Modern oak

by Jonathan Damery, Associate Editor of Arnoldia
September 30, 2019

Modern oak

The arching silhouette of Quercus variabilis (1581-77*F). Photo by Jonathan Damery.

I have no numbers or statistics to prove this, but this fall, at least locally, appears to be quite good for acorns. The roads around Jamaica Plain are covered with an increasingly dense flour of smashed red oak (Quercus rubra) acorns, and the bounty has been plummeting much more profusely than last year. Fall is also, of course, the season for plant collecting expeditions. (The reason for this convergence goes without saying.) When I think of plant collecting in the modern era—the time of airplanes and automobiles, rather than, say, steamboats and horseback—my mind inevitably turns to a 1977 expedition to Korea and Japan, undertaken by Arboretum horticultural taxonomists Stephen Spongberg and Richard Weaver. One of the striking specimens from this expedition is an oriental oak (Quercus variabilis, accession 1581-77*F) growing near Faxon Pond.

The bristle-tipped leaves of Quercus variabilis (1581-77*F). Photo by Jonathan Damery.

I remember first admiring this tree a decade ago, particularly noting the leaves, which to me—then a college student, participating in the Hunnewell Internship program at the Arboretum—seemed exceptionally unusual for an oak. The leaves are about six inches long and relatively narrow, the margins lined with bristle-tipped teeth. This year, after a burst of horticultural attention around Faxon Pond, which opened the understory, the tree itself—not simply the leaves—has popped to the foreground. It isn’t a large specimen compared to older oriental oaks elsewhere in the collection (for instance, accession 16889*A, growing along Oak Path), but it leans gracefully towards the road, no doubt shaped by almost four decades of growing in the shadow of a large white oak (Quercus alba). One of the branches swoops towards the ground—a graceful genuflection—bringing the leaves into view. The few acorns that are visible overhead are still green, their rowdy caps (technically cupules) almost enclosing the seed.

Acorns for this tree were collected on, what I always like to call, the first modern plant-collecting expedition for the Arboretum. After Ernest Henry Wilson—the famous Arboretum plant collector of yesteryear—returned from his final expedition to Japan and Korea in the early months of 1919, no Arboretum staff returned to those countries (at least for official Arboretum-sponsored plant collecting) until Spongberg and Weaver’s six-week expedition in 1977. The objectives for their trip were, in part, to expand the diversity of the Arboretum’s holdings for individual species, even in the case of species like Quercus variabilis, which were already represented in the collections, and, simultaneously, to increase the research value of the collections.

The curious acorns of Quercus variabilis (753-94*A), photographed in 2015. Photo by William (Ned) Friedman.

At the time of the expedition, for instance, the Arboretum already possessed twelve oriental oaks, representing nine unique provenances. But only one of those accessions came from Korea, in 1905, and the corresponding data simply suggested that the acorns were collected near Seoul. On the 1977 trip, the collectors acquired more specific detail. From our plant records database, we learn that the acorns were collected in a coastal woodland at Uihang-Ri, located on a shoulder-like protrusion on the western side of the Korean peninsula. The collectors also acquired information about associate species occurring nearby, and, perhaps most interestingly, three other accessions from the same coastal woodland are growing in the Arboretum landscape today (Viburnum bitchiuense, accession 1797-77; Koelreuteria paniculata, 1605-77; and Platycarya strobilacea, 1781-77). As Arboretum collectors have continued to work in eastern Asia over the following decades, the level of information that is collected about each accession has only increased, often including information about soil, elevation, slope, and measurements of the parent tree. One can only imagine the types of research questions that will eventually be supported with these data, especially in an era of rapid and widespread environmental change.

Beyond this provenance intrigue, however, this oriental oak, simply, is worth seeing. In the latest issue of Arnoldia, Jon Hetman, writes about an old painted maple (Acer mono, accession 5358*A) growing down the road. He muses about the timeline for when that maple—grown from seed that arrived at the Arboretum in 1901—achieved its indisputable status as a museum masterpiece. In that case, the first reference to the tree as a showcase specimen seemingly occurred in the early 1980s, when the tree was rising into its eighth decade. With this oriental oak, I’m calling it now: so long as weather, pests, other potential detriments to the tree cooperate, this will enter the masterpiece class of tomorrow.

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