The vegetation of nigeria

Vegetation means the community of different kinds of species of plants growing together in an area and possessing certain general physical appearance. The vegetation is made up not only of different plant species, but also of plants having different growth characteristics. The three main plant lifes forms are trees shrubs and herbs.

The vegetation of Nigeria can be seen in three distructive groups or classes:

1. Forests

• Mangrave swamp forest/salt water
• Fresh water forest
• Rain forest

2. Savannah/Grassland

• Guinea savannah
• Sudan savannah
• Sahel savannah

3. Montane

SWAMP FOREST

The swamp forest occupies the Southern part of Nigeria, hence, it is found along the Cross Rivers. The swamp forest is divided into two parts namely; The mangrove and fresh swamp forest.

MANGROVE SWAMP/SALT WATER SWAMP FOREST

This is restricted to a coastal strip, 30 – 50km wide where fresh water from the rivers meet and mixes with the salt water from the rivers meet and mixes with the salt water from sea. This forest formation is fond North of the Atlantic Ocean. The fresh water is thus, polluted and render saline. As a result the soil swampy and water logged and the water is blackish hair salt and half fresh.

The typical vegetation is made up of mangrove plane of different species, hence, this bell is sometimes known as mangrove swamp. The vegetation is a tangled mass of stems and aerial roots. The roots are aerial because they tend to avoid the surrounding water.

The most important economic tree here is the red mangrove which yields good tough wood for pit. Other spices are cut down and used in boat and canoe building coconut palms grow in large numbers along the beaches in the belt.

THE FRESH WATER SWAMP FOREST

At the belt of the forest vegetation, the water are no longer salty hence, found north of the Mangrove swamp forest. The presence of Mangrove trees are noticed because they are the only trees that can thrive in salty (blackish) water environment and their roots are of economic importance because they can be used in the construction of railway sleepers. The trees serve as fuel and a type of acid called tannin used for leather works can be obtained from the bark.

The soil in this area is swampy and unsuitable for agriculture e.g. WSarri, Ahoada, Bomadi, etc. The major occupation of the people living within this environment is fishing,

IMPORTANCE OF MAGROVE

1. Raffia plants is used for making baskets, bags, brooms, cane, chair and the production of palmwine.
2. Mangrove trees are used for both buildings and firewood.
3. Farming activities such as swam price cultivation are embarked.

RAIN FOREST

This belt stretches from Western boundary of Nigeria, South – East world through Ibadan, Benin, Sapele, Akure, Abeokuta, Aba etc, across the Niger to the Obanhills. The average width is about 130km, though it is considerable narrower in the vicinity of the Niger wing to the Northward extension of the fresh water swamp.

The high annual rainfall is about 130 – 150cm in the West and over 200cm in the East, the high humidity is generally over 80% and the long wet season is 8 – 10months, ensure an adequate supply of water and the continuous presence of moisture in the air. This promotes perennial tree growth.

The trees are ranged in three distinctive levels or storeys

• The ground storey
• The middle storey
• The top storey

1. GROUND STOREY: The ground storey is made up of herbs, shrubs and some grasses growing up to a high of 3.6m. They are densest where the tall trees have been cleared along the forest edges where the sunlight succeeded on reaching them.
2. THE MIDDLE STOREY: The middle storey consists of tall trees 18 – 24m high possessing robust branches and heavy dark green foliage. The branches of one tree often interwine with those of others and this creates and almost continuous canopy of leaves which shut of the sun from the shrubs and herbs below. This storey is made up of hundreds of plant species which are usually described as “evergreen”.

In reality however, they do shed their leaves but all the time, new buds are opned out of the old leaves withered and died.

3. THE TOP STOREY: The top storey standing out like an island in an ocean of densely packed vegetation are the trees which belong to the top storey. They possess more crowns of pointed leaves resting on a few branches which inturn are carried by tall straight stems towering up to a height of between 30 and 60 metres. Here are valuable trees such as Mahogany, Obeche, Sapele, Wawa, Iroko, Apepe, Tropical cedars, Walnut.

To the above three groups, may be added a fourth which differs from the rest in that its plant exists only by depending on their nrighbours for food or for support or for both. These are: (i) Parasites            (ii) Saprophytes    (iii) Climbers                (iv) Epiphytes

1. PARASITES: This attach themselves to and live on the sap of the other larger living trees.
2. SAPROPHYTES: This dig dig their roots in and live and decay vegetable mater, particularly dead soft wooded tree trunk. Different type of fungi, of which the original mushroom is the commonest. Examples belonging to this group.
3. CLIMBERS: The plant of this group do not sap any other trees. Instead, they grow from the ground and like their neighbour make effort to receive sunlight. They are tall and candy they cannot stand on their own so they climb the tall trees as their easiest way up. The liana is the best known examples of a climber.
4. EPIPHYTE: In this group, belongs some curious types of climbers. They twist round the tall trees quite well but raw roots which they leave dangling in the air. Some of this type of plant are sometimes known as killers or straight.

IMPORTANCE OF RAIN FOREST

1. It provides tropical hard wood like Iroko, Obeche, Mahogany, Sapele etc timbers for communication purposes.
2. It serves as a source of foreign exchange. The exploitation of the limberable trees and the cash crops exported roots countries provide great foreign exchange to the country
3. Lumbering of these trees provide employment e.g. for the lumber men
4. Farming activities especially one cultivation of tree crops in plantation e.g. rubber, cocoa, oil palm etc.
5. Provision of food: The forest vegetation makes it possible for the production of both food and cash crops.
6. Wildlife and tourism: The forest is the natural habitat of wildlife and often serves as tourist centres e.g. old Oyo park, Yankari games reserve.
7. Forest provides wood as a source of fuel.

GUINEA SAVANNAH

This savannah is found in Enugu, Lokoja, Ilorin, Markodi, Osogbo etc. This is the broadest vegetational zone in Nigeria occupying nearly half the area of Nigeria.

It is located in the middle of the country, extends southwards to southern Nigeria, and pushes its head northwards beyond the latitude of Zaria. It covers the area which has 100 – 150cm of annual rainfall and where the wet season lasts for 6 – 8months. Another name for this vegetation is parkland savannah which is made up of the typical combination of tall grasses and some trees which gives it the appearance of a park. Examples of trees, oil beans tree and isoberling trees. The trees grow in duster, generally not more than 6m high and are inter – spaced with elephant grass growing to aheight of 3 – 3.6m

SUDAN SAVANNAH

This vegetation belt is found in Sokoto, Kastina, Kaduna, Kano, Dutse, Bauchi etc. The belt is mostly found in the far North and it stretches from the Sokoto plains through the northern section of the high plain of Hausa land to the Chad basin. It is typical of places where the total annual rainfall is between 65 and 100cm and the relative humidity is constantly below 40% except in the few wet months when it is sometimes goes up to an average of 60%. The duration of the dry season is about 6 – 8 months in this area.

The zone holds the greatest density of population in Northern Nigeria, produces important economic crops like groundnut, collar, millet and maize and has the highest concentration of cattle in the country.

The landscape is less generously covered with plain than the guinea savannah. The actual vegetation is made up of short grasses, 1.5 – 2 metres high and some stunted trees. The trees are (isoberlina trees) acacia, date palm, baobao, silk cotton plant. Some trees withered in dry season and srout on the beginning of rainy season.

SAHEL SAVANNAH

This is found in Maiduguri and Damaturu. This is the last vegetational zone to be found in Nigeria as one approaches the desert fringe. It is limited to a triangular piece of land in the North-eartern corner of the country where the annual rainfall drops below 65cm and the length of the fry season exceeds eight months. The air here is perpetually dry except for one or two months in the middle of the very brief we season. The grasses in this area are short and tussocky, 0.5 – 1 metres high. The acacia is the chief tree with gum-arabic, date palm, baobao etc.

MONTANE

This vegetation is found in Jos plateau, Bauchi highland and Adamawa plateau area. The vegetation is associated with highland areas and it has varied trees at its side, it has grasses at its windward side i.e. trees. There is presence of short, scattered and deciduous trees.

MAP OF NIGERIA SHOWING THE VEGETATIONS

IMPORTANCE OF SAVANNAH

1. Savannah encourages livestock farming because of the presence of grasses which serves as food for livestock animals like cattle, sheep and goat.
2. Sacannah also promotes arable crops farming auch as rice, millet, maize, guinea corn etc.
3. It provides employment opportunities for farmers and cattle rearers.
4. It leads to development of game reserves
5. Savannah trees are used for firewood. The wood from savannah are used for making fire for cooking.
6. Tourism savannah bells create tourism and recreation for people through game reserve.

Problems Associated With Forest Exploitation

These problems include:

1. Soil erosion
2. Depletion of natural vegetation
3. Exploitation causes flooding
4. Problem of transportation of logs
5. The disappearance of wild animals
6. High cost of lumbering and difficulty in cutting trees because they are not in in pure stands.

NIGERIA MAJOR SOIL ZONES

• Coastal swamps/alluvial soil zone
• Forest soil zone
• Lateritic soil zone
• Loess and sandy soil zone

Coastal Swamps or Alluvial Soil Zone

These types of soils are found along the coast of Nigeria in areas occupied by the Mangrove swamp forest i.e. Niger Delta areas of Warri, Port-Harcourt and Calabar.

They are also found along the flooded plains of rivers particularly the Niger and Benue coastal plains, Chad basin and Lokoja.

Alluvial soils are generally sandy, very previous and porous. Along the coastal swamps, the soils are usually day or muddy, this made them sticky and water logged. They are dark gray by rivers, waves and lakes since they are found mostly in the coastal areas, they are growth of variety of crops such as swamp rice, raffia palm and coconut in water logged areas, while in the valleys are smaller river crops like cocoyam and yams are grown.

RAIN FOREST SOIL ZONE

They are found in the tropical rain forest climatic zone of Nigeria, covering part of Enugu, Anambra, Ogun, Osun, Edo, Oyo, Ondo and Cross River state.

It is characterized by the feature of the tropical rainforest such as high temperature, high rainfall throughout the year, heavy cloud cover.

It is associated with the forest vegetation as the vegetation supplies humus to it through the fallen and decayed of leaves which as well protected it from erosion.

The rainforest soil zone contain laterictic soils which are characterized by excessive leading due to heavy rain fall, which lead to the removal of the nutrients even up to the sub soil (B-horizon) of the soil.

Forest soils are good and very suitable for the growth of some important crops as found in Nigeria like oil palm, rubber, cocoa, kolanut, etc.

LATERITIC SOIL ZONE

This type of soil has the largest area of covering in Nigeria as they are found occupying the interior part of country covering places like Benue, Kwara, Enugu, Plateau, Nigerm Kogi, Kaduna, Kebbi, Bauchi, Adamawa, Taraba etc.

They occur in areas with long period of dry season alternating with wet season, this they are synonymous to the Guinea savannah belt. Heavy leaching occur on the soil during the rainy season while capillary attraction takes place during the dry season.

They are generally reddish in colour due to the presence of iron content in them. They are sticky when wet, hard, pervious and of poor fertility when dry.

LOESS AND SANDY SOIL ZONES

These soil zones are found mainly in the extreme part of Northern Nigeria in places like Kano, Kastina, Bornu, Yobe, Jigawa, Sokoto and part of Kaduna occuring in the Sudan and Sahel savannah but of the country. They are formed directly from the parent material due to dryness and are transported and deposited by wind.

Growth of dense vegetation is abent due to little rainfall experience. The loess and sandy soils are composed of sandy, loam, friable and relatively easy to cultivate as they are not prone to much leaching. Crops like groundnut, millet, maize, guinea corn, cotton are widely grown. The absence of colloids in it make it loose and structureless and possesses grains which are coarse in texture.

PROBLEMS CONFRONTING SOILS IN NIGERIA

Major problems associated with soils in Nigeria are:

1. General lack of wide spread fertile soils in the country
2. A lot of the soils are seriously exposed to soil erosion as caused by agents of erosion like water and wind. This is mostly experienced in the Eastern and Nigeria states like Abia. Anambra, Imo, Ebonyi and Enugu. Other areas of soil erosion is the North-West of Nigeria (Kebbi and Sokoto). Bornu and Yobe in the North East of the country.
3. Lack of sufficient humus makes the soils unfertile thus affecting its productivity.
4. The threat of desert exroachment which is gradually overcoming Northern Nigeria.