News Release
University Affairs Office
1801 E. Cotati Avenue
Rohnert Park, CA 94928-3609
(707) 664-2122

SSU Biologists Tracking Sudden Oak Death
Fungus at Fairfield Osborn Preserve

11 a.m., Friday, Dec. 15
Fairfield Osborn Preserve,
6543 Lichau Road, Penngrove, CA.

Biological research on oak trees at the Preserve suffering
from Sudden Oak Death will be explained. Students with
global positioning satellite units will show how tree locations
are determined. Biology professor Nathan Rank of Sonoma
State University, UC Davis researcher Jenny Davidson, and
Julia Clothier, Preserve Manager, will answer questions
from journalists interested in how the disease can be
recognized, the possible impact on the community’s
oaks, and potentials for curbing the problem.

ROHNERT PARK— Biology professors from Sonoma State
University are tracking evidence of Sudden Oak Death
Syndrome in trees at the 210-acre Fairfield Osborn
Preserve and now say "the disease has probably
already progressed to an alarming degree within
the Preserve's boundaries."
The deadly fungus has now been reported in Sonoma
County in Jack London State Park, Kings Ridge, Austin
Creek State Recreation Area, Sugarloaf State Park, along
Bodega Highway, and Cazadero, according to
the UC Davis web site at
The Preserve, located east of the campus in Penngrove,
is an educational resource for the community at large and an
educational and research facility for the University.
Thousands of school children visit the Preserve every year
on guided tours, and members of the public participate in
organized weekend hikes and field workshops in the fall
and spring.
"We don't know yet whether oaks on Sonoma Mountain
will suffer a massive die-off," said Preserve Director Nathan
Rank, a biology professor. "But the disease may be spreading
more slowly at the Preserve than other locales it has surfaced in,"
Rank added. "It may be that temperature is the reason,"
Rank said.
"The Preserve has a warmer microclimate than most of
Marin County where the fungal disease has effectively decimated
the oak population in many areas." There is no known cure
for the disease.
Northern Californians have witnessed a dramatic die-off of oak
trees in coastal woodlands surrounding the Bay Area in recent
years. Entire stands of oaks have succumbed in some areas.
Tan oaks and coast live oaks have suffered the highest levels
of mortality, but some black oaks have been affected, said Rank.
SSU students visit the Preserve to learn about its ecology,
natural history, archaeology, geology, and geography as
part of their coursework. Scientists at SSU and the surrounding
area also use the preserve as a natural laboratory for
studying ecological processes.
Rank is coordinating a symposium on January 15 at the
Double Tree Hotel in Rohnert Park with researchers from other
California State University campuses, University of California faculty,
students, land managers, and others. They hope to combine
research efforts and develop a strategy to understand how the
disease is spread.
"The presence of the disease at a nature preserve where
biologists are already actively researching oak ecology presents
an opportunity for study, and we hope, for control," said Rank
who is spearheading the effort with his colleagues
Dr. Hall Cushman and Julia Clothier, Preserve Manager.
During the summer, scientists at UC Davis, led by
Dr. David Rizzo, identified the disease-causing agent as a
fungus that is closely related to another fungus that kills
Port Orford Cedar in southern Oregon. It is more distantly
related to the fungus that caused Potato Blight and
caused massive starvation in Ireland in the mid-19th century.
Over the past year, Clothier had noticed the leaf canopies
on several coast live oak trees near the Preserve’s Education
Center were turning brown. This fall, Rizzo and his co-workers
isolated the fungus from several Preserve coast live oak trees
that showed symptoms of Sudden Oak Death.
These findings prompted SSU faculty members to
organize a survey of the Preserve with Clothier, Preserve
volunteers, several graduate students and undergraduate
SSU students used the Department of Biology's state-of-the-art
Global Positioning System units to determine exact locations of
diseased trees in the oak survey. These locations will be later
used for geographic modeling of disease occurrence and spread.
Rank reported that more than sixty trees possessed active or
recently dried bleeding spots, which are characteristic of early
stages of the disease. Twenty trees showed evidence of crown
death, and damage from bark beetles associated with late
stages of the disease was noted on a number of trees.
Afflicted trees can be found throughout the Preserve, but
Rank said most trees still show no signs of being affected
by the disease, and there is as yet "little evidence of
widespread crown death or wholesale tree death in
Preserve oaks."
DIRECTIONS: The Fairfield Osborn Preserve is located at
6543 Lichau Road in Penngrove in Sonoma County.
Phone (707) 795-5069.

Nathan Rank, (707) 664-3053,;
Julia Clothier, (707) 795-5069,


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Last Modified: 12/8/00