Graduation Year

2025

Document Type

Campus Only Senior Thesis

Degree Name

Bachelor of Arts

Department

Environmental Analysis

Reader 1

Heather Williams

Reader 2

Char Miller

Rights Information

2025 Katherine D Kett

Abstract

The Goldspotted Oak Borer (GSOB), Agrilus auroguttatus, is an invasive beetle that affects oak trees in Southern California. The GSOB was discovered in Southern California in 2004 and has caused mass oak mortality over the past 20 years. The beetle was likely brought to the region through mass transportation of firewood into San Diego County from Arizona. The larvae feed on the cambium layer of the oaks through the spring until they emerge as adults in mid-May leaving behind D-shaped exit holes. Working with the Wildlands Conservancy, our project team traveled to Bearpaw Reserve five times throughout the spring semester to survey the California Black Oaks (Quercus kelloggii) for signs of the GSOB. The prevalence rate of the GSOB in the oaks is eight percent, with just 53 trees containing at least one exit hole out of the 636 trees surveyed. Through mapping of survey data correlations between GSOB infestation and diameter at breast height (DBH), slope, and aspect were explored. While current work on this project has ended, there are still countless projects to be done with the GSOB and the Wildlands Conservancy. The findings from our survey underscore the need for continued research into the GSOB and awareness to the general public about the consequences of transporting firewood. With this research and continued monitoring there is a possibility of saving Southern California’s oak woodlands.

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This thesis is restricted to the Claremont Colleges current faculty, students, and staff.

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