Invasive Beetles Threaten California's Oak Trees

Goldspotted oak borers are damaging California's oak trees, increasing wildfire risks and causing ecological and economic losses, with mitigation focused on local firewood sourcing and tree management.

2 minute read

July 11, 2024, 11:00 AM PDT

By Clement Lau


Close-up of yellow and black goldspotted oak borer beetle on blade of grass.

Mailmuda / Adobe Stock

Goldspotted oak borers (GSOBs), invasive beetles originating from Arizona and Northern Mexico, have been causing significant damage to oak trees in California. These beetles likely arrived in the state in the early 2000s through infested firewood. Female GSOBs lay eggs in the bark of susceptible oak trees, and the resulting larvae bore into the tree's living tissue, disrupting the flow of water and nutrients. This activity damages or kills the tree, and as the larvae mature into adult beetles, they emerge in the spring, continuing the destructive cycle.

The increasing mortality of oak trees due to GSOB infestations has led to a rise in fuel loads, exacerbating wildfire risks in California's already fire-prone landscape. The loss of oaks also has significant economic, ecological, cultural, and aesthetic impacts on public, private, and tribal lands in Southern California. The dead and dying trees contribute to the overall danger during hot and dry wildfire seasons, making the management of this invasive species crucial for the region's safety and environmental health.

To mitigate the spread of GSOBs, experts like forest entomologist Beth Kyre from the US Forest Service emphasize the importance of sourcing firewood locally and adhering to firewood guidelines, encapsulated in the slogan "burn it where you buy it." Additionally, removing heavily infested trees and using chemical protection on unaffected trees can help manage and reduce the infestation. Public awareness and adherence to these practices are essential to control the spread of these invasive beetles and protect California's oak trees.

Sunday, June 30, 2024 in Fox 5

portrait of professional woman

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching. Mary G., Urban Planner

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching.

Mary G., Urban Planner

Get top-rated, practical training

Concrete Brutalism building with slanted walls and light visible through an atrium.

What ‘The Brutalist’ Teaches Us About Modern Cities

How architecture and urban landscapes reflect the trauma and dysfunction of the post-war experience.

February 28, 2025 - Justin Hollander

Complete Street

‘Complete Streets’ Webpage Deleted in Federal Purge

Basic resources and information on building bike lanes and sidewalks, formerly housed on the government’s Complete Streets website, are now gone.

February 27, 2025 - Streetsblog USA

Green electric Volkswagen van against a beach backdrop.

The VW Bus is Back — Now as an Electric Minivan

Volkswagen’s ID. Buzz reimagines its iconic Bus as a fully electric minivan, blending retro design with modern technology, a 231-mile range, and practical versatility to offer a stylish yet functional EV for the future.

March 3, 2025 - ABC 7 Eyewitness News

View of mountains with large shrubs in foreground in Altadena, California.

Healing Through Parks: Altadena’s Path to Recovery After the Eaton Fire

In the wake of the Eaton Fire, Altadena is uniting to restore Loma Alta Park, creating a renewed space for recreation, community gathering, and resilience.

March 9 - Pasadena NOw

Aerial view of single-family homes with swimming pools in San Diego, California.

San Diego to Rescind Multi-Unit ADU Rule

The city wants to close a loophole that allowed developers to build apartment buildings on single-family lots as ADUs.

March 9 - Axios

Close-up of row of electric cars plugged into chargers at outdoor station.

Electric Vehicles for All? Study Finds Disparities in Access and Incentives

A new UCLA study finds that while California has made progress in electric vehicle adoption, disadvantaged communities remain underserved in EV incentives, ownership, and charging access, requiring targeted policy changes to advance equity.

March 9 - UCLA Luskin Center for Innovation