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Sudden Oak Death (SOD) Update 2013

October 11, 2013

Scientists at UC Berkeley held a public workshop last week to announce the results of the 2013 SOD Blitz.  A video of the workshop is available here.  The annual SOD Blitz engages citizen volunteers in identifying bay laurel trees infected with the pathogen that causes Sudden Oak Death.  Bays are tested because the infection is more easily identified in bays than oaks.  Scientists who study SOD believe that although the pathogen doesn’t kill bays, they are considered the primary vector of the disease to oaks that are killed by the pathogen.   

SOD mortality - Sonoma County

SOD mortality – Sonoma County

About 500 volunteers participated in the 2013 SOD Blitz which took place last spring.  The pathogen is most easily identified in the spring when it is still wet and cool.  Over 13,000 samples were taken from about 2,000 trees.  The samples were tested in laboratories for the pathogen.  Thirty-one percent of the samples were symptomatic for the disease. 

The infection rate was lower in 2013 than some previous years because it was a dry year.  The infection rate was highest in 2011, which was a particularly wet year.  Infection rate correlates positively with rainfall and lower temperatures.  Therefore, infection rates are higher in coastal locations and lower in inland locations.  Infection rates increased significantly in 2013 in Santa Cruz and South Skyline Blvd in San Mateo County.

SOD mortality - US Forest Service

SOD mortality – US Forest Service

Mortality rates vary by oak species.  Tan oaks are most vulnerable to the disease, which is expected to kill 100% of infected tan oaks.  Coast live oaks are slightly less vulnerable to the disease.  About 90% of infected coast live oaks are expected to die.

The results of five years of SOD Blitzes have been mapped and can be viewed here

SOD Workshops are scheduled all over California in October and November to advise the public about preventative treatments for oaks: 

10/12 Sat 10am Burlingame Hills – 120 Tiptoe Lane (off Canyon Rd.), Burlingame, CA Steve Epstein – steve@burlingamehills.org

10/20 Sun 10am East Bay – Spillway picnic area, Tilden Regional Park (near Lake Anza) Map Link Amelia Marshall – Amelia.marshall@att.net

10/23 Wed 1pm UC Berkeley – UC Berkeley Campus, SOD Treatment Training Workshop Webpage Link

11/1 Fri 7:30pm Atherton – Los Altos Library, S. San Antonio Rd, Los Altos, CA Arvind Kumar – arvind.kumar@cnps.org

11/2 Sat 10am Sonoma – Location TBA, Lisa Bell – lkbell@ucanr.edu

11/9 Sat 10am Los Altos Hills – Foothills Park 3300 Page Mill Road, Los Altos Hills, CA Sue Welch – sodblitz09@earthlink.net

 11/12 Tue 8:30am San Francisco Presidio – Location TBA

11/12 Tue 6:30pm Mendocino – Fort Bragg Town Hall, Fort Bragg, CA Lori Hubbart – lorih@mcn.org

11/13 Wed Santa Lucia Preserve – Time and Location TBA

11/14 Thur 6 pm Potluck, 7 pm talk by Matteo Garbelotto from UCB on “Biology of the SOD pathogen and disease control strategies”, UCSC Arboretum, 1156 High St, Santa Cruz, CA Map Link Brett Hall – brett@ucsc.edu

11/16 Sat 10am Marin – Dominican University, 155 Palm Ave., Joseph R. Fink Science Center, Room 102, San Rafael, CA Kristin Jacob – kristinjakob@att.net

11/16 Sat 1pm Napa – Pelusi Building, 2296 Streblow Drive at Kennedy Park, Napa, CA Bill Pramuk – info@billpramuk.com

11/17 Sun 10am South Skyline – Saratoga Summit Forestry and Fire Protection (CalFire) CDF fire station, Jane Manning – skyline_sod@yahoo.com

11/23 Sat 10am Montalvo – Montalvo Arts Center, 15400 Montalvo Road, Saratoga, CA Kelly Sicat – KSicat@montalvoarts.org

11/24 Sun 1pm Oakland – Joaquin Miller Park, Oakland, CA Kimra McAfee – coordinator@sausalcreek.org

3 Comments leave one →
  1. October 11, 2013 3:59 pm

    Do the folks that want to cut down 85,000 non native trees, leaving mostly the oaks, ever read something likes this??????

    • October 11, 2013 4:38 pm

      Good Question! Surely a few native plant advocates are aware of Sudden Oak Death, but I don’t know how widespread that information is in their community. I know the Garber Park stewards are aware of it because they have participated in the SOD Blitz and their website announces the SOD Blitz. Some of the oaks in Garber Park are infected with the SOD pathogen. However, I have corresponded with one of the Garber Park stewards who insists that the pathogen is not going to actually kill many oaks, despite the opinion of the scientists who are studying it.

      The Environmental Impact Study for the project that proposes to destroy all non-native trees on the properties of UC Berkeley and the city of Oakland, as well as radically thin non-native trees in the East Bay Regional Park District, made no mention of Sudden Oak Death. Given that the plans claim that oaks will magically occupy the bare ground without being planted, this seemed to be an unfortunate omission. That story is told in a previous post: https://milliontrees.me/2013/05/21/fema-projects-could-result-in-a-treeless-landscape-in-the-east-bay/.

      Native plant advocates have an uncanny ability to tune out information that doesn’t fit with their agenda.

  2. October 20, 2013 2:12 pm

    Exactly! And why we should treasure every non-native tree that we are lucky to have!

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