Published in The BANAR June 2012
by Councillor Rainer Bloess
What is the Ash Borer and why is the City of Ottawa asking residents not to move firewood or other wood materials out of the immediate area (i.e. to cottages or campsites) and to buy and burn firewood locally?
The handiwork of this natural troublemaker, a wood boring beetle which lives and feeds under the bark of ash trees, has been evident in our region since July of 2008 and, since ash trees make up 25% of the urban and rural forest across our region, the economic and environmental threat posed by this pest is significant. Ash trees in Ottawa currently number at least 75,000 on streets and in parks and 180,000 at the edges of our natural areas. Left to its own devices the emerald ash borer could potentially destroy all of these trees within 10 to 15 years.
Currently in force is a Canadian Food Inspection Agency ministerial order prohibiting the movement of firewood and ash-tree products from Ottawa and Gatineau to surrounding regions to limit the spread of the pest which has already killed millions of ash trees in Ontario.
As well, City Council has approved a management strategy which includes not only the regulation of wood movement and disposal, but also the removal of affected trees, selective professional injection of those trees that can be saved and replaced. Increasing public awareness is also part of our municipal strategy. Early signs are unusually thin tree crowns, bark splitting and grooving and leaf growth in the lower part of stems where it was not present before.
In Blackburn Hamlet, there are pockets of affected ash trees primarily in Bearbrook Park and John Kemp Park on Cleroux. As the city crews work on limiting the damage, the primary objective is to save as many trees as possible. Where possible, our forestry department applies an injection called TreeAzin as a mitigation measure. Ash trees located on City property are thoroughly assessed to determine if they will respond well to TreeAzin. But, some trees may be too infected to be treated, in poor condition due to other health factors, or simply in a poor location. In Blackburn about 40 to 50 trees will get this treatment this year.
The cost of the TreeAzin treatment is directly related to the size of the tree. For example, for an average sized 40 cm diameter tree, the City’s cost is ~$6.00 per centimetre or $240 and the private commercial cost is estimated as high as $10 per centimetre or ~$400. The injection needs to be done every other year and the duration of efficacy is not known at this time. An interesting fact— to this day, the City is injecting the remaining American Elm trees from the 1960’s and 1970’s injection program.
If you have questions or suspect an infestation, please contact the City at 311@ottawa.ca for additional information.