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Part II
COUNTRY BRIEFS (continued)

NAMIBIA (continued)

1.1.2 Present situation of the woody vegetation

Present areas

It has not been possible to find forest inventory reports nor other forest studies. The tentative figures given below are derived mainly from the interpretation of Landsat satellite imagery and using the framework of the phytogeographic regions of the Unesco vegetation map of Africa (second edition by F. White).

The 1979 FAO Production Yearbook details the present land-use as follows;

Land-use classesAreas
(in thousand ha)
  1967 1979
Arable land   644   655
Permanent pasture5290652906
forest and woodland1042710427
other land1835218341
Total land area8232982329

The forests and woodlands are situated in northern Namibia. A part of the permanent pasture land corresponds to wooded savanna.

A satellite imagery analysis prepared by FAO (6) covers the northwestern part of Namibia over an area of 22 million ha, or approximately 25% of the country. It is based on visual interpretation of Landsat 1 images. To the south it is limited by the latitude 23°90' S, to the east by the straight line from 23°90' S and 15°40' E to approximately 17°15'E on the angolan border, to the north by Angola and to the west by the Atlantic Ocean. In the following list separate information is given for this part and for the rest of the country.

Areas of natural woody vegetation estimated at end 1980
(in thousand ha)

North-west    570  2155  665  2820  3390195  6815
Rest of country  142013275  335136101503013530500
Whole of country  1990154301000164301842033037315


In a 1964 report the Odendoal Commission proposed the establishment of about ten Bantustans (“homelands”) totalling 32.6 million ha approximately or nearly 40% of the total area. Most of the productive woodland area is situated in the homelands of northern Namibia: Okavango, Ovamboland, Bushmenland and East Caprivi. Central and southern Namibia are covered by private farmland of the white population, whereas the Etosha National park and the coastal area is state land (2).

Legal status and management

The Etosha national park has a total area of 2 227 000 ha of which 1 million ha more or less is covered with woodlands and trees savannas (NHc/NHO2r = 1 000). In the national park no wood production, nor any collection of forest produce, is allowed.

Most of the woodlands are intensively managed as ranchlands with occasional burning. No information is available on any forest management for wood production except for 60 000 ha which have been reserved in Ovambo and Okavango for plantations.

Forest utilization

Log harvesting

Little information is available on timber exploitation and collection of forest produce. Potentials for forestry development are limited by the shortage of water. The only woodlands exploitable for timber are situated in northern Namibia, covering 2 million ha approximately, most of it in Ovambo and Okavango and only 40 000 ha in East Caprivi. Main species are kiaat (Pterocarpus angolensis), rhodesian teak (Baikiaea plurijuga), chivi (Guibourtia coleosperma), mangetki (Ricinodendron rautanenii), Burkea africana and Kirkia acuminata; but only kiaat is commercially exploited for timber production (2). Tambok (Spirotachys africanus) from the Grootfrontein and Tsumeb districts is used as pitprops for copper mines. A small volume of rhodesian teak is exported. A wood processing factory at Ashatahi in Owambo processed annually teak to a value of almost R 400 000 (US$ 560 000 in 1972/1973) for local use (no volumes indicated) (2).

Other forest products

A variety of other forest products are collected from the forest. Many trees and shrubs are used for fuelwood, a major source being Acacia giraffae. Hottentots sell charcoal of this species from the Namib desert in Swakopound and Walvis Bay (2). Fruits, gum and roots are an important food source, such as the fruits of Ricinodendron rautanenii as main staplefood for the bushmen (3).

A large part of the rural population, especially the nomadic bushmen in the north-east, rely on the rich wildlife for a substantial part of their living.

Visiting of the national parks and game reserves by foreign tourists is an important activity. Tourist traffic increased from 12 350 in 1960 to 280 000 in 1973 with a revenue from the camps of more than 1 million rand (1.4 million US$) (2).

1.1.3 Present situation of the growing stock

No figures are available for the growing stock of the northern mixed woodlands. An estimation of gross volume (VOB) and actually commercialized volume (VAC) of the productive woodlands (NHc/NHO1) has been derived from the corresponding figures for similar vegetation types in neighbouring countries. For the Chobe woodlands of Botswana the gross volume (VOB) was estimated at 20 m3/ha; a forest inventory of 8 million of woodlands in the Cuando/Cubango district in southeastern Angola gave gross volume ranging from 8 to 45 m3/ha. Since growing conditions are somewhat less favourable than in this part of Angola, and similar to those in Botswana, the same estimate obtained for this latter country has been adopted for Namibia, i.e. a VOB of 20 m3/ha. The actual commercial volume (VAC) of 1 m3/ha can be considered as an acceptable average mainly made up of Burkea africana, and Kirkia acuminata (2). These species are also found in the unproductive open formations (NHc/NHO2i) but to a lesser extent.

Growing stock estimated at end 1980
(totals in million m3)


1.2 Plantations

Little information is available on plantations. Plantation trials with Eucalyptus spp. are carried out near Tsumeb and Grootfontein in northern Namibia (250 ha) for timber for the mines (World Atlas of Agriculture, 1976), i.e. PHH 1 = 250 ha. Areas of approximately 25 000 and 35 000 ha have been reserved in Ovambo and Okavango respectively for the establishment of plantations (2). Except for these plantation trials these does not seem to be significant area of forest plantations.

2. Present trends

2.1 Natural woody vegetation

2.1.1 Deforestation

Although the overall population density of Namibia is the lowest for Africa (less than 1.5 per km2), over half of the population is concentrated in the more humid northern third where all the woodlands are found. Shifting cultivation is a common practice. Of the 160 000 families living in the north (4), probably some 60 000 families are involved in shifting cultivation; if it is assumed that each of them clears annually 0.5 ha of woodlands, annual deforestation would amount to 30 000 ha. The productive woodlands (NHc/NHO1) are subject to the highest pressure; the resulting annual decrease of NHc/NHO 1 is estimated at some 10 000 ha and that of the unproductive ones (NHc/NHO2i) at 20 000 ha. Deforestation also occurs as the final phase of degradation caused by continued overgrazing, repeated fires or overexploitation of fuelwood.

2.1.2 Degradation

Livestock raising is one of the main activities in Namibia and grazing occupies almost 70% of the total country area (6). The FAO Production Yearbook of 1979 gives 8.3 million heads of cattle in 1970 and estimates this number at 10.4 millions in 1979, or an increase of 25% over 9 years. 4% of the pasture land of northern Namibia show indication of serious overgrazing and degradation of woody vegetation (6). Savanna fires which are said to come from Botswana are also affecting large parts of the vegetation. Bushmen and other people often start fires to stimulate new growth which attracts game.

2.1.3 Trends in forest utilization

No information is available on future trends in forest utilization but it seems likely that the small scale harvesting of timber for local use and some export will continue. Game cropping by the rural population should remain an important utilization.

2.1.4 Areas and growing stock at end 1985

The considerations of the above paragraphs lead to the following projections of areas of woody vegetation and corresponding growing stock in the productive woodlands (NHc/NHO 1).

Areas of natural woody vegetation estimated at end 1985
(in thousand ha)


Growing stock estimates at end 1985
(in million m3)


2.2 Plantations

No information is available on planned plantation activities for the period 1981–85.


  1. Kaplan, 1 et al. 1971 “Area Handbbok for the Republic of South Africa. Appendix: South West Africa (Namibia)” - DA Pam 550–93

  2. FAO 1976 “Namibia, a Preliminary Note Towards a Country Development Brief (revised) - Food and Agriculture Sector” - Rome

  3. Lee, R.B. 1978 “Subsistence Ecology of King Bushmen” - Thesis-University of California, Berkeley (U.S.A.)

  4. Economist Intelligence Unit 1980 “Quarterly Economic Review of Namibia” - Spencer House - London

  5. FAO 1980 “Workshop Paper on Agriculture Fisheries and Food Security (for Namibia, held Maputo, August 1980)” - Rome

  6. FAO 1980 Satellite Imagery Analysis for Reconnaissance Survey of Natural Resources in Namibia - by C. Travaglia, J. Schade and A. Arenas - AGO/NAM/78/004 - Rome


Le Niger, d'une superficie de 1 267 000 km2 est compris entre les parallèles 11°37'et 23°23' de latitude nord et les méridiens 0 et 15° de longitude est. C'est un pays complètement enclavé qui compte plus de 500 000 km2 de désert vrai, dont le Ténéré. D'un point de vue climatique le reste du pays comprend les zones suivantes:

La saison pluvieuse de Juin à Octobre dans le sud avec un maximum de précipitations en Aôut, est de plus en plus brève à mesure que l'on va vers le nord, tandis que les pluies deviennent de plus en plus irrégulières et faibles. La saison sèche d'Octobre à Juin, est chaude jusqu'en Novembre, puis relativement fraîche jusqu'à la mi-Mars, très chaude en Avril et Mai sous l'influence d'un vent d'est brûlant et désséchant. Les reliefs, en particulier dans l'Aïr recoivent des précipitations plus abondantes que les bas pays au climat désertique.

Le relief est constitué par le socle africain primitif recouvert de sédiments et débris continentaux et aplani par l'érosion. Les altitudes de cet ensemble monotone sont comprises entre 200 et 500 mètres. Cependant les massifs très anciens ou éruptifs se dressent au nord-ouest, dans l'Aïr où les monts Tamgak (1 800 m) surplombent la vallée d'Iferouane, et les étendues dunaires du Ténéré. Les altitudes, s'élèvent rapidement au nord-est, dans les confins occidentaux du Tibesti (Tchad), ainsi qu'au nord de Zinder dans le Damergou. Au sud-ouest, depuis la frontière du Mali, jusqu'à Gaya, le fleuve Niger coule sur 300 km dans une large plaine entaillée de vallées sèches. Au sud-est le territoire englobe la rive nord-ouest du lac Tchad.

La végétation naturelle de la région a subi fortement l'influence de l'homme et est actuellement très clairsemée. Sa composition ne doit refléter qu'imparfaitement ce que pouvait être la végétation climacique initiale. On peut distinguer:

La population du Niger compte environ 5,3 millions d'habitants en 1980 dont près de 4 millions d'agriculteurs sédentaires et 1,2 million de pasteurs nomades. Elle croît au rythme annuel de 2,9% environ, la population agricole croissant elle au rythme légèrement inférieur de 2.3%.

1. Situation actuelle

1.1 Végétation ligneuse naturelle

1.1.1 Description des types de végétation

Il convient de souligner que le Niger a été un des pays les plus frappés par la sécheresse de 1967–74 et que les formations ligneuses dégradées ou même détruites durant cette période ne se sont pas reconstituées.

Formations forestières feuillues denses (NHC)

Elles sont constituées par les quelques galeries forestières du sud du pays où l'on rencontre les espèces soudano-guinéennes et les quelques rôneraies denses noyées dans des zones à rôniers de plus faible densité. Les essences des galeries sont celles de la savane arborée décrite ci-après auxquelles s'ajoutent des essences soudano-guinénnes: Lannea acida, Pterocarpus erinaceus, Khaya senegalensis, Daniellia oliveri, Burkea africana.

Formations forestières feuillues ouvertes (NHc/NHO)

Ce sont les savanes arborées du domaine sahélo-soudanien. Ces formations forestières sont fortement entamées ou pratiquement épuisées. Il existe toutefois encore quelques îlots de savane boisée dense (sud de Niamey et région de Say). Parmi les essences caractéristiques on peut citer le tamarinier (Tamarindus indica), le karité (Butyrospermum parkii) le kapokier (Bombax costatum), le néré (Parkia biglobosa), Combretum glutinosum, Cassia siberiana, auxquels s'ajoutent dans la savane humide Hyphaene thebaica, Borassus aethiopium et Parinari macrophylla.

Formations essentiellement arbustives (nH)

Ce sont les steppes arborées ou arbustives des domaines sahélien et sahélo-saharien. On y observe le faciès de “brousse tigrée” dont on ne sait s'il est un faciès climacique ou de dégradation. La steppe sahélienne est caractérisée par la brousse à Combretum. Le gommier (Acacia senegal) est présent en abondance surtout dans l'est du pays, le gao (Acacia albida) colonisant les terres agricoles. On y rencontre également le rônier (Borassus aethiopium) et le doum (Hyphaene thebaica). Dans la steppe sahélo-saharienne les arbres les plus fréquents sont Acacia raddiana, A. seyal et dans une moindre mesure, Commiphora africana. A la limite avec la zone saharienne les épineux (Acacia raddiana) sont présents et accompagnent le doum.

1.1.2 Situation actuelle de la végétation ligneuse

Surfaces actuelles

D'après les statistiques du Service forestier (3) le domaine forestier est important, de l'ordre de 14 millions d'ha. Cependant les zones couvertes d'une végétation ligneuse arborée ou arbustive sont inférieures car le chiffre précédent inclut des zones de végétation sans éléments ligneux ou à composante ligneuse très faible (3). Le tableau suivant a été reconstitué essentiellement à partir des données trouvées dans les documents (3), (4) et (6).

Surface estimées de végétation ligneuse naturelle à la fin de 1980
(en milliers d'ha)


On a estimé que 70% environ des forêts classées (206 000 ha) et en projet de classement (234 000 ha) correspondait à des formations productives au sens de cette étude (NHc/NHO1). Le document (5) signale que certaines formations forestières au sud de l'isohyète 750 mm sont encore pratiquement intactes dans les régions de Say, Gaya, Tera qui sont peu peuplées du fait des maladies qui les ravageaient (onchocercose, tripanosomiase) et dont il serait bon d'envisager le classement car elles pourraient être rapidement aliénées à l'agriculture.

La plus grande partie du parc national du “W” (334 000 ha) et de la réserve totale de faune adjacente du Tamou (142 000 ha) sont couvertes de savanes boisées ou arborées (NHc/NHO2r).

Le document (4) indique qu'il existe 3,3 millions d'ha de surface de “forêts” dans les 14 millions d'ha de terres forestières. Après déduction de l'ensemble du parc national et de la réserve de Tamou (NHc/NHO2r) et des formations productives on aboutit à une surface de formations forestières improductives au sens de cette étude de 2 150 000 ha (NHc/NHO2i).

Les surfaces de jachère forestière ont été estimées très grossièrement à partir du chiffre donné pour les jachères dans le document FAO “Shifting cultivation and soil conservation in Africa” tenant compte de ce qu'une partie de cette surface est dépourvue de synusie ligneuse secondaire.

La surface de formations arbustives (nH) a été obtenue par soustraction à partir de la surface totale des terres forestières des différentes formations arborées.

Certaines formations à densité plus élevée que celles de la très grande majorité des formations mixtes forestières et graminéennes méritent d'être signalées. Il s'agit des rôneraies (27 000 ha environ au Dallol-Maori), des gommeraies denses (plus de 100 000 ha) et des doumeraies denses (plus de 10 000 ha).

Propriété et statut légal

Comme dans les pays francophones voisins, les formations forestières font partie du domaine de l'Etat et sont soit des forêts classées avec réglementation des prélèvements soit des forêts protégées sans statut précis où peuvent s'exercer des droits coutumiers de pâturage, de culture et de coupe de bois.

En plus des 206 000 hectares de forêts classées et des 654 000 hectares en projet de classement, (234 000 ha de forêts et 420 000 ha de réserve de faune de la Sirba), il convient de signaler un massif global de 782 000 ha incluant les 334 000 ha du parc du “W”, les 142 000 ha de réserve totale de faune de Tamou et 306 000 ha de réserve partielle adjacente du nord-est.

Des “périmètres en défens” sont indiqués dans le document (6) dont 69 000 ha de gommeraies à titre temporaire et 71 000 ha de périmètre de défens et restauration des sols à titre définitif.


On ne peut parler d'aménagement des surfaces boisées. Il s'agit pour le moment de permettre la reconstitution des peuplements par des mises en défens et des reboisements. Toutefois le problème le plus urgent est le ravitaillement en bois de feu des populations. Comme dans toute la région sahélienne, le Service forestier essaie d'élaborer des projets dans le cadre d'actions intégrées avec les autres secteurs du développement rural. En ce qui concerne les gommeraies denses naturelles dans l'est du pays un projet de protection et d'exploitation a été mis au point en 1975–76 avec l'aide de la Banque mondiale. Il prévoyait la protection pour une exploitation rationnelle de la gomme arabique de 2 000 ha de gommeraies jeunes et denses. En fait dès 1976 la protection était déjà effective sur 5 186 ha.

La protection de la faune et les aménagements sylvo-pastoraux reçoivent une attention particulière. Toutefois le manque de moyen et de personnel qualifié ne permet pas de réalisations concrètes.

Exploitation forestière

Pour le moment l'exploitation porte surtout sur le bois de chauffage et le bois de service à partir des peuplements naturels et des plantations en plein et des brise-vent. Le développement de l'urbanisation a engendré un marché du bois dont le développement suit l'accroissement de la population. On est donc passé d'un stade de cueillette à un stade commercial avec tout ce que cela comporte comme abus et destruction.

L'exploitation du bois de feu qui représente 88% dans l'approvisionnement en énergie du pays est importante et entraîne une désertification autour des centres urbains, notamment Niamey. En 1980 pour une population de 5,3 millions d'habitants, on prévoit une consommation de 5,85 millions de stères. Cette consommation avait été, en 1971, pour une population de 4,13 millions d'habitants, de 2 150 000 m3 et de 850 tonnes de charbon de bois. Pour la seule population urbaine estimée en 1974 à 200 000 personnes la consommation de bois de feu avait été de 104 000 m3 soit plus de 200 000 stères.

Le rônier au Niger a une importance particulière pour la construction des cases et comme bois de service et il provient exclusivement du Dallol-Maori à 300 km au sud de Niamey (1) (2).

L'exploitation des rôniers, contrôlée par le Service forestier, est passée de 800 pieds à 4 500 pieds en 1968. Le terme d'exploitabilité (60 à 100 ans) dépend de la vitesse de croissance; les diverses parties du rônier sont utilisées: tronc, feuilles pétioles, racines, bourgeon terminal et gomme. La possibilité serait de l'ordre de 3 000 pieds par an mais cette possibilité pourrait être augmentée, notamment par l'arrêt de la coupe des feuilles.

Enfin l'exploitation du gommier mérite une mention particulière. Les régions de production en 1977 étaient au nombre de trois: départements de Diffa, de Zinder et de Maradi. Les marchées locaux ou lieux de traite sont tous situés dans le département de Diffa. La saignée n'est généralement pas pratiquée et la production gommière provient essentiellement d'une cueillette à caractère extensif où les populations nomades ont la plus large part.

Il faut signaler pour terminer que l'exploitation forestière sous l'isohyète 750 mm où les forêts sont encore intactes (Say, Gaya, Toré) est freinée pour le moment par l'absence de population due aux maladies (onchocercose, tripanosomiase).

1.1.3 Situation actuelle des volumes sur pied

On ne dispose actuellement d'aucune indication valable sur le matériel sur pied et sa répartition. Il est également très difficile de chiffrer un potentiel et une productivité de peuplements très hétérogènes, appauvris et soumis à des préìèvements intenses. Les volumes sur pied ne dépassent jamais sous l'isohyète 600 mm, 20 stères/ha (5). Il est néanmoins probable qu'une mise en défens rigoureuse, associée à une opération de régénération extensive par semis pourrait permettre des productions supérieures.

On a estimé que le volume brut moyen à l'ha (VOB) des formations productives (NHc/NHO1) était de l'ordre de 15 m3/ha et que le volume actuellement commercialisable de bois d'oeuvre (VAC) ne saurait dépasser 1 m3/ha.

Volumes sur pied estimés à la fin de 1980
(totaux en millions de m3)


La productivité des peuplements presque intacts dans la région de Niamey (forêt de Guisselbodi, et dans l'Ader-Doutchi-Maggia) se situe autour de 0,5 st/ha/an (pour les formations zonales à Combretacées et Mimosacées). Pour les peuplements plus denses au sud des départements de Niamey et de Dosso, la productivité peut atteindre 1 à 1,5 st/ha/an (5).

1.2 Plantations

1.2.1 Introduction

Dès les années 60 des essais ont été entrepris sur les techniques et les espèces à utiliser aussi bien pour la production du bois en sec et en culture irriguée que pour la conservation des sols et les améliorations pastorales. Ils ont servi de base aux divers reboisements qui ont été effectués notamment après la période de sécheresse exceptionnelle de 1967–74.

Les actions de plantation au Niger ont eu et continuent à avoir plusieurs objectifs. En reprenant la classification utilisée dans le document “Le rôle de la foresterie dans la lutte contre la désertification et sa contribution au développement” par J.C. Delwaulle, on peut distinguer:

1.2.2 Surfaces des plantations réalisées

La diversité des actions et des financements, l'absence d'un inventaire des boisements, et l'ignorance dans laquelle on s'est trouvé pour cette étude sur le degré de réalisation et de succès des multiples programmes rend hasardeuse l'estimation des surfaces effectivement réalisées et réussies à la fin de 1980. Il ne semble pas qu'il existe de plantations ayant pour objectif essentiel la production de matériau pour les industries du bois et toutes les plantations peuvent être cataloguées comme plantations “non-industrielles” au sens de cette étude. Les estimations de surface données ci-dessous sont basées essentiellement sur les documents (3), (5) et (6). Elles ne sont pas censées inclure les plantations en lignes de toutes sortes (rideaux-abris, brise-vent) ni la surface totale des périmètres restaurés, mais seulement les plantations en plein.

Le chiffre de 6 350 hectares de plantations est donné pour fin 1976 dans le document (6). Cependant il semble qu'il faille le réduire sensiblement car il inclut sans doute des plantations ayant échoué et peut-être également des périmètres non plantés en plein.

Surface estimées des plantations non-industrielles réalisées à la fin de 1980
(en milliers d'ha)

CatégorieEssencesAnnées76–8071–7566–7061–6551–6041–50Avant 41Total
Classe d'âge0–56–1011–1516–2021–3031–40> 40
P=P..2=PH.2=PHL.2Acacia albida, A. nilotica,
A. senegal, Anacardium occidentale, Azadirachta indica, Eucalyptus camaldulensis, et autres 1
3,52,00,5    6,0

1 Telles que Parkinsonia aculeata, Prosopis africana, Dlbergia siseco, Cassia siamea (9).

Les deux acacias (gao et gommier) représentent la majeure partie des plantations. Fin 1973 les eucalyptus ne couvraient encore que 40 hectares plantés à titre expérimental (réponse au questionnaire FAO sur les eucalyptus).

1.2.3 Caractéristiques des plantations

Quelques chiffres utiles ont été trouvés dans le document (5). En ce qui concerne le neem (Azadirachta indica) on peut escompter une production comprise entre 3 et 4 stères/ha/an pour des plantations en sec à 5m × 5m avec une rotation de 6 ans sous l'isohyète 600 mm dans les environs de Niamey (chiffre confirmé par J.C. Delwaulle dans “Plantations forestières en Afrique tropicale sèche”). L'Eucalyptus camaldulensis peut avoir une productivité supérieure à celle du neem mais il est beaucoup plus sensible que ce dernier à des périodes de sécheresse prolongée. En sylviculture irriguée, en bordure du fleuve Niger, à proximité de Niamey, l'accroissement moyen annuel trouvé sur des plantations expérimentales d'eucalyptus et d'Acacia nilotica a été trouvé compris entre 20 et 30 m3/ha. On table pour des plantations irriguées d'Eucalyptus camaldulensis, à 2,5 × 2,5 m (ou 4 × 1,6 m), soit 1 600 pieds à l'hectare et avec une rotation de 3 ans, sur une production annuelle moyenne de 25 stères par an, soit sur l'ensemble de la rotation 500 perches représentant 20 stères et 55 stères de bois de feu.

2. Tendances actuelles

2.1 Végétation ligneuse naturelle

2.1.1 Déforestation

Les statistiques agricoles de la FAO font état d'un accroissement des terres arables de 2 178 000 ha dans les années 1961–65 à 3 112 000 ha en 1978, ce qui représente un accroissement annuel de la surface agricole de 2,4%, de l'ordre de l'accroissement annuel de la population agricole, représentant une surface additionnelle de 75 000 ha en moyenne par an actuellement.

Utilisant un chiffre estimé pour le Mali, on peut admettre comme ordre de grandeur du défrichement par dégradation ultime (due à la surexploitation pour le bois de feu autour des grandes agglomérations) une surface de 5 000 ha.

C'est donc au total une surface de l'ordre de 80 000 ha de végétation ligneuse naturelle qui disparaît annuellement. On admettra en première approximation que cette surface se répartit entre 10 000 ha de formations arborées productives, 50 000 hectares de formations arborées improductives (NHc/NHO2i) et le reste en formations arbustives (nH).

2.1.2 Dégradation

La sécheresse des années 1970 a entrainé la degradation de la plupart des peuplements ligneux. Les coupes excessives de bois de feu autour des agglomérations, les feux de brousse la “dent du bétail” et les phénomènes d'érosion entrainent un dépérissement de la composante ligneuse des formations végétales naturelles, ce qui motive les projets de mise en défens.

2.1.3 Tendances dans l'exploitation forestière

Le document “L'énergie dans la stratégie de développement du Sahel” envisage une croissance de la consommation en bois de chauffe de 2 800 000 m3 en 1975 (dont 340 000 m3 en zones urbaines) à 5 8000 000 m3 en 2 000 (dont 1 200 000 m3 en zones urbaines). Ces prélèvements complémentaires considérables se feront en grande partie sur la végétation naturelle car les surfaces de plantation de bois de feu qui seraient nécessaires pour satisfaire ne serait-ce que la consommation des zones urbaines paraissent hors de portée des possibilités actuelles de réalisation (de l'ordre de 800 000 ha de plantations en sec à 3 stères/ha/an). Du fait de la faible productivité des peuplements naturels, de leur vulnérabilité à d'autres causes de dégradation (feux, surpâturage, érosion) il est à craindre que leur dégradation ne fasse que s'aggraver dans les années qui viennent, à moins d'une politique énergique d'aménagement des formations naturelles.

2.1.4 Surfaces et volumes sur pied à la fin de 1985

Surfaces de végétation ligneuse naturelle estimées à la fin de 1985
(en milliers d'ha)


Volumes sur pied estimés à la fin de 1985
(en millions de m3)


2.2 Plantations

Comme on a eu l'occasion de le signaler les types de plantation sont très variés et les projets en cours de réalisation (ou seulement à l'état de formulation) très nombreux. Le Centre d'investissement FAO/Banque mondiale a proposé en 1977 pour le seul financement partiel de la Banque mondiale pour le court terme les programme suivants (7):

D'autres financements extérieurs (bilatéraux, multilatéraux, organisations non-gouvernementales) s'ajoutant aux efforts nationaux vont permettre l'établissement dans les cinq prochaines années de nombreuses plantations en plein et en ligne. Il est difficile d'estimer une surface totale des plantations en plein réussies pour cette période et on l'a très grossièrement évaluée à 8 000 hectares.

Surfaces estimées des plantations non-industrielles réalisées à la fin de 1985
(en milliers d'ha)

CatégorieEssencesAnnées81–8576–8071–7566–7056–6546–55Avant 46Total
Classe d'âge0–55–1011–1516–2021–3031–4040
P=P..2=PH.2=PHL2Acacia albida, A. nilotica,
A. senegal, Anacardium occidentale, Azadirachta indica, Eucalyptus camaldulensis et autres.
8,03,52,00,5   14,0


  1. FAO 1969 “Projet “Mise en valeur du Dallol Maori” - Rapport des consultants en matière forestière” - par J.C. Delwaulle et Galabert - Rome

  2. Gschladt, W. 1972 “Le rônier au Dallol Maouri, Niger” - in Bois et Forêts des Tropiques, No. 145 - Nogent-sur-Marne (France)

  3. Direction des Eaux et Forêts 1976 “Les problèmes forestiers du Niger” - Rapport présenté à la consultation sur le rôle de la forêt dans un programme de réhabilitation du Sahel (Dakar, 26 Avril – 1er Mai 1976) - Niamey

  4. Anonyme 1977 “Niger - Le développement forestier - Situation au Niger” - Stage pratique d'échanges et d'expériences dans les domaines forestier et industriel - (Abidjan, 13–24 Avril 1977)

  5. Barbier, C. 1977 “Problèmes forestiers et sylviculture au Niger” - Rapport de consultant- Niamey

  6. FAO/Direction des Eaux et Forêts 1977 “Projet d'étude et de planification de l'utilisation des sols et des forêts” - FAO TF NER/18 - USA- Rome

  7. Programme de coopération FAO/Banque mondiale 1977 “Sahel central - Mission de reconnaissance forestière” - Rapport No. 17/77 - CESA. 1 - Rome

  8. Marchand, B. 1978 “Approvisionnement en énergie domestique à Niamey” - Rapport de stage de Maîtrise Sciences Economiques effectué à la Caisse Centrale de Coopération Economique de Niamey - Niamey

  9. Représentation au Niger de la FAO 1978 “Rapport semestriel No. 2/78” - Niamey


Nigeria occupies a total area of 923 768 km2 between latitudes 4°15' N (southern tip of the Niger delta on the Atlantic ocean) and 13°55' N (north western frontier with Niger) and between longitudes 2°45' E (southern frontier with Benin) and 14°40' E (northern frontier with Cameroon). The straight distance corresponding to the latitude and longitude ranges are respectively 1 050 and 1 300 km approximately. The general relief is that of a plateau culminating in the central northern part of the country (Jos region) and divided in three parts - south west, south east and north - by the Niger river and its main tributary, the Benue river. Mountainous ranges, some of them culminating at more than 2 000 metres, are bordering the central and northern sections of the frontier with Cameroon.

The vegetation of Nigeria is determined by climate, in particular by the rainfall and the severity of the dry season but profoundly affected by farming, fires and soil (1). The following main vegetation zones can be distinguished (1) (26):

The savanna zones extend in this order from south to north, with the sahelian zone covering only 1% approximately of the total area of the country along the northeastern border with Niger.

Altitude is a dominant factor for vegetation only on the higher elevations of the Bauchi plateau and in the mountainous area along the central section of the cameroonian border.

The 1963 census gave a total population of 55.67 million inhabitants (7) (47). With a likely annual average growth rate of 2.5 –2.7% since 1963, the total population could amount in 1980 between 84.7 and 87.6 million people. Assuming a proportion of 65% of agricultural population this latter would amount to approximately 56 million persons. However the 1978 edition of the FAO Production Yearbook (vol. 32) assumes a lower total population and a lower proportion of agricultural population (55%) and estimate this latter at 37.84 million in 1978, corresponding approximately to 38.8 million in 1980 (growing at an average rate of 1.3%). The overall density in 1980 is of the order of 92–95 hab/km2, one of the highest in Africa. Agricultural population density would be either 61 hab/km2 using statistics provided by (7) and (47) or 42 hab/km2 according to the FAO Production Yearbook. In 1963 the agricultural population in the erst while called Western and Mid - Western states, where most of the productive high forest is left, was 9 million inhabitants which would correspond now to 11.2 million inhabitants or 1.6 million families (with 7 members by family). This last figure gives an idea of the formidable pressure exerted on the high forest by agriculture.

1. Present situation

1.1 Natural woody vegetation

1.1.1 Description of the vegetation types

The following description is mainly based on (1) using the broad classification of this study as a general framework.

Closed broadleaved forests (NHC)

The high forests on dry lands are grouped by Keay under the generic term of lowland rain forest. A broad division can be brought between the drier northern types, formerly called “mixed deciduous forest” by Mac Gregor and Richards, and similar to the semi-deciduous forests of neighbouring Cameroon, and the wetter southern types. Sterculiaceae - obeche (Triplochiton scleroxylon), Sterculia spp., otutu (Nesogordonia papaverifera), Mansonia altissima, Cola spp., Pterygota spp., Mildegardia -, Ulmaceae (Celtis spp.), Moraceae - rokko (Chlorophora excelsa), ogiovu or oro (Antiaris africana) are well represented in the drier types together with such commercial species as afara (Terminalia superba) and Benin mahogany (Khaya grandifoliola). More south the Meliaceae and Leguminosae are more represented: Benin mahogany gives way to Lagos mahogany (Khaya ivorensis) and other Meliaceae include the Entandrophragma species - sapele (E. cylindricum), gedur - nohor (E. angolense), heavy sapele or omu (E. candollei) -, apopo (Lovoa trichilioides), obobo (Guarea cedrata), obobo nekwi (G. thompsonii). Most representative leguminous trees are Cylicodiscus gabunensis, agba (Gossweilerodendron balsamiferum), ayan or anyaran (Distemonanthus benthamianus) and ekhimi (Piptadeniastrum africanum). Ekki (Lophira alata), Sapotaceae with heavy wood and opepe (Nauclea diderrichii) are more prominent further south. This latter species has been abundantly used in plantation.

Generally speaking it can be said that the forests are progressively richer floristically as one goes from north to south-east. About 300 species or species groups were identified in the inventory of the Oban forest reserves (400 000 ha) in the Calabar province at the southeastern tip of the country (15).

A large part of the remaining blocks of mature high forest were created Forest Reserves. They cover 2.3 million ha approximately in the moist forest and derived savanna sones of which approximately 1 640 000 ha are still forest in 1980 (about 1 250 000 ha of forest on dry land, the rest being mostly swamp, riparian or mangrove forests). The rest of the reserved area is mostly in the form of forest fallow (370 000ha) or has been replaced by plantations (180 000 of planted areas), or is covered by savanna. The forest area on dry land outside the forest reserves is being seriously encroached on by agriculture. In effect the forested area outside forest reserves are mostly composed of swamp forests (31.5%), riparian forests (17%), mangrove (14%), oil palm forests (19%) and raphia palm forests (3%), the forest on dry land amounting only for less than one sixth of the total forested area outside forest reserves.

The various stages of forest reconstitution after clearing by agriculture exist, although the population pressure and the shortening fallow periods do not allow in most cases for secondary growth to develop into high forest. If the period of cultivation is long and the soils relatively poor, grasses invade the farmlands and fires start spreading over. The original forest may then be replaced by dervied savanna with only relics left, especially on hills and ridges where farming has not been possible. This type of induced vegetation is widespread in the densely populated southeastern states.

Two particular types of secondary growth occupy extensive areas in the high forest sone of Nigeria. Oil palm forests (Elaeis guineensis) are grown extensively, especially in the states of Rivers, Cross River and Imo. They are generally scattered and form often a mosaic with farmland. They consist of dense stands of naturally regenerated oil palm with an even canopy varying between 10 and 15 metres (46). Similarly rubber plantations are in many cases developing in mixture with a natural growth of indigenous trees such as Anthocleista sp., Chlorophora excelsa, Elaeis guineensis, Musanga cecropicides, Pentaclethra macrophylla, Terminalia superba, Trema guineensis etc… (46). Oil palm and rubber forests, either in large blocks or intermixed in mosaics with other land uses, covered at the end of 1976, 1 270 000 and 9 560 000 ha respectively (49).

Edaphic types of high forests cover at the same time approximately 67% of the total forest cover or 4 750 000 ha (49). This propertion is increasing steadily as these forests are much less encroached by agriculture than those on dry land.

Riparian forests, mainly in the derived savanna zone and along the large rivers in the guinean savanna zone cover 1 250 000 ha and are characterized by abura (Mitragyna ciliata) and Uapaca spp. and various Leguminosae such as Berlinia spp., Brachystegia spp.

Fresh water swamp forests are the most extensive edaphic forest type and will soon become the most extensive forest type in Nigeria with more than 1 900 000 ha (without raffia stands) (49). They are bordering inland mangrove forest and are found in all seasonally flooded areas along the main rivers. The largest concentration is in the Niger delta. Main species are those already indicated for the riparian forests to which can be added Nauclea vanderguchtii, Oxystigma mannii and Symphonia globulifera, and communities of monocotyledons like Pandanus candelabrum and Raphia spp. These latter have been separated from other swamp forests in the interpretation of radar imagery and they cover 210 000 ha approximately (49). Oxystigma mannii occurs also in nearly pure stands: 3 500 ha of such stands had been identified in the forest inventory of the forest reserves of Cross River State (15).

The mangrove swamp forests extend over 970 000 ha approximately all along the coast from Cameroon to Benin. They are characterized by three species of Rhizophora: R. racemosa, the most common species is the pioneer at the edge of the alluvial salt swamp, R. harrisonii is dominant in the middle of the Rhizophora zone and R. mangle on its inner limit. Other species, more often found in stunted and shrub form, are Avicennia nitida and Laguncularia racemosa. Associated with the main mangrove formation is a strand vegetation which grows at the edge of the swamps mainly near the sea board with Conocarpus erectus and other woody species.

Open broadleaved forests (NHc/NHO) and scrub formations (nH)

Woodlands and shrublands occur on the largest part of the Guinea, Sudan and Sahel zones of Nigeria. Their total extension including the corresponding fallow areas has been estimated from radar imagery at 50 650 000 ha approximately, that is 55% of the total country area, and 65% approximately of the savanna climax area estimated at some 78 million ha. As for all African savannas, it is difficult to make a clear distinction between those which have a tree cover and those which are predominantly covered with shrubs, the more so as many of them have a mixture of trees and shrubs in varying proportion. Tree vegetation is generally rare in the Sudan and Sahel zones while it is more common in the Guinea and the derived savanna zones. The vegetation of these two latter zones is cursively presented in (26) and (38) as follows: “In the Guinea zone, acacias are relatively rare, and trees which are completely bare in the dry season are rare. Large areas in the northern and median Guinea zones are dominated by Isoberlinia doka, and one distinction between the northern and median Guinea zones is the association of Uapaca togoensis and Bridelia ferruginea in the latter but not in the former. In the southern Guinea zone Isoberlina doka is much rarer, and Daniellia oliveri is a very abundant tree (though it occurs in other zones). The tree vegetation of the derived savanna zone is broadly similar to that of the southern Guinea zone, though the grass composition differs. Evidence that the derived savanna zone once was originally rain forest and would revert to it if protected against fires and cultivation is given by certain relict and indicator species, and by the survival of patches of a rain forest type on areas distant from streams and other sources of additional moisture”.

Interpretation of radar imagery distinguishes “broadleaved woodland” with the following tree species: Annona senegalensis, Butyrospermum paradoxum, Cussonia barteri, Daniellia oliveri, Isoberlinia doka, Lannea acida, Monotes kerstingii, Prosopis africana, Terminalia avicennioides, Uapaca togoensis. In addition “wooded shrub grassland with patches of woodland” is a class containing also large areas of woodlands, sometimes up to the north of the country along the valleys and in the forest reserves.

The following is the description by (26) and (38) of the vegetation of the Sudan and Sahel zones: “The Sahel zone is characterized by small, widely dispersed, small-leaved trees, particularly acacias, of which Acacia tortitis subspecies raddiana is the most common. In the Sudan zone acacias also occur, particularly Acacia albida, A. seyal, A. nilotica and, in the northern parts A. senegal, but they are not nearly as dominant except on special soil types. A fairly high proportion of the trees are deciduous in the dry season. Some characteristic species (though not confined to this zone) are Anogeissus leiocarpus, Sclerocarya birraea, Combretum micranthum and Guiera senegalensis”.

Interpretation of radar imagery distinguishes the following (predominantly) shrub vegetation types:

1.1.2 Present situation of the woody vegetation

Present areas

A radar coverage (NIRAD) of the whole country was taken between October 1976 and March 1977 and the imagery was then interpreted for vegetation and land-use mapping at the scale of 1/250 000 (46). Areas covered by each vegetation and land-use class have been estimated by dot counting. This work constitutes an incomparable baseline for assessing the situation at end 1976 (49). The details of this estimation are summarized in the following table:

CategoryNIRAD Interpretation classProportion
Areas (in thousand ha)
Whole countryForest ReservesOutside F.R.
NHCf1Mature forest100992641351
Mature disturbed forest100667441226
Mosaic mature disturbed/immature forest75640230410
Mosaic mature disturbed/oil palm farmland5055-55
Swamp forest2038345338
Mosaics rubber/swamp, oil palm/swamp, farmland/swamp, swamp/rubber/farmland1081378
Riparian forest1001 2251151 110
Mosaic farmland/riparian forest5021-21
 Subtotal NHCf1-4 0641 4752 589
NHCf2(i)Swamp forest801 5331791 354
Mosaics rubber/swamp, oil palm/swamp, farmland/swamp, swamp/rubber/farmland4032310313
Mangrove forest10097331942
Raffia palm forest10020918191
 Subtotal NHCf2-3 0382382 800
NHCaImmature forest10020415189
Oil palm forest10072614712
Rubber forest10045312441
Mosaic farmland/immature forest1002 567722 495
Mosaic farmland/oil palm forest1004715466
Mosaic farmland/rubber forest10030129
Mosaic farmland/immature for./oil palm forest10067029641
Mosaic farmland/immature for./rubber forest100935121814
Mosaics farmland/swamp, farmland/riparian forest5015310143
Mosaics swamp/rubber/farmland, rubber/swamp, oil palm/swamp50272-272
Mosaic mature disturbed/oil palm/farmland5056-56
Mosaic mature disturbed/immature2521380133
 Subtotal NHCa-6 7503596 391
NHc/NHOBroadleaved woodland501 9763351 641
Mosaic broadleaved/riparian forest5012316107
Wooded shrub grassland with patches of woodland307 1241 2325 892
 Subtotal NHc/NHO-9 2231 5837 640
NHc/NHOaMosaic farmland/wooded shrub grassland with patches of woodland504 6111354 476
nH (includes fallow areas)Shrub grassland1001 232621 170
Wooded shrub grassland1008 0181 4116 607
Upland wooded shrub grassland/riparian forest1002856279
Dense shrub grassland1001 779891 690
Non-thorny shrubland and thicket10040337
Thorny shrubland and thicket10015ε15
Thorny/non-thorny shrubland and thicket1002 0016631 338
Mosaic thorny/non-thorny shrubland and thicket/farmland10024-24
Complex thorny/non-thorny shrubland and thicket/grassland shrub10092191
Wooded shrub grassland with patches of woodland7016 6232 87413 749
Broadleaved woodland501 9763351 641
Mosaic broadleaved/riparian forest5012316107
Mosaic farmland/wooded shrub grassland with patches of woodland504 6111354 476
 Subtotal nH-36 8195 59531 224

From the results of the above table, areas for 1980 have been estimated taking into account the deforestation rates given in section 2.1 for closed forests and woodlands.

Areas of natural woody vegetation estimated at end 1980
(in thousand ha)

Forest Reserves3801 0001 380  2401 620  4001 350    20011 550   150  5 600
Outside F.R.ε1 5901 5902 7404 3307 350 7 2507 2504 75031 200
Total3802 5902 9702 9805 9507 7501 3507 4508 8004 90036 800

1 Estimated woodland area in game reserves (NHc/NHO 2r).


Document (5) describes land ownership as follows: “Land is communally owned and this ownership is unvariably vested in the natural rules. This is recognized in the Forestry Law. In the reservation programme a machinery for obtaining the consent of owners and regularising rights is normally set in motion. Two forms of ownership of the forest estate are in existence: (a) state forest which is owned, controlled and managed by the Forestry Department and (b) local government reserve which is owned by various local government councils and is under a dual control and management by the council and the state”. However, in document (44), written in 1978, it is said that the magnitude of the dual control in forest reserves is decreasing and the right previously exercised by local councils to “own, possess and control forest estates in the southern states of the country has been withdrawn”. The same document mentions that “such a development may take place in all or most of the northern states before long”.

Legal status and management

Forest reserves, which constitute the forest estate of the country, cover an approximate area of 10 million ha or 10,8% of the total area of the country1. Using the data of who previous table and those given for plantations (section 1.2) the forest estate is distributed approximately in the following way:

closed forests (NHCf)16,2% 
woodlands (NHc/NHO)15,5% 
shrubland (nH)56,0%(including areas affected by agriculture)
forest plantations (P)1,6% 
 Woody vegetation89,3% 

The balance (10,7%) corresponds to grasslands (with or without scattered woody elements) and forests and woodlands affected by agriculture (NHCa and NHc/NHOa). Some additional forest reserves are being proposed for Rivers state (137 800 ha according to (50)). Forest reserves in the high forest region will soon contain the only high forest left in the country. All large-scale forest plantations are included in forest reserves.

A national park was created in 1975 (Kainji Lake national park) of a total area of approximately 525 000 ha resulting from the merging of the Borgu game reserve in Kwara state and the Zugurma game reserve in Niger state (northern Guinea zone). Yankari game reserve in the sudanian zone covers 225 000 ha approximately. Few other constituted game reserves are mentioned in (17) in the south western states (game reserves of Old Oyo, Orli River, Gilli-Gilli, Kwale). Thirty other game reserves are proposed in the various ecological zones of the country covering a total area of the order of 2.6 million ha (the extent to which these proposals overlap on existing forest reserves is not known).

In the mid sixties the following was said about management of the high forests of the country (5): “Yield control (in western and mid-western Nigeria) is generally on area basis, but where sufficient data are available and it is administratively desirable, basal area control is combined with area control. In the high forest, a provisional rotation of 100 years has been adopted and, where necessary, a felling cycle of 25 years is prescribed. It is now being contemplated in view of the presence of young pole crop and the realization that the forest is more or less a selection forest that instead of exploiting a hundredth of the area annually, a fifty year cycle should be adopted.”

“It is laid down that no forest reserve shall be exploited without being regenerated. The most usual form of regeneration is natural regeneration. The classical Tropical Shelter-wood System has been adopted and modified to suit local conditions and has achieved varying success. Where there is genuine land hunger, taungya is used and has been very successful. In exceptional cases where natural regeneration has failed and taungya is not feasible, regeneration has been by direct plantation but the more usual method in such cases is enrichment planting.”

“The same principle applies in eastern Nigeria, namely, that no forest reserve shall be exploited without being regenerated. Both the taungya system and method of direct plantation are in operation where they are applicable. The Tropical Shelterwood System has never been successful in the Region and has not therefore been applied on any large scale. In its place, large scale regeneration has been achieved by enrichment planting in the high forest.”

In 1964 the area of the forest estate managed under formal working plans amounted to 1 797 000 ha distributed geographically as follows:

North(former northern Nigeria):   571 000 ha
Southeast(former eastern Nigeria):   107 000 ha
Southwest(former western and mid-western Nigeria):1 112 000 ha

The reassessment of the outcome of Tropical Shelterwood System, the heavy pressure on high forest and the need to supply an increasing demand for wood products have shifted the emphasis from natural regeneration towards plantation. Consequently intensive management of the natural forests, in the meaning used in this study, implying in particular the application of silvicultural treatments, has been progressively abandoned and working plans where they exist are frequently out of date (23). This is the reason why no significant area has been put in the category NHCf1m (intensively managed productive closed broadleaved forests).

Forest utilization

Log harvesting

The high forest is the main source of logs, a small quantity coming from the riparian forests and the woodlands in the savanna regions and from plantations (32). In 1974 estimated log production (2 300 000 m3) was distributed in the following way (32):

logs into sawmills and plywood mills:     1 700 000 m3
logs into match factories and pole plants:           20 000 m3
logs used for pitsawing:200–300 000 m3
logs exported:         300 000 m3

The main supply areas are still the southwestern states although the proportion coming from the southeastern states is increasing since most of the undisturbed forests are found there. Less than half of the log input comes from mill's own forest concessions (32). Log exports have decreased over the years from an average of 670 000 m3 in the years 1961–65 to 355 000 m3 in the period 1966–79 and 215 000 m3 in the period 1971–75 according to FAO Yearbook of Forest Products (average annual export in periods 1961–65 and 1966–70 are estimated at 515 000 m3 and 275 000 m3 respectively in document (28)). According to FAO Yearbooks average annual sawlog and veneer log production has been the following over the last twenty years (in thousand m3):

1 2701 3051 555 (est)2 195 (est)

Although incomplete these statistics show the general increase of recorded log production in the country.

Output per ha seems to have increased also during these years, together with the number of species accepted by local and export markets. Figures are somewhat variable but illustrate this general trend. (2) quotes an average yield in the former Western State of 35 m3 per ha; but smaller figures are found in (2) and (21). The former has calculated an average output per ha of forest reserve of 16–17 m3 in the years 1961–70 while the second indicates in 1972 an average of 21 m3. (29) gives yields of 30 m3 and 46 m3 in some forest reserves of the former Western State during the early 70's. Finally (43) uses a global average of 35 m3/ha, a figure which has been used as VAC (volume actually commercialized) in section 1.1.3.

1 The total area has increased regularly from 97 000 ha in 1900 to 8 563 100 ha in 1960 and 8 951 500 in 1968 (24). For the year 1970 various figures are given: 9 342 000 (47), 9 897 600 (14), 11 608 600 (23). More recent assessments are found in (42) and (47) - 9 651 800 ha in 1974 - and in (49) (10 006 200 ha).

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