About the moth
The hemlock looper moth is an endemic insect that experiences population outbreaks approximately every 15 years.
Its larvae hatch in the spring and aggressively feed on foliage, causing the most damage between July and October.
It feeds on coastal coniferous species which makes Stanley Park particularly vulnerable.
Hemlock looper moth outbreak
In 2020, Stanley Park experienced a hemlock looper External website, opens in new tab outbreak.
Though 160,000 of these trees were affected — including western hemlock, Douglas fir, and grand fir — only a fraction of these trees are a risk to public safety and will need to be cut-down.
As part of our progress in phase 1, less than 8,000 trees were removed, which addressed 25% of the total affected forest area.
This outbreak also affects parts of West and North Vancouver, where many trees are dying.
After recent droughts and hard winters, trees in Stanley Park were more vulnerable to the looper outbreak and less likely to recover.
What's happeningPhase 2 tree work and traffic impacts
Phase 2 work approved by the Park Board will ramp up gradually starting on October 15 and finish in early 2025, followed by replanting in spring 2025.
Tree work will concentrate on areas heavily used by the public adjacent to the Aquarium, Brockton Point, Chickadee Trail, and along the northwest seawall.
Managing the hemlock looper outbreak and wildfire risks
Hemlock looper populations usually decrease when the weather interrupts their life stages and when predators such as parasitic wasps and birds eat them.
Using pesticides is not an option because they harm other, non-target insects like butterflies that live in the forest ecosystem.
We're addressing the outbreak and wildfire risks with support from a forestry consultant. Their expert report PDF file (4 MB) outlines a careful approach, focusing on risk mitigation and ecological enhancements for long-term forest health.
