XVI International Botanical Congess

Worldwide trends in forestry have been to establish plantations of rapidly growing trees. This reduces logging of native and old growth forests. While this action is generally positive, significant negative consequences that are emerging. For example, diseases thought to be associated with single pathogen introductions appear to be caused by a large number of genotypes. Pathogens of related native plants also become adapted to exotic plantation species, and later threaten the trees where they are native. Efforts to establish biological control of insect pests have led to accidental introductions of new pathogen genotypes. Furthermore, efforts to control plantation trees that have become weeds leads to conflict between forestry and environmental organizations. There is clearly an urgent need to review these issues.