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Coast Live Oak Cankers in Years of Heavy Rain

The Coast Oak develops cankers that appear as cracks in the trunk of the tree.   This problem is typically due to a season of heavy rain.  The Bay Area has had several years of heavy rain and as a result many of the Coast Oaks have developed cankers and require treatment.

A phosphite compound, sold under the brand name of Agri-fos is injected directly into the tree’s vascular system by a trained professional. Organosilicate (brand name: Pentra-Bark) can be applied directly to the bark of the tree.

The oaks impacted by this disease include:  coast live oak, shreve’s oak, black oak and canyon live oak which can be treated by injection or bark application.  Tanoaks can only be treated by injection.



Live Oak The Atherton Tree Committee is a volunteer, non-profit, community based organization dedicated to the preservation of Atherton's heritage trees. The committee participates in a variety of programs designed to educate residents about the value of trees in our environment and to encourage appreciation and protection of our urban forest resources. For more information about town ordinances, policies, inspections, and plan reviews contact the Atherton Town Arborist, Kevin Kielty (650-515-9783, or link to the Town of Atherton Web Site. For more information about the Tree Committee contact Rachel Croft, President (650 323-4714,