6. Cultural ecology
If anything expresses plainly our relation to environment, it is the way people use and invest environments. The environment soon becomes, an engineered one; the way it is occupied and used is sensitively registered in the forms that are created. The composition of an engineered environment, and the relative location of its several features, are clues to and controls of the occupant's ecology. These features themselves respond to what may be called "ecological" conditions; their character and location tell much about the local culture, and become more comprehensible when studied as the issue of an interplay between two sorts of influences. These forces are;
  • the constant adjustments and coordinations among the individual members of the whole complex of man-made installations;
  • and the relationships between an installation and those outside elements of its own surroundings that affect it.
We should not expect to find a Buddhist temple in a Bantu kraal, a steel mill in a camp of Inuit, a field of pineapples in Saskatchewan, or a decayed log full of pale white grubs providing a feast to a crowd of Chicagoland suburbanites. In each of these unlikely cases, we might ask, "How can this be here?" This is a most useful question. It leads, once the location of certain features  is known,  to  consideration  of what  are  the necessary conditions for their presence.
Whether it be a grove of Sequoia sempervirens that demands summer moisture and high winter temperatures and so grows only near the northern California coast, or a petrol-station that depends on heavy automotive traffic and therefore occupies a corner of a busy intersection,  the location  of  any  geographic feature  conforms  to certain "rules." The very presence of a redwood tree or of a petrol pump presupposes certain circumstances in the present or the past that have allowed it to become established, and certain impulses or processes that have been sufficient actually to accomplish its establishment. In other words, both necessary  and   sufficient  conditions   exist  for  its occurrence.   The occurrence of a ghost-town suggests that the conditions for its establishment no longer obtain. On the other hand, those conditions identified as necessary to the incidence of  a  certain feature do not automatically ensure its appearance. For example, although the climatic and soil conditions of the Congo Basin are well suited to the establishment of Amazonian or Indonesian forest trees, such trees do not occur there: the impulse to theirdiffusion is lacking. But by the same token, the recognition that , the necessary natural conditions for the growth of the Brazilian rubber tree (Hevea) were present in Malaysia has led to the creation there of a major rubber-producing center.
When  necessary environmental  circumstances  are  known, the establishment of crop plants becomes possible in new areas; and, indeed, once the requirements of any engineered feature of environment are known, its development can proceed wherever the appropriate conditions are found. To dig a mine, a body of ore must be present; the geologic structure must be such as to support the excavation; facilities must be available to ventilate, drain, and shore up the interior passageways; means must be at hand to dislodge the ore, to carry it, to pass it on for processing and use. It is also necessary that the ore be of some use to a society, that other installations exist to smelt and form it, to transport it, and to sell the final product, and that it have a potential body of consumers. Given all these and other necessary conditions, the mine still will not be sunk until someone takes the initiative to acquire jurisdiction over the land and rights of exploitation, to assemble a crew of workmen, to install the necessary equipment, and to arrange for disposal of the product of the mine; this initiative is the sufficient condition for the presence of a mine. We cannot tell where or when it will obtain, but only where it might be possible and where it may not.
By asking "How can this be here?" of the various and specialized kinds of artificial features, we equip ourselves to estimate the potential development of the human ecology of particular territories under various cultural and societal forms.
Similar questions can be asked about a bridge—where can it span the stream? what routes shall it link? by what technique can it be built? what material may be used for its construction? —and about a cornfield, a watch- factory, a beauty- parlor, or an apartment house.
In each case, regardless of great differences among the circumstances that influence its location, the ecology of any feature involves first both the natural conditions of the place and the characteristics of the people concerned; and, second, it involves the composition and layout of the existing engineered environment. All of these circumstances are effective only as they bear on a particular feature at a given spot, and cultural ecology defines the integrated management people and natural resource of production to maintain its economy .