I HIGHLY recommend the "Economics of Protected Areas" by John A. Dixon and Paul B. Sherman (c)1990, Washington DC: Island Press. The just of their work is that any preservation should compare benefits against cost. The direct costs of establishment, monitoring and protecting; the indirect costs of pestilence or other damages; and the costs of lost opportunity, the benefits society looses by protecting the area. Weighed against these costs should be economic assessments of the many benefits of protection. These benefits MAY include recreation and tourism, watershed protection, the preservation of ecological processes, the preservation of genetic resources, education and research values, consumptive benefits such as the harvest of resources, plus non-consumptive benefits like aesthetics and mental health. In addition, there may be unknown future values as the result of new discoveries. While their work is primarily for the preservation of outdoor spaces, many of their theories and formulas would apply to the preservation of cultural resources. Ed Harrison [log in to unmask]