A Tale of Two Species: Ash Trees and Emerald Ash Borers
Today I’m going to share a sad story.
This edition of Species of the Week will be a double feature. I’m going to talk about Ash trees and the Emerald Ash Borer.
Once upon a time, developers built my subdivision. As is typical here, they planted a single tree in front of each property. On my particular street (and many others), they selected Ash for every single property. When we bought our house a few years ago, we were happy with the canopy of relatively mature trees that kept our street green and shaded.
Ash Trees (Fraxinus spp.) are deciduous. They have compound leaves, with 5-9 leaflets. Buds and branches are arranged in opposite rather than alternate patterns. Ash seeds are attached to a wing. If you want to identify an ash, there is a helpful key here: http://www.toronto.ca/trees/pdfs/IdentifyingAshTrees.pdf
The Emerald Ash borer (Agrilus planipennis) is roughly 1 cm long (1/3-1/2 in), and 3 mm wide (1/8 in). It has metallic green shiny wings. The best way to identify these guys is probably by finding dying ash trees. The larval state of the borer weaves around underneath the bark of ash trees, and destroys the tree’s ability to move nutrients and water. After infestation, trees typically die within 1-3 years.
As the insect is native to China and Eastern Asia, it is presumed to have come over accidentally in wood packaging or crates. All species of ash trees (except the Mountain Ash – which is not a true ash) are affected by the Emerald Ash Borer.
In 2002, the EAB was identified in Canada. In 2010, they found the Emerald Ash Borer in my region. Despite efforts to stop transmission, such as regulating the movement of firewood in restricted areas, the beetle has spread across my city.
Our street trees were looking a little bare over the past few years, so I was starting to worry. This summer, we saw a trap high in the tree across the street. It was a green sticky box, intended to identify the locations of infestation. When I spoke with the city forestry department, they confirmed that the EAB is on our street, and the most afflicted trees will start coming down within a year.
Here is a picture of what I believe to be a dead Emerald Ash Borer on a trap we found sitting beside the road. It’s the best picture I’m going to get of the beetle.
All of the ash trees on my street, that’s roughly 20 mature trees on a small court, have just received a death sentence. It is only a matter of a couple of years before my street is bare. The city will only be able to afford to replace them with small starter trees.
As sad as this situation is for my street alone, ash trees form a fairly major part of the canopy in our community. A large number of them reside in our parks and conservation areas. I just noticed a whole series of them dying in a nearby conservation area.
I doubt I have to convince you of the benefits of mature trees. They provide health benefits, shade, habitat for birds, insects and other wildlife, they reduce urban heat island effects, increase property values, and the list goes on. A human health study was even performed on areas devastated by the EAB, and “Results suggest that loss of trees to the emerald ash borer increased mortality related to cardiovascular and lower-respiratory-tract illness.” Here is the abstract: http://www.ncbi.nlm.nih.gov/pubmed/23332329
While the trees still remain standing on our street, they do not have much longer. I shudder to picture what the street will look like in a few years.
And they didn’t live so happily ever after (until the trees grew back).
Has the Emerald Ash Borer affected your neighbourhood?
Posted on August 2, 2013, in Species of the week, Uncategorized and tagged ash borer, ash tree, beetles, canopy, conservation areas, EAB, Emerald Ash Borer, firewood, infestation, infested, insects, nature, shade, subdivision, trees. Bookmark the permalink. 8 Comments.