Guinea-Bissau, country of western Africa. Situated on the Atlantic coast, the predominantly low-lying country is slightly hilly farther inland. The name Guinea remains a source of debate; it is perhaps a corruption of an Amazigh (Berber) word meaning “land of the blacks.” The country also uses the name of its capital, Bissau, to distinguish it from Guinea, its neighbour to the east and south.
Guinea-Bissau is bounded by Senegal to the north, Guinea to the east and south, and the Atlantic Ocean to the west. It includes the Bijagós (Bissagos) archipelago and other islands that lie off the coast.
Almost all of Guinea-Bissau is low-lying and bathed daily by tidal waters that reach as far as 62 miles (100 km) inland. In the southeastern part of the country, the Fouta Djallon plateau rises approximately 600 feet (180 metres). The Boé Hills extend from the western slopes of the Fouta Djallon to the Corubal basin and the Gabú Plain.
The coastal area is demarcated by a dense network of drowned valleys called rias. The Bafatá Plateau is drained by the Geba and Corubal rivers. The Gabú Plain occupies the northeastern portion of the country and is drained by the Cacheu and Geba rivers and their tributaries. The interior plains are part of the southern edge of the Sénégal River basin. The uniform elevation of the mature floodplain allows rivers to meander and renders the area susceptible to flooding during the rainy season. Some eastern portions of Guinea-Bissau form a part of the upper basin of the Gambia River system.
Tidal penetration into the interior, facilitated by Guinea-Bissau’s flat coastal topography, carries some agricultural advantage:
In recent decades a boom in cashew cultivation has taken place in Guinea-Bissau, leading to the replacement of traditional slash-and-burn agriculture by a cash crop. As a result, the country is currently one of the world’s largest producers of raw cashew nuts and the cashew sector has acquired enormous importance in Guinea-Bissau’s economy. Changes induced by the cashew boom at social and environmental levels are yet to be analyzed and understood. The present study provides an account of the process of cashew expansion in Guinea-Bissau, reviews the current situation and discusses its future prospects. The cashew tree was introduced into the country by the Portuguese in the XIXth century, but only effectively expanded in the mid-1980s. It is largely cultivated by small farmers around villages and also plays a role in land ownership, since land tenure practices are linked to the planting of trees. The effects of this cashew boom on habitat fragmentation, fire regimes and biodiversity are still to be assessed. On the other hand, the spread of pests and diseases is becoming a problem. Strong dependence on a single cash crop also renders the country vulnerable to market fluctuations, entailing risks to local producers and the national economy. In the medium term, losses of export earnings can occur, which may impact the living standards and food security of Bissau-Guineans both in urban and rural areas.
Guinea-Bissau is located in West Africa, between 10º 59’ – 12º 20’ N and 13º 40’ – 16º 43’ W According to the National Institute of Statistics and Census, in 2014 1,514,451 inhabitants populated an area of 36,125 km2. Outside of the capital, Bissau, the population is mainly rural and very few services and infrastructures are in place. The climate is tropical, with alternating wet and dry seasons, and the vegetation can be divided into three main zones: (i) littoral (mangroves, palm groves, woodlands and forest); (ii) transitional (mosaic of woodland and savanna woodland; tall grass savanna in the inner valleys); and (iii) interior (woodland, savanna woodland and shrubby or herbaceous steppes). As a consequence of human intervention, mostly shifting agriculture and fire, the most common types of vegetation found in Guinea-Bissau are secondary formations (Catarino et al., 2008). Wildfires are liable to occur every dry season and deforestation was estimated to reach 1 % per year in the period 1990-2000 (FAO, 2014).
The cashew tree, A. occidentale, of the Anacardiaceae family, is an evergreen tree growing to a height of 8-20 m depending on soil characteristics and climate. It normally starts flowering by the third year, attaining full production by the eighth year. The period of full production can last up to 20-30 years and the lifespan of the tree is variable. The nut, which is the true fruit, is a kidney-shaped achene that does not split open after drying. Inside the shell, which contains corrosive oil, is a large curved 2-3 cm seed, the edible cashew nut. As the nut matures, the peduncle at the base enlarges into a fleshy, bell-shaped, fruitlike structure, popularly known as the false fruit or cashew apple. This thin-skinned edible false fruit has yellow spongy and juicy flesh, which is pleasantly acidic and slightly astringent when eaten raw, but highly astringent when green (Behrens, 1996).
From its origin in northeastern Brazil, A. occidentale spread to South and Central America. The first record of cashew in Africa dates back to the end of the XVIIIth century although Johnson (1973) mentioned that it might have been introduced long before that date. It is now cultivated in many tropical countries mainly for its highly appreciated nuts (Orwa et al., 2009). The cashew tree grows at altitudes of up to 1000 m, in mean annual temperatures ranging