Vallejo, CA… Stop the spread of nonnative insects – An act as simple as transporting firewood can lead to widespread devastation.
Since 2008, the Pacific Southwest Region Forest Health Protection staff of the U.S. Forest Service (USFS) has been cooperating with the California Department of Food and Agriculture (CDFA) to monitor the flow of firewood into the state. CDFA records information on all loads of firewood inspected at their 16 agricultural border protection stations and also confiscates any wood that contains insects or signs of fungal disease. This data is sent to USFS ecologist Matthew Bokach for analysis and reporting.
Almost 60 million pounds of firewood have been recorded entering the state in the previous five years. Just over half (54 percent) of this weight has been in large commercial shipments of pre-packaged pieces, while the rest has been in private vehicles and typically in much smaller loads. Over the same five-year period, at least 815 individual forest pests were prevented from being carried to over 200 named destinations within California.
Some of the notable species that were intercepted on firewood include emerald ash borer and gypsy moth, both of which were transported to California illegally in violation of nationwide Animal and Plant Health Inspection Service quarantines. The most dramatic example occurred in July of 2010, when a couple from Michigan was stopped in their RV at the Topaz border station (south of Lake Tahoe). Inside their vehicle was ash firewood containing adult and larval emerald ash borers. This is the furthest this invasive exotic species has been carried and detected from its federal quarantine area in the Northeast and Upper Midwest, where it has killed millions of urban trees and cost municipalities and homeowners billions of dollars in tree removal costs and lost property values.
Firewood has been brought to California in private vehicles from 46 other states (including Alaska), Canada, and Mexico; while potential forest pests have been transported to California from 42 other states, Canada, and Mexico (Map 1). Top destinations to which firewood bearing potential pests was being transported were the greater Los Angeles urban area (95 forest pests), the Sacramento urban area (63), Yosemite National Park (45), the Sacramento urban area (63) and the San Francisco-Oakland urban area (36). Over a quarter (28 percent) of the forest pests were in vehicles with California license plates, bringing firewood back to the state from somewhere else.
Even insects native to the U.S. can become devastating pests if moved to an adjacent state. Less than half (46.6 percent) of the wood borers native to Arizona also occur in California. The gold-spotted oak borer is a wood borer native to southeastern Arizona that was introduced into San Diego County, California in the early-2000s, most likely from firewood. In its new environment this beetle infests at least four new host species of oak that have no co-evolved defense mechanisms; the result has been tens of thousands of trees killed with no known mechanism for containing the insect’s spread. Any one of the hundreds of firewood-borne pests intercepted at CDFA border stations every year could be the next gold-spotted oak borer or emerald ash borer in its effects if successfully introduced into a new area. This is particularly true in California, where non-native pests could have infested over 95 percent of the state had they reached their destinations. It’s worth noting that almost the entire state of California is within 50 miles of a federal or state park or forest.
How you can help:
– Leave firewood at home – do not transport it to campgrounds or parks.
– Use firewood from local sources.
– If you have moved firewood, burn all of it before leaving your campsite.
– Don’t bring firewood from other states back into California.
For more information on the firewood issue in California, please visit the website of the CA Firewood Task Force: www.firewood.ca.gov.
For media materials related to emerald ash borer, please check out:
For photos of the effects from the gold-spotted oak borer or from effects from Sudden Oak Death, etc. see: www.flickr.com/photos/usfsregion5/sets/72157626792000599/
Caption for Map 1: Number of forest pests intercepted in firewood at CDFA border stations from other states and adjacent countries, 2008-2012.