90 



Fumigation of logs, especially with methyl bromide, has been 

 put forward as an effective treatment, but work done in New 

 Zealand (Cross, 1991) indicated that Methyl Bromide would 

 only penetrate about 100 mm in green wood - in other words, 

 organisms livxng deep in the wood would escape completely 

 (e.g. ambrosia beetles, normal and flat headed borers). 

 Heat treatment, properly conducted at the right temperatures 

 and of proper duration, offers perhaps the best solution, 

 but much remains to be learned about the thermal death 

 points of many organisms. Further, there is considerable 

 resistance to this treatment because it adds cost to the 

 export process. 



Several techniques have been suggested to obtain pest -free 

 logs; however, some species are able to avoid these 

 treatments and establish themselves in new regions resulting 

 in almost invisible to very dramatic changes in the natural 

 habitats . The risk of unintentional or accidental 

 importation of unwanted pests or diseases should be 

 recognized and balanced against the possible benefits of 

 such importation. The benefits are likely to be short-term 

 and the damage to natural resources long-term. One has only 

 to look the northeastern forests of The United States and 

 Canada to see the consequences of only a few introduced 

 diseases and insects. These forests have been changed 

 forever. 



