“I soon found myself observing when plants first blossomed and leafed, and I followed it up early and late, far and near, several years in succession….”
Henry Thoreau, Journal, 1856
In Concord, Massachusetts, spring is coming earlier. Using plant flowering data collected by one of Concord’s most famous residents, Henry Thoreau, from 1852–1860, Boston University biology professor Richard Primack and his team of graduate students have found that, on average, spring flowers in Concord bloomed a full twenty days earlier in 2012 than in Thoreau’s time—and their statistics clearly show a close relationship between flowering times and rising winter and spring temperatures.
Early Spring: Henry Thoreau and Climate Change, a ground-breaking exhibition at the Concord Museum from April 12 through September 15, 2013, explores three centuries of careful observation of seasonal natural phenomena in Concord, a pool of data on the relationship between climate and biology that is essentially without parallel in North America. The exhibition also provides an extraordinary opportunity to examine the Concord Museum’s renowned Thoreau collection that includes the desk on which Thoreau wrote Walden, together with examples of his original field notes, journal recordings, seasonal charts, and botanical specimens. This material has never before been exhibited together.
Henry Thoreau (1817–1862) is one of the most read, beloved, and influential of American authors. He thought and wrote expansively about the natural world in a way that has, since his time, come to be called ecological. For the last ten years of his life, he devoted a portion of every day to a large-scale project to gather and analyze data on the changing phenomena of the seasons. He measured snow depth, watched for the day when the ice melted off Walden Pond, noted the arrival of songbirds in the spring, and above all, recorded the first flowering time for hundreds of plant species in Concord. “I often visited a particular plant four or five miles distant, half a dozen times within a fortnight, that I might know exactly when it opened,” Thoreau wrote in his journal.
The exhibition draws upon the Concord Museum’s unparalleled Thoreau collection of 250 objects, preserved by the Museum for more than a century. The collection includes the humble green desk at which Henry Thoreau wrote, his Walden bedstead, his snowshoes, spyglass, walking stick notched for measuring snow, and his copy of Wilson’s American Ornithology. These icons of American literary and natural history will be exhibited together with rare historical material—Thoreau’s seasonal charts, field notes, and journal—on loan from The Morgan Library and Museum. Additionally on view will be examples of Thoreau’s own herbarium specimens from the Harvard University Herbaria, and Thoreau’s flute book used for pressing plants, on loan from the Louisa May Alcott Memorial Association.
Thoreau’s choice of Concord as a subject was emulated by a continuum of naturalists, some amateur and some professional, in the 19th, 20th, and 21st centuries. The observations of these citizen scientists—carefully recorded over many years—now form an invaluable resource for scientists interested in the topic of climate change. Dr. Richard Primack, Professor of Biology at Boston University and Guest Scholar for the exhibition, has successfully used the data collected by Thoreau and later Concordians as comparatives to sets of data that he and his graduate students have been actively collecting in Concord since 2008. The work of the Primack Lab is a cornerstone of the Early Spring exhibition.