded by a $1 million grant from the California Natural Resources Agency, supported by Assemblywoman Cottie Petrie-Norris (D-Irvine).
Implemented in partnership with the Irvine Ranch Conservancy, a nonprofit organization that manages the Irvine Open Space Preserve, the project addresses wildfire threats caused by invasive, non-native grasses that have become widespread throughout the preserve. As these grasses dry out each spring, they create highly flammable conditions that can fuel the rapid spread of wildfire, posing a risk to the surrounding community, including 500 homes located within a quarter mile of the preserve boundary and more than 1,500 homes within a half mile.

Work began in August 2023 as the first phase of a broader five-year, 105-acre habitat restoration capital improvement effort. The project is designed to reduce ignition potential, interrupt the rapid spread of fire, maximize the ecological benefits of native vegetation, and minimize adverse effects on public safety.

The initial restoration phase was completed in March, with a five-year vegetation management commitment in place to ensure the restored habitat remains healthy, sustainable, and resilient to wildfire.

“Bommer Canyon is a crown jewel of the Irvine Open Space Preserve, but the growth of invasive plants had left it vulnerable to wildfires,” said Assemblywoman Petrie-Norris. “The fuel modification and restoration work completed at Bommer Canyon is a vital line of defense for the City of Irvine. This project proves that effective wildfire mitigation goes hand-in-hand with ecological restoration. I am proud to have partnered with the City of Irvine and Irvine Ranch Conservancy to demonstrate how state and local partnerships can protect our communities from the growing threat of wildfires and preserve our natural landscapes.”

“Bommer Canyon Preserve is a defining feature within Irvine,” Mayor Larry Agran said. “Through this project, completed with our partners at the Irvine Ranch Conservancy, we have strengthened the resilience of our open space, helping to safeguard neighborhoods and preserve this remarkable landscape for future generations. This project would not be possible without the support of Assemblywoman Cottie Petrie-Norris. We are grateful for her continued partnership and advocacy on behalf of our City.”

The restoration design used strategic fuel modification and landscape planning to establish natural fuel breaks across the site. Treatment methods included:

  • Planting moisture-retaining willow and mulefat shrubs along two drainage ways
  • Installing cactus pads on dry ridgetops to interrupt fuel continuity\
  • Enhancing a naturally wet meadow
  • Establishing oak woodland patches throughout the area

The remaining acreage was managed through repeated mowing cycles to exhaust non-native weed seed banks prior to planting native plant species.

Nearly 9,000 container plants representing 16 native shrub, tree, cactus, wildflower, and bunchgrass species were planted across the site. Many of these species are slow-growing and difficult to establish from seed, making container planting the most effective approach for creating a more resilient and fire-resistant landscape. The restored habitat also supports state and federally protected wildlife, including the California Gnatcatcher and Coastal Cactus Wren.

"Wildfire is one of the most severe threats to both our communities and our precious wildlands," said Michael O'Connell, CEO of Irvine Ranch Conservancy. "IRC was thrilled to partner with the City of Irvine on this critical habitat restoration project that reduced highly flammable vegetation and the risk of fire in the Open Space Preserve."

One of Orange County’s oldest cattle ranches and former farmlands, Bommer Canyon Preserve is part of the 5,200-acre Irvine Open Space Preserve, a mosaic of some of the most rare and biologically diverse ecosystems in the world, including wetlands, oak woodlands, grasslands, and coastal sage scrub. It has been designated a Natural Landmark by both the State of California and the U.S. Department of the Interior for its preservation of critically important flora and fauna.

Bommer Canyon is open daily from dawn to dusk for the public to enjoy self-guided hikes on specific trails. In addition, the Irvine Ranch Conservancy offers guided hikes and activities throughout the year.

For more information on Bommer Canyon and upcoming guided hikes, visit letsgooutside.org/iosp.