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El Niño poses threat to West Coast oaks, tribal cultures

Officials at UC Berkeley are warning coastal residents to help prevent the spread of a water-borne mold, the cause of a deadly plant disease threatening California tribal lands. The National Weather Service predicts an El Niño fall and winter which creates perfect conditions to spread Sudden Oak Death Syndrome. Experts at the California Oak Mortality Task Force noted in a statement released in October that public education is a key factor in protecting California’s susceptible oaks and tanoaks from the deadly pathogen.

Since the 1990s, more than one million oak and tanoak trees have died from this pathogen in 14 California counties, and at least another million are infected. Mortality rates range from 50 to more than 90 percent. Phytophthora ramorum, the miniscule water mold that causes SODS, is also responsible for causing twig and foliar diseases known as ramorum blight in numerous other species including California bay laurel, Douglas fir and coast redwood.

Photo by Debra Utacia Krol Acorns have been central to many California tribes’ culture and economy, however, Sudden Oak Death Syndrome threatens to wipe out up to 90 percent of oaks and tanoaks in coastal regions.

COMTF member Dave Rizzo of University of California Davis said infection levels are expected to rise dramatically if a full blown El Niño hits California because “it is a disease characterized by waves of infection that normally coincide with wet years.”

California tribes are gravely concerned that the disease will further impact tribal cultures already endangered from more than three centuries of genocide and development pressures. Oaks and tanoaks are central to these tribal cultures; acorns were once the principal food of many California tribes, and the gathering and preparations of acorns was – and still is – a time for families to come together, to share stories and to pass on cultural knowledge from one generation to the next.

“The tribes’ overarching concern is for the oaks, since they are such an important food plant for both humans and for wildlife that are also culturally important such as deer and acorn woodpeckers,” said Jennifer Kalt, a botanist with the California Indian Basketweavers Association. She said tribal elders and cultural practitioners are very concerned about damage to plants of cultural importance, since species that may host P. ramorum include many plants used for weaving and other cultural uses.

The pathogen, which apparently was accidentally imported in the late 20th century, can be easily spread on pant legs, shoes, tires and auto bodies, or from transporting basketry or medicinal plants out of an infected area.

Katie Palmieri, COMTF’s public information officer, said tribal elders and land managers met with federal and state officials about SODS in 2002. COMTF developed protocols in partnership with tribes and organizations like CIBA and published fact sheets, posters and other materials for distribution to tribal communities. COMTF continues to coordinate prevention and treatment efforts with tribes.

SODS researchers also work to answer questions posed by tribal elders, land and forest managers, and cultural practitioners. Some questions are easily answered: “We advise gatherers who, for example, soak hazelnut wood to boil the water before dumping it,” Palmieri said. Although hazelnut is not affected by the mold, it can act as a carrier to other, uninfected regions.

Other questions aren’t so easy to address, however. Kalt said some tribal members worry that ingesting the water-borne mold will make them ill because basketweavers use their teeth and mouths for weaving. “I just don’t think it has been studied, probably because it didn’t occur to the researchers.” However, Palmieri said that to date, researchers have found no adverse health effects from handling or ingesting the mold.


Photo by Debra Utacia Krol The Hoopa Valley.

COMTF advises that during this wet winter, “It should be assumed that the leaves, twigs and wood of host species, soil and water in an infected area are all infectious. Movement of any of these substrates, or use of recycled water without chemical treatment, should be avoided in order to prevent further spread of the pathogen.” SODS experts also recommend avoiding accidentally introducing the mold through plant material and soil via shoes, pets, tools, or tires from infested areas.

“Time is of the essence, as preventative treatments [such as the pesticide Agro-Foss] must be applied in the fall and spring,” said Matteo Garbelotto, a forest pathology specialist at UC Berkeley. “If we are to arm trees with as much resistance to the pathogen as possible, we must take action this fall.”

Tribes are also using other prevention protocols. Basketweavers, medicine people and other cultural practitioners along the Pacific Coast have altered gathering practices to prevent spreading the pathogen. Gatherers don’t enter quarantined lands during wet seasons. They also wash mud and soil off vehicles, equipment, clothing, and footwear with a bleach solution before leaving what may be an infected area when working in gathering areas.

Most of all, they are praying for an end to the epidemic that threatens their culture.

More information can be found online.