Perils of buying oak firewood
By Marshall Smith, Staff Reporter
At a Sept. 15 workshop, biologists and entomologists studying the threat of the goldspotted oak borer (GSOB), which could affect 39 million acres of California Oak, warned of its imminent spread. The projected costs of dead tree removal could be enormous and the public is a direct agent for spreading infestation through transportation of infested firewood. “This is the first of many workshops,” said Dr. Tom Scott, one of the speakers and organizers, noting that it is important to get the message about the GSOB threat out to the public.
GSOB is relatively new to California. First detected in 2004 and linked to elevated levels of oak mortality in 2008, GSOB infestation is currently localized in San Diego County. Spread occurs through beetle flight and importation of infested oak firewood. “It’s an agile flyer,” said Dr. Tom Coleman, Forest Service entomologist. “And it does not look as if it [GSOB spread] is slowing down.”
In areas of San Diego County where infestation is heaviest (for example, Descanso in the Cleveland National Forest), oak mortality is already at 85 percent and is certain to reach 100 percent. Most threatened are California black oak, coast live oak and canyon live oak. What complicates the scientific fight against GSOB spread in California is the fact that here, unlike Arizona, Mexico and other areas where GSOB has existed for many years, there are no natural predators. And although the science of combating GSOB infestation and spread in California has made strides since 2008, it is still in its infancy.
Presently, attendees at the workshop confirmed there are no state or local plans for containing spread. No agency is attempting to interdict firewood from infested areas or to prohibit importation across state or national borders.
Riverside and San Bernardino counties are targeted for trapping and for creating ground surveys in 2010 and 2011 to track potential spread northward. Currently, GSOB has been found as far north as halfway between Julian and Aguanga.
In terms of scientific tools in the stop-GSOB toolbox, applying insecticide on the boles and large branches of high value trees is the only preventive option currently available. Applications however are both expensive and protection is temporary.
Attendees were pessimistic about stopping the inevitable GSOB northward migration because of the infant state of the science to combat spread, and about no governmental plan to prevent transport of infected oak and no existing plan or mechanism to “certify” firewood as GSOB-free. The public can choose to buy firewood other than oak. That, according to workshop organizers, may be the best option at this point.
GSOB, infected oak can be detected by crown thinning, unique D-shaped exit holes, bark staining and distinctive woodpecker foraging that produces black galleries under the bark.
Marshall Smith can be reached at email@example.com.