Exotic Forest Pests and Their Impact on Trade

Kerry Britton

INTRODUCTION
Exotic pests can wreak ecological havoc when they establish spreading populations in forest ecosystems. Millions of dollars are spent in many countries each year to prevent the entry, establishment, and spread of exotic pests - yet, still they come! The sheer volume of global shipping today has amplified the danger beyond the scale of regulatory barriers conceived in the 20^th century. It is now time for a fresh consideration of the problem and to develop options for dealing with it on a global scale.

How Do They Get Here?
Exotic forest pests most often arrive on logs, wood, and wood products, including wood chips and the wood used in pallets and shipping containers. Nursery stock has carried many undetected pests that “jump” onto native hosts soon after arrival. Even metal shipping containers and the infrastructure of grain ships, have provided sufficient cracks and crevices to hide “hitchhiking” pests.

Why Are Exotic Pests a Problem?
Exotic pathogens like the fungus that causes Chestnut Blight or the Pine Wilt nematode can spread like wildfire when they find a host population that did not evolve with it. The new host lacks resistance genes that generally protect co-evolved hosts from such catastrophes. Chinese chestnut, for example, has strong resistance mechanisms which contain (and wall off?) the invading fungus. Scientists have worked for many years to incorporate these useful genes into American chestnuts, and are near to achieving this goal.

Exotic insect pests often multiply explosively because they have left their natural enemies behind, and few parasites and predators in the new land are adapted to use them as prey. Reuniting an exotic insect pest such as Gypsy Moth, with its natural enemies, is one way scientists have fought back once an exotic pest has become established.

What Can Be Done About The Exotic Pest Problem?
One thing scientists the world over agree on is that it is MUCH, MUCH better AND cheaper to prevent the entry and establishment of exotic pests than to fight these “ground wars” once the borders have been penetrated.

Regulations to prevent pest entry are sometimes hotly disputed, with allegations of trade protectionism masquerading as ecosystem preservation. This workshop was proposed and organized by an international group of concerned scientists, who perceived a need for frank discussion of the science behind the regulation of exotic pests. There are many questions we hope to discuss in this forum. Why should we spend so much money trying to control these pests? What tools are available, and how well do they work? What are the current and proposed regulations, and what burden will they lay on international trade? Are all the proposed rules necessary or do some of them restrict trade unnecessarily? Can we come to an agreement about what is known and NOT known? Can we identify areas of uncertainty where additional research is needed?

To get the discussion started, “speakers” were invited to write short papers on specific topics. These are recognized experts in their field, but we all know that many experts can have a variety of opinions and interpretations of the same set of facts. So, we hope that these presentations will be regarded as jumping-off points for lively discussion. In fact, if we are successful, the discussion part of the workshop will offer the most value because it is where we can begin to iron out the differences of opinion and interpretation that plague regulatory issues worldwide.

This Internet discussion will remain “live” (i.e., open for additions by anyone wishing to make comments or ask questions) from April 16-29, 2001. We welcome your comments. If you feel inhibited by your responsibility to represent your organization’s stance on a topic, you may contact the session moderator to post comments anonymously.

ABOUT THE WATERCOLORS: When I invited Dr. Eugene Odum, considered by many to be the Father of Modern Ecology, to discuss his views of forestry and pests in general, I told him that we also wanted photographs to illustrate each author’s paper. Dr. Odum’s wife Martha was an extremely talented artist, who captured, in the course of their travels together, the “Essence of Place” that epitomizes the biodiversity we seek to preserve by preventing the homogenization of the world’s flora and fauna. Their reproduction here is a result of his generous permission, and the assistance of the University of Georgia Press, who provided reproductions used in two books of Martha’s work.