Pest Risk Assessment Forest Service of the Importation of Miscellaneous Publication No. 1495 September 1991 Larch from Siberia and the Soviet Far East United States Pest Risk Assessment on Department of Agriculture the Importation of Larch Forest From Siberia and the Service Soviet Far East Miscellaneous Publication No. 1495 September 1991 CONTENTS CONTRIBUTORS ................... ........................................ i EXECUTIVESUMMARY ...................................................... S-l CHAPTER 1. INTRODUCTION Statement of Purpose ................................................... l-1 Background ........................................................... l-1 Proposed Importation ................................................... l-2 Resources at Risk ...................................................... l-2 Biological Considerations ................................................ l-5 CHAPTER 2. THE RISK ASSESSMENT APPROACH. Conceptual Framework ................................................... 2-l The Risk Assessment Process .............................................. 2-1 Pest Risk Assessment Core Team .......................................... 2-1 CHAPTER 3. CASE HISTORIES ‘OF PEST INTRODUCTION Introduction .......................................................... 3-l Gypsy Moth .......................................................... 3-l Chestnut Blight ........................................................ 3-2 Dutch Elm Disease ..................................................... 3-4 Port-Orford-Cedar Root Rot .............................................. 3-6 White Pine Blister Rust .................................................. 3-7 Pine Wilt Disease ...................................................... 3-9 CHAPTER 4. ORGANISMS POSING RISK introduction .......................................................... 4-l Asian Gypsy Moth and Nun Moth ........................................ 4-l Summary of Natural tHistory and Basic Biology of the Pest ................ 4-1 Specific information Relating to Risk Elements .......................... 4-5 Probability of Pest Establishment .............................. 4-5 Consequences of Establishment ............................... 4-5 Estimated Risk .................................................. 4-6 Additional Remarks .............................................. 4-6 Pine Wood Nematodes .................................................. 4-6 Summary of Natural History and Basic Biology of the Pest ................. 4-6 Specific Information Relating to Risk Elements .......................... 4-6 Probability of Pest Establishment .............................. 4-6 Consequences of Establishment ................... : ........... 4-7 Estimated Risk .................................................. 4-8 Larch Canker .......................................................... 4-8 Summary of Natural History and Basic Biology of the Pest .... :............ 4-8 Specific Information Relating to Risk Elements .......................... 4-9 Probability of Pest Establishment .............................. 4-9 Consequences of Establishment ............................... 4-9 Estimated Risk .................................................. 4-9 Additional Remarks ............................................... 4-9 SpruceBarkBeetle ..................................................... 4-9 Summary of Natural History and Basic Biology of the Pest ................ 4-9 Specific Information Relating to Risk Elements .......................... 4-10 Probability of Pest Establishmt~nt .............................. 4-10 Co~xeqncwxs of Establishment ............................... 4-10 Estimated Risk .................................................. 4-11 Annosus Root Disease ................................................... 4-11 Summary of Natural History and Basic Biology of the Pest ................ 4-11 Specific lnformation Relating to Risk Elements .................... ..... 4-12 Probability of Pest Establishment .............................. 4-12 Consequences of Establishment ......................... ...... 4-12 Estimated Risk .................................................. 4-13 CHAPTER 5. ECONOMIC EFFECTS EVALUATION Introduction .......................................................... 5-l Defoliator Insects ...................................................... 5-2 Pine Wood Nematodes .................................................. 5-7 LarchCanker ........................ ..~........, ..................... 5-17 Spruce Bark Beetles ..................... : ................................ 5-21 AnnosusRoot Disease........................: ........................... 5-23 CHAPTER 6. ECOLOGICAL EFFECTS EVALUATION The Resource ......................................................... 6-1 Recreation ............................................................ 6-1 Wildlife.. ............................................................ 6-2 Potential Pest Impacts ................................................... h-2 Environmental Stress .................................................... 6-3 Habitat Modification .................................................... 6-4 Criteria for Assessing Ecological Impacts .................................... 6-4 Proportion of the Total Susceptible Plant Cover in the System .............. 6-4 The Role .of the Susceptible Plant Species in the Ecosystem ................ 6-4 Adaptability and Aggressiveness of Potential Introduced Pests .............. 6-4 Asian Gypsy Moth ............................................... 6-4 Nun Moth ...................................................... 6-5 Pine Wood Nematode ............................................. 6-5 Larch Canker ................................................... h-5 Annosus Root Disease ............................................ 6-5 Spruce Bark Beetle ............................................... 6-5 Ecological Impacts of Large-Scale Infestations ................................. 6-5 Asian Gypsy Moth ............................................... 6-6 Nun Moth ...................................................... 6-8 Pine Wood Nematode ............................................. 6-9 Larch Canker ................................................... 6-10 Annosus Root Disease ............................................ 6-10 Spruce Bark Beetle ............................................... 6-10 Summary ............................................................ 6-10 CHAPTER 7. CONCLUSIONS Summary of Potential Economic Costs ...................................... 7-l REFERENCES ............................................................... Ref-1 Appendix A. List of Pests Intercepted on Logs From the Soviet Union ......................................................... A-l Appendix B. L.etters of Correspondence Between APHIS and the Forest Service ............. B-l * Appendix C. Estimated f’otential Volume of Soviet Log Imports to the United States . _ . _ . _ . _ . C-l Appendix D. Soviet Forest Resources and Host Timber Species Profiles Soviet Forest Resources . _ . _ . I . ~ _ . ........ D-l Species Distribution . _ _ . _ _ . _ . _ . _ . ....... ........ D-4 Problems of Development . _ . ....... ........ D-4 Logging Techniques . _ . _ . _ _ . _ . _ _ _ _ _ _ _ ....... ........ D-5 Transportation . _ . ....... ........ D-7 Soviet Forest Classification . ........ D-9 Host Timber Profile . ........ D-10 Family Pinaceae Linde. Genus Larix Mill.-Larch . ........ D-10 Family Pinaceae Lindl. Genus Pinus L.-Pine . ........ D-15 Family Pinaceae Lindl. Genus Ahies Mill.-True fir . ...*. ........ D-19 Family Pinaceae Lindl. Genus Picea Die&.-Spruce . ........ D-24 Family Pinaceae Lindl. Genus Piceu Dietr.-True fir . ...*. ........ D-25 Appendix E. Pest Risk Assessment Methodology .................................... E-l Appendix F. Participants of the First Siberian Timber Workshop ..... 1................. F-l Appendix G. Participants of the Second Siberian Timber Workshop ..................... G-l Appendix H. Pests and Pathogens on Coniferous Trees of the Eastern Soviet Union . H-l Appendix I. Pest Species Profiles . _ . _ . _ . _ . _ . _ . I-1 Appendix J. Assessment Of Timber Economic impacts of Potential Defoliators Associated with Siberian Logs . _ . _ _ . _ . _ . _ . _ . J-1 Appendix K. Potential Economic Impact of L,arch Canker in the Western United States . K-l Appendix L. Report on the Site Visit to the Soviet Union June 28 to July 16, 1991 . L-l Tables Table 4-l. Siberian Forest Pests of Concern on Bark (Hitchhikers) . _ . _ . 4-2 Table 4-2. Siberian Forest Pests of Concern in Bark and Inner Bark . 4-3 Table 4-3. Siberian Forest Pests of Concern in Wood _ . 4-4 Table 5-1. Price, Quantity, and Welfare impacts of Reduced Growth Caused by Defoliators, Best Case Scenario . _ . _ . _ . 5-5 Table 5-2. Net Welfare Impacts Resulting From Defoliators in Millions of 1967 Dollars, Best Case . .._..._..._...._...................... 5-6 Table 5-3. Acres of Ponderosa Pine Timberlands Infected by Pathogenic Nematodes After Hypothetical Introduction in Imported Siberian Logs . 5-9 Table 5-4. Economic Analysis of Pine Wood Nematode Infestation .................... 5 -11 Table 5-5. Current Value of Stand Conversion Costs After Nematode Infection ........... 5-13 Table 5-6. Present Value of Cash Flow and Residual Stand Value After 35 Years Without Nematode Jnfection . _ _ . _ . _ _ . _ . _ . _ . _ . _ 5-15 Table 5-7. Financial Loss From Larch Canker on Western Larch Under Three