The correlation between climate and vegetation is evident in Africa, where, despite the rapid destruction of natural vegetation by humans and animals, there are still vast areas of natural vegetation. There are two main zones in Sub-Saharan Africa.
AREAS OF EQUATORIAL FOREST
The rainforests cover just under 1000 km in latitude and approximately 2250 km from west to east, from the Cameroon coast and Gabon to the eastern borders of Congo - Kinshasa (to the mountains flanking the Rift Valley to the Ruwenzori, the Virunga Mountains and Ugoma (northwest of Lake Tanganyika). The equatorial forest has a wide variety of trees (very high biodiversity), the largest of which exceptionally reach 65 m high and whose trunks are straight and without branches on the largest part of their barrel. The rainforests contain many useful plants and trees. The equatorial forest still grows in sub-equatorial regions but has a face adapted to the short dry season: certain species of trees lose their leaves during this period.
These regions, which often is the front of the equatorial forest facing the savannah, is very rich in oil palm (Elaeis guineensis), a species found in the rainforest but who suffers from competition from large trees because it's a kind of light (sun-loving): it thrives and proliferates on the margins of the forest, greatly aided by the man who cleared the forest (and thus opens the way to sunlight), protects the palm trees (which are her very useful), by spreading seeds by their behavior or in fact plantations. So there are a whole range of types of palm groves in Elaeis, natural palm grove (very rare and always small in size) to the palm plantation through the palm groves called sometimes "subspontaneous" but actually most often "anthropogenic "that is to say, whose existence is largely due to the same man if he is not plantations.
Benefits of the rainforest: provides shade; it is less hot; provides many edible fruits and leaves; plant material for construction: wood (for the frame and the frame, sheets for roofs). The forest gives much organic matter: after burning, you can still grow, even in poor soil.
Drawbacks of to the rainforest: the forest is difficult to clear because of the density and size of trees. Trees prevent grasses from growing: difficulty raising herbivores (cattle, sheep, goats). The forest is a formidable obstacle to relational life: because of its density, the many fallen trees; the trails are quickly overgrown; the view never wears away: one is lost very easily in the forest.
Climate
The climate allows the growth of the rainforest is the equatorial climate (eg Boende in the heart of the rainforest of the Congo) and, margins, the sub-equatorial climate. It is a warm and humid climate all year round, rainy throughout the year or in any case more than 6 or 7 months a year. If we define the equatorial climate as a hot and wet climate all year (without a single dry months), it is found only in continental position at the heart of the Congolese forest (Ouesso, Kisangani and Boende) and in two annexes one located near the equator in the northern hemisphere (climate of the Gulf of Guinea from the bottom: the climate of Douala to 4 ° north latitude, so 450 km from the equator), the other very far from the equator in the southern hemisphere: the climate of the east coast of Madagascar (Tamatave Toamasina alias and Fort-Dauphin alias Taolagnaro: up to 25 ° south latitude - beyond the Tropic of Capricorn, about 2800 km from the equator). Note that 4 degrees north and south latitude, is roughly the forest area limit in Equatorial Africa (except the east, due to the altitude and drought). In areas of equatorial climate, the morning time is often sunny and clear but heat rises during the day until around 14 hours of cumulus develop, which rise and increasingly take the form of cumulus -nimbus giving heavy rains with thunder and lightning.
The hydrography of the equatorial forest regions
Regular rainfall explains the density and power of the river system: the rivers are numerous, sustainable, abundant, regular (especially when their area covers both hemispheres); they together to form the confluence of the rivers in high flow, the largest of which is the Congo, the second river of the earth by his speed (far behind the Amazon, another equatorial river, but American). Another equatorial river: Ogooué (more strictly than the equatorial Congo has a huge basin that goes well beyond the equatorial climate zone).
Benefits of hydrography in rainforest regions: the water never fails, either for men or for livestock (in principle Savorgnan Pierre de Brazza on Batéké trays - in a climate of the sub-equatorial region - feared a time to die of thirst!) The fish is abundant everywhere. Large rivers have communication pathways canoes and large ships.
Disadvantages due to hydrography in rainforest regions: the rivers are an obstacle to land travel: need many ferries, bridges, embankments etc. No route is possible without enormous work; not enough bottom for boats; canoe that you can not move and only during high water; no shipping is possible at low water.
The fauna of the rainforest regions
The forest is home to a wildlife consists mainly of insects, reptiles, birds and small mammals (antelopes, rodents, and monkeys). Forest dwellers consume much these animals. Large mammals are now few (buffaloes, elephants, chimpanzees and gorillas, panthers). This is progress for humans living in these forests from the perspective and the danger and damage to crops (elephants, great apes). Foreign environmentalists, they regret the disappearance (or scarcity) of the great wildlife.
THE SAVANNAH AREAS
Definition of the savannah: this is a high grassland, closed and perennial in tropical climates. It derives in general, as a result of human action, an original dry forest and clear: it is an anthropogenic vegetation. There are following types of savannas: Grassland, eg in the "valley of Niari" in Congo - Brazzaville and in the "Accra plains" south of Ghana; Bushland, eg in the Pool region (Brazzaville region); Savanna: for example in Burkina Faso and Senegal (in most of these countries); Savannah park: with trees together in bunches, such as "Pout forest" in Thies region in Senegal. A tree-ring, characteristic of dry savannas: the baobab (Adansonia digitata). Its abundance and presence are related to the presence of the man (it is a calcareous tree). In savannahs (especially those in the northern hemisphere), species diversity is much lower than in the forest. The woody flora varies with humidity greater or lesser climate: wet savannah has many broadleaf trees; dry savannah has especially thorny (acacia). Savannah often includes gallery forests. Savannah burns easily (because it is a closed training and there is a long dry season) and its trees are few and small: the clearing is easy, as the hunt with fire. The savannah, grassland, natural pastures show that - they are often of poor quality - nevertheless, allow practicing large livestock (cattle) and small livestock (goats and sheep). The traffic is generally very easy savannah: the view goes away (except in some cases of very dense very tall grass savannah) the trees are spaced; the trails are not rapidly cleared by vegetation; we see the sky, allowing to move. Straw abounds Country seccos (woven straw pieces) and straw roofs (when in rainforest roofs are tree leaves).
Disadvantages of savannah vegetation-related forest: Savannah offers much less fruit and edible plants (leaves, stems, roots, etc.) that the forest. It offers some shade: the need for a cap. Walking and working are painful in the sun, hence the preservation of shade trees near the huts in the fields. Savannah gives relatively little organic matter: the possibility of growing more dependent on mineral wealth and the structure of the soil, attorneys in the rainforest regions. Some African farmers, like Kuni of Congo - Brazzaville in the "Niari plain" offset the weakness of biomass concentrating on parallel ridges where the uprooted weeds in clumps, with clods of earth adhering to the roots, are burned.
Climate: tropical climate with alternating seasons moderately rainy. The savanna climate is a warm climate with the alternating rainy season and a dry season. These are the climates of deciduous woodland areas, often transformed into savannah more or less wooded forest, more or less raised by the action of man, and depending on the intensity of this action (population density, seniority stand, changing densities in time). These climates occupy two large areas on both sides of the equatorial zone, areas above, as the distance from the equator, the sub-desert areas (or sub-arid).
Hydrography of savannah regions
The opposition of two rainfall seasons resulting in a contrasting hydrological regime. The drainage system is generally less dense. The rivers are not permanent and there where permeable rocks (sandstone, limestone, arena) can store rainwater and release it gradually. In periods of low (and often dry low water) oppose flash floods after showers: the case of Senegal and Niger. We try to control the flow with dams (Manantali on the Upper Senegal, Kainji on the Niger).
Advantages: rivers (which could be called wadis - the geographical sense that this word has in French - not in its meaning in Arabic where it simply means "River River") often dry.
Disadvantages: There are much fewer fish regions. We do not bother to build bridges: in winter, there is often a total isolation of many villages, unknown isolation in the forest zone. Without the dam, the water is often lacking for irrigation since the rivers are dry much of the year.
Bibliography
Aryeetey-Attoh, Samuel. Geography Of Sub-Saharan Africa. Upper Saddle River, N.J.: Prentice Hall, 1997.
De Blij, Harm J. A Geography Of Subsaharan Africa. Chicago: Rand McNally, 1964.
Dickinson, Gordon. "Soil And Water Conservation In Sub-Saharan Africa: Towards Sustainable Production By The Rural Poor". Applied Geography 12, no. 4 (1992): 382.
King, Brian. "Conservation Geographies In Sub-Saharan Africa: The Politics Of National Parks, Community Conservation And Peace Parks". Geography Compass 4, no. 1 (2010): 14-27.
Udo, Reuben K. The Human Geography Of Tropical Africa. Ibadan: Heinemann Educational Books, 1982.
