Bay Area Tree Mortality

Please check this page for continuing updates on the increased tree mortality seen across the Bay Area in recent months.

An investigation into the causes of recent widespread Acacia spp. mortality in the San Francisco Bay Area – Matteo Garbelotto, UC Berkeley. Two fungi, Diaporthe and Dothiorella have been consistently isolated from acacia showing recent dieback in the San Francisco Bay Area. They both start as endophytes, living inside trees without any obvious effect on tree health, then may become pathogens with the onset of predisposing stress factors (for example, drought). This work is preliminary and ongoing. A similar study on declining Eucalyptus is starting up.

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Aerial view of dead and dying eucalyptus on East Bay Regional Park District lands. December 2020. Credit: EBRPD
Dead blackwood Acacia, (Acacia melanoxylon) in the Leona Heights area, Oakland, Alameda Co., October 2020. Credit: US FS PSW
Dead blackwood Acacias along Mountain Blvd in Oakland. November 2020. Credit: US FS PSW
Diseased manzanita (Arctostaphylos), gray pine (Pinus sabiniana) and knobcone pine (Pinus attenuata) at Mt Diablo, Contra Costa County in March 2021. Credit: Chris Lee, CALFIRE