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On the trail of the elusive paperbark maple

by William (Ned) Friedman, Director of the Arnold Arboretum
September 30, 2015

On the trail of the elusive paperbark maple

The Arnold Arboretum of Harvard University has launched a 10-year initiative to expand and refine our collections of living plants–The Campaign for the Living Collections. This cross-institutional effort focused on plant exploration, collection, and production aims to enhance the Arboretum’s resources for research and conservation.  The Campaign kicked off officially in late summer with a domestic collecting trip to northern Idaho led by Manager of Plant Records Kyle Port, and continued through the month of September with an expedition through western China by Curator of Living Collections Michael Dosmann. Here is his report from the field.

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Michael Dosmann in China, standing next to A. griseum. Note its distinctive rust-red, exfoliating bark.

Nothing offers perspective on species’ rarity quite like attempting to locate it in the wild. During the first few weeks of September, I joined my colleagues from the North America-China Plant Exploration Consortium (NACPEC)–Tony Aiello (The Morris Arboretum), Kris Bachtell (The Morton Arboretum), and Kang Wang (The Beijing Botanical Garden)–on a quest to document the rare paperbark maple (Acer griseum) in its natural range in western China. Armed with notes and coarse GPS coordinates of about ten populations (most of those already known to science), we set out on a grand tour covering six of China’s provinces and adding more than 3500km to our odometer.

We were thrilled to have located all but two of the populations, which was no mean feat. Unlike the beautiful specimens that stand out like beacons in the Arnold Arboretum or home landscapes around the temperate world, most of these trees were small, growing in dense forest cover, and typically situated on steep slopes with inclines exceeding 50 degrees. One such population, growing in Chongqing, would have completely escaped our grasp had we not stopped in a local village to ask if anybody knew of these red-barked trees. Luckily, a local farmer not only knew of them but offered to take us up the slippery and rock-strewn slope to the trees. Our luck was great, indeed, for otherwise we could have been standing a mere 100 feet away from them and been none the wiser.

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Paperbark maple fruit (winged samara)

During each population’s sampling, we gathered an herbarium specimen (voucher), as well as silica-dried leaves of most if not all individuals for further DNA extraction and analysis. (A few populations were riddled with seedlings, so we did not sample from each of these youngsters.) We were also on the lookout for seed, to complement the two distinct E. H. Wilson collections gathered for the Arboretum a century ago, and the more recent 1994 NACPEC collection of the tree. These three introductions of A. griseum represent, essentially, the entire gene pool of the plant outside of China. Out of all of these populations and 100s of trees, we found only one tree bearing any fruit. We were thrilled to have had even this good fortune, and gathered a small supply to bring back to our respective collections and coax into germination. Look for a future update to see how they have fared under our cultivation and care.

This intense and focused trip did not leave much time for other collections–some days left us in the car for over eight hours. However, we did make some collections of seed and vouchers from high-priority taxa including Sinowilsonia henryi (sinowilsonia) and Corylus fargesii (Farges filbert), the latter from the largest individual of the species any of us in our collecting team had ever seen!

–Michael Dosmann

2 thoughts on “On the trail of the elusive paperbark maple

  1. Would it be possible to add a map, not detailed enough perhaps to show exact locations, but to show the route of your travels?

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