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Western red cedar (Thuja plicata), an iconic tree species of the Pacific Northwest, is in trouble. In the past few years, there have been widespread reports of dieback throughout the tree’s range (Northern California to Alaska, west to Montana). Mapping by the U.S. Forest Service’s Aerial Survey has confirmed that the dieback is widespread. Trees in the Washington Park Arboretum have also been affected.

Changing climate patterns and repeated periods of summer drought appear to be major drivers in the dieback, however much more data needs to be gathered. A new community-science program called Forest Health Watch (www.foresthealth.org) has just launched at Washington State University (WSU), with funding from the US Department of Agriculture, and its pilot project is designed to aid and promote research about the western red cedar dieback. Anyone with access to a smart phone and the iNaturalist app can help researchers gather data and support the search for solutions.

Read all about it in the latest issue of the Arboretum Bulletin.

A grove of dead and dying Thuja plicata in the Arboretum. Climate change and extended drought are thought to be responsible.