Native ash species are facing hard times, especially in southern Quebec. Their No. 1 enemy is the emerald ash borer, a flying insect that feeds on ash tree leaves.

As with other “stowaway” insects, firewood transportation is one of the ways this invader spreads; an insect that, otherwise, does not venture far on its own.

SOS—ash trees in danger

Whether the ash trees are healthy or unhealthy before infestation, almost all of them succumb to an emerald ash borer infestation. It is the larvae of the emerald ash borer (creamy white in color) that cause the worst damage to the trees, by boring galleries under the bark.

Infested trees begin to decay at the crown within the first year of infestation. Almost half of the branches, for that matter, can die during a single year. To date, tens of millions of trees have been destroyed in the U.S.

In Quebec, a large number of ash trees populate the forests and cities; it goes without saying that losing these trees could create an imbalance in the environment.

A foreign invader

The emerald ash borer is a metallic green insect with a long, narrow body. A native to Asia, it was first detected in North America in 2002 in Detroit and is believed to have arrived in a shipment of freight.

The species subsequently spread through natural means, but humans unwittingly contributed to the spread by transporting infested nursery stock and firewood to neighbouring regions. In fact, if an individual moves firewood from his cottage to his house, for example, the insect can then infest—and destroy—thousands of trees in another region.

A strict policy

The Canadian Food Inspection Agency (CFIA) is the organization responsible for the fight against invasive species such as the emerald ash borer. The CFIA adopted a strict policy to control the movement of firewood: an individual can face a fine of up to $50,000 and/or prosecution for moving firewood outside of a regulated area without prior authorization from the CFIA.


Detection and prevention

Early detection of the emerald ash borer is difficult. However, there are certain signs of infestation:

  • Cracks in the tree bark;
  • Appearance of exit holes (when the adult insects chew through the bark to emerge);
  • Increased activity from woodpeckers—they detect the larvae under the bark;
  • Leaves turned yellow during the growing season (May to August), etc.

The inspection of trees and treatment, as needed, should be done by experts. You can, however, take precautionary measures.

What you can do:

When buying firewood

  • First verify the firewood’s origin.
  • Buy your firewood locally and burn it onsite.
  • Never move your firewood (regardless of the type of wood) outside of the limits of a CFIA regulated zone.


Ash trees on your property

Affected municipalities have adopted control measures for ash trees and their residue under their jurisdictions. Contact your municipality or check its website for information concerning local policies for ash tree management.

  • If you notice signs of infestation or you capture an emerald ash borer, notify your municipality or the CFIA at 1-800-442-2342.
  • Cut down decaying ash trees that cannot be protected against the ash borer. However, avoid cutting down or pruning ash trees between March 15 and September 30 (this is a high-risk period for the spread of emerald ash borers).
  • Before cutting down any trees, read your municipal regulations; you can then dispose of your branches, trunks, stumps and leaves in an appropriate manner and at authorized sites.
  • Take swift action to protect ash trees that can be saved using an appropriate treatment.
TreeAzin and professional treatments
TreeAzin is a Canadian-certified insecticide used to control and prevent the emerald ash borer with some effectiveness. The product is injected at the base of the tree during the growing season (between May 15 and Aug. 31). It is recommended the application be repeated every two years.

Important: TreeAzin may only be applied by a professional certified by Quebec’s Ministère du Développement durable, de l'Environnement et de la Lutte contre les changements climatiques.
  • Though not forbidden, we do not recommend planting new ash trees on your property: for the moment, there are no ash varieties that are resistant to the emerald ash borer.
  • Finally, diversify tree, shrub and perennial species planted on your property.

Other information sources:

Conseil québécois des espèces exotiques envahissantes (in French only)