Article by Marianne Elliot and Michael Yadrick

The Arbutus ARME is a new organization of botanical and community-powered people focused on expanding research, conservation, restoration and educational efforts related to Pacific madrone trees. The ARME in Arbutus ARME is a shorthand abbreviation of the Pacific madrone’s Latin name: Arbutus menziesii.

Pacific madrone, also known as madrona or madroño, is the largest flowering tree of the family Ericaceae.

Unique, exfoliating bark of madrone. Photo provided by Michael Yadrick

Madrone trees may not be as widely recognized as other regional icons like salmon, orca or Bigfoot, but they are arguably the most captivating native tree we encounter in Cascadia.

Pacific madrone stem(s) twist and lean, and its bark characteristically displays shades of orange, green, and red to cinnamon colors as it peels with age and sun exposure.

Madrones have flat, glossy leaves the tree retains throughout the year. Some birds dine on the large red berries that persist into winter and live in the tree trunks opened by cavities of decay. People too can utilize the berries, leaves and bark for culinary and medicinal purposes.

Unfortunately, Pacific madrones are becoming increasingly susceptible to diseases such as heart and butt rots, leaf diseases and cankers. This phenomenon is due to a combination of thinning stands, soil loss and compaction, fire suppression and other urban impacts.

Healthy and blighted Pacific madrone leaves. Photo provided by Marianne Elliot.

Symptoms of madrone decline date back to the late 1960s and early 1970s when severe canker and dieback symptoms were observed on madrones throughout the Pacific Northwest. Trees in in Seattle’s Magnolia Bluffs neighborhood were hit particularly hard during that period.

Since then the complex of diseases affecting Pacific madrone continue to threaten the species. Leaf blight, for example, attacks madrones every spring and was very damaging in the spring of 2011.

Cankers like these contribute to madrone decline. Photo provided by Michael Yadrick.

The presence and severity of diseases on madrones is heavily influenced by climate. Dieback and canker symptoms worsen in drought years while foliar diseases become more prevalent in years that have extended cool, wet spring weather.

Washington State University’s Plant Pathology Program gathered partners and stakeholders together a few years back for the April 2016 Future of Madrone Symposium. Participant brainstorming spurred a wish list of research questions and follow-up actions including creation of a survey/database dedicated to learning more about the condition of madrone.

As part of that effort we are now submitting data via the TreeSnap mobile app to determine a more exact geographical range of the species while also pinpointing healthy and diseased trees from people’s mobile observations.

We’re asking for your help: You can help us collect data on the range and health condition of madrone!

Please check out the following to learn more or stay in touch:

Other near future projects include hosting another symposium dedicated to madrone research and conservation, and publishing a guide dedicated to the care and cultivation of the species. Let us know if you would like to be more involved!

This picture shows the largest madrone in Washington (located in Port Angeles, WA) when it was in fair health. Today this tree is experiencing heavy dieback and continued decline. Photo provided by Marianne Elliot.


Marianne Elliot is a Research Associate at Washington State University Extension Puyallup specializing in Forest Pathology.

Michael Yadrick is a Plant Ecologist with City of Seattle Parks and Recreation, supporting the Green Seattle Partnership.