Emerald Ash Borer

Emerald-Ash-BorerThe Emerald Ash Borer (EAB) is a pest introduced from Asia that has killed millions of Ash trees across southern Ontario and North America.

Crews have begun removing Ash trees infested with the Emerald Ash Borer from City parks and boulevards in order to protect residents and their property.

The Emerald Ash Borer has infested most Ash trees in the city and by the end of 2015 many of the infested trees will have died. Deceased Ash trees are a public safety risk, as after an Ash tree succumbs to infestation its limbs are prone to snap off.

Even if an Ash tree appears to be healthy now it will eventually become infested.

How to Report a Dangerous Tree

If you suspect that a tree within a City park or on a boulevard is infested with the Emerald Ash Borer call 905.688.5600.

Unfortunately, the City is unable to assist with the treatment or removal of infested trees on private property.

Removal of Ash Trees from City Parks

  • Ash trees will be removed based on priority, not based on park. This will result in crews visiting the same parks multiple times, as crews are focused on removing individual, high priority trees.
  • High priority trees are those trees most likely to injure people or damage property.
  • Work will last throughout 2014 and 2015.
  • Crews will do their best to mark trees slated for removal.
  • Parks will not be closed while Ash trees are being removed.
  • Tree removal will be done Monday to Friday during the day so residents can enjoy parks on evenings and weekends.
  • Trees removed from parks will be replaced. Replacement trees will be planted in order based on when Ash trees were removed.
  • Replacement trees will be comprised of a diverse range of species, designed to protect the urban forest and reduce the impacts of other invasive species.
  • There are 114 parks maintained by the City of St. Catharines.

Removal of Ash Trees from Boulevards

Infested boulevard trees will be removed using the following process:

  1. Call 905.688.5600 if you believe your tree is infested.
  2. An arborist will assess your tree.
  3. If the arborist determines your boulevard tree needs to be removed you will receive an informational door hanger.
    • You will have 14 days from the date the hanger was issued to comment on your tree removal. Comments can be made by emailing citizensfirst@stcatharines.ca or by calling 905.688.5600
  4. Your tree will be scheduled for removal based on its priority, but removal is subject to change due to emergencies.
  5. Depending on the size of the tree and available resources your tree may be removed in two or three stages:
    • The crown of the tree may be removed first, leaving the trunk.
    • The trunk may be cut down to ground level in one visit. If the trunk is left standing, the City will be back to remove it at a later date.
  6. A crew is then scheduled to grind out the stump, remove the grindings and backfill with soil and seed. At this point, a property owner can request a new tree.

Please note: The City of St. Catharines will NOT remove trees from private property.

Requesting a New Tree

Tree on City streetTo request a new tree follow these steps:

  1. View the list of trees approved for boulevard planting and select the type of tree that you would like to be planted.
    • Property owners should select different types of trees than their neighbours to assist in creating a diverse and healthy urban forest. Having a variety of species helps protect trees from pests and diseases that spread through an area and target specific tree types.
    • The arborist that inspects your tree and schedules the removal can assist in selecting an ideal species for your site. This is only done at the request of the property owner. If you are interested in this service please call 905.688.5600 when you receive notification of the tree removal.
  2. Call 905.688.5600 and request a tree. Be ready with your name, address, preferred tree type and contact information.
  3. The City or its contractor will plant the tree for you.
    • The City has a spring planting season which runs from April to June and a fall planting season which runs from September to November. Planting in both seasons is weather dependent.
    • The deadline to request a new tree is April 1 for the spring planting season and Aug. 30 for the fall planting season.
    • In some situations you will need to wait until the next planting season for the new tree.  

Removal of Ash Trees from Private Property

It is recommended that you contact a private certified arborist to inspect a tree on private property that is showing signs of Emerald Ash Borer. The arborist will be able to confirm the presence of the Emerald Ash Borer and recommend treatment options.

The city encourages citizens to treat their Ash trees and limit the movement of firewood wherever possible to help contain the spread of Emerald Ash Borer. 

How to Tell if a Tree is Infested

Identify Ash trees and Emerald Ash Borer infestation with help from this EAB Identification Guide

Crown Dieback:Crown Dieback

Severely attacked trees may exhibit crown dieback as the canopy dies from the top down. Leaves may wilt or turn yellow during the growing season.


Woodpeckers feed on the larvae under the bark. Look for increased Woodpecker activity and where Woodpeckers are peeling back layers of bark.

Exit Holes:

Once fully mature, the adult beetles emerge through exit holes they chew through the bark. These holes are distinctly D-shaped and are 3.5 to 4 mm across.

Bark Cracks:Bark Cracks

Vertical splits of 7 - 10 cm are often present over larval galleries. These are often more noticeable on young trees that do not already have splits from growth-related expansion.


Winding S-shaped larval tunnels snake under the bark where larvae bore channels. Removing the bark exposes larvae and sawdust-filled galleries.

Learn more about the Emerald Ash Borer

  1. Infestation occurs when the beetle lays its eggs on the tree bark and in bark crevices on the trunk and branches.
  2. The larvae then tunnel beneath the bark and feed on the layer of live cells between the bark and the sapwood (the Cambium), cutting off the transport of nutrients and water to the tree.  

Additional Resources

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