142 



Potential Future Introductions 



The losses enumerated above are likely to increase rapidly as a result of additional pest 

 introductions. Such introductions are, unfortunately, likely to occur if American firms greatly 

 increase imports of logs or rough-cut lumber from other temperate regions. Even the rather 

 cursory risk assessments already completed (for Siberia, New Zealand, and Chile) was the best) 

 estimated losses to commercial timber in the west at between $25 million and $58 billion (USDA 

 Forest Service 1991; USDA Forest Service 1992). None of these estimates includes costs 

 associated with loss of jobs, recreational amenities, or ecological values; or losses in parts of the 

 country east of the Rocky Mountains. 



RECOMMENDATIONS 



The most efficient method of preventing new costly pest introductions — although never 

 completely effective — is exclusion: preventing the organism from entering the country. That task 

 belongs to the Animal and Plant Health Inspection Service (APHIS). Quarantines are especially 

 imp)ortant to forestry because the long period before trees reach maturity slows developn]^ent of 

 disease-resistant strains (Boyce 1961). 



APHIS is now considering promulgation of regulations governing raw wood imports in order to 

 improve control efforts.' Unfortunately, the draft regulations are far from adequate. New 

 Zealand provides a model for a more effective exclusion program. 



First, the draft regulations would impose few new controls for wood imports from areas other 

 than Siberia. This approach is inadequate because the threat is global: damaging pests can arrive 

 on wood or horticultural products from anywhere, certainly any temperate region. Examples of 

 damaging pests introduced from Europe include Dutch elm disease, the common (or larger) pine 

 shoot beetle (Kucera 1992.), the spruce beetle, and Asian and hybrid gypsy moths. 



Second, APHIS must give greater attention to fungi and other pathogens, which appear to pose a 

 greater threat than do most insects.^ 



Third, as one risk assessment makes clear, bark-inhabiting insects often persist on "de-barked" 

 logs, and pests are often transported on dunnage, crates, or pallets (USDA Forest Service 1993). 



'See Federal Register Vol. 59, No. 13 (January 20, 1994). 



^Examples of introduced diseases which have or are now causing serious decline of species 

 include: Chestnut blight CrypphonecCria parasitica (Murrill); "Dutch" elm disease Ceratostomella 

 ulmi (Buisman); White pine blister rust Cronartium ribicola (Fischer); Scleroderris canker 

 Ascocalyx abieUna (Lagerberg); Dogwood anlhracnose Discula destructiva (Redlin); beech bark 

 disease Nectria coccinea var. [adnata (Lohman, Watson & Ayers), butternut canker Sirococcus 

 clavigignenn-juglandacearum, Port-Orford-Cedar root rot Phytophthora lateralis (Tucker & 

 Milbrath). Truly damaging exotic insects do occur; examples include the balsam woolly adelgid, 

 hemlock woolly adelgid, and probably the Asian strain of gypsy moth. 



