About 14.8% of Nigeria, or roughly 13,517,000 hectares (33,400,000 acres) is classified as forest or woodland. High forest reserves occur mostly in Ogun, Ondo, and Oyo states; savanna forest reserves, chiefly in the northern states, are limited in value, yielding only firewood and local building materials. In 2000, 67,767,000 cu m (2.4 billion cu ft) of roundwood were produced, 85% for fuel. That year, Nigeria's consumption of fuel wood and charcoal was third highest in Africa. Exports of timber and finished wood products were banned in 1976 in order to preserve domestic supplies. The ban was subsequently lifted and the forestry sector recorded gains. However, the country suffers from desertification, anemic reforestation efforts, and high levels of domestic wood consumption.