Mystery Oak Disease pg.5
“I don’t buy the direct relationship to pollution,” he says. “We can infect very healthy trees and still kill them.” The disease has not wiped out whole forests, and Garbelotto believes many coast live oaks may have enough tolerance to survive the pathogen.
Redwoods may be endangered
Unknowns puzzle the scientists, chief among them how far the disease will spread and what other species might succumb to it. The discovery of spores on redwoods is particularly sensitive in California, where giant redwoods are a major tourist draw and redwood timber is a $500 million-a-year industry. Spores could have been splashed on a few redwoods and they’ll have no effect. Or redwoods may turn out to be hosts. In the worst- case scenario, the trees are susceptible to the disease. Garbelotto and Rizzo are trying to infect mature redwoods with Phytophthora ramorum to see if they’re susceptible. Test results won’t be known until later this year. “At this point we have no evidence to suggest the disease affects the big redwoods,” Garbelotto says.
If redwoods come under quarantine and lumber must be treated to get rid of the pathogen before it can be shipped, those pricey redwood decks will get even pricier, and small timber companies would suffer. “It could be an economic disaster for a lot of people. It could potentially put us out of business,” says Bud McCrary, co-owner of Big Creek Lumber Co. in Santa Cruz. “How would you show that that particular lumber doesn’t have any of those spores?”
An even more intriguing question is whether Phytophthora ramorum has migrated or been carried to the Sierra Nevada. Scientists need more than a positive DNA sample from a single tree to confirm that it has. Garbelotto is eager to collect more samples when the snow melts in the mountains. All bets would be off if the pathogen is confirmed there in a climate wholly different from the coast. One of the West’s major ecosystems could be threatened. And the theory that the disease might be incapable of wreaking harm in a new environment would be open to doubt.
“We saw Dutch elm disease devastate America’s elms. We saw the same thing with chestnut blight years ago,” says John Rosenow, president of the National Arbor Day Foundation in Lincoln, Neb. “Oaks are such an important tree nationwide that we certainly hope scientists can isolate it to a small area.”
