News & Views Issue 81: Bad News for California Oaks

Bad news for California oaks

“Sudden oak death,” a pathogen that has killed millions of oak and tanoak trees in California’s coastal forests since 1995, has officially reached “Phase 3" epidemic levels. According to the report in the Proceedings of the National Academy of Sciences, eradication is no longer possible.

The killer is a waterborne and airborne mold (Phytophthora ramorum) that infects trees and causes trunks to crack open and bleed sap. Although some trees seem immune to the pathogen, millions of acres have already been affected. By 2030, the tree-killer is expected to cover 5,400 square miles.

Removing infected trees and planting disease-resistant species can help contain the disease but unless a cure can be found, California must live with the disease’s impacts, which include increased risk of forest fires.

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