This USD 100,000 per year estimate does not include foreign visitors. Foreign visitors outnumbered domestic visitors by four to one in 1988. Assuming foreign tourists place the same USD 35 per trip value on MCFR as domestic users do, foreign visitation would represent an additional USD 400,000 to USD 500,000 of international recreation value annually. In fact, foreign visitation is likely to be worth far more since foreign tourists probably value the site more than domestic visitors due to their higher income and lack of nearby substitutes. At current visitation rates, the net present value of domestic and international recreation is about USD 2.5 million and USD 10 million, respectively, assuming a 4% real interest rate. Given that the Reserve comprises 10 000 ha2, the combined domestic and international recreational value averages about USD 1250 per ha2. Given that visitation has been growing at 15% a year for the past five years, this present value estimate is probably far too low. Nonetheless, the price which the reserve currently pays to acquire new land is between USD 30 and USD 100 per ha. This suggests expansion of protected areas near this reserve is a well-justified investment, both from an economic and social perspective. Clearly, there are several assumptions built into the valuation presented. The travel cost per kilometer, especially the values for time and fixed costs (car purchase and maintenance), are uncertain. The cost for private travel versus public transit is assumed to be the same, but may not be. Finally, it should be noted that the recreational value of a standing forest is but one of its potential benefits. The total value of the forest includes benefits from renewable harvests of many commodities, biological diversity, ecological services, and sites for scientific research. As we gradually develop methods to value these benefits, the argument for conserving the standing forests grows in strength and soundness. Further, as natural sites become rare, the benefits of preserving the remaining sites will only increase. It is imperative that all of the economic benefits of conserving tropical rain forests be explored and quantified as soon as possible. In this manner we will come to understand the actual and potential benefits of conservation, and may prevent irretrievable losses of precious biological resources