URBANA, Ill. – Nothing beats the warmth of a crackling fireplace on these coldest days of the year. Each winter, as my family enjoys the cozy warmth of our woodstove room, I’m always thankful for the firewood supply we’ve been fortunate enough to accumulate.
Most of the wood we burn comes from sources very near to our house, but from time to time we’ve purchased firewood from others. When we do, I’m always very picky about the wood we bring to our property. Some of this pickiness is based on tree species since certain species burn much hotter than others, but most of my concern centers on the location this wood came from prior to being stacked in our woodshed.
Don’t move firewood
Moving firewood has become one of the major pathways for invasive insects to reach new areas. Many of these pests are transported right along with the wood since they use trees for all or part of their life cycle. It has become a growing problem in recent years, resulting in major outreach efforts by the U.S. Department of Agriculture, state agencies, and others who are concerned about the impacts to our urban and natural forests from these damaging, non-native pests.
Emerald Ash Borer
The emerald ash borer (Agrilus planipennis) has been one of the most significant firewood hitchhikers in recent history. This non-native insect is virtually eliminating native ash trees from forests across the eastern U.S. as larvae feed on and kill trees. With plentiful dead ash trees in its wake, there is no shortage of firewood and larvae often hitch a ride along with transported wood.
As researchers have looked at natural dispersal rates of EAB compared to human-aided dispersion, it has become abundantly clear that human movement of ash has greatly increased the rate of spread. This pest was first identified in Detroit in 2002 and has since spread to Northern Illinois in 2006 and downstate. Currently, it is believed to be present in all Illinois counties and fully confirmed in most. This rate of spread could not have occurred without human help.
EAB and Quarantines
Prior to EAB arrival in Illinois, the movement of ash firewood was restricted based on both state and federal quarantine requirements. As it approached our borders, officials closely monitored the spread of EAB, systematically applying county-level firewood quarantines to limit its spread. In 2015, EAB was so widespread across Illinois that state quarantines were lifted. However, federal quarantines remained in place, restricting firewood distribution across state lines, until January 2020 when those requirements were lifted as well. Today, all efforts toward EAB at the federal level are now focused on mitigation and control of this pest, as opposed to outreach related to ash firewood movement.
Although EAB-related restrictions have been lifted, there is still concern with the movement of firewood in Illinois. Specifically, the spongy moth (Lymantria dispar) has spurred quarantines for eight counties in northeastern Illinois since its first detection in 2006. This pest is less host-specific and its egg masses may be spread by firewood from a wide range of species, not just ash. Fortunately, the Illinois Department of Agriculture is very active in both monitoring and control of this pest which has greatly reduced its spread. However, the potential for new infestations in other areas remains if firewood from these northern counties is transported out of the quarantine area.
You can stop the spread
All of us need to be aware of where we transport firewood and where we source our own supply. Beyond the insect pests mentioned here, there are diseases that can inadvertently be brought to Illinois on firewood as well. It is difficult to predict where the next threat may come from and limiting human distribution via firewood is an important part of stopping the spread of invasive species to our state and others.
For more research-based information on invasive species, visit go.illinois.edu/invasive or connect with your local Illinois Extension county office at go.illinois.edu/ExtensionOffice.
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