cktimes.ca Archives for Nature Link
Nature Link
Trees and Exotics
Tuesday, January 7, 2003
The culprit is commonly called the Emerald Ash Borer (Agrilus planipennis), sporting a metallic green colour. It is a native of China, Korea, and Japan. I don't know much about it yet, but apparently it has hit the Windsor area, and may be spreading eastward. It originated in Michigan, where it has destroyed millions of trees. A quarantine has been initiated in the state, whereas export of ash wood in any form is prohibited. This extends into Essex County also.
There is talk recently of creating a several kilometre wide "firebreak" so that it does not reach Chatham-Kent and points farther east. Personally I don't think this will stop it – only slow it down. These things always manage to spread one way or another. Apparently this means removing all species of ash trees. Considering the lack of trees around these parts, it won't leave much. I will have to learn more about this disease and what can be done about it. There is quite a bit of information about the problem on the web.
We all have heard about Dutch Elm disease. It first appeared in North America in the early part of the 20th century along the east coast. It spread rapidly, reaching Ontario in the mid 1940's. By the 1960's, it was killing most of the elms in this area. The disease is a fungus called Ophiostoma ulmi, carried by bark beetles. It originated in Holland, hence "Dutch". It kills elms quite quickly. Within a year, an infected tree will completely die. Infected trees should be removed and burned immediately, even though this will only slow the spread of the disease. There are still quite a few small elms around, but when they get a little older, they will succumb.
Some older trees still exist, and have developed a resistance of sorts. Seeds from these trees are collected in order to grow and develop a more blight-resistant strain.
The accompanying photo shows a unique elm that used to be seen west of Wallaceburg along Dufferin Avenue. In its youth, it was bent over to mark a trail. The growing point took root, and the tree grew with three main trunks as the photo shows. It was a common practice by natives to mark trails. This particular tree died in the mid 1960's after contracting the dreaded Dutch Elm disease.
There are many other diseases and exotic invaders in our natural world. This is one of the main reasons why many of our native species (including trees, fish, animals, etc.) are disappearing. The marked decline or disappearance of native fish for example, is mainly due to non-native invasive species, not from the dietary habits of Cormorants. But that's another topic for a future column.
