Section of Sonoma Plaza Park Closed Due to Tree Hazard

Posted on May 23, 2024

A photo of Sonoma City Hall with the word 'Announcement' over the it.

UPDATE 6/13/24:

Following a comprehensive assessment following the tree’s diagnosis of Oak Root Fungus (Armillaria mellea) it has been determined that the American Elm poses no imminent danger. As a result, the barricades have been removed around the tree.

Original Post

For public safety, a portion of the Northeast quadrant of Sonoma Plaza Park near the Bear Flag Statue is temporarily closed.

Important Safety Information: A large American Elm in the park has been diagnosed with Oak Root Fungus (Armillaria mellea), a serious condition that compromises the tree’s stability. The tree exhibits extensive fungal growth around its base, indicating a highly infected root system. This makes the tree unstable and at risk of collapsing.

Closure Details:

  • Affected Area: The immediate vicinity around the infected American Elm
  • Reason: Risk of whole tree failure due to compromised root system
  • Safety First: This area is off-limits to all visitors

About Oak Root Fungus:

  • Affects tree roots, moving up to the root collar and trunk
  • Causes root rot and can lead to tree collapse
  • Learn more about the disease on the University of California Agriculture & Natural Resources website.

Next Steps: The infected tree will undergo further evaluation to determine if it can be saved. While the disease is not expected to spread to other trees, the City will develop a comprehensive management plan to monitor and protect other park trees.

We appreciate your understanding and cooperation as we work to maintain a safe and beautiful park for everyone. Thank you for your patience and cooperation.

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