The State of American Forests in 1884

Slate blogger Rebecca Onion recently offered a post on the digitization of maps originally produced to display data collected by Charles Sprague Sargent, a botanist and first director of the Arnold Arboretum. The maps were published in 1884 as part of the 580-page Report on Forest Trees of North America (Exclusive of Mexico) for the Census Office of the Department of the Interior.

This report forms an invaluable snapshot for anyone trying to understand changes in the North American forest over the last 130 years. For instance, the last map in the report shows the distribution of redwood along the California coast. It displays both those areas where all merchantable (i.e., commercially viable) quantities of the species had been removed and those areas that still had in excess of 200,000 bd. ft. per acre.

Sargent, who was from the generation that preceded Gifford Pinchot, was not trained as a forester. His influence on the profession, however, has been significant. His comprehensive, two-volume Manual of the Trees of North America first published in 1905 is still a go-to reference on my bookshelf. Taxonomists may change the names and groupings of trees, but the basic characteristics of individual species remain constant over many generations.

The other part of the story is the David Rumsey Map Collection. The collection contains 150,000 maps, 30,000 of which are available online. Publication dates span from 1492 to 2007. There are 16 Sargent maps in the collection.

Rumsey, the president of Cartography Associates, started building the collection after working for 20 years in real estate and finance. In addition to digitizing and making the maps available as images, Rumsey is working on mapping and visualization software.

His Georeferencer allows the production of locationally accurate overlays in 2 or 3-D. I tried this with one of the Sargent maps of North America. Due to large extent of the map and the difference in the projections used, my test was less than successful. This does not diminish the potential of Georeferencer to be a powerful tool for looking at change over time and bringing history to life.