The Library of Congress has an excellent online archive of environmental photographs taken by Chicago field ecologists during the formative years of ecology and the Chicago school of Sociology.
[Left: Mesophytic forest, Cold Spring Harbor, New York, http://hdl.loc.gov/loc.award/icuaep.nyp9 ]
This collection consists of approximately 4,500 photographs documenting natural environments, ecologies, and plant communities in the United States at the end of the nineteenth and the beginning of the twentieth century. Produced between 1891 and 1936 by a group of American botanists generally regarded as one of the most influential in the development of modern ecological studies, these photographs provide an overview of important representative natural landscapes across the nation. They demonstrate the character of a wide range of American topography, its forestation, aridity, shifting coastal dune complexes, and watercourses. Comparison of early photographs with later views highlights changes resulting from natural alterations of the landscape, disturbances from industry and development, and effective natural resource usage. The photographs were taken by Henry Chandler Cowles (1869-1939), George Damon Fuller (1869-1961), and other Chicago ecologists on field trips across the North American continent."