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This semi-regular e-newsletter celebrates all-things Pacific madrone, highlighting our conservation and restoration efforts while connecting tree researchers and enthusiasts along the way
New to the ARME this month
Orlando de Lange
Orlando de Lange is a Plant Molecular Biologist at UW by day, and moonlights as a citizen science organizer and workshops director at SoundBio Labs, a community lab in Seattle's U-district. The lab is equipped with equipment for molecular biology and microbiology and is open to anyone wanting to learn from our workshops our carry out a research project, ideally a project that involves and benefits our regional community. Orlando is particularly keen to get a project going that would in some way benefit research into the causes or solutions of Madrona decline. Ideas floated so far include micropropagation and microbiomics from environmental samples. So if anyone has ideas for projects, or just wants to find out more about SoundBio they can get in touch at

The Collective

Demystify Madrone: If It Leans, Will It Fall Over?
Some people may be concerned with the inclination of madrones to deviate from the perpendicular. We understand the concern, particularly for homeowners in an urban area inheriting a tree that is leaning AND showing signs of disease and decline.
 A reputable arborist could properly assess risks associated with any leaner.

The species shows a great deal of plasticity as they grow and advantageously reach for available light. Compared to the typical conifer, like the Douglas fir, a little (or even a big) lean of 15-20 degrees for madrone doesn’t necessarily mean the tree will fail. One may notice that madrones growing in a crowded forest may display a straighter form than those growing out in the open. And as trees age, their need for light may increase. They can thrive on tough sites where other species would suffer like rocky outcrops and shorelines. In more open conditions, the characteristic growth form is the twisted, multi-stemmed tree that distinguishes them from other trees.
Madrones are in bloom from mid-March until June. Their flowers are pollinated by a wide range of birds and insects. These animals are attracted to the nectar produced in the flowers. Look for hummingbirds, both Rufous (Selasphorus rufus) and Anna's (Calypte anna) hummingbird have been observed visiting madrone flowers.

YouTube video of various insects pollinating madrone flowers:
Learn more about pollinators and the plants they visit:
TreeSnap Update
We have data! Pacific madrone has been on TreeSnap since last winter, and since then thirty people have submitted 155 observations. Most of the observations have been centered around the Seattle area, however, people have been snapping trees in places as far north as Anacortes, WA and as far south as Monterey, CA. Great job Spring travelers, Ruth Baetz and Luke Armitstead, who snapped trees in Oregon and California! Interestingly, more than half the observations note that tree canopy is relatively healthy with less than 10% damage to the tree crown, though these trees still exhibit disease symptoms like blight, leaf spots, wilting leaves, and lesions. We are snapping most trees in mixed stands and stand-alone trees with a little less occurrence.

We encourage people to visit areas and snap trees at the edges of the range. The photo above is from an older USDA silvics manual. Moving forwad, we really need data from British Columbia, Oregon, Central/Southern California to build a more precise range map for the species. Also remember to leave comments about things like flowering and leaf blight – both can be seen now. You can see the current observations here: 

Featured Disease – Leaf blight
Symptoms of blight on Pacific madrone (Arbutus menziesii) appear after periods of cold weather in winter or early spring. Leaf symptoms include spots that coalesce and form blotches, usually in areas where water collects including the tips and edges. Foliar blight on madrone usually affects the lower parts of the crown and is most common on trees growing in a shaded, humid environment. The problem may become more severe after periods of extreme cold. The fungus Phacidiopycnis washingtonensis has been isolated from madrone twigs and foliage with blight symptoms. This fungus also causes rot in apples that are in cold storage.

Management of foliar diseases generally includes pruning infected twigs and cultural practices that improve tree vigor and prevent stress. Raking and removing leaves in the autumn helps control some leaf spot diseases but has minimal effect on anthracnose and blight, since the fungus is present in the twigs.

It’s important to remember that trees are resilient and while the madrones may appear to be dead from leaf blight, they will often recover when the new foliage comes out.


The Arbutus ARME met on March 23 in Puyallup, where we explored madrone basics, forest ecology, pathogens, conservation efforts and propagation tips, and the TreeSnap app for survey and mapping. The outdoor portion included a visit to one of the madrone common garden sites where we are studying the genetics of this tree. We learned to recognize disease symptoms and tested out TreeSnap.
Upcoming Events!
The 2019 Urban Forest Symposium will take place on Tuesday, May 21 from 9:00am to 4:00pm. The Honorable Hilary Franz, Washington State's Commissioner of Public Lands, will be joined by local experts from academic, nonprofit, business, and government sectors, for a robust discussion of climate change impacts to the urban forest, and how local communities are taking action. City of Seattle Plant Ecologist, Michael Yadrick, will be presenting "Global weirding impacts on our local urban forests" - with a little madrone info slipped in there. Speaker and program information available at:
Job opportunity
Full-time, temporary Biological Weed Control Field Assistant for the 2019 field season. The hourly wage is $17-$19, depending on experience. A detailed position description is at this link: .
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