Western Redcedars

Evidence of Western Redcedar Dieback
To estimate the presence of dieback in western redcedars in Burlington, Mount Vernon, and Anacortes this author visited the cities' parks and used them as samples for the extent of dieback in the two towns.

In Burlington, many of the trees were cut for the development of playgrounds. However, a notable stand of redcedars grows in Maiben Park, also home to the Burlington Community & Senior Center. This grove is a splendid example of second-growth redcedars. Burlington Parks Supervisor Jim Rabenstein observed that dieback is not currently a problem in the park's redcedars. However, in 2019, several Burlington residents reported concern about dieback in town. In response, the parks department hired certified arborists from Urban Forestry Services/Bartlett to assess the redcedars in Maiben Park. Approximately 100 native forest trees were assessed—about 94 were redcedars. The report noted the "exceptional nature of this grove," with redcedars measuring up to 90 inches in diameter at 4.5 feet and in good condition. However, the report stated that drought mitigation planning will be essential in preserving this valuable community resource as long as possible. The report suggested that mulch be added under the trees to mitigate increasing drought stress and heavy foot and bicycle traffic under the trees.

In Mount Vernon, no significant dieback was evident in most of the city's parks. Dieback, however, has occurred among several redcedars at the southern edge of Bakerview Park, most likely due to the compacted turf beneath them. Hillcrest Park, with its numerous redcedars in a natural setting, has yet to show any significant dieback. These second-growth trees are estimated to be at least as old as the park itself where, in March of 2024, the city held a 100^th birthday in celebration of the park's founding.

Five years ago, a dieback of the western redcedars occurred at Little Mountain Park, a 522-acre park in southeast Mount Vernon. In response, Sean Corcoran, the Operations Supervisor in the Mount Vernon Parks & Enrichment Services, said that the city requested help from Washington State University Extension, Forestry Division, to assess redcedar dieback in a northeast section of the park. Forest experts determined that root rot (Armillaria) brought on by drought had caused the dieback. Crews removed most of the damaged trees.

Community Scientists and Western Redcedar Dieback Map
Washington State University, WSU, has invested considerable energy and resources in observing Western Redcedar dieback in Washington state via their WSU Extension Forestry division. Working from the hypothesis that redcedar dieback is a consequence of the region's recent drought, WSU has launched the "Forest Health Watch" to keep track of dieback occurrences. To participate as a "citizen scientist," access their website at https://foresthealth.org/redcedar and report the dieback. Your information will help confront the looming disappearance of these giants in our midst. A detailed map of "citizen scientist" reports is also available. The website also provides multiple links to research on identification, biology, ecology, distribution, ethnobotany, and relevant pests and diseases.

The best action today's gardeners and homeowners can take to prevent redcedar dieback is to keep the soil around their trees weed-free and mulched and to discourage heavy foot traffic. Learn more about how to help your trees beat the summer heat.