Through science-based restoration and stewardship, Irvine Ranch Conservancy sees new growth in natural areas affected by wildfire and invasive plants and animals.
On October 9, 2017, the Canyon 2 Fire broke out in the area around Gypsum Canyon Road near the 91 Freeway. It quickly spread, burning thousands of acres within the northern portion of the Irvine Ranch Natural Landmarks, including all of OC Parks’ Weir Canyon Nature Preserve. This area contains an abundance of rare habitats and wildlife, including one of the largest intact coast live oak woodlands in Orange County, making it one of the most ecologically important areas on the Irvine Ranch Natural Landmarks. The fire, which destroyed or damaged almost all the vegetation growing in the canyon, is one of many challenges Irvine Ranch Conservancy faces when managing the natural resources in Weir Canyon. However, thanks to the hard work and dedication of Conservancy staff, partners, and volunteers, and helped by recent winter rains, vegetation is beginning to return, and many oak trees show signs of new growth. Before the fire tore through the area, Conservancy staff were hard at work monitoring and fighting the spread of an invasive tree pest known as the Gold-Spotted Oak Borer (GSOB) beetle. This tiny beetle disrupts and depletes the ability of trees to take up nutrients by laying its eggs on the bark of the trees. The larvae then burrow beneath the bark to feed, and eventually kill the tree.
GSOB beetles were not the only challenge. Due to its close proximity to residential neighborhoods, unauthorized access is also a persistent issue within Weir Canyon Nature Preserve. These activities alter wildlife movement and often damage rare and important habitats. After the Canyon 2 Fire, unauthorized access increased significantly since perimeter fences were burned away. However, OC Parks, aided by Conservancy staff, has now rebuilt much of the destroyed fencing and gates, and new native plant growth has begun, including many fire-following flower species.
To further improve the health of the Canyon, the Conservancy began an oak restoration project in Weir Canyon funded by the California Department of Fish and Wildlife and in partnership with the Orange County Fire Authority, to replace trees that have been removed due to GSOB infestation and damaged in the recent fire. To date, nearly 1,200 sets of acorns have been planted that will one day become shady oaks. Volunteers and staff monitored light and temperature and used satellite imagery to pick the best areas to plant the new oak trees.
Volunteers helped collect and prepare acorns, placed them in holes surrounded by wire baskets – to protect them from rodents – and with waist-high plastic tubes on top to protect new seedlings and provide the best conditions for the young trees to thrive. Conservancy staff have also been removing invasive plants in the Canyon since immediately after the fire. These restoration efforts are extremely important to create conditions in the burned areas that allow for natural regrowth and the establishment of new native plants as well as preventing highly flammable weeds from taking over. “Volunteers, staff, and agency and academic partners have been crucial in our long-term conservation efforts in Weir Canyon and elsewhere,” said Dr. Nathan Gregory, Director of Science and Stewardship for the Conservancy. “People are working tirelessly to survey the changes in the vegetation and wildlife communities after the fire, remove invasive plants, and plant acorns.”
Weir Canyon was closed to public access for several months to allow for recovery to begin but has now been re-opened for free, volunteer-guided programs offering a firsthand look at the recovery of the woodlands, grasslands and coastal sage scrub habitat. Activities in early spring will allow the public to see many of the flowers that emerged following the fire. The Fire Recovery: Watch Weir Grow hike on Saturday, March 9 and the Second Sunday in Weir Canyon: Oaks and Vistas Cardio Hike on March 19 are great chances to explore Weir Canyon and learn about how the land recovers from fire and the many challenges to keeping it healthy and resilient. Opportunities also exist to get your hands dirty and help restore and manage the land. For more information on activities and to sign up for stewardship programs, visit https://letsgooutside.org/activities.
####
Irvine Ranch Conservancy
Irvine Ranch Conservancy is a non-profit, non-advocacy organization created in 2005 to help preserve and support the Irvine Ranch Natural Landmarks, enhancing the public’s
connection to the land while helping partners and landowners with all aspects of stewardship. The Conservancy offers a variety of free, guided outdoor programs for all nature enthusiasts including hiking, mountain biking, horse-back riding and much more. For more information visit www.letsgooutside.org.
Christine Graves
PR & Event Marketing Specialist
