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Northern Research Station
11 Campus Blvd., Suite 200
Newtown Square, PA 19073
(610) 557-4017
(610) 557-4132 TTY/TDD

Emerald Ash Borer

Survival in Firewood

Research Issue

[photo:] two stacks of ash firewood - part of a research study on eab survival in firewoodSince the discovery of the emerald ash borer (EAB) in Michigan in 2002 it has been realized that firewood is one of the main pathways by which this insect has been moved to new locations by humans.  The current federal quarantine regulates movement of firewood in all infested states.  Because inspectors cannot generally look at firewood and determine the species of tree from which it was cut and also when it was cut, the firewood restriction generally covers all firewood or at a minimum all firewood from hardwood trees.  Many people have wondered for how long after cutting would EAB adults continue to emerge from infested ash firewood.  We designed a study to address this question.

 Our Research

We cut EAB-infested ash trees from July through October.  Trees were cut into firewood-length logs with some of the logs left whole and some split into small pieces.  We exposed the firewood to different storage treatments including: tarped, un-tarped, in full sunlight, and in the shade.  The temperature and relative humidity was compared among piles of firewood from each treatment.

Overall, at least a few EAB adults were able to emerge from firewood representing all cutting dates and all storage treatments.  EAB survival was lowest for the firewood that was cut early during larval development (July and August), compared to later months (September – December).  EAB survival was lower in split logs compared to whole logs.  However, placing a tarp over piles of firewood did not necessarily lower EAB survival.  It appeared that tarping moderated temperature extremes and increased relative humidity.

In a follow-up study, we caged some of the previously used firewood during the winter months after EAB had emerged during the immediate past summer.  We did this in order to see if any adults would emerge the second season after cutting.  Although numbers were low, a few EAB did emerge, indicating that EAB can emerge from cut firewood for at least two consecutive years.  

Expected Outcomes

Our results will be useful to regulatory personnel and resource managers when setting guidelines for moving EAB-infested firewood.  Our findings indicate that EAB-infested firewood should be stored for a minimum of two years to be sure that practically all EAB emergence has ended.  Alternatively, ash firewood that has been seasoned for less than two years could be subjected to some other approved treatment if it is necessary to move the wood before two years. 

Research Results

Petrice, Toby R.; Haack, Robert A. 2007. Can emerald ash borer, Agrilus planipennis (Coleoptera: Buprestidae), emerge from logs two summers after infested trees are cut? Great Lakes Entomologist 40:92-95.

Petrice, Toby R.; Haack, Robert A. 2006. Effects of cutting date, outdoor storage conditions, and splitting on survival of Agrilus planipennis (Coleoptera: Buprestidae) in firewood logs. Journal of Economic Entomology 99: 790-796.

Research Participants

Principal Investigators

  • Robert Haack, US Forest Service- Northern Research Station Research Entomologist
  • Toby Petrice, US Forest Service- Northern Research Station Entomologist

Last Modified: 12/07/2017

About this Research Area
About Emerald Ash Borer
Selected Studies
Featured Publication

Petrice, Toby R.; Haack, Robert A. 2006. Effects of cutting date, outdoor storage conditions, and splitting on survival of Agrilus planipennis (Coleoptera: Buprestidae) in firewood logs. Journal of Economic Entomology 99: 790-796.