A Study on the Viability of Street Trees After Construction Injuries in Toronto

Hendri Deetlefs

Advisors: Amy Blood, Sara Baron, Andrew D. Almas & Ryan Senechal

Abstract

In growing cities worldwide, construction projects and trees are constantly in conflict. Currently, there is little empirical data collected on the survivability of trees that have been impacted or injured by construction. This research examines trees following construction in a large North American city. The City of Toronto, Canada, issues tree injury-related permits to landowner applicants who are developing properties. Using a novel process, we examined one hundred and twelve city-owned trees impacted by construction between 2005 and 2021. Each application file was analyzed to see if proper steps were followed to assess the tree’s species tolerance to construction impacts. The results indicate that current standards may not be effective and may require updating to ensure better outcomes for trees following injury. This study recommends a management plan through policy change to ensure that all applications submitted are screened and reviewed to meet the latest industry standards. More research is needed to determine tree tolerance to any proposed impact and to increase survivability. If each proposed encroachment, whether root injury or canopy reduction, is accurately addressed and mitigations are in place, trees will have a better chance of survival.

Keywords: Street trees, Approved injuries, Construction impacts, Tree species injury tolerance.

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