Many of the visitors to Stanley Park in the last several years have noticed the mounting number of defoliated and dead mature (80 years to 150 years of age) and old growth (150 years +) conifers in the park forest. They are being greedily attacked by the Western Hemlock Looper moth in their larval stage (a caterpillar that arches its back when crawling). It was fully expected when it first arrived to die out in 1 to 2 years. Uncontrolled, it is attacking the forest again this year (year 3) with even greater vengeance. Judging by the numbers of caterpillars and the numbers of flying moths, it looks like it will continue again next year, or until all of the mature trees are severely set back or dead.
The Vancouver Board of Parks and Recreation has had discussions with the Ministry of Forests , Lands and Natural Resource Operations Coast Region's Forest Health Officer two and one-half years ago about controlling the pest but the Board felt, with due consideration, they would not attempt any procedure such as aerial spraying with Bacillus thuringiensis (Btk). Btk was used successfully and without controversy this spring to cover 300 hectares in Surrey and in other areas of the Lower Mainland being attacked by another defoliator, the Lymantria moth, (see link below). This year, the looper has expanded greatly from north-east to south-west in the park. The General Manager's Office responded to my e-mail with the following:
"Thank you for reaching out regarding the trees in Stanley Park. The trees located on the North end of Stanley Park that appear dead have suffered from the elevated population of Hemlock Looper Moths that have surged during the past summer seasons. Though the Looper Moth are native to this area they put additional stresses on Hemlock trees and other species (Douglas for and Grand fir) within the forested areas as evident from the Lions gate bridge. Dramatic shifts in elevated temperatures, including the heat dome in 2021 and prolonged periods of drought, have further exacerbated tree mortality since over mature trees are susceptible to the moths feeding on them. The moths population boom typically occurs in an 11 to 15 year cycle. Effects of the Moth have been seen across the entirety of the North Shore with many trees dying in the process across various municipalities. Hazard mitigation efforts will be undertaken to remove the trees once determined to be hazardous to ensure public safety along both the Seawall and other high use areas of the Park. The majority of mortality has occurred within the short term. The response plan will be a multi-year effort engaging First Nation partners as well as several stakeholders. Fire fuel loading will also be reviewed in the course of an RFP to develop a holistic plan to cover the emerging issue." (e-mail dated August 29, 2022)
The Metro Vancouver watershed was hit hard in 2020 with 300 hectares of forest affected of the 20,000 hectares in the Capilano watershed alone. At its closest proximity to Stanley Park, it is just 6km away and was likely the source of the looper infestation in the park. No spraying was carried out. The Stanley Park forest is about 300 hectares or 75% of the total area of the park in total. What may be argued for improving forest resilience by leaving it to nature in a large, closed-access though scenically significant, watershed is not appropriate for Stanley Park and its millions of visitors where forest aesthetics and recreation values are intertwined with ecological values and health values (the fresh air lungs of Vancouver).
On August 31, 2022, I had a detailed conversation with Joe McLeod, City Arborist about how the city is going forward with the issue of the dying and dead trees in the park. The City obtained LiDar and multi-spectral aerial photography this past month and are awaiting the data to be processed. I appreciate the effort being undertaken, including the call for proposals (see below) on how to manage the risks going forward of the now changed forest, including visual landscape aesthetics.
After talking with Joe McLeod, I learned why they did not or perhaps did not feel they should act at the early each stages of looper development each year, and the wish to avoid public criticism. I also heard from the Executive Director, Invasive Species Council of Metro Vancouver on the same day whose comments were similar, but are withheld here pending further joint communication from the organization and the Stanley Park Ecology Society.
Hindsight is 20:20, as the saying goes, but had the Parks people acted on recommendations by FLNRO to control the pest with Btk, made known to them two-and-one-half years ago or longer, we would likely still have most of our famous mature conifer forest in Stanley Park. Now we'll have to wait many generations before the forest reaches that age, character, ecological complexity, and important contribution to the healthy atmosphere of the City. Did it have to be that way?
The City of Vancouver now has a Request for Proposals out regarding forest management in Stanley Park going forward over the next several years. The "Consulting Services for Stanley Park Forestry Initiatives" (PS20220119-ACCS-RFA) can be accessed on the City of Vancouver portal. As stated in the RFP, "The City of Vancouver (“City”), as represented by its Board of Parks and Recreation (the “Park Board”) is seeking proposals from multi-disciplinary consultant teams (“Consultant”) led by an urban forestry or environmental management/consulting firm with expertise in urban forest assessment and management planning. The project team must include staff or sub-consultants with experience in forestry, arboriculture, planning, urban ecology, integrated pest management, silviculture, planning, and wildfire risk assessment. The successful Consultant will have prior experience leading similar projects of scope and complexity and will work closely with Park Board staff to: 1) Provide an assessment of Hemlock Looper impacts to trees and forest areas in Stanley Park and an associated mitigation response plan in combination with hazard mitigation efforts that are of high importance related to target values; 2) Provide an assessment and mitigation plan for wildfire risks in Stanley Park; and, 3) Create an inventory of Hemlock Looper and wildfire risk areas as polygons in Stanley Park."
The RFP PDF can also be downloaded at the bottom of this page. Closing date was November 1, 2022. Unlike in my discussion with the City Arborist (above), there is no mention in the RFP of forest aesthetics, or visual impact assessment/mitigation/rehabilitation in the internationally important, extensively used, Stanley Park. Following extensive salvage logging, the restoration and rehabilitation of the forest will require a gigantic effort, and human generations to reach its recent glory again. Many of its trees now being lost were around when the park was first opened in 1888 by Lord Stanley.
A Bit of Stanley Park's History
Stanley Park is officially designated as Stanley Park National Historic Site of Canada by Parks Canada in 1988, and thus is infinitely worthy of our unwavering protection and commanding the excellence of stewardship and fullest duty of care. The park was first opened in 1888 by the Governor General of Canada (1888-1893), Lord Frederick Arthur Stanley.
K.B. Fairhurst, PhD, RPF, November 5, 2022
In the news October 13, 2022:
Forest along North-east Stanley Park Seawall - major infestation and die-back 2021.
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