Ecosystem services are worth many trillions of dollars per year to the planet but are in decreasing supply as the demand increases. Among these services are those mentioned above: provision of watersheds, regeneration of soils and maintenance of the organisms within them, prevention of erosion and siltation, decomposition of wastes (dead organisms and their products), nutrient cycling, maintenance of the water cycle and rainfall levels, control of pathogens (especially insects), provision of food, medicines and fibers, maintenance of local and regional climate, reduction of wind damage, prevention of desertification and flooding, maintenance of renewable natural resources, and many others. Attempts to replicate the ecosystem services of natural forests and other ecosystems have not been satisfactory. Among these attempts are the construction of dams for flood and drought control (rather than retaining forests and natural ecosystems), using pesticides rather than relying on natural pest control, using fertilizers rather than allowing natural soil maintenance, and so forth. These replacements, often deleterious, are also tremendously expensive and require large amounts of energy. (Costanza, et al., 1997) have estimated the annual values of tropical forest contributions to ecosystem services as follows: climate regulation, $223 per hectare; disturbance regulation, $5 per hectare; water regulation, $6; water supply, $8; erosion control, $245; soil formation, $10; nutritional cycling, $922; waste treatment, $87; food production, $32; raw materials, $315; genetic resources, $41; recreation, $112; cultural, $2; for a total value per hectare per year of $2007. Assuming an area of 1.9 billion hectares of tropical forest, this gives a total value for tropical forests of $3.815 trillion dollars per year.