Emerald Ash Borer

The Emerald Ash Borer is a highly destructive invasive beetle that infests ash trees. It has killed millions of ash trees in North America and poses a major environmental threat to urban and forested areas in Hamilton. It has the potential to destroy Hamilton’s entire Ash tree population by the year 2020.

Mountain Ash is not in the same family and is not affected by the Emerald Ash Borer.

Ash trees are an important part of Hamilton's urban and rural landscape. They are commonly found on city streets, woodlots, windbreaks and forests.

Ash trees

An Ash tree typically has:

  • Opposite branching, so leaves and twigs are in opposite positions on the stem, not staggered.
  • Compound leaves - leaves that have more than one leaflet, while the entire leaf has one bud at its stem base. The leaflets are positioned opposite with one at the top. Ash trees typically have five to nine leaflets per leaf.
  • Rigid bark with diamond-shaped ridges (on a mature tree).
  • Seeds that hang in clusters and are dry and oar-shaped.

How Emerald Ash Borers spread

The Emerald Ash Borer spreads naturally through beetle flight; the beetle is capable of flying distances of 5 km in search of a host tree. The Emerald Ash Borer is also spread by people moving material infested with the beetle such as firewood and nursery stock. The Canadian Food Inspection Agency regulates the movement of material outside the quarantined area. 

Emerald Ash Borer larvae feed underneath the bark and block nutrients and water from moving throughout the tree. The tree may be dead within a few years of the initial infestation.

Signs of Emerald Ash Borer infestation usually become apparent once a tree is heavily infested.

Removal of infected trees

Who is responsible for removal of infected trees depends on where the tree is located on your property:

The City will remove an infested ash tree from your property if it is located within the road allowance. If the tree in your front yard is showing signs of being infested with the emerald ash borer, call 905-546- 2489 to have your tree assessed. The City will plant a replacement tree once the infested tree and stump is removed.

You are responsible for all trees that are not on the City’s road allowance. This includes the treatment, removal and disposal of dying or dead Ash trees. Contact an arborist to discuss your options.

If you elect to have your tree removed, ensure that the materials are not moved outside the CFIA quarantined area. The wood and mulch can be utilized for firewood and landscape use within this area.

Contact the Canadian Food Inspection Agency at 1-866-463-6017 or Phytosanitary Requirements to Prevent the Introduction Into and Spread Within Canada of the Emerald Ash Borer for further information.

City Ash trees

In 2012 City Council approved the plan which included the removal of 10% of Hamilton’s Ash tree population each year for a 10 year period. At the current decline rate, it is anticipated the Ash population may be removed in the next four years. Each Ash tree that is removed is replaced with a new species of tree to help diversify Hamilton's urban forest. More information on the Street Tree Planting Program.

The City has also been using injectable pesticide on healthy Ash trees of significance. These trees are treated annually during periods of heavy infestation then subsequently every two years. Treating all City-owned Ash trees is not economically feasible.