I ’ve been celebrating the life, and mourning the loss, of the centenarian silver maple (Accession 12560*C) that grew along Meadow Road. After almost a century and a half in this spot, this magnificent specimen was removed due to its deteriorating health. But oh, the many ways it served! Its precocious spring flowers supplied nectar for bees. The canopy shaded and cooled the air. MIT chemists gathered its flowers to study the polymers (sporopollenin) that compose its pollen. Instructors used its cut twigs for an International Society of Arboriculture identification test. But most important of all, this giant sentinel welcomed every one of us who walked below. Strolling tourists marveled at its sheer mass, children measured the twisty trunk’s diameter, and generations of staff and docents greeted it like an old friend. What if Benjamin Watson had never provided those seeds back in 1881? What would the Arboretum have been like these past 140 years without it?
Some twenty years before our silver maple was planted in the ground, great things were afoot in Washington, D.C. and in states across the country: the USDA was founded and the Morrill Act (the legislation that established land-grant universities) was signed in 1862. Good things resulted from these and other public initiatives to follow (Yellowstone was created in 1872, and the National Park Service was established in 1916). Through these, the US has preserved natural lands, curated irreplaceable collections, conducted research on woody plants, and educated
student and lay person alike. Although the Plant Hardiness Map originated at the Arnold in 1927, it was the USDA that improved it in 1960 and, with updates every decade or so, provides an essential tool used by gardeners everywhere. How can one argue that these very good and very great things are not worth public support (i.e., tax dollars)?
The US has preserved natural lands, curated irreplaceable collections, conducted research on woody plants, and educated student and lay person alike.
Public support permeates the Arboretum: by my tally, over 1600 plants (10%) representing 600 taxa alive in the permanent collection are the result of it. We have Metasequoia glyptostroboides trees collected from wild populations in China in 1990 and donated by John Kuser, professor at Rutgers (a publicly supported, land-grant university). There are a half-dozen Malus accessions collected by Frank Meyer (explorer-botanist for the USDA) in China a hundred years ago, and over a dozen Malus sieversii (which gave rise to the domesticated apple) collected from Central
Asian populations by a host of USDA scientists several decades ago. Incredible plants, all of them. Just as some came from the wild, others were made. Scientists at the US National Arboretum (USNA) hybridized Magnolia ‘Galaxy’ in 1963 and released in 1980. We received our original accession in 1974, and its huge, purply-magenta flowers have been part of our cavalcade of color every spring since. More recently, we have been growing hybrid hemlocks from the USNA that tolerate that scourge, the hemlock wooly adelgid. These crosses between resistant Tsuga chinensis and susceptible T. caroliniana include ‘Traveler’ (hybridized in 1992, introduced in 2020) and ‘Crossroad’ (hybridized in 1998, introduced in 2022). Tree breeding is a slow affair, with progress measured in decades. Thank goodness for places like the USNA, one of the few places in the US still employing tree breeders, where generations of hybrids have been created, evaluated, and introduced by generations of scientists and curators, all to society’s benefit.
Speaking of hybrids, the Plant Collections Network (PCN, to which the Arnold
Arboretum’s eight Nationally Accredited Collections belong) is a collaboration between the American Public Gardens Association and USDA. PCN benchmarking has helped us take our collections of Acer, Carya, Fagus, Forsythia, Ginkgo, Stewartia, Syringa, and Tsuga from great to exemplary, and I know it has been the same for other North American gardens.
In 2011, I joined staff from USDA’s North Central Regional Plant Introduction Station in Ames, Iowa (home of the National Plant Germplasm System [NPGS] repository responsible for ash) on expeditions to collect three species (Fraxinus americana, F. nigra, and F. pensylvanica) in Pennsylvania and New York. We collected enough seed from enough mother plants to capture entire populations’ worth of genetic diversity,
enough to completely rebuild them in the future. It was timely, as emerald ash borer—which kills trees after a few years—had just arrived. Those populations, devastated in nature, are preserved (at least for now). This and other repositories possess incredible facilities, expertise, and long-term commitment to maintain wild and crop germplasm. And because NPGS is the largest germplasm-repository system in the world, it serves a public good of global significance.
Since 2007, I have been a member of the Woody Landscape Plant Crop Germplasm Committee, which comprises university and garden scientists, members of the nursery industry, and USDA curators and researchers. We advise on matters related to the acquisition, curation, and research use of woody plant accessions held among the many repositories, often in response to biotic and abiotic threats. Last fall, members of our committee published a call-to-action paper, “Seeing the Forest for the Trees,” in HortScience, which described the litany of challenges woody plants face—threats in the wild and in our urban forests and managed landscapes. We highlighted exploration, conservation, and research solutions to real-world problems, and hoped that our report could serve as a playbook for government and university scientists to direct future work. And who knows, maybe it would spark new public and private investments to safeguard against future threats. I was unprepared
for a new threat, one from within (DOGE), which would brutally girdle tree research and stewardship initiatives of vital public funding—funding I would say was already insufficient. The callous cutting of our nation’s programs will devastate not just the existing canopy (literally and figuratively), but also future replacements. Even if funding is restored at some point, the damage is going to last for a long time.
I know our late silver maple will be replaced by another great tree doing good things—our nursery is a constant pipeline of them. But imagine an indiscriminate clearcut through the Arboretum’s collections, without understanding the repercussions or having plans for any replacements. It might be like the Hurricane of 1938, an unplanned and unprepared-for disaster that ripped some 1,500 of our trees asunder. Make no mistake, such a storm is rising.
Michael S. Dosmann is the keeper of living collections at the Arnold Arboretum.