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Mountains Recreation and Conservation Authority Proactive Response to Threat of Goldspotted Oak Boarer in Oak Trees on its Public Parkland

May 30, 2024

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LOS ANGELES, CALIFORNIA (May 30, 2024)— New infestations of Goldspotted Oak Borer (GSOB) were discovered on MRCA land for the first time this spring in native oak trees at two locations in East and Rice Canyons, and Whitney Canyon in the Santa Clarita Valley. The terrain is more rugged and inaccessible than most known areas of GSOB infestation. As several trees were in severe decline or dead, GSOB has likely been present for at least 3-5 years.  While these are the only areas of MRCA land where the pest has been identified, every measure is being taken to prevent further infestation and spread in all of the jurisdiction.

GSOB is an invasive pest that originated in Arizona and has been spreading from San Diego north for the past 16 years. It is primarily spread through the movement of oak firewood. GSOB typically targets more mature oaks. If the GSOB reached the Santa Monica Mountains National Recreation Area, it could begin an infestation among the 600,000 coast live oak trees.

The MRCA is leveraging Regional Forest and Fire Capacity (RFFC) Program funds granted by the California Natural Resources Agency and California Department of Conservation to immediately address these areas of GSOB and develop a long-term strategy. As this is a serious regional issue, MRCA is working in collaboration with partner entomologists, pathologists and forest managers from Los Angeles County Fire, the Angeles-San Bernardino National Forests, CALFIRE, and University of California Agriculture and Natural Resources (UCANR), as well as representatives from LA County Agricultural Weights and Measures, and the Resource Conservation District of the Santa Monica Mountains, and in consultation with private pest management contractors and various land managers dealing with GSOB in San Diego and Orange Counties.

Management of GSOB consists broadly of annual monitoring via ground and aerial surveys, and treatment including removal of amplifier trees and insecticide treatment of lightly to moderately infested trees (with full consideration given to minimizing environmental impacts). Crews from the nonprofit TreePeople will conduct ground surveys following US Forest Service-developed GSOB survey protocols.

This summer, CSUN will conduct aerial drone surveys to collect fine-scale data for targeting future ground surveys as well as to better inform a proposed fall 2024 NASA DEVELOP project that will utilize drone and satellite imagery to analyze GSOB infestation on MRCA land.

Treatment options are still being evaluated with outside experts but will likely include de-barking amplifier trees and either burning, chipping, or burying infested bark, with complete removal and chipping to less than 3” of amplifier trees that are able to be accessed by traditional equipment. Pesticide treatment will follow an integrated pest management strategy beginning this fall, which will include trunk injections and/or topical applications of insecticides by contractors.

As GSOB management in Southern California is an evolving science, novel approaches and experimentation should be welcomed in collaboration with researchers and tribes. The cycle of treatment, removal, and monitoring will be repeated on an ongoing basis, and GSOB management must now form a permanent part of MRCA budgeting and planning. MRCA will also make RFFC funds available to partner organizations, tribes, and agencies to increase their capacity for GSOB and other wildfire resilience projects including public education and messaging.

The Mountains Recreation and Conservation Authority (MRCA) is a local government public entity exercising joint powers of the Santa Monica Mountains Conservancy, the Conejo Recreation and Park District and the Rancho Simi Recreation and Park District. The MRCA is dedicated to the preservation and management of local open space and parkland, wildlife habitat, coastal access, watershed lands, and trails in both wilderness and urban settings, and to ensuring access to public parkland and coastal resources. The MRCA works in cooperation with the Santa Monica Mountains Conservancy and other local government partners to acquire parkland, participate in vital planning processes, work towards wildfire resilience, and connect wildlife habitat. The MRCA manages more than 75,000 acres of parkland that it owns and that are owned by the Santa Monica Mountains Conservancy. It is one of the lead agencies revitalizing the Los Angeles

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