Sudden oak death is killing trees across California. Could Cambria be next?
North Coast property owners whose lands include oak or bay laurel trees are on alert.
The dreaded sudden oak death that is decimating some species statewide is inching further south from Big Sur toward San Luis Obispo County.
Sudden oak death (SOD) could be especially devastating in Cambria, where the town’s rare native forest of Monterey pines has been especially hard hit by bark beetles, fungal infections such as pitch canker and advanced age. The landmark 3,400-acre pine forest also includes many oak trees and bay laurels, both of which are susceptible to SOD.
According to www.suddenoakdeath.org, the pathogen Phytophthora ramorum, which is known to cause SOD, has had “devastating effects on coastal forests in California and Oregon.”
Since the mid 1990s, SOD has killed millions of tanoak trees and several other oak tree species — including coast live oak, California black oak, shreve oak and canyon live oak — and caused twig and foliar diseases in numerous other plant species, including California bay laurel, Douglas fir and coast redwood.
SOD has been confirmed in 15 counties in California where higher rates of infection were found in 2019 on susceptible tree hosts, according to a newsletter report released by the California Oak Mortality Task Force on Dec. 4.
Sudden oak death hits close to home
In the summer, Christine and Gordon Heinrichs of Cambria participated in a statewide annual study of the spread of sudden oak death by citizen scientists. They examined North Coast bay laurel and oak trees in yards, forested areas and other locations, snipping off and bagging leaves that looked suspect.
According to research from the 2019 blitz and more recent date, a “wave of sudden oak death mortality” has hit the Big Sur region of Monterey County, the October 2019 edition of the California Oak Mortality Task Force newsletter said.
“Phytophthora ramorum has been present in Big Sur for over two decades, but there is new expansion of tanoak mortality in Big Creek, Mill Creek, Plaskett Creek, and Willow Creek,” the report says.
According to the newsletter, Big Sur resident Kerri Frangioso, a UC Davis researcher, reports that those creek watersheds “look similar to how the Big Sur valley looked during the early 2000s, with numerous standing dead tanoaks.”
“Additionally,” the report says, “in 2018, UC Davis detected the pathogen in the Salmon Creek watershed for the first time, which moved the boundary for the known P. ramorum infestation southward towards the border with San Luis Obispo County.”
The wave of mortality is associated with warm rains during the “very wet winter” of 2016 and 2017, researchers say, “since it takes a few years following infection for tanoak mortality to occur.”
According to the report, coast live oak die more slowly than tanoak, “so mortality is just starting to appear on oaks, especially those in close proximity to California bay laurel.”
For more information, go to www.suddenoakdeath.org or email Kerri Frangioso at kfrangioso@ucdavis.edu.
