The Republic of Guinea is moderately forested with around 26 percent forest cover and an additional 44 percent of other wooded land. Much of the original forest in Guinea has been cleared, and the current forest cover comprises a high proportion of secondary forest. The largest tracts of closed forest are moist evergreen forests in the southeast characterised by species such as Guarea cedrata and Lovoa trichiliodes. Remnant tracts of montane evergreen forests are found on the Fouta Djallon plateau, in the centre of the country, and semi-deciduous forest occurs in riparian strips, especially along the banks of the Niger River. Mangroves and swamp forests occur near the coast. Savannah woodlands dominate Guinea's forest area In the northeast Sudanian savannah characterised by Isoberlinia doka is naturally predominant. In other areas of cleared forest, regenerated mosaic "parkland" is dominated by Lophira lanceolata and Daniellia olivera. Guinea has a modest network of conservation areas, protecting around 2 percent of the country's forests.
The Republic of Guinea, located in western Africa, is bounded on the north by Guinea-Bissau, Senegal, and Mali; on the east and south-east by Côte d'Ivoire; on the south by Liberia and Sierra Leone; and on the west by the Atlantic Ocean. It covers an area of 245 857 km2 between latitudes 7° and 12° 30´ N and longitudes 8° and 15° W.
A chain of eroded mountains running south-east and south from Senegal and Mali crosses the country toward Sierra Leone, Liberia and Côte d'Ivoire. The northern part of this chain reaches an altitude of 1 500 m in the Fouta Djallon mountains in Guinea, where most of the major rivers of West Africa rise.
In general terms, four natural regions can be distinguished:
- Coastal Guinea is a low, hot, humid plain bordering the ocean for about 300 km, with a high rainfall ranging from 2 000 to 4 000 mm and averaging 3 400 mm; Conakry receives 4 600 mm of rain per year;
- Central Guinea is dominated by the Fouta Djallon mountain massif, which is a large plateau with an altitude of 600 to 1 500 m, a colder, drier climate than coastal Guinea and an annual rainfall of 1 800 mm;
- Upper Guinea is a flat region east of the Fouta Djallon plateau with a Sudano-Guinean climate and a rainfall of 1 000 to 1 700 mm (average 1 550 mm);
- Forested Guinea is made up of the south-eastern part of the country, bounded on the west by Sierra Leone, on the south by Liberia and on the east by Côte d'Ivoire. Its climate is what is called "Guinean forest", with an annual rainfall of about 2 000 mm. It has a fairly uneven terrain and includes most of the country's closed forests. It includes the Nimba Range of mountains and the highest point in the country at 1752 m.
The principal rivers are the Bafing (the upper course of the Sénégal) and the Gambia, both of which rise in the mountains of the Fouta Djallon and flow north-east. Many smaller rivers rise in the Fouta Djallon and descend to the coastal plain where they divide into many branches. The Niger and its important tributary, the Milo River, originate in the forested Guinea highlands.
Guinea has a tropical climate with variations due primarily to differences in altitude. Average temperatures range from 27° C at lower to 20° C at higher elevations. Rainfall varies by region as indicated above. The climate in the highlands is equatorial with no clearly distinguishable seasons. April is the hottest month and July or August the wettest. The rainy season in the remainder of the country occurs from April or May to October or November.
Forest cover Vegetation
The low- and medium-altitude closed rainforests of Guinea are continuations of the forests of Liberia and western Côte d'Ivoire (the three countries share the Mount Nimba mountain massif). These forests correspond to the categories given in F. White's UNESCO/AETFAT/UNSO Vegetation Map of Africa as a "mosaic of Guineo-Congolian lowland rain forest, wetter types, and Guineo-Congolian lowland rain forest, drier types". Their composition is similar to that of the forests of neighbouring Liberia, and the commercial timber species are those found in the evergreen and semi-deciduous closed forests of West Africa: red wood species such as Meliaceae (mahoganies - Khaya spp.; aboudikro, sipo, kosipo - Entandrophragma spp.; bossé - Guarea cedrata; dibétou - Lovoa trichilioides), niangon (Tarrietia utilis) and iroko (Chlorophora excelsa)); white woods for joinery and veneering such as samba (Triplochiton scleroxylon), fraké (Terminalia superba), framiré (Terminalia ivorensis), avodiré (Turraeanthus africana), ilomba (Pycnanthus angolensis), silk-cotton (Ceiba pentandra) and ako (Antiaris welwitschii); and hard, heavy woods such as azobé (Lophira alata), badi (Naucla diderrichii) and dabéma (Piptadeniastratum africanum) (Khalidou Diallo, 1978).
In the forest-savannah mosaic zone (the Guéckédou, Kissidougou and Beyla regions), which represents the transition between savannah and forest proper (the Macenta and Nzérékoré regions), the closed forest is scattered into islands that are now disappearing as a result of bush fires and clearing. In addition to some of the species mentioned above, species such as trade sougué (Parinari excelsa), Pentadesma butyracea and Anisophyllea zaurina are also found. Further north, such stands occur only in humid areas, especially along watercourses in the form of gallery forests, which cover an appreciable area of the country.
Small mountain stands of evergreen forest containing bastard mahogany (Khaya senegalensis) and iroko have been identified on satellite images of central Guinea, particularly on the southern and south-eastern edge of the Fouta Djallon plateau.
Mangroves cover a large area because the coastline is broken up by many estuaries, islands and peninsulas. There are two main species, red mangrove (Rhizophora racemosa) and white mangrove (Avicennia nitida) (Khalidou Diallo, 1978). Two other Rhizophora - R. mangle and R. harrisonii - are also noted. Mangroves are used for firewood and construction timber.
There are many natural stands of bamboo (Oxytenanthera abyssinica) in the central Guinea region.