White Ash / American Ash (Fraxinus americana)

Though Ash trees have traditionally been useful for their pleasing appearance, and as material for tool handles and furniture, they’ve recently become a burden for GTA home owners.

Ash trees were commonly planted across Toronto (especially in suburban neighbourhoods such as Scarborough and Mississauga) in the 1950s’ through the 1990s’. Ash trees planted for residential purposes provide good shade cover and are less messy than other shade trees, such as the Manitoba Maple.

Emerald Ash Borer (EAB)

Ash trees flourished in Ontario until the early 2000s’. Enter the Emerald Ash Borer (EAB). In 2002, this beetle, native to China and Eastern Asia, was first spotted in Northern Michigan. Several months later it had found its way to Southern Ontario. Since 2002 the Emerald Ash Borer has spread across Ontario and devastated Toronto’s Ash tree population. It’s estimated there are more than 100,000 dead or dying Ash trees in Scarborough alone. A direct result of the Emerald Ash Borer.

Emerald Ash Borer Life Cycle

True to its name, the adult beetle has a metallic green carapace and bright, emerald green underside. In May adult beetles emerge from trees creating ‘D’ shaped holes in the Ash tree’s bark. These ¼ inch ‘D’ shaped holes are the most distinctive trademark of the Emerald Ash Borer, and make detection easy. These holes are usually visible on the base of the tree.

Once the beetles have mated, the female lays hundreds of eggs on the bark of the tree during the warm Spring and Summer months. These eggs hatch and bore through the exterior bark, and into the softer layer underneath. This layer is essential to the vitality of the tree as it’s where new growth forms.

Once the larva have hatched, they spend the winter months burrowing through and eating the cambium layer of the tree (between the hard wood and exterior bark). This process cuts off the water flow to the top and outer branches of the tree. When a tree is infected with the Emerald Ash Borer, large sections of the tree’s canopy turn from green to yellow, are bare of leaves, and small branches and twigs will fall off. The tree’s source of energy has been eaten away; the tree cannot supply itself with water and nutrients. Larvae turn into fully formed insects in May, and the cycle repeats.

Emerald Ash Borer in Toronto

The spread of the Emerald Ash Borer is highly visible across Toronto, Scarborough, Mississauga, North York, and the surrounding boroughs. Often, once the beetle has been introduced to a neighbourhood, its spread is visible as it moves from one tree to the next. Where Ash trees once formed a nicely shaded street of healthy trees just 10 years ago, they’ve now turned to bare, dead and dying hazards. Once a tree has lost its leaves completely, it begins to dry out on the inside of the branches and stems. This process leaves often large, brittle sections of the tree in danger of breaking off and causing damage. It is therefore best to be proactive about your Ash tree.

Tree Removal of Dead and Dying Ash Trees

If you have a dead or dying Ash tree, it is best to remove it sooner rather than later. As your tree dries out smaller branches will fall off, creating a mess for your garden or lawn. Larger branches could fall off and cause damage to surrounding objects or buildings. Once a tree has dried out completely, it may fall over or become too dangerous for a tree climber to ascend into. If this is the case, extra equipment such as a bucket truck or aerial lift would be required to remove the tree. Finally, dying trees are a breeding ground for the Emerald Ash Borer and contribute to their proliferation.

Cardinal Tree Care provides full tree removal for clients who have dead or dying Ash trees. In the city of Toronto, dead or nearly dead Ash trees that are greater than 30 cm in diameter at chest height (all trees on private property smaller than 30 cm in diameter are not heritage trees) are exempt from tree removal permits. Cardinal Tree Care provides Arborist Reports and will contact the municipal department necessary to apply for a permit exemption. The cost of this application service is deducted from the total cost of removing the tree once the work is completed.

Safe Disposal of Infested Ash Trees

Cardinal Tree Care complies with new legislation regarding the safe and responsible disposal of infested Ash trees. Parts of Southern Ontario have recently been placed under an Emerald Ash Borer quarantine, which prohibits the transport of wood (including firewood) from within the quarantined area to other parts of the province.

New Ash Borer Resistant Strains of Hybrid Ash Under Development

There are new Ash Borer resistant strains of hybrid Ash trees being developed for consumers. These strains are often a hybrid between the Blue Ash and Manchurian Ash (native to Asia, home of the Emerald Ash Borer). Cardinal Tree Care is keeping up to date with the availability of these strains of Ash, and hopes to offer these trees to clients in coming years.

More Information About the Emerald Ash Borer