Countries

The Gabonese Republic, located in west central Africa, lies across the equator between latitudes 3° S and 2° N and longitudes 9° and 14° E and has an area of 267 670 km². It is bounded on the north-west by Equatorial Guinea, on the north by Cameroon, on the east and south by the Republic of the Congo, and on the west by the Atlantic Ocean.

Gabon has three main geomorphological regions:

• The sedimentary basin in the west is made up of secondary formations (basically marl, limestone and sandstone) and the ground is slightly rolling. Forest completely covers the basin, except for some coastal bars and very sandy islands (in the bays region) occupied by savannah;
• The old Precambrian base occupies the eastern half of Gabon and is made up of plateaux with a medium altitude (about 600 m). In the north and north-east, rivers with shallow beds and flat, marshy valleys have worn only slightly into these plateaux, but in the south, the Ogooué and its tributaries have gouged out deep valleys intersected by rapids. An area of sandstone interspersed with schist extends over the south-eastern part of the area, where the terrain is uneven. Lastly, along the frontier with the Congo the table of the Batéké tertiary plateaux of sandstone and continental sand rises up, dominating the base by 100 to 200 m. The forest that covers almost all the base stops abruptly at the Batéké plateaux, which are totally covered by savannah. On the geological strata of the Franceville region, forest and savannah overlap in a complicated mosaic, while equatorial savannah penetrates the forest in the mid-Ogooué region;
• The northern rim of the base is formed by the Cristal Mountains, with peaks between 800 and 900 m, carved out of granite and extending south with the N'Djolé Mountains of similar heights, carved out of metamorphic rock. In the south, the granite massifs of Mayombe and Chaillu enclose a vast synclinorium of schisto-sandstone and schisto-calcareous sediment. The Mayombe in the west forms a long north-south ridge often exceeding 800 m and traversed by the Nyanga River, while the Chaillu in the east is over 1 000 m and rivers have etched out deep valleys in it. Forest covers the whole mountainous rim of the base except for a deep corridor of savannah with two branches at the end that exactly follow the tongue of schisto-calcareous sediment.

The climate is described as transitional equatorial and varies markedly from one end of the country to the other. Rainfall in particular ranges from 4 000 mm at Cocobeach on the coast at the country's north-western point to 1 500 mm at Tchibanga in the south-west, decreasing steadily away from the coast. The year has four seasons: a short dry season from January to February, often marked only by an easing of the rains; a rainy season from March to May; a long dry season from June to October; and a long rainy season from October to December. North of a line between Okondja and Oyem, the summer dry season is less pronounced, but the winter easing of the rains becomes a proper dry season. In the south-west, however, the long dry season is longer, reaching six months at Mayumba. Such a long dry season is very exceptional in terms of the whole part of equatorial Africa covered by closed rainforest. No other tropical rainforest experiences as long a dry season as that suffered by most of the Gabonese forest. This is also true of the severity of the dry season, for three-quarters of Gabon receives less than 25 mm of rain per month during these three or more months.

There are two other major climatic features: high atmospheric humidity throughout the year, and heavy cloud cover throughout the dry season due to the permanent presence of a ceiling of stratus clouds, thus reducing the amount of exposure to the sun, the total quantity of light radiati

The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries.