Dutch Elm Disease

In recent decades, Dutch Elm disease has made its way across Europe and was eventually introduced into the Elm populations in Eastern North America.

Despite the efforts of many pest control personnel and arborists, a large percentage of the American Elm population has been destroyed by this disease. In the last few years, the progress of the disease across North America has been slow, but unchecked. The disease is now found in all parts of this continent except in Alberta and BC.


The Alberta 'Stop Dutch Elm Disease' Society (StopDED) has been formed to promote awareness of Dutch Elm Disease and other critical pests of landscape trees. They coordinate monitoring of insects that may carry the disease or cause it to spread, as well as maintain the provincial response plan for DED infection. St. Albert has been an active member of the Society and its goals. For more information on the Society and their work, please visit the StopDED web page.

Pruning Practices and Guidelines

Elms should be pruned to remove any dead wood, which would attract the beetles to the tree. Elm bark beetles and Red Elm Weevils spend part of their larval life cycle in the cambium (inner bark) of the elm trees then emerge to feed and mate in other trees. This movement between trees is one of the main causes of the spread of DED. Logs and branches of Elms should not be stored or moved, unless to a proper disposal facility. You may be aiding the spread of tree disease and insect population. This pruning must be done between October 1 and March 31, as the pruning cuts cause wounds that attract the beetles. In line with several Albertan municipalities, St. Albert has established Bylaw #5-98, which makes it illegal to prune Elms between April 1 and September 30 without expressed written permission from the City.

The tree maintenance crew has established a collection point for Elm wood at the St. Albert Compost Depot. All Elm wood and diseased tree prunings can be brought to the site and placed in the marked area. This material is kept out of the compost stream and burned. This method of eliminating deadwood will help avoid attracting the beetle that could carry the disease, and from providing a site, the beetle could use as a nursery to increase its population.

The City prunes Elms annually on a rotating basis. This consists of removing dead wood, crossing branches and for proper form and lifting of these trees.

Working Outside? Protect Your Elms.

Planning outdoor home renovations or work in the yard? Protect your elms.

Damage done to the roots, trunk or crown is permanent and, if extensive, can be fatal. This can lead to the decline of the tree and make it more susceptible to beetles and Dutch elm disease.

Roots are one of the most vital parts of a tree. Damage to the roots can cause the tree to become unstable, especially during storms. This could lead to property damage and the possibility of it becoming a liability.

Learn how to protect your trees during construction. 


Canadian Urban Forest Network

University of Florida powerpoints

University of Florida - Root Pruning Guidelines

International Society of Arboriculture

International Society of Arboriculture - Prairie Chapter

Reporting Damaged, Broken or Diseased Trees

If you would like to report a tree that needs to be trimmed or if it is damaged, broken, or diseased, please report the issue online or call 780-459-1557. These requests are recorded and sent to the appropriate section. They will then be inspected and scheduled for repair based on their level of severity.

Related Pages

Last edited: February 24, 2022