Trees help to control water and wind erosion and they recycle vital nutrients, such as nitrogen, back into the soil. Trees also grow where agricultural crops might fail, allowing production on marginal lands. Back to top Forests and medicine For 75 to 90 percent of the people in developing countries, natural products represent the only source of medicine. The active ingredients found in 25 percent of prescription drugs come from medicinal plants. Nearly all of the so-called alternative medicines are also based on plant extracts.
Forests are among the most important living genebanks on earth.
Many of the foods we consume today originated as wild crops in the forests. Genetic improvement has much to gain from existing wild species, which may possess valuable traits that can be incorporated into their cultivated relatives to make them hardier and more disease-resistant. If deforestation is not controlled, however, it could be the single greatest cause of species loss over the next 50 years. Back to top Forests for energy Wood energy is drawing increasing attention as an environmentally friendly source of energy. Wood is still people's main source of fuel for cooking, processing and preserving food, and will continue to be for many years to come.