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A. A Deadly Pathogen Found in California Redwoods and Douglas Firs

Narrator: This is Science Today. Plant pathologists were recently stunned to learn that a deadly pathogen that's killing thousands of coastal oak trees in the West, has also been found in California's coastal Redwood trees and in Douglas fir saplings. It's called sudden oak death syndrome and according to David Rizzo of the University of California, Davis, it was first discovered in California in 1995.

Rizzo: We think the main cause of sudden oak death is a fungus or fungus-like organism known as Phytophthora and that is what initially gets in there, it can kill trees on its own, but often it will stress trees that other organisms can also come in.

Narrator: In large trees, Rizzo says the earliest symptoms are a bleeding or oozing coming directly out of the bark.

Rizzo: As the tree goes on it shows less vigor and often times though, the tree will apparently appear to die over a period of a few weeks, but the tree has probably already been infected for quite a while before that.

Narrator: Researchers are not yet sure how the disease will impact redwoods and firs. For Science Today, I'm Larissa Branin.