Aerial view of the Stanley Park forest, surrounded by water

Stanley Park forest management

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 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 all phases, approximately 14,000 trees have been removed. In addition, over 75,000 new seedlings of diverse species have been planted through a 3-year donation from Western Forest Products A total of 71% of Stanley Park’s forested areas have now been treated.

This outbreak also affects parts of West and North Vancouver, where many trees have been impacted.

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 3 work for hemlock looper response is complete for spring 2026 and will resume in fall 2026

At the Park Board meetings on July 21, 2025, and November 3, 2025, we received approval to advance work in the remaining untreated areas within the internal trail areas of the park. 

Work completed in spring 2026 focused on the west side of the park. The next stage of Phase 3 will resume in fall 2026 and will focus on internal trail areas on the east side of the park. 

If work is required over the summer months, this will be complete by internal operations crews.

No further traffic impacts are expected at this time.

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 (4 MB) outlines a careful approach, focusing on risk mitigation and ecological enhancements for long-term forest health.

Contact information, partner agencies, and website policies

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