The Centre Region () occupies 69,000 km2 of the central plains of the Republic of Cameroon. It is bordered to the north by the Adamawa Region, to the south by the South Region, to the east by the East Region, and to the West by the Littoral and West Regions. It is the second largest (after East Region) of Cameroon's regions in land area. Major ethnic groups include the Bassa, Ewondo, and Vute. Yaoundé, capital of Cameroon, is at the heart of the Centre, drawing people from the rest of the country to live and work there. The Centre's towns are also important industrial centres, especially for timber. Agriculture is another important economic factor, especially with regard to the province's most important cash crop, cocoa. Outside of the capital and the plantation zones, most inhabitants are sustenance farmers. 2008 presidential decree abolishes provinces In 2008, the President of the Republic of Cameroon, President Paul Biya signed decrees abolishing "Provinces" and replacing them with "Regions". Hence, all of the country's ten provinces are now known as Regions. Geography Land The Centre's soil is primarily composed of Precambrian deposits of metamorphic rocks, such as gneiss, mica, migmatites, and schists. Granite dominates from about 4˚ N and to the Adamawa border. Faults along the border with the South Province have deposited metamorphic schists and quartzites, with some granite. Laterites are also common, caused by the decomposition of the crystalline rock. Red ferrallitic soil dominates most of the province, including the forested zone and much of the savanna area. Though as deep as ten metres, this soil is leached by silica and percolating water, making it only marginally productive for agriculture. However, it is usable as a building material, and traditional houses in the province are made from red, sun-dried bricks of mud. Toward the northern border, this soil becomes lightly evolved with large deposits of raw minerals, and at the confluence of the Sanaga and Mbam rivers, it is a mixture of several soil types. Drainage The Sanaga is the most important river in the province, as its many falls and rapids make it an important source of hydroelectric power. It also supports varied agriculture, as it is prone to flooding during the rainy season. It is navigable from Nachtigal Falls to Edéa in the Littoral Province. Several smaller tributaries that drain the Centre's Mbam division form the Sanaga. The Djérem flows in