cktimes.ca Archives for Ecowrappin'


Ecowrappin'

With Larry Cornelis

Emerald Ash Borer – Alien Invaders

Tuesday, April 22, 2003

Around 1900, the most common tree to be found in the eastern deciduous forest was the American Chestnut (Castanea dentata). It ranged from southern Ontario south through the eastern states to Georgia and Alabama. The American Chestnut was a valuable lumber tree that produced sweet nuts from a young age. Most of you reading this have probably never seen an American Chestnut or tasted one of their sweet nuts. That's because, in 1904, New York's Botanical Garden received and planted a shipment of Chinese Chestnuts. Shortly afterwards, American Chestnuts were dying in and around the Botanical Gardens and by 1907, they were dying over 100 miles away. The trees were being killed by a parasitic fungus that had come came to America on that first shipment of Chinese Chestnuts. By the 1920's the fungus was killing trees in Pennsylvania and Virginia and by the 40's it had covered the entire range of the species and by the 60's nary a native American Chestnut could be found. Only root suckers remained.
Of course, this is about the same time (the 60's) when our Elms (all species) started to die from another import, the Dutch Elm disease. Dutch Elm disease is a pathogenic fungus from Asia that is spread by beetles. It is called Dutch Elm disease because Dutch botanists were the first to identify the fungus after it had invaded Europe. Today, there are still a few mature Elms to be found and most seedlings seem to make about 15-20 years of age before they die.
The loss of these two species was very devastating to our eastern forests and the wildlife that depended on them. This was a loss of probably close to fifty percent of the trees in some forests. Of course, the gaps left by the Elms and Chestnuts were eventually filled by other tree species such as Oaks, Hickories, Maples and Ashes etc.
Now, our Ashes are in peril. Around 1997, the Emerald Ash Borer was unknowingly imported to the Detroit, Michigan area from China ("made in China" could be the underlying theme of this article). By last summer, thousands of Ash trees were dying in the Detroit-Windsor area and the Emerald Ash Borer was identified as the culprit. It attacks and kills Ash trees (all species including the rare and threatened Blue Ash) with a one inch diameter stem and larger. It kills both healthy and unhealthy trees in its path. So far, this beetle only attacks Ashes but there are subspecies in Asia that also attack hickories, walnuts and elms. Hopefully, this will not be the case here.
Ashes (Fraxiinus spp) account for about 20-40% of the trees in our forests today and this could be another huge loss if it spreads across the eastern deciduous forests. Presently, it has only been found in Essex County in Ontario and Livingston, Macomb, Oakland, Monroe, Washtenaw, and Wayne Counties in Michigan, although a new site was identified near Toledo Ohio a few weeks ago.
Every effort must be made to stop this pest from spreading. An action plan is being formulated which includes educating the public, monitoring and surveying, creating ash-free barriers and enforcing a quarantine on all Ash trees (nursery stock and lumber) and firewood. The Canadian Food Inspection Agency (CFIA) is enforcing the order of quarantine and more information about the order is available at  HYPERLINK http://www.inspection.gc.ca www.inspection.gc.ca.
New sites of infestation should be reported immediately to the CFIA. Things to look for include Ash trees in decline, basal sprouting, splits in bark, serpentine tunnels under dead bark and "D" shaped exit holes made by adult beetles.
Hopefully, governmental agencies and other organizations can stop this pest from spreading. I would suggest we need to deal with imports and global trade more seriously. Hundreds of alien organisms are arriving at our seaports and airports annually. Many are benign, some problematic, but some, such as the Emerald Ash Borer, S.A.R.S. (Sever Acute Respiratory Syndrome) and the West Nile virus are very serious.

Yours in Nature
Larry Cornelis