171 



refers to the apparent frequenqr with which pests are transported in dunnage or 

 crates (USDA Forest Service 1993). These data indicate the need to incorporate such 

 material into phytosanitary controls on wood imports. Midgation procedures for dun- 

 nage associated with imporu from Siberia and New Zealand were not discussed in 

 their respecuve risk assessments. 



Another inconsistency among the reports is the level of risk assigned to a particular 

 pest or pest complex. The risk can vary considerably without an apparent explana- 

 tion. As an example, the New Zealand assessment assigned a high risk to the wood- 

 wasp and its associated fimgus (USDA Forest Service 1992). In contrast, the Sinx/ 

 Amylostereum complex is only briefly mendoned in the Siberian assessment (under a 

 different generic name for the wasp, Paururus), and no risk is assigned (USDA Forest 

 Service 1991b). In addiuon, several reviewers of the draft assessments expressed con- 

 cern over the level of risk assigned to possible reintroductions of pests already pre- 

 sent in North America. Their comments focus on the possibility that an introducuon 

 of a different genetic strain or variety would increase damage to current host species 

 and/or expand the host range. 



The lack of knowledge of foreign tree species' biology and interactions with pests in 

 their native environment was emphasized in the Chilean assessment. In several pas- 

 sages, (he authors complained that the paucity of informaiion on most indigenous 

 pests of the hardwood species hampered the assessment of their impact in North 

 America. Without this information, assessments could underestimate potential pests 

 and associated damage to North American forests. 



