MANAGING NATURAL ENVIRONMENTS
There are many dimensions to environmental quality and, thus, many dimensions to the threats to this quality. These may range from minor local disturbances causing physical or psychic discomfort, to large- scale ecological upsets that may affect the length of time man can occupy the earth ( Brubaker, 1972). In this study we address issues that cover the entire range of environmental threats.
The theoretical portions of this book are devoted to an abstract, and therefore widely applicable, treatment of the side effects, or externalities, associated with human economic behavior. These range from minor spillovers that impinge on the amenities of life, to major results of irreversible decisions. The problems taken up in the applied studies, while specific, are important in the models they offer for dealing with environmental considerations that have mostly been neglected in the decision-making process. That is, our empirical work is concerned with the valuation of the opportunity costs of economic activities that can be expressed as loss of amenities otherwise available from a natural environment. It consists of explorations in the relative valuation of amenity and commodity resources.
While the empirical portion of the study does not deal with the gravest environmental threats, it should not be inferred that the problems addressed are of minor significance or little economic consequence. Indeed, the aesthetic dimensions of the environment have been of such profound and persevering concern to the American people that they have occupied an important position in conservation and environmental legislation and policy. It is interesting to note, for example, that the Wild and Scenic Rivers Act preceded the National Environmental Policy Act (NEPA) by a year and the Wilderness Act by several years. In a decade that witnessed the commissioning of a national outdoor recreation resources review, we also saw passage of the Classification and Multiple Use Act of 1964, which required the Department of the Interior to recognize the