This is a research monograph in which I explore and evaluate the biophysical relationship between ambient climate and the form and function of the associated vegetation. I hope the results will be useful in anticipating the changes to be expected in vegetated surfaces under conditions of slowly changing climate.

At the 70 percent of Earth's surface which is water, the atmospheric boundary conditions are, under idealized circumstances, readily expressible in terms of the classical laws of thermodynamics and fluid mechanics. For the remaining 30 percent of the surface however, there is a greater or lesser presence of vegetation, and the boundary conditions are determined in part by biological behaviors which differently constrain the moisture and energy fluxes. In such cases the boundary conditions are termed “interactive” because the structure and type of vegetation help to determine the climate through their exchange of heat and moisture with the atmosphere, while the climate through its supply of moisture, carbon dioxide, and light to the surface helps to determine the type and structure of the vegetation.

This book is devoted to theoretical generation of these atmospheric boundary conditions at vegetated surfaces under conditions which are necessarily highly idealized. As John Monteith (1981, p. 753) said: “in a topic such as this, progress can be made only if the number of variables is held to a minimum at every stage in the analysis…”.