Sequent Occupance

The concept of sequent occupance can be attributed directly to Derwent Whittlesey (1890–1956). He coined the term and proposed the principle of sequent occupance in his 1929 article of this title. The article opened with a declaration stating that human occupance of area, like other biotic phenomena, carries within itself the seed of its own transformation. He also stated that the view of geography as a succession of stages of human occupance establishes the genetics, or historical development, of each stage in terms of its predecessor. Thus, by implication, he prescribed the study of sequent occupance as integral to historical geography as well as regional geography. With sequent occupance essentially an analogue model, Whittlesey averred that the analogy between sequent occupance in chorology and plant succession in botany would be apparent to all. But he also qualified this, admitting that the botanist's problem is less intricate. The development of plant associations generally involves fewer agents and is more tractable and traceable than the multiplicity of changes, both biophysical and cultural, that combine to create chorologic formations. Having identified sequent occupance as a key to explaining chorological process, or the formation of[Page 426] regions, he also advocated its study in particular areal cases as a method for advancing chorology.

As a demonstration of his model, Whittlesey offered an illustrative case involving a 15-square-mile district in northern New England. Four stages, or occupance sequences, were discernible. The then current occupation, or third stage, consisted of sporadic livestock pasturage amid a landscape of second-growth forest and grassy glades marking former trails and roads. This was preceded by a thoroughgoing subjection of the land to farming. A largely self-sufficient population occupied and exploited all but the most unyielding terrain. The initial occupation was by a few Indians who lived a migrant life. They hunted and gathered, and by implication they had little impact on the virgin mixed forest. The fourth stage, as yet unrealized, was projected to be occupance by forests once more but periodically cut for wood pulp or lumber by nonresident owners. Unremarkably, he closed by affirming that in this New England district each generation of human occupance is linked to its forebear and its offspring. More provocatively, he concluded his short article with the assurance that the life history of each generation discloses the inevitability of the transformation from stage to stage. Notable in this demonstration model was the absence of chronology. In keeping with the generalizing or nomothetic tenor of model building, dating of the transitions or durations are elided in this specific case. Yet Whittlesey intended for his model to be applied to quite specific regional or chorologic units ranging in scale from the microgeographic (e.g., his test New England district) to large regional expanses. He also assumed that once a comparative record of sequent occupancies was established, the number of actual sequence patterns that ever existed would be small.

Whittlesey's article and advocacy must be viewed within the context of the times. During the decade of the 1920s, several geographers besides Whittlesey offered programmatic schemata for advancing human geography, particularly human–environment interactions and the resultant evolution or development of regions and landscapes. In 1923, Harlan Barrows, one of Whittlesey's colleagues at the University of Chicago, delivered his presidential address to the Association of American Geographers. Titled “Geography as Human Ecology,” it sought to replace the waning but still influential environmental determinist outlook in North American geography with an emphasis on “human adjustments” to physical environmental conditions and constraints. Like Whittlesey later, for Barrows the inspiration drawn from biological ecology was more impressionistic than precise. Although Barrows's main affiliation (curiously) was with historical geography, his design for a human ecologized geography was directed mostly toward contemporary cases and questions. The second major statement was published by Carl Sauer in 1925. Titled “Morphology of Landscape,” it set forth a program for cultural geography in which cultural landscapes and the historical study of their origins and modifications comprised the organizing principle. Unlike either Barrows or Whittlesey, Sauer eschewed the notion that identifying stages, whether of human occupancy or of landscape change, should be the object of either geographic theory or geographic practice. In part, he was concerned with distancing himself from the Davisian physiographic cycle of erosion with its celebration of staged evolution. He was also skeptical of any system, or accounting of it, that transformed primarily through endogenous or internal change. Sauer soon was to see cultural diffusion, and other forms of exogenous change, as the mainspring of landscape evolution. Although Whittlesey made room for exogenous change in deflecting given trajectories of occupance's sequencings, those geographers who followed his method over the next decade or so were more model bounded rather than less so.

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