Valuing values: A history of wilderness economics
Bowker, J. M., H. K. Cordell, and N. C. Poudyal.  2014.  International Journal of Wilderness, 20(2): 26-33.

Abstract:
Prior to the U.S. Wilderness Act of 1964, economics as a science was hardly considered applicable to the types of human values set forth in this pathbreaking legislation. Economics was largely confined to the purchasing and labor decisions of households and firms as well the functioning of markets and economies. However, around this time, John Krutilla (1967) in his seminal paper entitled “Conservation Reconsidered” recognized the economic importance of benefits from nature that were not traded or valued by conventional markets. During the next 50 years, economists developed theoretical and methodological tools that allowed economic values, or dollar metrics, to be estimated for wilderness and other protected nature. In this article, we review the conceptual basis for an economic understanding of wilderness benefits and values. This review is followed by a brief summary of empirical studies about economic values of wilderness. We then use this information to derive rudimentary dollar metrics for the National Wilderness Preservation System.