> Home > Municipal Government > Municipal Departments > Public Works > Parks & Trails > Caring for our trees > Clearwing Ash Borers

Clearwing Ash Borers

Identifying an Infested tree

Infested Tree

Green ash tree infested with Clearwing Ash Borer, also known as Lilac Borer.


Clearwing Ash Borers

A Clearwing Ash Borer is a moth that is native to North America. The larvae of this moth are known for feeding on tree bark and damaging branches or even killing trees.

The Problem with Clearwing Ash Borers

Clearwing Ash Borers can be an issue in Wood Buffalo as there are numerous ash trees growing on municipal property and right of ways, or even on private property. The risk is that affected trees could die and create a hazard due to falling branches or even falling trees.

Removing Damaged and Infested Trees

To address this issue, the Municipality will periodically remove trees that are either dead from the pest, or will not survive due to the extent of the pest’s damage.

If a Green Ash tree has been removed from the right-of-way (ROW) in front of your house, this is due to heavy infestation. A notice will be dropped off to inform residents of trees that need to be removed from the ROW. Please remember that the ROWs are municipal property.

The Municipality does not enter private property without permission from the property owner. The Municipality will, however, remove trees from municipal property, right-of-ways and public boulevards.

Should you have any questions or need further information, please review the FAQ’s below, or contact Pulse at 780-743-7000 or at rmwb.ca/pulse.


Why did the Municipality remove the tree from my front lawn?
The RMWB owns a strip of land along the front of most titled properties, usually for the purposes of utility location, called a right-of-way (ROW). The ROW may be divided from your home by a sidewalk, or it may be directly against your front yard, and not appear as a separate space. Many of the trees planted in the ROW’s or within 3m of the curb have been planted by the RMWB and, as such, are the RMWB’s responsibility to remove in case of tree death.

Will I be getting a new tree?
The RMWB is in the process of replacing a massive number of trees damaged or removed by the 2016 Wildfire and is focusing on replacing these trees first. Trees not located in these priority areas have been added to a list for replacement but it may be years before non-priority areas are reached.

What about the stump?
RMWB Parks staff will be coming to remove the tree stump.

How do I know if other Green Ash trees are infested?
Look for woodpecker damage on the trunk and main branches. Woodpeckers attack the pest and create large holes and remove bark in their search for food. Look for pupal skins sticking out of the trunk. These are left behind as the pest moves out of the tree as it becomes an adult. There may also be frass borings, which look like sawdust, on the ground at the base of the trunk or on the branches or in the wounds. View the photo gallery on this page for some visual examples of infested trees.

How can I protect other trees from damage?
A healthy tree will be more resistant to the pest and survive damage better. Keep trees well-watered, avoid damaging the tree, especially at the base and main branches. You can also fertilize the tree.

Can I plant my own ash tree in the municipal right-of-way (ROW) to replace a tree that was removed?
Residents may plant a tree themselves, but must keep a few important considerations in mind:

  • Trees planted on municipal land would become municipal property, and as such can be removed by municipal staff or for construction activities.
  • The municipality cannot maintain the newly planted trees with watering, fertilizing or supervising. These tasks must be the resident’s responsibility. If residents are not willing to take on these tasks then they should wait for the tree to be replaced by the municipality.
  • The tree MUST be located where the ash tree was removed. Residents may NOT plant trees where they choose as there are numerous considerations including utilities under the ground in ROW areas.
  • Residents are responsible to get utility locates before they dig. This includes Alberta One-Call, Shaw cable (not a member of Alberta One-Call) and RMWB utilities.
  • Right tree, right place – the tree must be properly zoned (zone 2 or better) and an appropriate species for their location. For instance, a conifer tree with wide growing low branches is a poor choice as it will stick out into the street and cause damage to vehicles. A list of appropriate boulevard trees can be found in the Engineering Servicing Standards on pages 10-35 and 10-36.
  • Replacement ash trees are not recommended as the Ash Borer insects will continue to be a problem.

FLOOD RECOVERY: Information and resources