Isaiah Bowman’s Forest Physiography

I Introduction

The history of physical geography in the USA is strongly tied to the research and teachings of William Morris Davis at Harvard University in the late 19th century. Davis taught geomorphology and physical geography to an entire generation of American geographers and geologists, and published landmark volumes in physical geography (Davis, 1902, 1909) in addition to literally hundreds of scientific papers (Daly, 1944). Physical geography during this period was often referred to by the contraction-term physiography. The term physiography was clearly intended to serve as an overarching term for the universe of concepts typically taught in physical geography classes, including geodesy, meteorology, climatology, soils, plant distributions, and geomorphology. Widely used textbooks from the early 20th century (Salisbury, 1929; Tarr and Martin, 1917) with the term physiography in their title were topical compendiums of the entirety of the field of physical geography.

Early 20th-century American geography was also a period that saw the rise of regional geography as a prevailing paradigm. Regional geography courses became the standard teaching practice in American geography departments. The first American textbook that combined the emerging regional paradigm with the concepts of physiography was Isaiah Bowman’s 1911 classic Forest Physiography. The title of this work was, perhaps, a disservice in that it does not truly describe the contents of the book, as will be shown.

Isaiah Bowman was trained as a physical geographer, first under Mark Jefferson at the State Normal College in Ypsilanti, Michigan (now Eastern Michigan University), and subsequently under the acknowledged master of American physical geography, William Morris Davis, at Harvard University. Bowman received a BS degree from Harvard in 1905 and was subsequently hired at Yale University as an Instructor of Geography (Wright and Carter, 1959). While working as an Instructor at Yale, Bowman also pursued his PhD. He conducted extensive expeditions in South America, in a region that included southern Peru, northern Chile, northwestern Argentina, and the highlands of Bolivia. He received the PhD in 1909 with a dissertation that reflected his emerging expertise in both physical geography and his region of choice, ‘The Physiography of the Central Andes’ (Wright and Carter, 1959).

Although trained primarily in physical geography, his extensive travels in the Andes led Bowman to think of himself as a regional geographer; indeed, he was one of the first American geographers to identify himself in such a fashion. According to Wright and Carter (1959: 45), ‘when answering a questionnaire addressed to American geographers in 1907, [Bowman] alone specified “regional geography” as the branch of the subject that interested him the most’. Bowman’s interests in both physical and regional geography were soon manifested in an American physical geography classic.

II The writing of Forest Physiography

During his time at Yale, Bowman was tasked with teaching a course on physiography to students in the Yale Forestry School. Bowman found that the forestry students needed extensive background in the physical geography of the USA as well as its regional physiographic variation. In order to provide his students with appropriate background, Bowman wrote Forest Physiography (1911), tellingly subtitled Physiography of the United States and Principles of Soils in Relation to Forestry. Forest Physiography is a weighty volume of over 750 pages (including index), of which roughly the first 100 pages are devoted to teaching principles of soils to Yale forestry students. ‘Part One – The Soil of Forest Physiography’ includes chapters on the importance, origin, and diversity of soil, and individual chapters on soil variables such as soil water, soil texture, soil temperature, chemical features of soils, organic matter in soils, and soil classification. This section of the book is itself a fine example of the state of knowledge of soil science in the early 20th century.

With a sufficient background in soils thus provided, Bowman then launches into the heart and soul of Forest Physiography, ‘Part Two – Physiography of the United States’. The entirety of the remainder of the book, except for four brief appendices, is comprised of Part Two. Part Two begins with a chapter introducing the concept of regions to the forestry students, and provides a quick primer on the concept of physiographic regions, and climatic and forest regions of the USA. With that brief background on the regional geography of American climatic and biogeographic districts, Bowman then examines every physiographic province of the USA in individual chapters, beginning with the largely unknown (to a Yale student, because Yale is located on the east coast of the USA in New Haven, Connecticut) west coast of the USA and working his way toward the more familiar US east coast. Twenty-five individual chapters on the physiographic provinces of the USA are provided in stunning detail.

III Bowman’s ‘Physiography of the United States’

The 25 chapters comprising Part Two of Forest Physiography describe the state-of-knowledge of American physiographic provinces as they were then understood. Differences exist among how the physiographic provinces were defined and mapped in Bowman’s book versus their later elucidation in Fenneman’s better-known Physiography of Western United States (1931) and Physiography of Eastern United States (1938) volumes, but the major regions of American physiography are clearly outlined and recognizable on Bowman’s Plate IV, ‘Physiographic Provinces of the United States’, included as a fold-out inset between the appendices and the index of his volume.

Bowman’s chapter-by-chapter examination of the individual physiographic provinces set the pattern and standard for subsequent regional physiographies such as those by Fenneman (1931, 1938) and Atwood (1940). Each chapter is richly illustrated with photographs (many from the files of the US Geological Survey), topographic and geologic cross-sections, block diagrams, and a variety of maps including portions of topographic maps that at the time were the very latest efforts published by the US Geological Survey. The nature of the boundaries of each province was clearly described. The written descriptions of the topography, landform types, and landform origins are rich in detail, albeit at times richly Davisian in their attention to erosion cycles. The Davisian nature is understandable both in terms of the historical period when the book was published and in terms of Bowman’s training under Davis’ tutelage at Harvard. Each chapter concludes with comments on the climatic characteristics of the province and a seemingly quirky description of the forest resources of that province, but this so-called quirk is a function of the audience the book was designed for, the forestry students of Yale University.

IV The legacy of Forest Physiography

After the publication of Forest Physiography, the field of physiography did not become ‘regional physical geography’ overnight. As stated earlier, subsequent books by Tarr and Martin (1917) and Salisbury (1929) published in the USA continued to present physiography as physical geography from a strictly topical perspective. Nonetheless, the regional approach to the presentation of physical geography in the USA began to become a dominant paradigm. Within the realm of geomorphology, particularly as a result of the works of Nevin M. Fenneman, who was appointed by the Association of American Geographers in 1914 to chair a committee tasked with preparing a map of the physiographic divisions of the USA, the boundaries of the US physiographic provinces became standardized (Fenneman, 1914, 1917). These provinces were subsequently the topics in Fenneman’s landmark volumes on the physiography of the western (Fenneman, 1931) and eastern (Fenneman, 1938) USA. Subsequent books by Atwood (1940), Thornbury (1965), and Shimer (1972) continued the regional geomorphology tradition in the USA well into the period when process geomorphology was becoming a dominant paradigm in the discipline.

A popular general regional physical geography of the United State by Hunt (1967) continued the Bowman legacy into the modern era. Regional physiography has begun a resurgence in the classroom in the USA since the 1960s when both Hunt’s (1967) and Thornbury’s (1965) texts were widely used in both geography and geology departments. A recent volume by DiPietro (2013) is clearly in the tradition of Bowman’s Forest Physiography. It remains to be seen if regional physiography classes will become re-established as important cornerstones of undergraduate curricula in physical geography and geology programs, but the legacy of regional physiography and Isaiah Bowman’s Forest Physiography continues to be felt across geography and geology departments throughout the USA.