Guelph's EAB Plan – a brief up-date

Staff memo.

This note is to provide an up-date on EAB-related activities. The elements of the plan and their current status are briefly outlined below.


“Branch sampling” – looking for EAB larval activity under the bark of branches – was done on 218 trees throughout the city in May and June. The areas around Clairfields West, which are known to be infested, were excluded. Only two of these samples were positive, Additional infested trees have since been confirmed. The only confirmed locations north of College Ave. are at 45 Municipal St. (!) and Glasgow Street at Essex Street. Given the very high incidence of adult EAB found throughout the City during the 2013 monitoring program, it’s reasonable to expect many additional confirmations this summer, and a much higher incidence of “positives” in future branch sampling efforts.


Recent inventory efforts focused on “ash-dominated landscapes” to enable a rapid assessment of those areas most at risk from EAB. This process is now complete for ash-lined streets and high-traffic, ash-dominated park areas, such as the picnic area adjacent to the playground at Riverside Park. The rationale was to focus first on the areas that would be most devastated by the loss of ash trees, and to generate site-specific plans for each of these areas.

Site-Specific Response Plans

Each ash-dominated area now has a draft plan that specifies which ash trees have been selected for injection treatments, and which have not, The plans also will address supplementary planting opportunities. Each ash tree was assessed, and the most healthy, structurally uncompromised trees were selected for injection. Untreated trees are expected to die within 3 – 10 years, and at that time, a new tree will be planted in that same location. Other planting opportunities in close proximity are identified for immediate action, so that in some cases, as much as a decade of growth can accrue before removal of the declining ash trees.

Communication Plan

The communications plan is being implemented, and includes media releases, brochures, posters, newspaper advertisements, webpage up-dates, Holler articles, factsheets for City staff, radio spots, and social media messages.

Community Engagement

On ash-dominated streets, about three thousand households are being asked by mail to review the proposed plan for their neighbourhood and help shape it with their suggestions of planting spots.

Injection Treatments

A request for tenders is currently posted for TreeAzin injection treatments of approximately five hundred City-owned trees. This work is expected to be done in August.


Thirty City-owned ash trees were removed last year because of EAB-caused mortality, and ninety are slated for removal later this year. The Clairfields West area was home to all of these trees. It’s expected that this list will continue to grow through the summer and beyond.

Tree Planting

Removals will trigger planting of replacement trees on the same spot, plus additional trees will be planted in close proximity to ash-dominated areas, either before or after the subject ash trees are impacted by EAB. The exact number of trees to be planted this year has not been fixed, but at least 125 large-caliper trees are expected to be planted this fall.


It’s anticipated that the number of infested trees and areas will accelerate rapidly this summer and next, and that tree mortality numbers will likely be much higher next year.

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