Unfortunately, this link is rarely reflected in national development programs. However, inappropriate use of forests and forested land is threatening food security. Each year 15.4 million hectares of tropical forests are felled and burned to convert them to other land uses, mostly unsustainable small-scale farming and livestock pasture. Soils are impoverished when trees and shrubs are removed for fuelwood. This has global consequences because tropical forests are essential in maintaining the quality and stability of the world's environment.
Trees prevent soil erosion, enhance soil fertility and maintain soil moisture.
In Algeria, for example, trees are used to stabilize sand dunes and arrest desertification. Deep-reaching tree roots can help mobilize nutrients far below ground level for use by food crops. Windbreaks and shelterbelts protect crops from drying, damaging winds. In New Guinea, shelterbelts have significantly increased grain production. Trees also provide farmers with materials for fence posts, poles and farm implements.