It has been nearly forty years since F. E. Clements popularized the concept that natural communities of plants and animals have properties far beyond their components. Analogies were made between the level of organization and integration in whole organisms with the organization of natural communities, and ecologists searched for several years in an effort to describe these possible structural analogies. They succeeded to the point that we now recognize that some plant communities have a kind of "life history” we call successional development, analogous to the life cycle of an organism. But modern ecologists realize that ecosystems are integrated in a much more elegant way than simply by the structure and function of the system*s components, or its unique and often repeatable pattern of development. This concept of ecosystem integration is based on a recognition of green plants as acceptors of solar energy and the conversion of this energy into chemical energy by photosynthesis. They recognize the elaborate, intertwining transfer of this energy from one trophic level to another in the ecosystem, and the gradual dissipation of this energy as heat as it is converted into driving the vital processes of each of the living components. contained in the idealized ecosystem. Modern ecologists further recognize that even though energy flows through the system, eventually being released as heat, water and minerals circulate rather than flow. Water and minerals are both common limiting factors in the productivity of ecosystems. At present the manipulation of the hydrologic cycle is not very feasible, but some manipulation of the mineral cycle is, and for that reason I would like to spend the remainder of our time discussing this cycle, and some ways in which natural and controlled fires may affect it.