Nowhere on earth is the threat of biological impoverishment because of deforestation greater than in the Amazon Basin of South America. The Amazon supports approximately 300 million hectares of tropical forest, the largest single area of tropical forest communities in the world (Fig. 2). Estimates of global biodiversity point to the tropics as the source of 50 to 90% of all species on Earth (Wilson 1992); the richest forests often support over 300 tree species per hectare, approximately the same number …showed first 75 words of 2152 total…

…showed last 75 words of 2152 total…non-consumptive values in order to make economic benefit-cost analyses reflect the true value of nature, or, equivalently, the true costs of polluting and degrading the environment. The more humans damage the global environment, and permanently alter or disable the free ecological services that nature provides, the greater amount of money we will have to spend to provide these services ourselves. Some services, like global gas regulation or ozone, may be impossible to replace. ------------------------------------------------------------------------ **Bibliography**