Southeastern Geographer

A PHENOLOGICAL model for southeastern UNITED STATES Richard J. Kopec* In 1938, A. D. Hopkins introduced his magnum opus, Bioclimatics, A Science of Life and Climate Relations, culminating twenty years of research in entomology. (1) In this massive work, he set forth the principles of bioclimatics and provided a phenologic model for predicting the annual occurrence of natural phenomena in space and time. Remaining obscure for many years, this manuscript found periodic revival and has recently been rediscovered and reevaluated by some botanists. In a recent response to a request by Bliss (2) for help in establishing a phenology program as part of the International Biological Program, Leith and Radford (3) suggested the adoption of a modified phenologic model originally presented by Hopkins and subsequently adapted by Schnelle (4) and Kopec (S) to their needs. It is believed that an examination of phenology and Hopkins' Bioclimatic Law may serve to introduce and provide physical geographers and climatologists, by way of illustration, with a practical analytical tool in their studies of the physical environment . Phenology, defined as that science which deals with the influence of climate on the cyclic activity of natural phenomena, has been by and large ignored by practitioners of our discipline. With today's emphasis on ecological network studies and social concern with natural environment systems, a reexamination of phenology seems well advised. The influence that climate exerts on all biotic activity is pervasive, and perhaps because it is, its significance is diminished. Yet geographers are constantly made aware that climate control remains the primary environmental parameter in determining the cyclic behavior of physical phenomena , be it diurnal, annual or seasonal. A phenologic model which would permit prediction, within reasonable tolerances, of such reoccurrences as the beginning of the frost free season or the spatial character of annual insect migrations would be of considerable technical value. Further, a bioclimatic model would make possible the identification and understanding of the physical controls underlying cyclic aberration of phenomenal occurrence which would enhance the development of more realistic theoretical and empirical resource management models. Hopkins recognized the need for such a model and formulated the Principles of Bioclimatic Law which state as follows: ?Dr. Kopec is associate professor of geography at the University of North Carolina at Chapel Hill. The paper was accepted for publication in October 1971. 24Southeastern Geographer (1)Under the requirements of astronomic law, phenomena of life and climate should be equal under equal astronomic causes along the parallels of latitude around the earth. (2)Under the requirements of bioclimatic law, phenomena of life and climate as modified by terrestrial influences should be equal under equal influences at the same level across the continents along lines which depart from the parallels of latitude at the assumed rate of Io of latitude to 5° of longitude. These lines are called isophanes. (3)Since, however, the influences of the local, regional, and continental causation complex are never equal, departures or variations of the observed effects from the requirements of astronomic and bioclimatic law must occur. Such variations, as determined by bioclimatic methods and expressed in units of time, temperature, or distance, serve (a) as measures of the relative intensity of the modifying influences, and (b) as indices to the interpretation of causes and factors and to the prediction of bioclimatic elements at given geographic position within the latitude and altitude range of the influences represented by a record position and its variation indices. (4)Under the laws, principles, systems, and methods of bioclimatics, the bioclimatic elements of any record position can be analyzed and directly compared, on a strictly coordinate basis, with those of any other position or continent. (5)The bioclimatic zone and zonal types of a place, area or local region are the most reliable indices to the species of plants and animals and to the types of agriculture that are best adapted to the local conditions and requirements. (6) By providing this theoretical base neutralizing the controls of continentality , latitude and altitude, Hopkins made possible the prediction of phenomenal reoccurrences and the determination of the intensity and areal pattern of secondary climatic influences on the distribution of biophenomena. To illustrate the efficacy and flexibility of Hopkins' Bioclimatic...