Other forest products
Up to now, the productive savanna woodlands have provided mainly building poles and firewood. Total annual pole production can be estimated between 300 000 and 350 000 m3. Fuelwood is the unique energy source for cooking and heating in the rural areas and it is partly replaced by charcoal in the urban areas. At the per capita consumption rate of about 1 m3 of fuelwood and 0.2 m3 of charcoal, the production in 1980 can be estimated at 11 500 000 m3 of fuelwood and 950 000 m3 of charcoal (11). Other products include sningles, bamboos, canes, palm oil, palm wine, gums and resins, rubber and latex (6). Village industries such as wood carving, basket weaving, manufacture of mortars and canoe making continued among the rural population.
1.1.3 Present situation of the growing stock
Growing stock estimated at end 1980
(totals in million m3)
NHCf1uv | NHCf1uc | NHCf1m | NHCf2 | NHc/NHO1 | |||||||||||
VOB | VAC | VOB | VOB | AAC | VOB | VOB | VAC | ||||||||
m3/ha | total | m3/ha | total | m3/ha | total | m3/ha | total | m3/ha | total | m3/ha | total | m3/ha | total | m3/ha | total |
150 | 23 | 150 | 175 | 1.8 | 2 | 150 | 60 | 30 | 47 | 2 | 3.2 |
(7) mentions a growing stock, with minimum diameter set at 30 cm, for all forest reserves in the high forest zone (1 557 108 ha at that time) of about 177 million m3. Assuming that the diameter class 10–30 cm represents roughly 25% of the total volume above the diameter limit 10 cm, the volume over bark can be estimated at 150 m3/ha. Since the criterium ‘standing stock’ has never been determinant for the gazetting of forest areas it can be safely accepted that the average growing stock in the remaining unreserved forests is approximately the same. (7) gives also an adjusted annual allowable cut, for all species, of 1.8 m3/ha for sustained yield of the intensively managed forests. No data are available concerning the stocking per area unit for the productive woodlands (NHc/NHO1). Hence, the figures found in the table are those calculated for the neighbouring country Togo. However, the total volume is estimated a 50% higher, since most productive open forests are located in the derived savanna belt where rainfall is much more abundant (1 250–1 500 mm).
1.2 Plantations
1.2.1 Introduction
The oldest man-made forests date from early german occupation times (german Togoland) in 1900–1910 and are situated in the Guinea woodland savanna. Small woodlots communally raised can also be found around many villages, introduced probably in the same period. Some large trees are still found in these woodlots, but for the most part they have been heavily coppiced and even burnt (4). Taungya system was introduced as early as 1928. Between 1948 and 1961 the plantation activities were particularly well organized, with preliminary selection of the site by soil survey, the establishment of permanent nurseries and mechanical land clearing, stumping, site preparation and tending, all by tractor, although some taungya planting was still going on (4 774 ha thus planted by 1961). Most of these stands are composed of intermingled homogeneous blocks of the following principal species: Tectona grandis, Dalbergia sissoo, Anogeissus leiocarpus, Azadirachta indica, Gmelina arborea, Khaya senegalensis and Albizia lebbeck, the choice of species being governed by their end-use and the result of the site survey. Large scale mechanized planting was discontinued between 1961 and 1966 (4). Planting with the taungya system was then resumed on a larger scale and some 15 060 ha were added in the period until 1973. The early plots given out were small, of the order of 2.4 ha per annum and usually scattered, not too easily accessible and did not constitute manageable plantation units. A variation of the traditional taungya system was introduced in 1969. It is essentially the same, except that the Forestry Department was to fulfil all the functions normally performed by the farmer. In this way, it was expected to obviate the problems posed by over-abundance of land to the farming community (16).
Efforts are currently being made to convert the poorly stocked parts of the rain forest and the ecotone between closed forest and savanna into plantations of fast-growing species. Activities are restricted to areas already under forest reservation, due to the prohibitive cost of acquiring of and paying compensation for land under some other form or use. Presently, the programme is concentrated in 12 reserves. About 15% of all man-made forests are now established under the adapted taungya system.
The following main indigenous species are used in planting programmes: Terminalia ivorensis, Tarrietia utilis, Triplochiton scleroxylon, Mansonia altissima, Khaya ivorensis, and Anogeissus leiocarpus. The principal exotic species are Tectona grandis, Cedrela odorata, Gmelina arborea, Eucalyptus spp. and Pinus spp. (14).
Although no quantitative information is available, it is however known that the private gold mines have established plantations of teak, Gmelina and Cassia on short rotations for mine timber and that the Kade match factory has initiated planting activities with Cedrela and Gmelina for the manufacture of match sticks (17).
1.2.2 Areas of established plantations
Since no information is available concerning the specific purposes of the plantations, it has been assumed that only half of the established broadleaved man-made forests are industrial plantations. However, for reasons mentioned under 1.2.3, all teak stands of age 16 and older have been classified as fuelwood/poles plantations. Figures used in the tables are based on (17), taking into account the different age classes used in this study, and updating at end 1980. These estimates exclude regenerated parts of the natural forest. Planting forecasts given in (17) for the period after 1977 are the following: 500 ha/year for teak, 800 ha/year for the other broadleaved species (those mentioned under 1.2.1, including non-industrial plantations) and 300 ha/year for eucalypts.
Industrial plantations
Areas of established industrial plantations estimated at end 1980
(in thousand ha)
Category | Species | Years | 76–80 | 71–75 | 66–70 | 61–65 | 51–60 | 41–50 | before 41 | Total |
Age class | 0–5 | 6–10 | 11–15 | 16–20 | 21–30 | 31–40 | > 40 | |||
PHL 1 | Tectona grandis Other hardwood species | 2.05 3.80 | 3.37 5.50 | 3.33 2.95 | 1.25 | 1.45 | 1.00 | 0.35 | 8.75 16.30 | |
PH.1 = PHL1 | Subtotal hardwood species | 5.85 | 8.87 | 6.28 | 1.25 | 1.45 | 1.00 | 0.35 | 25.05 | |
PS.1 | Pinus spp. | 1.20 | 1.20 | |||||||
P..1 | Total industrial plantations | 7.05 | 8.87 | 6.28 | 1.25 | 1.45 | 1.00 | 0.35 | 26.25 |
The softwood plantation scheme (Pinus caribaea and P. oocarpa) started only in 1977, with an estimated annual planting rate of 300 ha up to 1985. Although the ‘other broadleaved species’ may include fast-growing species as e.g. Gmelina arborea, Eucalyptus spp., etc., the latter only represent a minor part of the industrial plantations as a whole. Thus they have all been classified under PHL1.
Other plantations
These are mainly established for fuelwood and poles.
Areas of established non-industrial plantations estimated at end 1980
(in thousand ha)
Category | Species | Years | 76–80 | 71–75 | 66–70 | 61–65 | 51–60 | 41–50 | before 41 | Total |
Age class | 0–5 | 6–10 | 11–15 | 16–20 | 21–30 | 31–40 | > 40 | |||
PHL2 | Tectona grandis Other broadleaved species | 2.05 3.80 | 3.37 5.50 | 3.33 2.95 | 6.00 1.25 | 3.67 1.45 | 0.30 1.00 | 0.10 0.35 | 18.82 16.30 | |
Subtotal PHL2 | 5.85 | 8.87 | 6.28 | 7.25 | 5.12 | 1.30 | 0.45 | 35.12 | ||
PHH2 | Eucalyptus spp. | 4.10 | 6.80 | 3.00 | 13.90 | |||||
P..2 = PH.2 | Total non industrial plant. | 9.95 | 15.67 | 9.28 | 7.25 | 5.12 | 1.30 | 0.45 | 49.02 |
Other broadleaved species include here also Azadirachta indica and Cassia siamea, the former mostly planted in the north of the country. Eucalyptus tereticornis, E. cadambae, E. intermedia, E. deglupta, E. citriodora and other eucalypts are mostly restricted to the south.
All plantations
Areas of established plantations estimated at end 1980
(in thousand ha)
Category | Species | Years | 76–80 | 71–75 | 66–70 | 61–65 | 51–60 | 41–50 | before 41 | Total |
Age class | 0–5 | 6–10 | 11–15 | 16–20 | 21–30 | 31–40 | > 40 | |||
PHL(PHL1+PHL2) | Hardwood sp.other than fast-growing | 11.70 | 17.74 | 12.56 | 8.50 | 6.57 | 2.30 | 0.80 | 60.17 | |
PHH | Fast-growing hardwood species | 4.10 | 6.80 | 3.00 | 13.90 | |||||
PH | Subtotal hardwood species | 15.80 | 24.54 | 15.56 | 8.50 | 6.57 | 2.30 | 0.80 | 74.07 | |
PS | Subtotal softwood species | 1.20 | 1.20 | |||||||
P | Total all plantations | 17.00 | 24.54 | 15.56 | 8.50 | 6.57 | 2.30 | 0.80 | 75.27 |
While some species are specific in their allocation to utility values (e.g. Khaya spp.), others fall under two or more headings and the objectives are achieved by growing them in the appropriate ecological zone (e.g. eucalypts). Only Cedrela odorata, Eucalyptus spp., Tectona grandis, Terminalia ivorensis and Triplochiton scleroxylon can be found in fairly large scale plantations. Only small areas are planted with the other species (4).
1.2.3 Plantation characteristics
- Tectona grandis was first introduced between 1900–1910. It was planted both in the woodland savanna and in the closed high forest. Most of the plantations, especially small woodlots, have been coppiced for firewood and have not been managed as timber stands, although the potential on good sites is considerable. The techniques of raising teak are well understood but due to the neglect of thinnings and frequent fires, the savanna plantations have been utilized for poles and fire wood only. Small village woodlots are maintained mainly for the supply of yamsticks. Coppice plantations are managed on a 10-year coppice rotation (4), while industrial plantations have a lifespan of 50 years (17).
- Azadirachta indica (neem) was introduced together with teak and is widely used as an amenity tree in towns and villages. Plantations of neem, worked on a coppice rotation of 8 years, have yielded 60–70 m3/ha in the first rotation (4).
- Various species and origins of eucalypts have been tried out mostly in the savanna zone, so far with varied success. Existing non-experimental plantations are managed under a rotation cycle of 10 years, with an estimated mean annual increment of 15 m3 (17).
- Pines (Pinus caribaea and P. oocarpa) were introduced only in 1977. They are assumed to yield a M.A.I. of 20 m3 over a rotation of 10 years (17).
- The M.A.I. of the oldest Terminalia ivorensis plantations with a density of some 200 to 250 stems per ha of an average DBH of 45 cm and of 23–25 m average height has been found equal to 9 m3/ha (11).
2. Present trends
2.1 Natural woody vegetation
2.1.1 Deforestation
Deforestation is going on in the unreserved closed forests due to increasing population, emphasis on food crop growing and diversification of cash and export crops. Unreserved closed forest thus constitute still an important salvage area of economically valuable broadleaved species. However, deforestation is decreasing, coming from an annual rate of 45 000 ha before 1976 (14) to an estimated 22 000 ha for 1981–85, as the remaining area of unreserved forest is reduced to a minute fraction of the total arable land area.
Average annual deforestation rates
(in thousand ha)
Periods | ||||||||||||
1976–80 | 1981–85 (projections) | |||||||||||
NHCf1uv | NHCf1uc | NHCf1m | NHCf1 | NHCf2 | NHCf | NHCf1uv | NHCf1uc | NHCf1m | NHCf1 | NHCf2 | NHCf | |
25 | 2 | 27 | 27 | 20 | 2 | 22 | 22 |
The main cause of forest destruction is shifting cultivation. It is practised throughout the country and is based on the fallow system. Food crops grow well for two or three years after which yield declines as the fertility of the soil becomes exhausted. Where, owing to land pressure, the fallows get shorter, the soil deteriorates as there is insufficient time for the natural regeneration to rehabilitate the soil and improve the nutrient status, with possible erosion hazards. The Protected Timber Lands Act aims at ensuring that proper timber exploitation precedes the farming of the remaining areas of unreserved forests (17). Other major hazards in the natural closed forests are illegal fellings and fires, but they are not responsible for deforestation stricto sensu. It is important to appreciate the fact that timber exploitation is not directly responsible for the rapid reduction of the commercial timber resources of the unreserved forests. This must be ascribed categorically to the extension, largely uncontrolled, of farming in the closed forest zone, about half of this for cocoa cultivation. It is, however, doubtless that extraction by major timber companies plays its part in the spread of farming through the opening up of new roads (2). The general system of creating a farm in the high forest is to cut the climbers, shrubs and small trees, and fell most of the trees in the upper and emergent canopies. This is done from about October to March, and towards the end of the dry season, the felling debris is burnt in piles. Burning of the brushwood is also used to kill the large trees which are not easily felled. Planting and sowing of the food crops begins in April with the coming of the rains. After the first year, the farm contains only plantains and cocoyams. They continue to give good crops until the fourth or fifth year, when the farm is usually abandoned. The fallow period depends a great deal on land shortage. This may be seven years or more. Near the towns the fallow period is very much reduced.
2.1.2 Degradation
In the savanna zone, especially in the Northern and Upper Regions, “Operation Feed Yourself” (18) has led to the systematic and undiscriminate destruction of large tracts of bush lands, which were converted into farm lands. Paddy rice cultivation has made devastating in-roads into the natural vegetation and reduced thousands of hectares of swampy bush lands into virtual treeless plains.
Savannas modified by extensive shifting cultivation have mainly two selected species left in the high canopy: Butyrospermum parkii providing shea-butter and Parkia filicoidea, providing edible seeds. A further stage of degradation produces open parkland with a mixture of perennial and annual grasses. There, the two species mentioned above are more scattered and largely consist of overmature trees. The final stage of degradation is practically treeless savanna with annual grasses under heavy cultivation and grazing (4). On worked out lands, the vegetation consists of a short scrub growth of Bauhinia rufescens, Combretum spp. and Piliostigma thonningii. Fires and grazing tend to keep down the height growth (1).
The annual rates of loss of productive and unproductive woodlands for the period 1980–85 are estimated at 20 000 ha and 30 000 ha respectively.
2.1.3 Trends in forest utilization
There is an increasing demand for wood and wood products at both national and local levels, corresponding to rising standards of living, growth of population, industrialization and urbanization. Efforts are being made to replace imported materials by wood components in building construction. There will be most likely no substitution for fuelwood and charcoal. On the contrary, there will be a shift away from fossil fuels, e.g. kerosene and gas, because of oil price increases and a rapid rise in production of charcoal for industrial purposes (development of Ghana's ferrous metal and calcium carbide production in the rural areas with the Opon Mansi iron and steel project). More fuelwood will be needed for tobacco curing and more charcoal for the sugar industry. A pulp mill is also envisaged in the near future (17) (18).
With the continuation of the promotion efforts for the use of secondary species, it can be expected that logging output per ha will increase up to the annual allowable cut in the managed forests.
2.1.4 Areas and growing stock at end 1985
Areas of natural woody vegetation estimated at end 1985
(in thousand ha)
NHCf1uv | NHCf1uc | NHCf1m | NHCf1 | NHCf2 | NHCf | NHCa | NHc/NHO1 | NHc/NHO2 | NHc/NHO | NHc/NHOa | nH |
54 | 1 157 | 1 211 | 397 | 1 608 | 6 590 | 1 475 | 5 250 | 6 725 | 2 880 | 300 |
Taking into account the deforestation and degradation rates set in the previous sections, the table above reflects an assessment of the likely situation as at end 1985. Of the 100 000 ha of destroyed unreserved high forest, 90 000 are believed to be taken up by non permanent agricultural activities or permanent cocoa/coffee farming under forest cover, the remaining 10 000 ha being lost for ever to agricultural or other permanent activities. About 10 000 ha of the managed forest estate will be converted into plantations of fast-growing species.
Another 100 000 ha of productive woodlands and 150 000 ha of unproductive savannas are estimated to be transformed into 200 000 ha of savanna under strong influence of agricultural cultivation and bush fallow (NHc/NHOa) and 50 000 ha of permanent pasture and, cropland (irrigated or not), non-industrial plantations and extension of urbanized areas. No significant change can be foreseen in the scrubland along the coast, since most activities are restricted to the grassland part of the zone.
The estimated areas of woody vegetation at the end of 1985 lead to the following corresponding growing stock:
Growing stock estimated at end 1985
(in million m3)
NHCf1uv | NHCf1uc | NHCf1m | NHCf1 | NHCf2 | NHCf | NHc/NHO1 | |||
VOB | VAC | VOB | VOB | AAC | VOB | VOB | VOB | VOB | VAC |
8 | 174 | 2 | 182 | 60 | 242 | 44 | 3 |
2.2 Plantations
The figures given in the following tables are derived from the projections made in (16).
Trials with other species currently being done in the various ecological zones of the country on the establishment of fast-growing man-made forests in areas where land pressure is not acute, continue (18). In the savanna zone special tree planting measures and plantation programmes will be instituted as a means of arresting the threat of the southward drift of the Sahel. In the short term, amenity planting will be carried out around institutions, parks, etc. on the approaches to towns and villages, around dams to reduce surface evaporation and to reduce water temperature. In the long term, the programme will include the creation and planting of barrier reserves along the northern borders, shelter belts around farm lands and the establishment of wood lots. Species that will be used are Khaya senegalensis, Tectona grandis, Acacia albida, Cassia siamea, Eucalyptus spp., Gmelina arborea, Anacardium occidentale and mangoes (18).
Industrial plantations
Areas of established industrial plantations estimated at end 1985
(in thousand ha).
Category | Species | Years | 81–85 | 76–80 | 71–75 | 66–70 | 56–65 | 46–55 | before 46 | Total |
Age class | 0–5 | 5–10 | 11–15 | 16–20 | 21–30 | 31–40 | > 40 | |||
PHL1 | Tectona grandis Other hardwood species | 2.50 2.00 | 2.05 3.80 | 3.37 5.50 | 3.33 2.95 | 2.20 | 1.00 | 0.85 | 11.25 18.30 | |
PH.1 = PHL1 | Subtotal hardwood species | 4.50 | 5.85 | 8.87 | 6.28 | 2.20 | 1.00 | 0.85 | 29.55 | |
PS.1 | Pinus spp. | 1.20 | 1.20 | 2.40 | ||||||
P..1 | Total industrial plantations | 5.70 | 7.05 | 8.87 | 6.28 | 2.20 | 1.00 | 0.85 | 31.95 |
Other plantations
In the following table it is assumed that all teck plantations established between 1980 and 1985 will be for the production of wood for industry.
Areas of established non-industrial plantations estimated at end 1985
(in thousand ha)
Category | Species | Years | 81–85 | 76–80 | 71–75 | 66–70 | 56–65 | 46–55 | before 46 | Total |
Age class | 0–5 | 5–10 | 11–15 | 16–20 | 21–30 | 31–40 | > 40 | |||
PHL2 | Tectona grandis Other hardwood species | 2.00 | 2.05 3.80 | 3.37 5.50 | 3.33 2.95 | 9.62 2.20 | 0.30 1.00 | 0.15 0.85 | 18.82 18.30 | |
Subtotal PHL2 | 2.00 | 5.85 | 8.87 | 6.28 | 11.82 | 1.30 | 1.00 | 37.12 | ||
PHH2 | Eucalyptus spp. | 1.50 | 4.10 | 6.80 | 3.00 | 15.40 | ||||
P..2 = PH.2 | Total non-industrial plantations | 3.50 | 9.95 | 15.67 | 9.28 | 11.82 | 1.30 | 1.00 | 52.52 |
The total annual planting rate of fuelwood and pole plantations between 1981 and 1985 is estimated at 700 ha (17).
All plantations
A general estimate of the situation of all man-made forests in 1985 is represented in the following table.
Areas of established plantations estimated at end 1985
(in thousand ha)
Category | Species | Years | 81–85 | 76–80 | 71–75 | 66–70 | 56–65 | 46–55 | before46 | Total |
Age class | 0–5 | 5–10 | 11–15 | 16–20 | 21–30 | 31–40 | > 40 | |||
PHL(PHL1+PHL2) | Hardwood sp. other than fast-growing | 6.50 | 11.70 | 17.74 | 12.56 | 14.02 | 2.30 | 1.85 | 66.67 | |
PHH | Fast-growing hardwood species | 1.50 | 4.10 | 6.80 | 3.00 | 15.40 | ||||
PH | Subtotal hardwood species | 8.00 | 15.80 | 24.54 | 15.56 | 14.02 | 2.30 | 1.85 | 82.07 | |
PS | Subtotal softwood species | 1.20 | 1.20 | 2.40 | ||||||
P | Total all plantations | 9.20 | 17.00 | 24.54 | 15.56 | 14.02 | 2.30 | 1.85 | 84.47 |
Bibliography
Taylor, C.J. 1952 “The Vegetation Zones of the Gold Coast” - Forestry Department Bulletin no. 4 - Accra
FAO 1958 “Prospects of Development of the Forest Industry” - based on the work of M.N. Gallant - Report to the Government of Ghana no. 863 - Rome
Foggie, A. 1959 “Ghana Forests and Forestry” - English text of an article published in ‘Bois et Forêts des Tropiques’ no. 65, May–June 1959 - Nogent-sur-Marne - France
FAO 1966 “Land and Water Surveys in the Northern and Upper Regions, Ghana - Forestry Report” - based on the work of R.A. de Rosayro - Travel Report no. 18 - Rome
Osafo, E.D. 1970 “The Development of Silvicultural Techniques Applied to Natural Forests in Ghana” - Forest Products Research Institute Technical Note no. 13 - Kumasi Ghana
Forestry Department 1971 “Annual Report” - Accra
Canadian International Development Agency 1972 “Ghana: Forest Products Transport Study” - based on the work of Swan Wooster Consulting Engineers - Vancouver, Canada
Forestry Department 1972 “Annual Report” - Accra
Forestry Department 1973 “Request to UN/FAO/WFP for Assistance in a Project for Economic and Social Development” - Accra
Forestry Department 1973 Tables for the Annual Report 1973 - Draft - Accra
FAO 1974 “Potential of Forest Industries Development in Ghana” - based on the work of W.J.MacInnes and P. von Carlowitz - ECA/FAO Forest Industries Advisory Group for Africa IND/59-MR/54 - Addis Ababa
Forestry Department 1974 “Progress Report 1966–72” - prepared for the Tenth Commonwealth Forestry Conference 1974 - Accra
FAO 1975 “Report on Forest Administration, Legislation and Concession Policy ‘Ghana’” - based on the work of Fr. Schmithüsen - Working Document Draft - Rome
Forestry Department 1976 “Ghana National Progress Report 1972–1973” - prepared for the fourth session of the African Forestry Commission - Accra
Ambassade de France au Ghana 1977 “Le bois et les industries de bois en Ghana” - Accra
Brookman-Amissah J. 1978 “Agrisilviculture for Production of Wood and Food Crops in Ghana” - Paper prepared for the Eight World Forestry Congress in Jakarta - Ghana - Kumasi
Forestry Department 1978 “National Progress Report on Forestry - Ghana 1976–1977” - prepared for the fifth session of the African Forestry Commission - Accra
Forestry Department 1978 “The Annual Estimates for 1979–80; Vol III: Lands, Natural Resources, Fuel and Power” - Accra
La República de Guinea Ecuatorial está compuesta de tres partes de tamaño e importancia forestal muy diferentes:
el Río Muni, se extiende sobre 26 000 km2 y tiene la forma de un trapecio limitado al norte (paralelo 2° 10' N) por el Camerún, al este (meridiano 11° 20' N) y al sur (paralelo 1° N) por el Gabon y al oeste por el Atlántico. 130 km. separan la frontera norte de la frontera sur y la profundidad promedio del país es de 200 km. aproximadamente;
la isla de Fernando Poo, de 2 017 km2 de área, más al norte (latidud media: 3° 30' N) compuesta por los conos de dos volcanes y culminando a 3 008 m.s.n.m.;
la pequeña isla de Annobon de 44 km2 de área (Pagalu) compuesta por un volcán de 900 metros de altura.
El territorio de Rio Muni está constituido por una franja litoral sedimentaria de 15 km de ancho y un escalonamiento en la dirección noroeste-sudeste de capas geológicas (de leptite a 300 m.s.n.m., de diorite y gabbro a 500 m.s.n.m) hasta la meseta de granite en la parte sureste a 600 m.s.n.m correspondiendo a la parte oeste de los “Montes de Cristal” en Gabon (2). La topografía es fácil en la parte litoral pero se halla más quebrada en el interior y algunas montañas alcanzan una altura de 1 100–1 200 m.s.n.m. Las lluvias varían entre 1800 mm (noreste) hasta 3 500–4 000 mm (al cabo San Juan en el suroeste) en el Rio Muni y sobrepasan 2 500 mm en Fernando Poo, alcanzando en algunos puntos más de 10 000 mm (3).
No se encontraron datos precisos sobre la población presente en el país. A partir de varios documentos (FAO, UN/ESA) y actualizando las cifras del documento (3) se ha llegado a una población guinea de 305 000 habitantes en Rio Muni (densidad: 12 habitantes/km2) y 35 000 en Fernando Poo, o sea un total de 340 000 habitantes. Una población extranjera adicional estaba estimada en 1968 en 56 000 y 11 000 en Rio Muni y Fernando Poo respectivamente (resultando en una densidad de 42 habitantes/km2 para Fernando Poo en esta fecha). La tasa promedio anual de incremento de la población es de alrededor del 1.8%.
1. Situación actual
1.1 Vegetación leñosa natural
1.1.1 Descripción de los tipos de vegetación
Formaciones arboladas latifoliadas densas (NHC)
La vegetación de todo el territorio del Rio Muni se clasifica como “bosque húmedo tropical en elevaciones bajas y medias” en el Mapa A.E.T.F.A.T./Unesco (1959) y como “mosaico de tipos relativamente húmedos” y “relativamente secos” de “bosque ombrófilo de baja altitud” en el segundo Mapa Unesco (White, 1980). Esos bosques mixtos tropicales son los mismos que existen en la primera y segunda zonas forestales del Gabon. Una característica fundamental de esos bosques es la presencia del ocume (Aucoumea klaineana) que desaparece solamente en algunas áreas al noroeste y noreste. Aunque algunos árboles de esta especie han sido señalados en el Camerun, en la frontera con el Rio Muni, el ocume es esencialmente nativo del Congo, Gabon y Rio Muni.
Una explicación comunmente aceptada de la presencia de esta especie es que caracteriza bosques regenerados después de la corta del bosque primario, por fines agrícolas, por poblaciones que fueron mucho más numerosas en los siglos anteriores (Aubréville, (1)). En efecto la regeneración del ocume es a menudo abundante en los “bicoros” (tierras forestales abandonadas después del cultivo y que se reforestan naturalmente).
Otras especies que caracterizan esos bosques son calabo (Pycnanthus angolensis o ílomba del comercio), las Myristicaceae como ekum (Coelocaryon klainei), Scyphocephalium ochocoa, bokapi (Staudtia stipitata o niove en el comercio), las otras Burseraceae tal como asia (Dacryodes buettneri o ozigo del comercio), Dacryodes spp., abe (Canarium schwenfurthii o aielé del comercio), Santiria trimera, las numerosas Caesalpiniaceae, algunas veces en masas puras o casi puras como andjung (Monopetalanthus spp., Didelotía brevipanieulata, Gilbertio dendron spp., akok - palisandro (Guibourtia ehie), oveng (Guibourtia tessmannii o bubinga del comercio, ekop-ekaba (Tetraberlinia spp.), elondo (Erythrophleum spp.), Dialium spp. y las Irvingiaceae como evès (Klainedoxa spp.), Desbordesia spp. y andok (Irvingia spp.). Otras especies características o endémicas son akoga (Lophira alata o azobe del comercio), Coula edulis (en los bosques primarios), Saçoglottis gabonensis, Scytopetalum klaineanum. Las Meliaceae se encuentran pero no en gran abundancia como embero (Lovoa trichilioides o dibetou del comercio), samanguila (Khaya ivorensis o acajou), abebay (Entandrophragma utile o sipo del comercio) y etom (E. cylindricum o sapelli del comercio), ndongomanguila (E. angolense o tiama del comercio). Akom (Terminalia superba o limba del comercio) y ayus (Triplochiton scleroxylon o obeche/samba del comercio), dos especies blandas muy importantes en el mercado internacional, se encuentran en los bosques secundarios pero no tienen la frecuencia y la importancia económica que tienen en otros países de Africa.
A lo largo de los ríos, en suelos pantanosos, el elobon (Mitragyna ciliata o abura/bahia del comercio) se encuentra comunmente y se aprovecha. Existen manglares con Rhizophora racemosa pero su extensión no es conocida.
Según la segunda versión del mapa Unesco de la vegetación africana, Fernando Poó está cubierta por “un mosaico de bosque ombrófilo de baja altitud y de formacion herbácea secundaria” y por “bosque montano indiferenciado” en las partes más altas de los volcanes. La mayor parte de los bosques no son aprovechables por razones de relieve pero antes de 1968 se explotaba el abeng o morera (Chlorophora excelsa o iroko del comercio) para uso local y especies blandas para chapas como calabo (ilomba), ekum y nsu (Daniellia spp.)
Formaciones arbustivas (nH)
Pequeñas sabanas o “praderas” se encuentran en las áreas arenosas de la granja litoral. Autores se acuerdan sobre el origen antropógeno de estas sabanas semejantes a aquellas de la zona litoral del Gabon (Aubréville, (1)). En la ausencia de un mapa de la vegetación del Rio Muni se estima en varios 10 000 ha. la superficie de esas sabanas y en 10 000 ha. la parte cubierta con arbustos (nH).
1.1.2 Situación actual de la vegetación leñosa
Areas actuales
Areas de vegetación leñosa natural estimadas a fines de 1980
(en miles de ha)
Regiones | NHCf1uv | NHCf1uc | NHCf1(u) | NHCf2(i) | NHCf | NHCa | NHc/NHO | nH |
Rio Muni | 780 | 220 | 1000 | 180 | 1180 | 1130 | ε | 10 |
Fernando Poo y Annobon | 5 | 10 | 15 | 100 | 115 | 35 | ε | ε |
Total país | 785 | 230 | 1015 | 280 | 1295 | 1165 | ε | 10 |
Los datos de este cuadro son muy aproximativos por falta de un inventario forestal nacional o de un mapa a gran escala de la vegetación, particularmente en Rio Muni. Las áreas de bosque denso (NHCf), bosque denso ya aprovechado (NHCf1uc) y de “barbecho de bosque” (NHCa) (varios facies de “bicoro” y de “mbur”) para 1968 son extraídas de los documentos (2), (4) y (5). A partir de esos datos y de las tasas de deforestación y aprovechamiento en los 12 últimos años, se han estimado las áreas en 1980.
De las indicaciones en (2) y (4) se ha asumido un área boscosa improductiva por razones de relieve del orden del 15% del bosque en la zona C de aprovechamiento, la más grande del Rio Muni. Esta área más los manglares (área estimada 20 000 ha) constituyen las áreas boscosas improductivas (NHCf2i). En el documento “Forest Resources of Africa” se menciona un parque nacional de 30 000 ha de las cuales 20 000 ha con bosques, pero no se ha visto una confirmación de eso en los otros documentos y se ha asumido ya que no hay bosque improductivo por razones legales (NHCf2r = 0).
Se ha asumido que un 80% del bosque de Fernando Poo no es aprovechable por razones fisicas (NHCf2i). A esta cifra se debria ańadir el área de manglares que no es conocida.
Propiedad
Según (4) todas las áreas boscosas del Rio Muni pertenecen al Estado o, en proporción pequeña, a las comunidades locales y no hay practicamente propiedad privada. (5) menciona que todos los bosques del Rio Muni son de propiedad estatal 1.
Estatuto legal y manejo
No existe a nuestro conocimiento bosques con un estatuto especial. A pesar de un sistema de adjudicación y control de las concesiones mäs elaborado que en otros países africanos, no se puede hablar de manejo intensivo de los bosques en el sentido de este estudio.
Aprovechamiento forestal
Madera en trozas
La Guinea ecuatorial se destaca, o por lo menos se destacaba hasta 1970, por el gran número de especies aprovechadas, práctica facilitada por el hecho que la mayoría de las “casas forestales” (compañías de explotación) - 6 de 8 en 1968-eran vinculadas con empresas españolas de tranformación. El análisis de la producción de 1964 de las 10 compañías de explotación se indica en el cuadro siguiente.
Especies | Producción | |
m3 | % | |
ocume | 60 450 | 18.7 |
calabo | 46 750 | 11.6 |
ekop-ekaba | 37 700 | 11.6 |
akom | 27 050 | 8.4 |
elondo | 13 300 | 4.1 |
embero | 12 900 | 4.0 |
ekum | 15 550 | 4.8 |
assia | 10 850 | 3.4 |
akoga | 10 050 | 3.1 |
6 especies | 5000–10000 (cada una) | 12.4 |
15 especies | 1000–5000 (cada una) | 12.5 |
17 especies | 100–1000 (cada una) | 2.2 |
43 especies | < 100 (cada una) | 0.3 |
Total | 323 900 1 | 100.0 |
Se puede ver que entre las 70 especies aprovechadas, 30 especies tienen una producción superior a 1 000 m3 (o 0.3% de la producción total) y que el ocume representa menos del 20% del volúmen total, mientras corresponde a un 90% del volumen extraído de los bosques similares del Gabon.
El volumen extraído por ha era consecuentemente más alto que en otros países africanos y, a nivel de todo el país (Rio Muni esencialmente), se podría considerar un volumen neto (VAC) de 25 m3 por ha (2) (4) (5), mientras en Gabon alcanza solamente 10 m3. Eso resulta en un área aprovechada anualmente (antes de 1970) de 20 000 ha aproximadamente. En los años 1963 a 1978 la evolución de la producción ha sido la siguiente:
Fuentes | Años | 1963 | 1964 | 1965 | 1966 | 1967 | 1968 | 1969 | 1970 | 1971–75 (promedio) | 1976–78 (promedio) |
Producción de trozas (miles m3) | |||||||||||
- según Anuarios FAO | 393 (promedio 61–65) | 463 | 500 | 500 | 530 | 5502 | 50 | 502 | |||
- (2): Rio Muni | 396 | 455 | 351 | ||||||||
Exportación de trozas | |||||||||||
- según Anuarios FAO | 360 (promedio 61–65) | 457 | 413 | 437 | 400 | 380 | 122 | 182 | |||
- (2): Rio Muni 1 | 379 | 438 | 356 | ||||||||
- (2): Rio Muni (empresas) | 361 | 382 | 369 | 331 | 377 |
1 con el factor 1 m3 = 0.8 tonelada.
2 estimación
Los datos son incompletos y no se refieren exactamente a la misma producción: el anuario de la FAO tiene en cuenta también la producción en Fernando Poo y de las concesiones de finca agrícola, mientras la referencia (2) se limita al Rio Muni y la (4) a las empresas de Rio Muni. Sin embargo, el cuadro muestra claramente dos aspectos importantes:
la predominnacia de las exportaciones de trozas, y la cantidad insignificante de madera elaborada localmente;
la reducción drástica de las actividades de aprovechamiento después 1970.
No se ha encontrado una referencia precisa sobre la situación en los últimos años y las cifras del anuario FAO son solamente estimaciones. Una producción anual de 50 000 m3 significa un área aprovechada de 2 000 ha aproximadamente.
Hasta 1970 la explotación de las compañías en Rio Muni era mecanizada con niveles de costos y precios similares a aquellos de otros países de Africa tropical. La explotación en las fincas agrícolas y también en Fernando Poo era más artesanal como debe ser mayormente ahora en todo el país después de la salida de los técnicos españoles. Es útil también mencionar que en los años 60 el desplazamiento progresivo de la explotación más al interno del país en zonas más inaccesibles y quebradas han creado un aumento de los precios como se pudo verificar también en Gabon.
Otros productos forestales
No fueron disponibles informaciones sobre la producción o el consumo de leña, carbón vegetal y otras maderas en rollo como postes, pilotes, etc…. Se estima en el anuario FAO de los productos forestales, una producción de 400 000 m3 de leña, o sea un poco más de 1 m3 por habitante por año.
1.1.3 Situación actual del volumen en pie
Para estimar los volúmenes en pie en Rio Muni se han usado resultados de inventarios forestales hechos en la región vecina de Gabon en relación con un proyecto de fábrica de pulpa. Se ha llegado para los bosques productivos intactos (NHCf1uv) a un volumen bruto promedio en pie de los fustes de todos los árboles de más de 10 cm de d.a.p. (VOB) igual a 220 m3/ha. El volumen bruto promedio en pie de los árboles con d.a.p más de 50 cm (210 m3) indicado en el documento (1) corresponde a un volúmen bruto con d.a.p más de 10 cm superior a 220 m3/ha. Sin embargo las parcelas de estudio son todas de bosque secundario viejo. El volumen promedio actualmente comercializado (VAC) de las trozas realmente extraídas ha sido estimado en 25 m3/ha para todo el país (ver sección 1.1.2). El volumen bruto promedio en los bosques productivos explotados (NHCf1uc) ha sido reducido por dos veces el volumen extraído en relación con el volumen bruto de los bosques intactos. El volumen bruto en los bosques inaccesibles ha sido estimado en 200 m3/ha aproximadamente.
Para Fernando Poo se han usado los resultados de un inventario en el suroeste del Camerún (40 km al norte de Buea) en una región de relieve accidentado y de composición aparentemente similar. Se llega a un volumen bruto en pie de 200 m3/ha para los bosques productivos y a un volumen tentativamente igual a 180 m3 para los bosques improductivos (NHCf2).
Volúmenes en pie estimados a fines de 1980
(totales en millones de m3)
Regiones | NHCf1uv | NHCf1uc | NHCf2 | |||||
VOB | VAC | VOB | VOB | |||||
m3/ha | total | m3/ha | total | m3/ha | total | m3/ha | total | |
Rio Muni | 220 | 172 | 25 | 19.5 | 170 | 37.5 | 200 | 36 |
Fernando Poo y Annobon | 200 | 1 | 25 | 0.1 | 150 | 1.5 | 180 | 18 |
Total país | - | 173 | 25 | 20.0 | - | 39.0 | - | 54 |
1.2 Plantaciones
No existen plantaciones industriales o para otros usos en Guinea ecuatorial. En el documento (5) se menciona una plantación experimental de 2 ha de ocume cerca de la ciudad de Rio Bonito.
2. Tendencias actuales
2.1. Deforestación
Aunque la agricultura migratoria es predominante en Rio Muni no se ha encontrado datos sobre su impacto en los bosques densos. (4) menciona que la agricultura migratoria está cambiando constantemente los límites del bosque. Los documentos mencionan también que la proporción de “bicores” y de agricultura migratoria es la más alta en la parte noreste del país (triángulo Mikomesen - Ebebiyin - Mongono).
A partir de los datos de población agrícola y, más precisamente, de una estimación de las familias que practican la agricultura migratoria (respectivamente 23 000 y 1 000 familias en Rio Muni y en las islas), se han calculado las áreas deforestadas en los últimos años (14 000 por año y menos de 1 000 respectivamente). Estas superficies han sido distribuidas entre el bosque en barbecho (NHCa) y el “bosque denso productivo explotado” (NHCf1uc) 1 proporcionalmente a las áreas respectivas de esas formaciones (80/20 aproximadamente en las dos regiones). A las áreas deforestadas por la agricultura migratoria, se añaden las áreas deforestadas cada año por otras razones (agricultura permanente principalmente: café, cacao, cocoteros, palmas de aceite); 1 000 ha. en Rio Muni y 100 a 200 ha. en las islas en las formaciones NHCf1uc y NHCa. Se ha considerado un ligero aumento de la deforestación en Rio Muni para los próximos cinco años debido al aumento natural de la población rural, al regreso de famílias emigradas en los 70' y al incremento de las áreas aprovechadas anualmente (véase sección 2.1.3).
Deforestación promedia anual
(en miles de ha)
NHCf1uv | NHCf1uc | NHCf1 (u) | NHCf2 | NHCf | NHCf1uv | NHCf1uc | NHCf1 (u) | NHCf2 | NHCf | |
ε | 2.5 1 | 2.5 | ε | 2.5 | ε | 3 2 | 3 | ε | 3 |
1 de los cuales 2.3 en Rio Muni aproximadamente
2 de los cuales 2.7 en Rio Muni aproximadamente
2.1.2 Degradación
No se sabe si existe una sobreexplotación de los bosques en relación con la producción de leña cerca de las ciudades y pueblos más importantes.
2.1.3 Tendencias en el aprovechamiento forestal
Se estima que el aprovechamiento forestal podría aumentar en el período 1981–85 hasta 200 000 – 250 000 m3 de trozas por año. La mayor parte del aprovechamiento se hará en la parte menos accesible de Rio Muni. Por otra parte una diversificación de las exportaciones hacia otros países europeos podría tener como consecuencia una disminución del número de especies comerciales (como en los países vecinos de Camerún, Gabon, y Congo). Por esas dos razones se asume que el volumen actualmente comercializado (VAC) podría disminuir de 25 a 20 m3/ha en promedio. El área aprovechada durante los cinco años podría alcanzar entonces 40 000 ha o sea 8 000 ha/año en promedio.
El consumo de leños y otra made en rollo como postes, pilotes, etc. aumentará más o menos en proporción con la población.
2.1.4 Areas y volumenes para fines de 1985
Areas de vegetación leñosa natural estimadas a fines de 1985
(en miles de ha)
Regiones | NHCf1uc | NHCf1uc | NHCf1 (u) | NHCf2 (i) | NHCf | NHCa | NHc/NHO | nH |
Río Muni | 740 | 247 | 987 | 180 | 1167 | 1145 | ε | 10 |
Fernando Poo y Annoboñ | 4 | 9 | 13 | 100 | 113 | 35 | ε | ε |
Total país | 744 | 256 | 1000 | 280 | 1280 | 1180 | ε | 10 |
Volúmenes en pie estimados para fines de 1985
(totales en millones de m3)
Regiones | NHCf1uv | NHCf1uc | NHCf2 | NHCf | |||||
VOB | VAC | VOB | VOB | VOB | |||||
m3/ha | total | m3/ha | total | m3/ha | total | m3/ha | total | total | |
Rio Muni | 220 | 163 | 20 | 14.8 | 170 | 42 | 200 | 36 | 241 |
Fernando Poo y Annobon | 200 | 1 | 20 | 0.1 | 150 | 1.5 | 180 | 18 | 20 |
Total país | - | 164 | 20 | 15 | - | 43.5 | - | 54 | 261 |
2.2 Plantaciones
Muy probablemente las plantaciones no van a ser consideradas prioritarias debido a la abundancia de materia leñosa para uso local. Se puede estimar que en 1985 existirán a lo sumo plantaciones a escala experimental.
Bibliografía
Capdevielle, J.M. 1969 “Tres estudios y un ensayo sobre temas forestales de la Guinea continental española” - Consejo superior de investigaciones científicas - Instituto de estudios africanos - Madrid
Jacobson, C.A. 1968 “Logging in Rio Muni (Guinea Equatorial)” - Documento FAO interno - Roma
FAO 1969 “Misión agricola en Guinea ecuatorial” - Roma
Vannière, B. 1969 “Mission d'inventaire forestier - 20 Juin – 29 Juillet 1969 - Guinée Equatoriale” - Roma
FAO 1972 “Forestry Report on Equatorial Guinea based on assignment FAO/EQG/70/001 of A.G. Forester” - Roma