Decades of forest destruction have turned once-productive lands into desert across the Horn of Africa, worsening a devastating famine that has killed tens of thousands of people in Somalia and elsewhere, forestry experts say. A new study by the Center for International Forestry Research, conducted in 25 countries, shows that forests provide about one-quarter of household income for people living in or near them, offering a critical defense against poverty. In parched regions like the Horn of Africa, forests help retain moisture and soil nutrients, providing a defense against wind erosion and a source of food and energy. According to an international coalition, the clear-cutting of forests and degradation of land across the region have done more than the drought to convert once-productive grazing areas into a barren landscape. The group, the Consultative Group on International Agricultural Research, has called for increased investments in reforestation and agroforestry projects across the region, saying similar efforts in Kenya and Niger have revitalized forests and provided critical food and other resources.