United States Department of Agriculture Animal and Plant Health Inspection Service Risk Assessment of the Movement of Firewood within the United States Source: Kosichfirewood.org (artist: Alastair Heseltine) Agency Contact: Plant Epidemiology and Risk Analysis Laboratory Center for Plant Health Science and Technology Plant Protection and Quarantine Animal and Plant Health Inspection Service United States Department of Agriculture 1730 Varsity Drive, Suite 300 Raleigh NC, 27606 Rev.1 20110105 1 Executive Summary Exotic and native forest pests such as Agrilus planipennis (emerald ash borer), Anoplophora glabripennis (Asian longhorned beetle), Dendroctonous ponderosae (mountain pine beetle), Ophiostoma novo-ulmi and O. ulmi (pathogens associated with Dutch elm disease), Cryphonectria parasitica (pathogen associated with chestnut blight), and Geosmithia sp. (pathogen associated with thousand cankers disease of black walnut) cause serious damage to urban and natural forests in the United States. These pests and many others disperse various distances through multiple pathways including movement of nursery stock and firewood. Firewood is a raw forest product that is widely utilized and moved throughout the United States with relatively limited consideration of the potential pests within or the associated risks. We conducted an assessment and examined factors that may affect the risk associated with the movement of firewood such as users, movement, insects and diseases, potential impact to natural and urban forests, and trends in firewood use. From our assessment, we estimate firewood to be a high-risk pathway for the movement of forest pests for the following reasons. • Firewood is a well-known pathway for the movement of wood pests. • The United States requires treatment of all imported firewood, with a few exceptions from Canada and Mexico. • Regulations prohibiting the domestic movement of firewood are already justified and in place for several states for five exotic forest pests. • Firewood readily moves commercially and privately throughout the United States. • Urban forests are particularly susceptible and increasing in number. • High diversity and coverage of forests in the United States. • The value of the economic resources in the United States at risk if exotic or native forest pests are spread to additional areas is very high. • High regulatory costs of forest pest management. Movement of firewood is a high-risk pathway for spreading non-native and native forest pests in the United States. We recommend that Federal and State regulatory agencies examine the current regulations for firewood movement and coordinate efforts to mitigate the potential risks, with primary focus on long-distance and urban area movement. Rev.1 20110105 i Table of Contents Executive Summary ......................................................................................................................... i List of Tables .................................................................................................................................. 2 List of Figures ................................................................................................................................. 2 Nature of the Problem ..................................................................................................................... 1 Statement of Purpose ...................................................................................................................... 1 Scope of the Assessment ................................................................................................................. 2 Definition of Firewood ................................................................................................................... 2 Overview of Treatments for Wood Products Entering the United States ....................................... 2 Current Federal Treatment Requirements for Firewood ................................................................. 3 State Regulations for Firewood ...................................................................................................... 3 Firewood Use in the United States.................................................................................................. 4 Description of Firewood Pathways ................................................................................................. 6 Firewood imported from other countries .................................................................................................. 6 Firewood distributors ................................................................................................................................ 8 Firewood users ........................................................................................................................................ 10 Home heating ...................................................................................................................................... 10 Camping .............................................................................................................................................. 14 Initiation, Approach, and Distribution of Pest Risk ...................................................................... 17 Pest Interceptions Associated with Firewood ......................................................................................... 17 Border Interceptions ............................................................................................................................ 17 Firewood Surveys and Studies ............................................................................................................ 19 Potential for Movement and Establishment of Pests in Firewood .......................................................... 20 Resources at Risk .......................................................................................................................... 23 United States Forests ............................................................................................................................... 23 Urban forests ........................................................................................................................................... 26 Economics of Forest Products and Regulatory Costs ................................................................... 27 Pests Associated with Firewood ................................................................................................... 28 Insects ..................................................................................................................................................... 29 Pathogens ................................................................................................................................................ 32 Rev.1 20110105 Evolving forest pathosystems and the concerns they raise with domestic movement of unmitigated firewood .................................................................................................................................................. 34 Historical examples ............................................................................................................................. 34 New Understanding and Risks ................................................................................................................ 35 Summary ....................................................................................................................................... 36 Authors .......................................................................................................................................... 38 Reviewers ...................................................................................................................................... 38 Editor............................................................................................................................................. 39 Acknowledgements ....................................................................................................................... 39 Appendices .................................................................................................................................... 40 Appendix A. Overview of treatments for wood products entering the United States ............................. 40 Appendix B. Insects associated with firewood (fact sheets). .................................................................. 45 Appendix C. Pathogens Associated with Firewood (fact sheets) ........................................................... 78 Appendix D. Literature Cited ................................................................................................................ 92 List of Tables Table 1. States with regulations relating to the movement of raw wood, including firewood. ...... 4 Table 2. Approximate weight per standard cord of various woods and ......................................... 5 Table 3. Ratings for popular firewood species. .............................................................................. 6 Table 4. United States firewood imports by custom districts (2009). ............................................ 6 Table 5. Estimated quantity and value of firewood utilized for home heating ............................. 11 Table 6. Fuelwood (cords) removed from public (BLM) lands 2003-2007. ................................ 12 Table 7. Orders of insects detected on firewood at California inspection